Integrated modified concrete with photothermal super-hydrophobic anti-icing interface and preparation method thereof

Abstract

The application relates to the technical field of functional building materials, and discloses an integrated modified concrete with a photo-thermal super-hydrophobic anti-icing interface, wherein a functional interface layer and a concrete base material form a seamless connection structure; the functional interface layer takes epoxy resin as a crosslinking matrix, takes nano-silicon dioxide and multi-walled carbon nanotubes as interface synergistic construction units, establishes a three-dimensional interpenetrating network among the construction units, the crosslinking matrix and a concrete hydrated calcium silicate gel through a silane coupling agent, and then is in-situ modified by a low-surface-energy fluorosilane to build a super-hydrophobic interface on a concrete surface layer; the multi-walled carbon nanotubes construct a continuous conductive heat transfer skeleton in the crosslinking matrix, the nano-silicon dioxide is filled in the gaps of the continuous conductive heat transfer skeleton and is anchored to the surface of the continuous conductive heat transfer skeleton to form nano-level protrusions, and the two synergistically form a skeleton-filling type hierarchical rough structure; and the functional interface modification layer forms an integrated whole with the concrete base material through the synergistic effect of physical embedding and chemical bonding and cannot be peeled off.

Description

Technical Field

[0001] This invention relates to the field of functional building materials technology, and in particular, to an integrated modified concrete with a photothermal superhydrophobic anti-icing interface and its preparation method. Background Technology

[0002] Concrete, as the most widely used structural material in modern construction and infrastructure, is extensively applied in traffic pavements, bridge structures, and various industrial and civil buildings. However, in service environments characterized by low temperatures, high humidity, and significant diurnal temperature variations, concrete, due to its porosity and hydrophilic properties, readily absorbs moisture from the environment, forming ice on its surface. Surface icing not only triggers freeze-thaw cycles, leading to the initiation and propagation of microcracks within the concrete and severely weakening its load-bearing capacity and durability, but also significantly reduces the friction coefficient of roads and bridges, posing substantial traffic safety hazards.

[0003] To address the problem of ice formation on concrete surfaces, current engineering practices mainly employ passive and semi-active protective measures such as mechanical removal, application of chloride-based de-icing agents, or electrothermal methods. Mechanical de-icing can easily damage the concrete surface structure, while chloride-based de-icing agents can induce steel corrosion and alkali-aggregate reaction. Electrothermal methods are energy-intensive and difficult to modify during construction. Therefore, developing functional concrete with long-lasting, self-responsive properties to inhibit ice formation or reduce ice adhesion at the source is an important development direction in the current building materials field.

[0004] Based on this, some new research directions have emerged, such as fabricating superhydrophobic surfaces by constructing micro- and nano-rough structures on the material surface and modifying them with low surface energy materials. Superhydrophobic surfaces can achieve passive anti-icing by trapping an air layer to inhibit the contact between water and the substrate. In addition, introducing photothermal conversion materials to convert solar energy into thermal energy, providing active heat input to delay icing or promote melting, is also an effective way to improve anti-icing capabilities.

[0005] However, existing technologies still have the following problems in terms of practical application and long-term durability: First, the interfacial adhesion is weak, resulting in a short service life. Existing solutions mostly employ a post-coating process, simply covering the concrete surface with a coating containing functional fillers. Due to the significant difference in thermal expansion coefficients between the concrete substrate and the organic coating, and the lack of effective chemical bonding, the interfacial adhesion mainly relies on physical-mechanical interlocking, resulting in low bonding strength. Under alternating hot and cold temperatures, wet and dry cycles, and external loads, the functional layer is highly susceptible to peeling and flaking, leading to protective failure.

[0006] Second, the micro-nano structure has poor stability. Nanoparticles dispersed in the coating by physical mixing alone have weak bonding with the substrate and are easily lost under external mechanical wear, rain erosion and environmental factors. As a result, the micro-nano hierarchical rough structure is difficult to maintain for a long time, and the superhydrophobic and photothermal properties degrade rapidly over time.

[0007] Third, their functionality is limited. Existing superhydrophobic and photothermal technologies are mostly used independently. Simple superhydrophobic coatings have limited anti-icing effects in the absence of light or in extremely cold conditions, while simple photothermal coatings, although they can generate heat, cannot effectively prevent moisture from spreading and penetrating. It is difficult to achieve the synergistic effect of water repellency and heating, and thus cannot meet the long-term protection requirements in complex environments.

[0008] In summary, existing technologies have not effectively solved the problems of weak bonding between the functional layer and the concrete matrix, vulnerability of micro-nano structures, and limited functionality, thus restricting the large-scale application of functional concrete in harsh environments. Summary of the Invention

[0009] This invention provides an integrated modified concrete with a photothermal superhydrophobic anti-icing interface and its preparation method. A three-dimensional interpenetrating network of Si-O-Ca / Si-O-Si is constructed between the hydration products and functional fillers on the concrete surface using a silane coupling agent. This induces multi-walled carbon nanotubes to assemble in situ into a continuous conductive and heat-transferring framework, and drives nano-silica to be directionally filled and anchored to the framework surface, constructing a framework-filler type micro / nano-level roughened structure. After in-situ modification with low surface energy fluorosilane, the photothermal conversion effect of the multi-walled carbon nanotubes and the low surface energy characteristics of the micro / nano-roughened structure are synergistically coupled. Through the dual effects of physical interlocking and chemical bonding, the functional interface layer and the concrete substrate are in-situ hybridized and non-removable. This addresses the technical problems of weak interfacial bonding between existing coatings and the concrete matrix, easy wear and peeling of micro / nano structures during service, and the inability of a single passive anti-icing mechanism to provide long-term protection in complex environments with high cold and high humidity.

[0010] According to one aspect of the present invention, an integrated modified concrete with a photothermal superhydrophobic and anti-icing interface is provided, comprising a concrete substrate and a functional interface layer in situ hybridized on the surface of the concrete substrate and within the surface openings and pores. The functional interface layer forms a seamlessly connected structure with the surface hydration products of the concrete substrate through chemical bonding. The functional interface layer uses epoxy resin as an in-situ crosslinking matrix and nano-silica and multi-walled carbon nanotubes as interface co-constructing units. A three-dimensional interpenetrating network is established between the constructing units, the crosslinking matrix, and the calcium silicate gel hydrated in the concrete through a silane coupling agent. Then, it is modified in situ with low surface energy fluorosilane to construct a micro / nano-level graded rough superhydrophobic interface on the concrete surface. Multi-walled carbon nanotubes construct a continuous conductive and heat-transferring skeleton within the crosslinking matrix. Nano-silica fills the gaps in the continuous conductive and heat-transferring skeleton and anchors to the surface of the continuous conductive and heat-transferring skeleton to form nanoscale protrusions. The two work together to form a skeleton-filled graded rough structure. The functional interface modified layer forms an inseparable integrated whole with the concrete substrate through the synergistic effect of physical interlocking and chemical bonding.

[0011] Furthermore, the silane coupling agent is 3-glycidoxypropyltrimethoxysilane, which acts as an interfacial bridge to simultaneously achieve multiple bonding. After the alkoxy groups of 3-glycidoxypropyltrimethoxysilane are hydrolyzed, they condense with the silanol groups on the concrete surface and the silanol groups on the nano-silica surface to form Si-O-Si bonds. Moreover, the epoxy groups of 3-glycidoxypropyltrimethoxysilane copolymerize with the curing agent in the system and embed into the resin crosslinking network during the epoxy resin curing process, thereby forming an integrated structure on the concrete surface without macroscopic interlayer delamination.

[0012] Furthermore, the aspect ratio of multi-walled carbon nanotubes is not less than 1000, and they are assembled in situ in epoxy resin to form a three-dimensional interconnected conductive network. The particle size of nano-silica is distributed in the range of 1 to 10 times the outer diameter of the multi-walled carbon nanotubes. It is fixed on the surface of the multi-walled carbon nanotubes through the interfacial bridging of the functional groups of silane coupling agent and the physical interlocking of the epoxy curing process, forming a multi-level rough morphology. The multi-walled carbon nanotubes also serve as photothermal conversion units, with a light absorption rate of not less than 90% in the near-infrared band, which is used to inhibit icing or promote melting of ice in low-temperature environments through photothermal conversion.

[0013] Furthermore, the low surface energy modifier is a fluorinated silane. The fluorinated silane is covalently bonded to the surface of the graded rough structure through silicon-oxygen bonds, so that the water contact angle of the concrete surface is not less than 160°, the roll-off angle is not greater than 5°, and the Cassie-Baxter wetting state is maintained for a long time.

[0014] Furthermore, the effective penetration depth of the functional interface modification layer is 10μm-50μm, the interfacial bonding strength between the functional interface modification layer and the concrete substrate is not less than 2.5MPa, and after 100 freeze-thaw cycles, the interface shows no cracking or peeling, and the superhydrophobic performance retention rate is not less than 90%.

[0015] Furthermore, the epoxy resin is a bisphenol A type epoxy resin, and the curing agent is a compound system of aliphatic amines and aromatic amines. By regulating the curing kinetics, the functional interface modified layer can simultaneously possess high crosslinking density and flexibility, adapting to the thermal expansion and contraction deformation of concrete substrates.

[0016] Furthermore, the raw material composition of the functional interface modification layer is: bisphenol A type epoxy resin, silane coupling agent modified nano-silica, silane coupling agent modified multi-walled carbon nanotubes, perfluorodecyltrimethoxysilane and compound curing agent. Each component forms a uniform modification system through an in-situ assembly process.

[0017] Furthermore, the functional interface modification layer is constructed on the concrete surface through a high-pressure spraying process. After spraying, it achieves chemical bonding with the concrete substrate through thermal induction curing. The resulting modified concrete has superhydrophobicity, wear resistance, and photothermal synergistic anti-icing properties.

[0018] According to another aspect of the present invention, a method for preparing an integrated modified concrete with a photothermal superhydrophobic anti-icing interface is also provided, for preparing the aforementioned integrated modified concrete with a photothermal superhydrophobic anti-icing interface, comprising the following steps: S100, performing silanization pretreatment on nano-silica and multi-walled carbon nanotubes to obtain modified dispersions respectively; S200, premixing epoxy resin with a compound curing agent, introducing a silane coupling agent, first adding the modified dispersion of multi-walled carbon nanotubes and dispersing it under high shear conditions to construct a continuous conductive structure in situ. An electric heat transfer framework is then mixed with a modified dispersion of nano-silica under low shear conditions, allowing the nano-silica to fill and anchor onto the surface of the continuous conductive heat transfer framework, thus constructing a precursor hybrid system in situ. In step S300, a low surface energy modifier is added to the precursor hybrid system and dispersed evenly to obtain an in-situ modified slurry. In step S400, the modified slurry is high-pressure sprayed onto the surface of a concrete substrate and cured under gradient controlled humid heat, allowing the modified slurry to penetrate into the open pores of the concrete surface and cross-link in situ, forming a functional interface modified layer integrated with the concrete substrate.

[0019] Furthermore, in step S400, gradient controlled humid heat curing includes two stages: the first stage induces the controlled hydrolysis and condensation of the silane coupling agent at a relative humidity of 60%-70% and a temperature of 80°C, promoting interfacial chemical bonding; the second stage promotes the complete cross-linking of the epoxy resin at a relative humidity of less than 30% and a temperature of 100°C, ultimately forming an integrated modified layer with controllable penetration depth and strong interfacial bonding.

[0020] The present invention has the following beneficial effects: 1. Eliminating the risk of physical interface delamination based on the integrated structural effect of chemical bonding: By constructing a four-in-one Si-O-Ca / Si-O-Si covalent bond anchoring system of "concrete-coupling agent-resin-filler" between concrete hydration products, epoxy resin matrix and functional filler through silane coupling agent, the chemical bonding effect replaces the traditional coating's physical mechanical interlocking mode; the functional interface layer is not only in-situ hybridized on the concrete surface, but also penetrates and embeds into the micron-level pores of the concrete surface, forming a truly seamless connection structure with the substrate. This chemical modification mechanism fundamentally eliminates the risk of interlayer delamination, peeling and cracking caused by the mismatch of thermal expansion coefficients between concrete and organic coating, volume stress caused by wet-dry cycles and external mechanical loads, ensuring the long-term structural integrity and reliability of the modified layer in complex service environments.

[0021] 2. A thermodynamically stable superhydrophobic interface is constructed based on the synergistic effect of the framework-filled hierarchical roughness structure: Utilizing the high aspect ratio of multi-walled carbon nanotubes, they are induced to preferentially overlap in the resin matrix to form a continuous, interconnected micron-scale support framework, providing structural rigidity. Simultaneously, the small size effect of nano-silica is utilized to precisely fill the gaps in the framework and firmly anchor it to the framework surface, forming nanoscale protrusions. The framework-filled hierarchical roughness structure constructed by these two synergies forms a micro / nano composite morphology with significant hierarchical differences on the concrete surface. This effectively traps air layers, maximizing the reduction of the actual contact area between droplets and the solid surface, thereby thermodynamically maintaining a stable Cassie-Baxter wetting state. This achieves excellent superhydrophobic properties with a static water contact angle ≥160° and a roll-off angle ≤5°, endowing the concrete surface with excellent water repellency, antifouling, and self-cleaning capabilities. Furthermore, the micro / nano structure is protected by the upper resin matrix, avoiding the defects of easy wear and detachment of purely physical stacked structures.

[0022] 3. Based on the active thermal management effect of conductive network and photothermal conversion, the synergy between passive water repellency and active anti-icing is achieved: While realizing the micro-nano rough structure, the high absorption characteristics of the continuous conductive framework constructed by multi-walled carbon nanotubes in the near-infrared band (800nm-2500nm) are fully utilized. It is used as a photothermal conversion functional unit to efficiently convert incident light energy into heat energy in low-temperature environment, actively increase the interface temperature, significantly delay the nucleation and growth rate of ice crystals, and promote the rapid melting of the formed ice. The melted liquid water is then rapidly rolled off by the superhydrophobic effect of the underlying micro-nano rough structure, blocking the retention of the liquid phase on the surface and secondary freezing, forming a closed-loop anti-icing system of "photothermal heat generation - interface temperature rise - ice melting - droplet rolling off". This effectively solves the technical bottleneck of the sharp drop in anti-icing efficiency of a single passive hydrophobic coating under no light or extremely cold conditions, and realizes the synergistic effect of passive water repellency and active anti-icing.

[0023] 4. Based on the mechanical reinforcement effect of the three-dimensional interfacial cross-linked network, the surface wear resistance and corrosion resistance are significantly improved: Under the bridging effect of the silane coupling agent, the epoxy resin forms a dense three-dimensional interpenetrating cross-linked network with the concrete hydration products and functional fillers. Combined with the nano-reinforcement effect of multi-walled carbon nanotubes, the density and surface hardness of the functional interface layer are greatly improved. It can not only effectively resist the damage to the micro-nano rough structure caused by wind and sand erosion, pedestrian trampling and vehicle wear, and ensure the durability of superhydrophobic properties, but also, the dense interface layer can act as a physical barrier to effectively block the penetration path of corrosive media such as chloride ions and sulfate ions. While giving the concrete surface excellent mechanical stability, it further improves the durability protection capability of the concrete matrix in harsh environments and extends the service life of infrastructure.

[0024] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 These are electron microscope images of the coating and the original filler obtained according to a preferred embodiment of the present invention, wherein... Figure 1 (a) is a SEM image of the 1µm coating surface under 10,000x magnification. Figure 1 (b) is a SEM image of the 10µm coating surface under 500x magnification. Figure 1 (c) is a SEM image of the original multi-walled carbon nanotubes (MWCNTs) at 30,000x magnification. Figure 1 (d) is the SEM morphology of the original nano-silica (nano-SiO2) under 30,000x magnification.

[0026] Figure 2 These are test graphs of the static water contact angle (CA) and dynamic sliding angle (SA) of the coating prepared according to a preferred embodiment of the present invention, wherein... Figure 2 (a) is a macroscopic morphology diagram of the static water contact angle of the coating surface. Figure 2 (b) is a screenshot of the software analysis of the contact angle measuring instrument. Figure 2 (c) is a schematic diagram of the photothermal conversion performance testing device. Figure 2 (d) is a real-time test curve of water contact angle / sliding angle.

[0027] Figure 3 This is a schematic diagram comparing the self-cleaning ability of mortar according to a preferred embodiment of the present invention, wherein... Figure 3(a) shows the self-cleaning effect of surface dust on P mortar (ordinary reference mortar, corresponding to experimental data of group KB), H mortar (single hydrophobic treatment mortar, without multi-walled carbon nanotubes, corresponding to experimental data of group S7), and CH mortar (integrated modified mortar, with multi-walled carbon nanotubes, the present invention scheme, corresponding to experimental data of group S8). Figure 3 (b) shows the droplet state diagrams for H-mortar and CH-mortar with different surface tensions. Figure 3 (c) is a schematic diagram of the self-cleaning mechanism of CH mortar surface. Figure 3 (d) are photos of CH mortar before, during, and after soaking in turbid water. Figure 3 (e) is a schematic diagram of the antifouling mechanism of CH mortar.

[0028] Figure 4 This is a graph showing the variation of water contact angle (WCA) and sliding angle (WSA) of the coating prepared according to a preferred embodiment of the present invention under different wear cycles. Figure 4 (a) is a schematic diagram of the tape peel test. Figure 4 (b) is a schematic diagram of a 200g load friction test.

[0029] Figure 5 These are diagrams illustrating the anti-icing effects of three different coatings on a concrete surface at -20°C, according to a preferred embodiment of the present invention. Figure 5 (a)- Figure 5 (c) is an illustration of the anti-icing effect of unmodified concrete substrate. Figure 5 (d)- Figure 5 (f) shows the anti-icing effect of modified coating 1. Figure 5 (g)- Figure 5 (i) is a diagram showing the anti-icing effect of the modified coating 2 / optimal group. Detailed Implementation

[0030] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below. Unless otherwise stated, the raw materials and reagents used in the following embodiments are commercially available or can be prepared by known methods.

[0031] This embodiment of the integrated modified concrete with a photothermal superhydrophobic and anti-icing interface includes a concrete substrate and a functional interface layer in situ hybridized on the surface of the concrete substrate and within the surface openings and pores. The functional interface layer forms a seamless, chemically bonded structure with the surface hydration products of the concrete substrate. The functional interface layer uses epoxy resin as the in-situ crosslinking matrix and nano-silica and multi-walled carbon nanotubes as interface co-construction units. A three-dimensional interpenetrating network is established between the construction units, the crosslinking matrix, and the calcium silicate hydrate gel of the concrete through a silane coupling agent. Then, it is modified in situ with low surface energy fluorosilane to construct a micro / nano-level rough superhydrophobic interface on the concrete surface. Multi-walled carbon nanotubes construct a continuous conductive and heat-transferring framework within the crosslinking matrix. Nano-silica fills the gaps in the continuous conductive and heat-transferring framework and anchors to the surface of the continuous conductive and heat-transferring framework to form nanoscale protrusions. The two work together to form a framework-filling type hierarchical rough structure. The functional interface modification layer forms an inseparable integrated whole with the concrete substrate through the synergistic effect of physical interlocking and chemical bonding. This invention relates to an integrated modified concrete with a photothermal superhydrophobic and anti-icing interface. It utilizes a silane coupling agent to construct a four-in-one Si interface—"concrete-coupling agent-resin-filler"—between the concrete hydration products, epoxy resin matrix, and functional filler. O Ca / Si O The Si covalent bond anchoring system replaces the physical-mechanical interlocking mode relied upon by traditional coatings with chemical bonding. The functional interface layer not only hybridizes in situ on the surface of the concrete substrate, but also penetrates and embeds itself into the micron-level pores of its surface, forming a seamless connection structure with the hydration products of the substrate without physical interfaces. This chemical modification mechanism fundamentally eliminates the risks of interlayer delamination, peeling and cracking caused by the mismatch of thermal expansion coefficients between concrete and organic modified layer, volumetric stress induced by wet-dry cycles and external mechanical loads, ensuring the long-term structural integrity of the modified layer in complex service environments. Multi-walled carbon nanotubes, due to their high aspect ratio, preferentially overlap in the resin matrix to form a three-dimensional continuous conductive and heat-transferring framework. This framework not only provides structural rigidity but also serves as the main channel for photothermal conversion and heat conduction. Nano-silica, as a functional filler, fills the pores of the three-dimensional continuous framework with its small size effect and chemically bonds to the surface of the framework tube walls, forming densely distributed nanoscale protrusions on the framework surface. The synergistic effect of the supporting and filling phases constructs a framework with significant hierarchical differences on the concrete surface. The filled micro / nano composite rough morphology can efficiently trap air layers, minimizing the actual contact area between the droplet and the solid surface, thereby thermodynamically maintaining Cassie stability. In its wetted state, Baxter achieves a static water contact angle ≥160° and a roll-off angle ≤5°, endowing concrete surfaces with excellent water repellency, stain resistance, and self-cleaning capabilities. Multi-walled carbon nanotubes, while constructing a three-dimensional continuous conductive and heat-transferring framework, form interconnected conductive pathways and photothermal conversion channels. This allows for the efficient conversion of incident light energy in the 800nm-2500nm wavelength band into heat energy, actively increasing the interface temperature in low-temperature environments, significantly slowing down ice crystal nucleation and growth rates, and promoting rapid melting of existing ice. The melted liquid water then rapidly rolls off due to the superhydrophobic effect of the underlying micro-nano rough structure, preventing liquid phase retention and secondary freezing on the surface. This process forms a closed-loop anti-icing mechanism of "photothermal heat generation - interface heating - ice melting - droplet rolling off," effectively solving the technical bottleneck of a single passive hydrophobic coating experiencing a sharp drop in anti-icing efficiency under conditions of no light or extreme cold, and achieving synergistic coupling of passive water repellency and active anti-icing. Under the bridging effect of silane coupling agents, epoxy resin forms a dense three-dimensional interfacial cross-linked network with concrete hydration products and functional fillers. Combined with the nano-reinforcing effect of multi-walled carbon nanotubes, the density and surface hardness of the functional interface layer are greatly improved. This not only resists the damage to the micro-nano rough structure caused by wind and sand erosion, pedestrian trampling, and vehicle wear, ensuring the long-term stability of superhydrophobic properties, but also acts as a physical barrier to effectively block the penetration paths of corrosive media such as chloride ions and sulfate ions. While giving the concrete surface excellent mechanical stability, this further enhances the durability of the concrete matrix in harsh environments. This invention relates to an integrated modified concrete with a photothermal superhydrophobic anti-icing interface. Through the synergistic design of chemical bonding anchoring, micro-nano hierarchical construction, and photothermal functional integration, the traditional concrete surface is transformed from a single structural carrier into an intelligent interface with self-responsive anti-icing capabilities. This breakthrough overcomes the technical bottlenecks of weak interfacial bonding, fragile micro-nano structures, and limited functionality of existing coating materials. It achieves a protective effect with the functional interface layer having the same lifespan as the concrete substrate, and synergistic passive water repellency and active anti-icing, thereby improving the service safety and durability of concrete infrastructure in harsh environments.

[0032] In this embodiment, the silane coupling agent is 3-glycidoxypropyltrimethoxysilane, which acts as an interfacial bridging agent to simultaneously achieve multiple bonding. After the alkoxy group of 3-glycidoxypropyltrimethoxysilane is hydrolyzed, it condenses with the silanol groups on the concrete surface and the nano silica surface to form Si-O-Si bonds. Furthermore, the epoxy group of 3-glycidoxypropyltrimethoxysilane copolymerizes with the curing agent in the system and embeds into the resin crosslinking network during the epoxy resin curing process, thereby forming an integrated structure on the concrete surface without macroscopic interlayer delamination. The alkoxy group at one end of 3-glycidyloxypropyltrimethoxysilane hydrolyzes to generate an active silanol group. This active silanol group undergoes a dehydration condensation reaction with the silanol groups dissociated from hydrated calcium silicate and calcium hydroxide on the concrete surface to form Si-O-Si covalent bonds and Si-O-Ca covalent bonds. This process bonds the organic molecular chain to the surface of the inorganic substrate in the form of chemical bonds, replacing the weak interaction interface of traditional physical adsorption or mechanical interlocking. It eliminates the physical interface between the organic and inorganic phases at the molecular scale, and makes the interfacial binding energy jump from the kJ / mol level of the physical adsorption energy level to the level of more than 100 kJ / mol of the covalent bond energy level, blocking the phase separation tendency caused by the difference in interfacial energy. The active silanol groups generated by the hydrolysis of 3-glycidyloxypropyltrimethoxysilane simultaneously undergo a condensation reaction with the silanol groups on the surface of nano-silica to form Si-O-Si covalent bonds. This reaction grafts organic functional groups onto the surface of nano-silica particles, effectively shielding the strongly hydrophilic silanol groups on the nano-silica surface and reducing the surface energy difference between the filler and the epoxy resin matrix, thereby inhibiting the agglomeration tendency of the nanofiller and ensuring its uniform dispersion in the matrix. The Si-O-Si covalent bonds establish a stress transmission channel between the nanofiller and the resin matrix. When external mechanical stress is applied to the composite material, the stress can be effectively transmitted and dissipated between the rigid inorganic nanoparticles and the flexible organic matrix through this chemical bond, avoiding the initiation and propagation of microcracks caused by stress concentration at traditional physical interfaces, and improving the density and cohesive strength of the functional interface layer. The epoxy group at the other end of 3-glycidyloxypropyltrimethoxysilane undergoes a ring-opening reaction with the epoxy group of epoxy resin under the action of the curing agent to form a COC ether bond. This reaction chemically bonds the silane coupling agent molecule into the epoxy resin crosslinking network, making the modified layer, which originally only existed on the surface of the filler, integrated with the overall resin matrix. This continuous chemical bonding structure of "concrete-silane coupling agent-resin" ensures that during the curing and shrinkage process of the functional interface layer, the shrinkage stress can be transferred to the surface of the concrete substrate through chemical bonds, avoiding interface delamination caused by shrinkage stress, and realizing seamless connection and coordinated deformation between the functional interface layer and the concrete substrate.The triple covalent bonds of "Si-O-Si bonds (concrete side) - COC bonds (resin side)" and "Si-O-Si bonds (filler side)" intertwine to form a three-dimensional network. This network structure greatly reduces the free volume of the interface region, reducing the penetration path of corrosive media caused by pore defects. The fixing effect of chemical bonds restricts the mobility of polymer chain segments, improving the glass transition temperature and chemical corrosion resistance of the resin matrix. This synergistic effect makes the functional interface layer not only a carrier of superhydrophobic function, but also a dense chemical barrier, effectively blocking the transport of chloride ions, sulfate ions, and water into the concrete matrix, thus improving the corrosion resistance and freeze-thaw resistance of the concrete matrix. The triple covalent bond network constructed by 3-glycidyloxypropyltrimethoxysilane achieves chemical topological interlocking at the molecular scale among the concrete substrate, functional filler, and epoxy resin matrix, eliminating the existence of physical interfaces and solving the technical problems of easy peeling, easy aging, and short protective life caused by weak interfacial bonding and many microstructural defects in traditional coatings.

[0033] In this embodiment, the aspect ratio of multi-walled carbon nanotubes is not less than 1000, and they are assembled in situ in epoxy resin to form a three-dimensional interconnected conductive network. The particle size of nano-silica is distributed in the range of 1 to 10 times the outer diameter of the multi-walled carbon nanotubes. It is fixed to the surface of the multi-walled carbon nanotubes through the interfacial bridging of the functional groups of silane coupling agent and the physical interlocking of the epoxy curing process, forming a multi-level rough morphology. The multi-walled carbon nanotubes also serve as photothermal conversion units, with a light absorption rate of not less than 90% in the near-infrared band, which is used to suppress icing or promote melting of ice in low-temperature environments through photothermal conversion. Multi-walled carbon nanotubes (MWCNTs) have an aspect ratio of not less than 1000. This geometric feature significantly reduces the percolation threshold when MWCNTs are assembled in situ on the surface of concrete within an epoxy resin matrix. Under low dosage conditions, they can interlock with each other through van der Waals forces and π-π conjugation effects, and form a three-dimensional interconnected conductive network through silane coupling agent functional group bridging and physical interlocking during epoxy curing. This network structure not only serves as a reinforcing phase for the functional interface layer, improving the flexural strength and fracture toughness of the composite material by bearing external loads and hindering microcrack propagation, but also acts as a high-speed heat conduction channel, rapidly transferring the Joule heat or lattice vibration heat generated by the photothermal effect of MWCNTs to the surrounding resin matrix and concrete substrate surface. Simultaneously, due to the formation of Si-O-Ca chemical bonds with concrete hydration products, it effectively inhibits interfacial delamination caused by thermal stress, ensuring the structural integrity and in-situ stability of the functional interface layer under thermal-cold cycling conditions. The particle size distribution of nano-silica ranges from 1 to 10 times the outer diameter of multi-walled carbon nanotubes. This scale matching ensures that the nano-silica particles are firmly anchored to the surface of multi-walled carbon nanotubes and the micron-sized pores formed by overlapping, through interfacial bridging of silane coupling agent functional groups and physical interlocking during the epoxy curing process. Multi-walled carbon nanotubes form a micron-sized rough framework, and nano-silica constructs nano-sized protrusions on this framework. The two work together to form a micro-nano composite rough morphology with significant hierarchical differences. This morphology is adsorbed onto the surface of multi-walled carbon nanotubes by van der Waals forces and is constrained by a three-dimensional network, making it difficult to fall off. This structure significantly increases the apparent roughness of the solid-liquid interface, allowing air to be trapped between the micron-sized pores and nano-sized protrusions, forming a continuous air cushion layer. This significantly reduces the actual contact area between droplets and the solid surface, thermodynamically driving and stabilizing the Cassie-Baxter wetting state, giving the concrete surface excellent hydrophobic properties and extremely low water droplet adhesion. Multi-walled carbon nanotubes serve as photothermal conversion units. The π electrons in their graphitized lattice structure undergo interband transitions after absorbing photon energy in the near-infrared band, and convert light energy into lattice thermal energy through a non-radiative relaxation process. Because their aspect ratio is not less than 1000 and they are assembled in situ in epoxy resin to form a continuous network, their light absorption rate in the near-infrared band is not less than 90%, ensuring that the functional interface layer can efficiently capture solar radiation energy and convert it into thermal energy under low-temperature light conditions, thus actively increasing the interface temperature.This thermal effect reduces the supercooling of water, slowing down the formation and growth rate of ice nuclei; it weakens the interfacial bonding strength between the ice layer and the solid surface, promoting the melting of the already formed ice-covered interface. Thus, on the basis of passive superhydrophobic water repellency, it superimposes active thermal management function, and through chemical bonding and physical interlocking structure with the concrete substrate, it enables heat energy to be effectively conducted to the surface of the substrate, avoiding interface failure caused by local overheating, and overcoming the protection limitations of a single passive anti-icing mechanism under conditions of no light or extreme cold. Multi-walled carbon nanotubes (MWCNTs) simultaneously serve as a mechanical reinforcement framework, a conductive and heat-transferring network, and a photothermal conversion unit, while nano-silica acts as a nanoscale rough building block and a mechanical reinforcement filler phase. The three-dimensional interconnected network constructed by MWCNTs forms Si-O-Ca chemical bonds with concrete hydration products through silane coupling agents, providing stable physical anchoring sites for nano-silica and preventing it from easily detaching under external mechanical wear or fluid erosion. The filling effect of nano-silica further strengthens the node strength of the MWCNT network and improves the shear resistance of the overall structure. The efficient photothermal conversion characteristics of MWCNTs, in synergy with the continuous heat transfer network they construct, ensure rapid conversion and uniform diffusion of photothermal energy. Through a seamless connection structure with the concrete substrate, heat energy is uniformly transferred to the surface, avoiding thermal stress concentration. The micro-nano hierarchical rough structure ensures that the liquid water after melting ice rolls off rapidly under gravity or weak external forces, forming a closed-loop anti-icing mechanism of "photothermal heat generation - interface heating - ice melting - droplet rolling off". By limiting the aspect ratio of multi-walled carbon nanotubes to no less than 1000, the scale matching relationship between the nano-silica particle size and the outer diameter of multi-walled carbon nanotubes, and the in-situ hybridization process mediated by silane coupling agent, the in-situ construction of three-dimensional conductive networks, the precise control of micro-nano hierarchical rough morphology, and the integrated optimization of photothermal conversion functions were achieved. This solved the technical problems of insufficient mechanical support of traditional functional layers, vulnerability of micro-nano structures, weak interfacial bonding, and single anti-icing mechanism. It has created a multifunctional integrated protection system for concrete surfaces with high mechanical stability, stable superhydrophobic properties, efficient active anti-icing capability, and long service performance.

[0034] In this embodiment, the low surface energy modifier is a fluorinated silane. The fluorinated silane is covalently bonded to the surface of the graded rough structure through silicon-oxygen bonds, so that the water contact angle of the concrete surface is not less than 160°, the roll-off angle is not greater than 5°, and the Cassie-Baxter wetting state is maintained for a long time. The alkoxy groups at the ends of fluorinated silane molecules generate active silanol groups under hydrolysis conditions. These active silanol groups undergo dehydration condensation reactions with the exposed silanol groups on the surface of micro-nano hierarchical rough structures (including concrete hydration products, nano-silica, and multi-walled carbon nanotube surfaces) to form stable Si-O-Si covalent bonds. This chemical bonding method firmly anchors the fluorinated silane molecules to the substrate surface, replacing the weak interaction mode of relying on van der Waals forces or hydrogen bonds in traditional physical coating or physical adsorption modification layers. Under external mechanical wear, rain erosion, ultraviolet radiation, or thermal cycling environments, the high bond energy of the covalent bonds effectively inhibits the migration, shedding, or degradation of low surface energy molecules, ensuring the long-term stability of low surface energy properties and solving the problem of functional degradation of superhydrophobic interfaces due to modification layer failure in complex service environments. Fluoroalkyl segments (such as perfluoroalkyl) in fluorosilane molecules have extremely low surface free energy. After the silicon-oxygen bonds are anchored to the surface of the rough structure, the fluoroalkyl segments spontaneously orient themselves toward the gas-solid interface driven by the minimization of interfacial energy, forming a dense, uniform and highly ordered molecular brush on the surface of the micro-nano hierarchical rough structure. This molecular brush shields the polar groups such as the originally hydrophilic silanol and epoxy groups of the matrix inside, so that the exposed chemical groups on the surface are all fluorocarbon groups with low surface energy. This reduces the critical surface tension of the concrete surface to an extremely low level. This essential modification of the chemical composition significantly reduces the interfacial energy of the solid-liquid interface, providing an extremely high thermodynamic energy barrier for the spread of droplets on the solid surface. This is the chemical basis for maintaining a high contact angle and a low roll-off angle. The micro-nano hierarchical rough structure provides the necessary geometric space for air trapping, while the low surface energy modification of fluorinated silanes reduces the tendency of the liquid phase to spread on the surface of the rough structure. The synergistic effect of the two prevents the droplet from wetting the bottom of the rough structure, instead trapping a continuous air cushion layer below the droplet, thus stably maintaining the Cassie-Baxter wetting state. In this state, the actual contact area between the droplet and the solid surface accounts for only a very small part of the apparent contact area, with the vast majority of the contact being liquid-gas contact. This results in the droplet exhibiting an extremely high static water contact angle (not less than 160°) and an extremely low roll-off angle (not greater than 5°). The low roll-off angle characteristic gives the droplet the dynamic behavior of rapidly rolling off the surface under the action of weak external forces (such as gravity, wind, or vibration), thus exhibiting excellent self-cleaning, anti-icing, and anti-fouling properties.While forming low surface energy molecular brushes, fluorinated silanes also form a dense hydrophobic silicone resin layer on the surface of the micro-nano hierarchical rough structure through hydrolysis condensation products. This thin layer physically encapsulates and isolates the multi-walled carbon nanotube framework and nano-silica filler phase, effectively blocking the erosion of the epoxy resin matrix and filler surface by moisture, oxygen, and ultraviolet light, delaying the ultraviolet aging and hydrolytic aging process of the resin matrix, and protecting the morphological integrity of the micro-nano rough structure. This hydrophobic thin layer fills the micropores on the surface of the rough structure, further reducing the surface energy and reducing liquid phase penetration caused by capillary action, thereby improving the anti-stripping ability of the functional interface layer under freeze-thaw cycle conditions. Fluorocarbon bonds (CF bonds) possess extremely high bond energy and chemical stability, exhibiting excellent resistance to acids, alkalis, salts, and organic solvents. When a fluorinated silane modification layer is applied to the surface of a micro-nano hierarchical rough structure, it not only reduces the surface energy but also constructs a chemically inert barrier between the concrete matrix and the external corrosive environment. This barrier effectively blocks the transport pathways of corrosive media such as chloride ions, sulfate ions, and carbon dioxide into the concrete interior, while also inhibiting the dissolution of cement hydration products on the concrete surface in an acidic environment. Thus, while endowing the surface with superhydrophobic properties, it further enhances the concrete matrix's resistance to chemical erosion and carbonation. By employing fluorinated silanes as low surface energy modifiers and utilizing silicon-oxygen covalent bonding to the surface of micro-nano hierarchical rough structures, the chemical composition and microstructure of concrete surfaces were synergistically optimized. This resulted in the construction of a thermodynamically stable, kinetically easy-to-roll, and chemically inert superhydrophobic interface. This solved the technical problems of weak adhesion, easy aging and detachment of low surface energy modifier layers in traditional superhydrophobic coatings, as well as the vulnerability of micro-nano structures to damage. It provides a protective system for concrete infrastructure that combines excellent superhydrophobic properties, long-term weather resistance, and high erosion resistance.

[0035] In this embodiment, the effective penetration depth of the functional interface modification layer is 10μm-50μm, the interfacial bonding strength between the functional interface modification layer and the concrete substrate is not less than 2.5MPa, and after 100 freeze-thaw cycles, the interface does not crack or peel off, and the superhydrophobic performance retention rate is not less than 90%. The surface of concrete substrates naturally contains micron-sized pores, capillary channels, and microcracks. By controlling the effective penetration depth of the functional interface modification layer within the range of 10μm-50μm, it is ensured that the epoxy resin matrix can fully impregnate and penetrate into the aforementioned micro-defects before curing. During the thermosetting process, the resin matrix undergoes cross-linking and curing, forming a large number of micron-sized resin-penetrated anchor columns that are physically embedded in the pores and microcracks of the concrete surface. This micro-scale mechanical interlocking structure transforms the traditional surface contact bonding mode into a volume bonding mode, increasing the actual load-bearing area of ​​the interface. When the interface is subjected to external shear stress or tensile stress, the stress can be uniformly transferred to the interior of the concrete substrate through these mechanical interlocking points, avoiding stress concentration at a single planar interface and thus eliminating the risk of interlayer delamination, peeling, and cracking caused by weak interfacial bonding. The penetration depth of 10μm-50μm is a specific range that has been mechanically adapted: if the penetration depth is less than 10μm, the resin cannot form an effective mechanical interlock, and the interface mainly relies on weak physical adsorption or chemical bonding, making it difficult to resist external mechanical loads; if the penetration depth is greater than 50μm, excessive resin penetration may lead to increased brittleness of the surface concrete, and the internal stress generated by resin curing shrinkage is difficult to release, which may induce microcracks at the interface. This limited range allows the functional interface modification layer to be anchored in the outermost weakened zone of the concrete (about 10μm), while avoiding intrusion into the strength contribution zone of the concrete. This depth control allows the functional interface modification layer and the concrete substrate to form a gradient transition in thermo-mechanical parameters such as coefficient of thermal expansion, elastic modulus, and Poisson's ratio, effectively mitigating the thermal stress mismatch caused by environmental temperature fluctuations, ensuring that the interface bonding strength is not less than 2.5MPa, and meeting the mechanical stability requirements under harsh engineering environments. After the functional interface modification layer penetrates into the open pores of the concrete surface, the solidified dense cross-linked network physically fills the original connected capillary channels, constructing a continuous physical barrier on the concrete matrix surface. Under freeze-thaw cycles, moisture cannot penetrate this dense barrier to enter the internal pores of the concrete, thus blocking the causes of saturation and expansion due to freezing inside the concrete. The mechanically interlocked structure formed by penetration effectively constrains the volume expansion and contraction deformation of the concrete surface during freeze-thaw cycles, inhibiting the initiation and propagation of surface microcracks. After 100 freeze-thaw cycles, the interface showed no cracking or peeling, confirming that the penetration depth design can effectively resist the repeated tensile and shear stresses generated by freeze-thaw cycles, ensuring the long-term stability of the integrated integrity of the functional interface modification layer and the concrete substrate under extreme temperature alternation environments.The effective penetration of the functional interface modification layer not only enhances the interfacial bonding force but also provides in-situ anchoring reinforcement for the micro / nano-level roughened structure constructed on the surface. The micro / nano-roughened structure is not merely attached to the coating surface but forms a dual physical and chemical bond with the concrete substrate through a penetration anchoring mechanism. Under external mechanical wear (such as wind and sand erosion, pedestrian trampling) or fluid shearing, this rooted structure effectively resists the detachment and displacement of micro / nano structural units. The superhydrophobic performance retention rate of no less than 90% after 100 freeze-thaw cycles stems from the protection of the micro / nano structure's morphological integrity by the penetration anchoring and the support for the chemical stability of the low surface energy modification layer, demonstrating the functional interface modification layer's ability to maintain a Cassie-Baxter wetting state under repeated physical and chemical erosion. The penetration depth of 10μm-50μm ensures that the chemical bonds between the functional interface modification layer and the concrete substrate (such as Si-O-Si and Si-O-Ca bonds formed by silane coupling agents) can fully expand in three-dimensional space, forming a high-density chemical bond network. This network structure not only provides high initial interfacial bonding strength but also resists the damage to interfacial chemical bonds caused by ultraviolet radiation, acid and alkali corrosion, and oxidative aging in long-term service environments. Compared with traditional surface coatings that are only physically attached, the penetration anchoring mechanism of this invention changes the failure mode of the functional interface modification layer from interfacial peeling to bulk failure, improving the service life of the protection system and achieving the same lifespan design for the functional layer and the concrete substrate. By precisely controlling the effective penetration depth of the functional interface modification layer within the range of 10μm-50μm, the synergistic optimization of mechanical interlocking, chemical bonding, and microstructure protection is achieved, solving the technical problems of weak interfacial bonding, easy peeling, and rapid performance degradation under freeze-thaw conditions in traditional coatings. This provides concrete infrastructure with an integrated protection system that combines high interfacial bonding strength, excellent freeze-thaw cycle resistance, and long-term superhydrophobic properties.

[0036] In this embodiment, the epoxy resin is a bisphenol A type epoxy resin, and the curing agent is a compound system of aliphatic amines and aromatic amines. By controlling the curing kinetics, the functional interface modified layer simultaneously possesses high crosslinking density and flexibility, adapting to the thermal expansion and contraction deformation of the concrete substrate. The bisphenol A type epoxy resin molecular backbone contains a rigid benzene ring structure and flexible ether bonds. Under the action of the curing agent, the epoxy groups undergo ring-opening addition polymerization to form a three-dimensional network structure with ether bonds and benzene rings attached to the sides. This structure endows the cured resin with high tensile strength, compressive strength, and modulus, providing necessary rigid support for the functional interface modified layer. This enables it to resist compressive and shear stresses generated by external mechanical loads (such as wind and sand erosion, pedestrian trampling, and vehicle passage), preventing the collapse or plastic deformation of the micro-nano hierarchical rough structure and ensuring the long-term effectiveness of the superhydrophobic function. Aliphatic amine curing agents possess high reactivity. The active hydrogens in their molecular structure can rapidly undergo addition reactions with epoxy groups at room temperature or lower, inducing initial cross-linking of the resin matrix, shortening construction time, and ensuring curing feasibility at low temperatures. Pure aliphatic amine-cured resins have a dense but brittle cross-linked network, making them prone to stress cracking. Aromatic amine curing agents contain rigid aromatic rings in their molecular structure. While their reactivity is relatively low, they can introduce more benzene ring structures after curing, improving the heat resistance and modulus of the cross-linked network. Simultaneously, their longer molecular chain segments can exert a certain plasticizing effect. Through compounding, aliphatic amines provide rapid curing impetus and an initial network framework, while aromatic amines regulate the free volume and mobility of the network chain segments. Their synergistic effect results in a functional interface modified layer after curing that possesses both high hardness and chemical resistance due to high cross-linking density, as well as suitable flexibility. This effectively releases the internal stress generated by resin curing shrinkage and prevents the initiation of microcracks at the interface due to stress concentration. Concrete substrate, as a porous inorganic non-metallic material, exhibits a significantly different coefficient of thermal expansion compared to organic resin matrices, and it undergoes expansion and contraction due to moisture and temperature variations under natural environmental temperature conditions. If the functional interface modification layer is too rigid, significant thermal mismatch stress will accumulate at the interface during temperature cycling, ultimately leading to coating cracking or peeling. In this invention, the flexible segments introduced by the aromatic amine curing agent synergistically form a crosslinking network with the aliphatic amine curing agent, endowing the functional interface modification layer with suitable elastic modulus and elongation at break. This allows it to adapt to the volume changes of the concrete substrate and undergo corresponding elastic deformation, rather than brittle fracture or interface delamination. This mechanical property ensures that the functional interface modification layer maintains a tight bond with the concrete substrate under fluctuating temperature conditions, solving the interface failure problem caused by thermal mismatch in traditional rigid coatings.The curing reaction of bisphenol A epoxy resin under the action of a compound curing agent proceeds simultaneously with the Si-O-Si and Si-O-Ca bonds formed by the hydrolysis and condensation of the silane coupling agent, jointly constructing a chemical bonding network of "concrete-coupling agent-resin". The appropriate curing rate controlled by the compound curing agent ensures that the resin matrix has sufficient flow time to penetrate into the open pores of the concrete surface while forming a high-strength cross-linked network, forming the micron-scale resin-penetrating anchoring column mentioned above. The appropriate flexibility of the cured resin matrix can buffer the stress transmission of external impact loads at the interface, protect the multi-walled carbon nanotube skeleton and nano-silica filling phase in the micro-nano hierarchical rough structure from brittle fracture, and maintain the integrity of the micro-nano morphology. The high-crosslink density three-dimensional network induced by the compound curing system effectively reduces the free volume of the resin matrix and decreases the diffusion coefficient of corrosive media (such as moisture, chloride ions, sulfate ions, and carbon dioxide) in the matrix, thereby improving the impermeability and chemical corrosion resistance of the functional interface modified layer. The dense network structure can shield the resin molecular chains from ultraviolet radiation and delay the photoaging process of the resin matrix. This protective effect ensures the long-term stability of the multi-walled carbon nanotube conductive network, the rough structure of nano-silica, and the low surface energy modification layer encapsulated in the resin matrix, thus achieving long-term protection of the functional interface modified layer under complex service environments. By selecting bisphenol A type epoxy resin and using a compound curing system of aliphatic and aromatic amines, precise control of the high crosslink density and flexibility of the functional interface modified layer is achieved, resolving the technical contradiction that traditional single curing systems cannot simultaneously achieve mechanical strength and deformation compatibility. Through the synergistic effects of chemical bonding, physical penetration, and mechanical adaptation, the long-term structural stability and functional durability of the functional interface modified layer under the thermal expansion and contraction deformation of the concrete substrate are ensured.

[0037] In this embodiment, the raw material composition of the functional interface modification layer is: bisphenol A type epoxy resin, silane coupling agent modified nano-silica, silane coupling agent modified multi-walled carbon nanotubes, perfluorodecyltrimethoxysilane and compound curing agent. Each component forms a uniform modification system through an in-situ assembly process. Nano-silica and multi-walled carbon nanotubes, as inorganic functional fillers, have surfaces rich in high-density hydrophilic silanol groups. If directly dispersed in an organic epoxy resin matrix, they will exhibit severe agglomeration due to extremely high surface energy differences, forming a weak interfacial phase. By pre-modifying the surface of these fillers with a silane coupling agent, the silanol groups generated by the hydrolysis of the silane coupling agent undergo dehydration condensation with the silanol groups on the filler surface, forming covalent bonds. Simultaneously, organic functional groups are grafted onto the filler surface. This modification process not only reduces the surface energy of the filler, making it match the polarity of the epoxy resin matrix, but also significantly improves the uniformity of filler dispersion in the matrix, preventing microphase separation. The organic functional groups grafted onto the filler surface can physically entangle with epoxy resin monomers or participate in cross-linking reactions during subsequent curing, establishing a chemical bond interface between the filler and the matrix. This effectively transfers loads and prevents crack propagation, solving the problem of mechanical property degradation and functional failure caused by uneven filler dispersion in traditional composite materials. Bisphenol A type epoxy resin, as a continuous phase matrix, contains rigid benzene rings and flexible ether bonds in its molecular chain that form a three-dimensional cross-linked network after curing, providing the necessary mechanical strength and stiffness. The compound curing agent (such as a mixture of aliphatic amines and aromatic amines) regulates the curing kinetics, enabling the epoxy resin to form a network structure with both high cross-linking density and suitable flexibility while curing rapidly. This network tightly encapsulates and fixes silane coupling agent-modified nano-silica and multi-walled carbon nanotubes, forming a uniform modified system. This uniformity ensures that the functional interface modified layer has consistent physicochemical properties on a macroscopic scale, avoiding local performance defects caused by component segregation (such as excessively low local hardness or lack of superhydrophobic properties), and providing a stable matrix support for the overall construction of micro-nano hierarchical rough structures. Perfluorodecyltrimethoxysilane, as a low surface energy modifier, has silanol groups generated from the hydrolysis of the alkoxy groups at the ends of its molecules. These silanol groups can undergo condensation reactions with the surface of micro-nano hierarchical rough structures to form strong covalent silicon-oxygen bonds. The perfluoroalkyl segments in its molecular chain are oriented to the outermost layer of the rough structure under the drive of interfacial energy, forming a dense and chemically inert low surface energy molecular brush. This molecular brush transforms the original polar surface of the substrate into a nonpolar fluorocarbon surface, reducing the solid-liquid interfacial free energy. This is the key chemical basis for achieving a water contact angle of not less than 160°, a roll-off angle of not more than 5°, and maintaining the Cassie-Baxter wetting state for a long time.The in-situ assembly process ensures that the components interact in a predetermined order and manner during preparation. Silane coupling agent-modified multi-walled carbon nanotubes preferentially overlap in the resin matrix to form a three-dimensional conductive network. Silane coupling agent-modified nano-silica then fills the gaps in the network and adheres to the tube wall surface, constructing a micro / nano-hierarchical rough morphology. Perfluorodecyltrimethoxysilane is finally applied to the surface of this rough structure. This sequential in-situ assembly process allows the photothermal conversion function of multi-walled carbon nanotubes, the roughing construction function of nano-silica, the low surface energy modification function of perfluorodecyltrimethoxysilane, and the mechanical support function of the epoxy resin matrix to work synergistically and without interference within the same system. For example, the conductive network constructed by multi-walled carbon nanotubes not only provides photothermal conversion channels, but its high aspect ratio also enhances the mechanical strength of the composite material; the filling of nano-silica not only increases surface roughness but also strengthens the nodal strength of the multi-walled carbon nanotube network. The dense cross-linked network formed by the curing of bisphenol A epoxy resin itself has excellent water and gas barrier properties. Combined with the silane coupling agent-modified filler to further enhance the network density, and the low surface energy modification layer of perfluorodecyltrimethoxysilane to seal the pores, the functional interface modification layer constructs a multi-dimensional dense protective barrier on the concrete matrix surface. This barrier can effectively block the penetration of corrosive media such as liquid water, chloride ions, sulfate ions, and carbon dioxide, preventing freeze-thaw damage, steel corrosion, alkali-aggregate reaction, and carbonation in the concrete matrix. The uniform modification system ensures the continuity of this protective barrier across the entire concrete surface, with no weak points, thereby significantly extending the service life of concrete infrastructure. By precisely defining the raw material composition of bisphenol A epoxy resin, silane coupling agent modified nano-silica, silane coupling agent modified multi-walled carbon nanotubes, perfluorodecyltrimethoxysilane, and compound curing agent, and combining it with in-situ assembly technology, the interface optimization of each functional component at the molecular scale, the structural construction at the microscale, and the performance uniformity at the macroscale were achieved. This solved the technical problems of difficult filler dispersion, weak interfacial bonding, single function, and uneven performance in traditional composite materials, and constructed a multifunctional integrated modification system that integrates high mechanical stability, excellent superhydrophobic properties, efficient photothermal anti-icing ability, and long-term durable protection.

[0038] In this embodiment, the functional interface modification layer is constructed on the concrete surface using a high-pressure spraying process. After spraying, thermal induction curing achieves chemical bonding with the concrete substrate, resulting in modified concrete that possesses superhydrophobicity, wear resistance, and photothermal synergistic anti-icing properties. The high-pressure spraying process utilizes compressed air or hydraulic power to break the pre-controlled viscosity of the functional precursor liquid into micron to submicron droplets, which are then sprayed onto the concrete substrate surface with high kinetic energy. These high-energy droplets effectively wet and penetrate the naturally distributed micron-sized pores, capillary channels, and microcracks on the concrete surface, ensuring not only the macroscopic geometric conformity between the functional interface modification layer and the substrate but also fulfilling the prerequisite for physical interlocking. Compared to traditional brushing or roller coating processes, high-pressure spraying significantly improves construction efficiency, eliminates defects such as uneven film thickness, missed areas, or brush marks caused by differences in manual operation, and ensures the consistency of the functional interface modification layer's thickness and structural uniformity across the entire concrete surface (including vertical surfaces, overhead surfaces, and complex curved surfaces), laying the foundation for subsequent curing to form a defect-free protective layer. Thermally induced curing technology provides activation energy through precise temperature control, simultaneously driving two key chemical reactions. It accelerates the ring-opening addition polymerization reaction of epoxy resin and compound curing agent, promoting the transformation of the resin matrix from a linear prepolymer to a three-dimensional cross-linked network. It enhances the reactivity of silanol groups generated by the hydrolysis of silane coupling agents with silanol groups on the surface of concrete hydration products (such as calcium silicate gel and calcium hydroxide), promoting dehydration condensation reactions to form high-density Si-O-Si and Si-O-Ca bonds. Thermal activation not only accelerates the reaction rate but also enhances the mobility of molecular chain segments, enabling silane coupling agent molecules to fully migrate to and dock with the active sites on the concrete surface, thereby constructing a dense chemically bonded network. This thermally induced chemical bonding mechanism replaces the traditional physical drying film-forming process, transforming the functional interface modification layer from a physical coating layer into a chemically bonded overall structure, completely eliminating the existence of physical interfaces. During the thermally induced curing process, the liquid precursor film formed by high-pressure spraying undergoes volume shrinkage as the solvent evaporates and the resin crosslinks. Since the precursor liquid has penetrated into the open pores of the concrete surface, this shrinkage is mechanically constrained by the pore walls, generating compressive stress, which further strengthens the mechanical interlocking effect between the "resin-penetrated anchor column" and the substrate. The thermally induced environment promotes the hydrolysis and condensation reaction of perfluorodecyltrimethoxysilane, so that its silicon-oxygen bonds not only firmly bind to the silanol groups on the surface of the micro-nano rough structure, but also form a dense hydrophobic silicone resin encapsulation layer on the surface of the rough structure. This encapsulation layer plays a dual role of physical protection and chemical anchoring for the multi-walled carbon nanotube skeleton and the nano-silica filling phase, ensuring that the micro-nano hierarchical rough structure has excellent wear resistance and aging resistance after curing.The presence of chemically bonded interfaces enables the functional interface modification layer to withstand shear and tensile stresses far exceeding those of the physical coating, thus maintaining the integrity of the micro-nano structure and superhydrophobicity under external mechanical wear (such as wind and sand erosion and pedestrian trampling). The three-dimensional conductive network constructed by multi-walled carbon nanotubes is stably fixed in the resin matrix during thermally induced curing, ensuring the continuity of its photothermal conversion channels and enabling it to efficiently convert light energy into heat energy under low-temperature light irradiation. The superhydrophobic properties reduce surface water residue through Cassie-Baxter wetting, while the photothermal properties actively increase the interface temperature to promote ice melting. The two achieve synergistic effects through the stable structure of chemical bonding, forming a closed-loop anti-icing mechanism of "photothermal heat generation - interface temperature rise - ice melting - droplet rolling off". This synergistic performance is not a simple superposition of the components, but is achieved by relying on the stable chemical and physical structure constructed by high-pressure spraying and thermally induced curing. The mechanized construction characteristics of high-pressure spraying make it suitable for rapid protection of large-area concrete infrastructure (such as roads, bridges, tunnels, and wind turbine tower foundations), significantly shortening the construction period and reducing labor costs. The thermally induced curing process can be flexibly implemented using electric blankets, infrared heaters, or hot air circulation equipment, adapting to field or on-site construction conditions. By precisely controlling spraying parameters (such as pressure, distance, and travel speed) and curing regimes (such as heating rate, curing temperature, and curing time), high reproducibility of product quality can be achieved, ensuring that each batch of modified concrete meets the design requirements for interfacial bonding strength, superhydrophobic performance, and photothermal conversion efficiency, thereby guaranteeing the long-term reliability of concrete infrastructure in harsh environments. By employing a high-pressure spraying process to construct a functional interface modification layer and combining it with thermally induced curing to achieve chemical bonding, the technical problems of low construction efficiency, weak interfacial bonding, easy damage to micro-nano structures, and uneven performance of traditional coatings have been solved. This not only achieves the homogenization, densification, and chemical construction of functional components on the concrete surface, but also enables the modified concrete to simultaneously possess excellent superhydrophobicity, wear resistance, and photothermal synergistic anti-icing properties through a stable interfacial structure support. This provides an efficient, reliable, and highly engineering-practical technical approach for the long-term protection and functional improvement of concrete infrastructure.

[0039] This embodiment describes a method for preparing integrated modified concrete with a photothermal superhydrophobic anti-icing interface. The method comprises the following steps: S100, pre-treating nano-silica and multi-walled carbon nanotubes with silanization to obtain modified dispersions; S200, pre-mixing epoxy resin with a compound curing agent, introducing a silane coupling agent, and then sequentially adding the modified dispersion of multi-walled carbon nanotubes and dispersing it under high shear conditions. By controlling the rheological properties, the multi-walled carbon nanotubes preferentially assemble to form a modified concrete with the original... In step S300, a continuous conductive and heat-transferring framework is constructed, followed by low-shear mixing with a modified dispersion of nano-silica. This allows the nano-silica to subsequently fill and anchor onto the surface of the continuous conductive and heat-transferring framework, thus constructing a precursor hybrid system in situ. In step S400, a low surface energy modifier is added to the precursor hybrid system and dispersed uniformly to obtain an in-situ modified slurry. In step S400, the modified slurry is high-pressure sprayed onto the surface of a concrete substrate and cured under gradient controlled humidification and heat, allowing the modified slurry to penetrate into the open pores of the concrete surface and cross-link in situ, forming a functional interface modified layer integrated with the concrete substrate. This invention provides a method for preparing integrated modified concrete with a photothermal superhydrophobic and anti-icing interface. Through a chain-like design of steps S100 to S400, precise control of the entire process from molecular interface modification to macroscopic structural construction of the functional interface modified layer is achieved. In step S100, nano-silica and multi-walled carbon nanotubes undergo independent silanization pretreatment. Organic functional groups are grafted onto the surface of the nanofillers using the hydrolysis-condensation reaction of 3-glycidyloxypropyltrimethoxysilane. This process transforms the surface of the nanofillers from hydrophilic to hydrophobic, reducing their surface energy and matching its polarity with that of the epoxy resin matrix. Simultaneously, the steric hindrance effect suppresses van der Waals attraction and hydrogen bonding between nanoparticles, preventing agglomeration and flocculation during subsequent blending. The independent dispersion strategy avoids competitive adsorption and sedimentation stratification caused by differences in density, particle size, and surface charge among different nanofillers, ensuring that multi-walled carbon nanotubes and nano-silica exist in their respective dispersions in a monodisperse or submonodisperse state, providing thermodynamically stable precursors for subsequent in-situ assembly to construct homogeneous micro / nano structures.In step S200, epoxy resin and compound curing agent are premixed, followed by the introduction of silane coupling agent, and then modified dispersion is added sequentially. This specific order of addition and rheological control strategy utilizes the characteristics of the system viscosity changing over time: when the resin viscosity is low, modified multi-walled carbon nanotube dispersion is added. Utilizing the high aspect ratio of multi-walled carbon nanotubes, they preferentially overlap with van der Waals forces through π-π conjugation in a low-viscosity fluid environment, forming a three-dimensional continuous conductive and heat-transferring framework. After the framework is initially formed and the system viscosity rises moderately, modified nano-silica dispersion is added. At this time, the nano-silica particles are limited by the already formed framework network due to size effects and cannot aggregate through the framework gaps. Instead, they are constrained and filled in the framework pores, while adsorbing onto the framework surface. This kinetic position-controlled assembly mode of first forming the framework and then filling effectively avoids structural collapse or single-scale formation caused by random distribution in traditional blending processes, ensuring the precise construction of micro-nano hierarchical rough structures. In step S300, a low surface energy modifier (such as perfluorodecyltrimethoxysilane) is added after the precursor hybrid system is constructed. This post-introduction strategy avoids the mechanical shearing damage to the perfluoroalkyl segments caused by the strong ultrasonic dispersion process, and prevents the decrease in hydrophobic properties caused by segment breakage. It also prevents the modifier from excessively consuming the active sites on the surface of the silane coupling agent or filler in the early high-activity stage, ensuring that it can specifically act on the surface layer of the micro-nano rough structure formed in the subsequent curing process. The perfluorodecyltrimethoxysilane is uniformly hydrolyzed in the dispersion, and its silanol groups undergo a condensation reaction with the silanol groups on the surface of the rough structure to form a pre-bonded hydrophobic layer before curing, laying the foundation for finally obtaining extremely low surface energy. Step S400 employs a high-pressure spraying process, using high-pressure gas to atomize the modified slurry into micron-sized droplets. The kinetic energy carried by these droplets allows them to effectively penetrate the uneven texture of the concrete surface, wetting and penetrating into the surface micron-sized pores and microcracks. The subsequent gradient humidity-controlled heat curing process involves pre-curing at a relatively high relative humidity and moderate temperature in the initial stage. These environmental parameters control the balance between the hydrolysis and condensation rates of the silane coupling agent, promoting full resin penetration and inducing the initial formation of interfacial chemical bonds (Si-O-Si, Si-O-Ca), while avoiding the formation of pinholes due to severe solvent evaporation. Subsequently, deep curing is carried out at a lower relative humidity and higher temperature. The high temperature activates the rapid cross-linking reaction between the epoxy resin and the curing agent, forming a high-density three-dimensional network, while accelerating the final bonding between the silane coupling agent and the concrete substrate. This gradient humidity control mechanism solves the problems of interfacial stress concentration, pore defects, and insufficient bonding commonly encountered in single-temperature curing.The interface modification in step S100 ensures the compatibility between the filler and the matrix; the in-situ assembly in step S200 constructs the functional structure; the surface modification in step S300 establishes the low surface energy characteristics; and the spray curing in step S400 achieves fusion with the substrate. These four steps are interconnected and indispensable. Without the modification in step S100, a uniform dispersion cannot be formed in step S200; without the precise assembly in step S200, a stable micro-nano structure cannot be obtained in step S400; without the subsequent introduction in step S300, stable superhydrophobic properties will be lacking after curing in step S400; without the gradient moisture-controlled curing in step S400, all the aforementioned efforts can only form a physically attached layer and cannot achieve chemical bonding integration. This synergistic effect of the entire process ensures that the functional interface modification layer of the final modified concrete not only covers the surface of the substrate but also embeds itself into the surface of the substrate through chemical bonding and physical penetration, forming an inseparable whole. This invention discloses a method for preparing integrated modified concrete with a photothermal superhydrophobic and anti-icing interface. Through a combination of stepwise silanization pretreatment, sequential addition and in-situ assembly, introduction of low surface energy modifiers, and high-pressure spraying combined with gradient controlled hygrothermal curing, the method achieves precise control of the microstructure of the functional interface modified layer and stable reproduction of its macroscopic properties. This method solves the technical problems of difficult dispersion of nanofillers, uncontrollable construction of micro-nano structures, weak interfacial bonding, and easy damage of functional components in traditional preparation processes. It provides a reliable and efficient technical path for the large-scale, high-quality engineering preparation of integrated modified concrete with a photothermal superhydrophobic and anti-icing interface.

[0040] In this embodiment, step S400, gradient controlled humid heat curing, includes two stages: the first stage induces controlled hydrolysis and condensation of the silane coupling agent at a relative humidity of 60%-70% and a temperature of 80°C, promoting interfacial chemical bonding; the second stage promotes complete cross-linking of the epoxy resin at a relative humidity below 30% and a temperature of 100°C, ultimately forming an integrated modified layer with controllable penetration depth and strong interfacial bonding. The gradient controlled humid heat curing process achieves kinetic decoupling and synergistic induction of the hydrolysis and condensation reaction of the silane coupling agent and the cross-linking and curing reaction of the epoxy resin by controlling the environmental humidity and temperature parameters in stages. The first stage sets the relative humidity at 60%-70% and the temperature at 80°C; this parameter combination is precisely matched to the reaction characteristics of the silane coupling agent. A relatively high humidity environment provides ample water for the hydrolysis reaction of the terminal alkoxy groups of the silane coupling agent, ensuring its full conversion into highly reactive silanol groups. Maintaining a relative humidity below 70% avoids irreversible condensation and aggregation of the silane coupling agent due to excessive free water, or the formation of air bubbles in the resin system. A temperature of 80℃ provides suitable activation energy, accelerating the dehydration condensation reaction between the hydrolyzed silanol groups and the silanol groups on the surface of hydrated calcium silicate and calcium hydroxide in the concrete layer, while preventing runaway reaction rates due to excessively high temperatures, allowing the chemical reaction to proceed smoothly and orderly. At this stage, the crosslinking reaction between the epoxy resin and the curing agent is in its initial low-viscosity phase, and the resin matrix exhibits good fluidity, fully wetting the open pores of the concrete surface. The Si-O-Si and Si-O-Ca bonds formed by the silane coupling agent at this time act as molecular bridging agents, achieving in-situ chemical anchoring of the resin matrix within the open pores of the concrete surface, establishing the chemical anchoring foundation for the functional interface modification layer, and effectively improving the interfacial bonding strength. The second stage is set with a relative humidity below 30% and a temperature of 100°C. This parameter combination aims to eliminate the interference of moisture on the epoxy resin curing process and promote its complete cross-linking. The dry environment with a relative humidity below 30% blocks the pathway for moisture to participate in the epoxy resin curing reaction, preventing moisture from vaporizing at high temperatures to form pores or causing the amine curing agent to deliquesce and fail, thus ensuring the stoichiometric balance of the curing reaction. The temperature condition of 100°C is significantly higher than that of the first stage, providing sufficient activation energy to drive the epoxy groups of the epoxy resin to undergo a complete addition polymerization reaction with the active hydrogen in the compound curing agent, forming a three-dimensional network structure with a high cross-linking density. This high-temperature curing process not only significantly improves the glass transition temperature, hardness, and chemical corrosion resistance of the resin matrix, but also further strengthens the stability and bonding density of the interfacial chemical bonds formed in the first stage through thermal excitation. This transforms the connection between the functional interface modified layer and the concrete substrate from initial physical penetration and preliminary chemical bonding into a thermodynamically stable covalent bonded whole.The relatively low temperature and suitable humidity in the first stage allow the resin matrix to maintain good fluidity while its viscosity increases moderately. This facilitates capillary ascent and penetration along the capillary channels of the concrete, forming micron-sized resin-penetrated anchor columns. The mild conditions in this stage also prevent capillary forces caused by violent solvent evaporation from collapsing the pore structure. The relatively high temperature and low humidity environment in the second stage induces volume shrinkage of the resin matrix. This shrinkage is constrained by the resin columns that have penetrated the pores, generating compressive stress and further strengthening the mechanical interlocking effect. The high temperature promotes the release of internal resin stress, preventing interface cracking caused by differences in curing rates between the inside and outside. This gradient change ensures that the effective penetration depth of the functional interface modification layer is stably controlled within the optimal range of 10μm to 50μm, guaranteeing sufficient anchoring force while avoiding surface embrittlement caused by excessive penetration. The temperature and humidity curves of the process of this invention are highly compatible with the selected 3-glycidyloxypropyltrimethoxysilane and the composite curing agent system of aliphatic amine and aromatic amine. The silane coupling agent preferentially completes the reaction with the substrate under the mild conditions of the first stage. Subsequently, under the high temperature conditions of the second stage, its epoxy end groups and the composite curing agent synergistically participate in the construction of the cross-linking network of the epoxy resin. This sequential reaction process enables the chemical bonding network at the interface to be seamlessly connected with the cross-linking network of the bulk resin, avoiding the formation of weak layers at the interface due to component segregation or incomplete reaction. The aliphatic amine in the composite curing agent ensures the initial curing speed, while the aromatic amine improves the toughness of the final cross-linking network. Combined with the reduced thermal stress from gradient curing, the functional interface modified layer can adapt to the thermal expansion and contraction deformation of the concrete substrate, solving the common problems of interface stress concentration and cracking and peeling in traditional single-temperature curing. By decoupling the curing process into two stages—bonding and cross-linking—and assigning precise temperature and humidity windows, the interference of environmental factors (such as fluctuations in ambient humidity and diurnal temperature variations) on curing quality is greatly reduced. Monitoring temperature and humidity parameters ensures consistent curing levels for each batch, avoiding quality fluctuations caused by relying solely on experience to judge curing effectiveness. This parameterized process control results in highly reproducible modified concrete with excellent interfacial bonding strength, superhydrophobic properties, and photothermal conversion efficiency, meeting the stringent requirements for material uniformity and reliability in large-scale concrete infrastructure protection projects. Step S400 employs a gradient controlled humidification and heat curing process: a first stage with a relative humidity of 60% to 70% and a temperature of 80°C, and a second stage with a relative humidity below 30% and a temperature of 100°C. Through precise control of the reaction kinetics of hydrolysis-condensation and cross-linking curing, this process maximizes the interfacial chemical bond density and optimizes the bulk mechanical strength. Simultaneously, it ensures controllable penetration depth and the integrity of the microstructure, solving the technical problems of weak interfacial bonding, numerous pore defects, high internal stress, and uneven performance in traditional curing processes.

[0041] This embodiment features an integrated modified concrete with a photothermal superhydrophobic and anti-icing interface. The functional interface layer is chemically bonded to the surface of the concrete substrate. The functional interface layer is composed of the following components, with the following mass proportions: The functional interface layer comprises an epoxy resin binder matrix, a curing agent, a silane coupling agent, multi-walled carbon nanotubes modified with the silane coupling agent, nano-silica modified with the silane coupling agent, perfluorodecyltrimethoxysilane, and an organic solvent. The epoxy resin binder matrix is ​​defined as 100 parts by weight, and the remaining components are as follows by weight: 40 to 60 parts curing agent; 20 to 30 parts silane coupling agent; 3 to 8 parts multi-walled carbon nanotubes modified with the silane coupling agent; 8 to 15 parts nano-silica modified with the silane coupling agent; 10 to 20 parts perfluorodecyltrimethoxysilane; and 600 to 800 parts organic solvent.

[0042] Within the aforementioned mixing ratio range, the epoxy resin binder is preferably bisphenol A type epoxy resin, whose three-dimensional interfacial cross-linked network formed after curing provides cohesive strength and a supporting skeleton for the functional layer. The curing agent is preferably a blend of aliphatic amines and aromatic amines; this blending ratio balances the room-temperature construction time with the heat resistance and chemical corrosion resistance of the cured product. The silane coupling agent is preferably 3-glycidyloxypropyltrimethoxysilane, and its addition amount must be significantly higher than that used in conventional physical blending to meet the requirement of constructing a four-dimensional integrated chemical anchoring network between concrete hydration products, the resin matrix, and nanofillers, rather than simply using it as a dispersant.

[0043] Multi-walled carbon nanotubes modified with silane coupling agents and nano-silica modified with silane coupling agents together constitute a framework-filled micro / nano-hierarchical rough structure. The mass fraction of multi-walled carbon nanotubes is controlled within the range of 3 to 8 parts to ensure the formation of a continuous, interconnected conductive and supporting framework in the epoxy resin-based binder matrix. Below 3 parts, it is difficult to form an effective percolation threshold, while above 8 parts, the system viscosity becomes too high to be applied. The mass fraction of nano-silica is controlled within the range of 8 to 15 parts to fill the gaps in the carbon nanotube framework and form nanoscale protrusions on its surface. The mass ratio of nano-silica to multi-walled carbon nanotubes is preferably controlled between 1:1 and 2:1 to form a hierarchical and stable two-scale rough structure.

[0044] Perfluorodecyltrimethoxysilane, as a low surface energy modifier, is sufficient at an addition of 10 to 20 parts to form a dense and regularly oriented monolayer on a rough surface, thereby minimizing the free energy of the concrete surface. Anhydrous ethanol is preferred as the organic solvent, used to adjust the viscosity of the precursor liquid to suit the spraying process, ensuring that the precursor liquid can uniformly wet and penetrate into the microstructure of the concrete substrate.

[0045] Through the synergistic effect of the above components and their proportions, the functional interface layer can undergo integral chemical bonding with the concrete substrate during the thermosetting process, thereby constructing an anti-icing interface with excellent superhydrophobicity, photothermal conversion capability and high mechanical stability on the concrete surface in situ.

[0046] Example 1: Preparation of integrated modified concrete.

[0047] (1) Concrete substrate preparation: Concrete specimens were prepared according to GB / T 17671-2021 standard. The specific steps were as follows: 450g of cement and 225ml of water (water-cement ratio 0.5) were mixed at low speed for 30s in a planetary mixer; 1350g of standard sand was added, and the mixture was mixed at low speed for 30s, then at high speed for 30s, paused for 90s, and then mixed at high speed for 60s. The mortar was poured into the mold, cured for 24h under standard conditions, demolded, and then cured for 28 days. After cleaning and drying, the specimens were ready for use.

[0048] (2) Preparation of precursor solution for overall surface modification: 2 g of epoxy resin E-51 and 1 g of curing agent (D-400 and DDM mixed at a mass ratio of 3:1) were added to 15 mL of anhydrous ethanol and magnetically stirred for 15 min; 0.5 g of silane coupling agent KH-560 was added and stirred for another 10 min to activate the resin system. Then, 0.2 g of nano-silica ethanol dispersion and 0.1 g of multi-walled carbon nanotube ethanol dispersion, which were uniformly dispersed by ultrasonication, were added in sequence and stirred for 10 min respectively; then 0.3 g of perfluorodecyltrimethoxysilane was slowly added dropwise, magnetically stirred for 30 min and ultrasonicated for 15 min to obtain a uniformly dispersed precursor solution for overall surface modification.

[0049] (3) Integrated modification and curing: Using a spray gun, the precursor liquid was uniformly sprayed onto the surface of the concrete specimen under a pressure of 0.5 MPa and a spraying distance of 15 cm. After spraying, the specimen was placed in an oven and cured at 80°C for 30 min to allow the solvent to evaporate and initially crosslink. Then, the temperature was raised to 100°C and cured for 30 min to promote the condensation reaction between the silane coupling agent and the hydration products on the concrete surface, thus completing the overall chemical integration of the functional interface and the concrete substrate, thereby obtaining the target integrated modified concrete component.

[0050] Example 1 (Conclusion on the feasibility of the preparation process): This embodiment successfully verified the rationality of the formulation of the overall surface modification precursor liquid and the feasibility of the spray-step curing process. By precisely controlling the raw material ratio (epoxy resin E-51, composite curing agent D-400 / DDM, silane coupling agent KH-560 and functional filler) and process parameters (0.5 MPa spraying pressure, 80℃ / 100℃ step curing), it was confirmed that a functional interface layer with a micro-nano hierarchical rough structure can be constructed in situ on the surface of the concrete substrate, and that the interface layer and the concrete substrate can form an integral, non-peelable structure through chemical bonding.

[0051] Example 2: Surface wetting and anti-icing performance test.

[0052] The surface of the integrated modified concrete was tested using a contact angle meter. The results showed that its contact angle with water was as high as 162.5° and the roll-off angle was less than 1°, indicating that the interface has excellent superhydrophobic properties. A static water droplet freezing experiment was conducted on a -20°C low-temperature constant-temperature platform. Water droplets on the untreated concrete surface froze completely within about 3 minutes; however, the freezing time of water droplets on the surface of the integrated modified concrete prepared by this invention was extended to 26 minutes. Furthermore, when simulated sunlight was applied, the surface ice layer melted and rolled off in a short time, demonstrating the synergistic anti-icing effect of photothermal conversion and superhydrophobicity.

[0053] Example 2 (Conclusions on wetting properties and anti-icing mechanism): This embodiment confirms that the integrated modified concrete surface possesses excellent superhydrophobic properties, with a static contact angle of up to 162.5° and a roll-off angle of less than 1°, meeting the Cassie-Baxter wetting condition criteria. Regarding anti-icing performance, this structure extends the water droplet freezing time from approximately 3 minutes in the control group to 26 minutes, a delay effect exceeding 8 times. Combined with photothermal response testing, it is confirmed that the photothermal conversion effect of multi-walled carbon nanotubes and the water-repellent effect of the micro-nano rough structure produce a significant synergistic anti-icing effect, achieving a closed-loop protection mechanism of "delayed freezing - photothermal melting - droplet roll-off".

[0054] Example 3: Self-cleaning and anti-fouling performance test.

[0055] The integrated modified concrete was fixed on a 10° inclined platform, and nano-silica powder was evenly sprinkled on the surface to simulate contaminants. Water droplets were dripped from above, and the water droplets quickly carried away the surface dust as they rolled, leaving a clean path. In addition, the component was immersed in a mud-water mixture and then removed, and no mud residue remained on the surface, indicating that the integrated modified interface endows the concrete with excellent self-cleaning and stain resistance.

[0056] Example 3 (Conclusion on self-cleaning and anti-fouling performance): This embodiment demonstrates that the micro / nano hierarchical rough structure combined with low surface energy modification endows the concrete surface with excellent non-adhesive properties. Under a 10° tilt angle, water droplets can effectively remove simulated contaminants (nano silica powder); in mud and water immersion experiments, the surface exhibits excellent anti-wetting and anti-fouling capabilities, with no mud residue. These results prove that the functional interface layer possesses reliable self-cleaning and anti-fouling protection functions in actual service environments (such as dusty and muddy environments), which can effectively reduce maintenance costs.

[0057] Example 4: Verification of interfacial bonding strength and durability.

[0058] To verify the integrated anchoring effect between the functional interface and the concrete, 100 high-strength tape peel tests and a 15-m sandpaper linear abrasion test under a 200g weight were conducted on the surface of the integrated modified concrete component. The test results showed that after undergoing rigorous mechanical action, the water contact angle on the component surface remained consistently above 150° without significant attenuation. This is attributed to the chemical bonding network constructed by KH-560 between the concrete and the functional layer, effectively resisting interfacial peeling caused by external stress.

[0059] Example 4 (Conclusions on interfacial bond strength and mechanical durability): This embodiment verifies the significant advantages of the described "chemically bonded network" in resisting external mechanical stress. After 100 cycles of high-strength tape peeling tests and a 15m sandpaper linear abrasion test with a 200g weight, the functional interface layer showed no peeling, flaking, or micro / nanostructure collapse, and the water contact angle remained consistently above 150°. This fully demonstrates that the four-level chemical anchoring structure of "concrete-coupling agent-resin-filler" constructed using KH-560 effectively overcomes the interfacial weaknesses of traditional physical coatings, endowing the modified concrete with excellent mechanical stability and long-term service durability.

[0060] in conclusion: The above embodiments fully illustrate that the integrated modified concrete provided by the present invention is not a physical coating in the traditional sense, but an integral modified structure that is integrated with the concrete substrate through chemical bonds. This structure endows concrete with excellent superhydrophobic, anti-icing, and self-cleaning properties while ensuring its high durability and reliability in complex service environments, and has broad application prospects in the field of cold-region concrete structure protection.

[0061] A comparative and comprehensive analysis of the experimental results of Examples 1 to 4 was conducted: The data from each embodiment corroborate each other, demonstrating that the integrated modified concrete with a photothermal superhydrophobic anti-icing interface and its preparation method successfully overcome the limitations of single-functional materials. The superhydrophobic properties (contact angle >160°) and photothermal anti-icing properties (8-fold increase in freezing time) of Example 2 mutually support each other; the self-cleaning properties of Example 3 verify the effectiveness of the low surface energy modification; and the mechanical stability of Example 4 proves the necessity of the integrated chemical bonding design described in Example 1. This synergistic effect of multi-dimensional properties resolves the contradiction in existing technologies where "more functions lead to lower stability."

[0062] The durability test results of Example 4 (no performance degradation after 100 peels and long-distance wear) contrast sharply with the anti-icing data of Example 2 (26-minute delay), highlighting the fundamental difference between the present invention and existing physical adhesion coatings. Traditional coatings will inevitably peel off under the same mechanical stress, while the present invention transforms the functional layer into part of the concrete substrate through chemical bonding, achieving a technological leap from physical coverage to chemical integration.

[0063] The process parameters of Example 1 (such as 0.5 MPa spraying pressure and 80℃ / 100℃ stepped curing) directly determine the performance of Examples 2 to 4. The comparative results show that this specific process not only ensures the penetration and anchoring of the precursor liquid into the micropores of concrete, but also ensures the orderly arrangement (skeleton-filler structure) of micro-nano fillers in the resin matrix, thereby ensuring the high reproducibility and reliability of the final product in terms of wettability, anti-icing properties, self-cleaning properties, and durability.

[0064] In summary, the integrated modified concrete with a photothermal superhydrophobic anti-icing interface and its preparation method provided by this invention successfully grows micro / nano hierarchical rough structures and photothermal responsive units on the concrete surface through a chemical bonding mechanism, forming an inseparable whole. Experimental data fully demonstrate that the integrated modified concrete with a photothermal superhydrophobic anti-icing interface and its preparation method of this invention, while endowing concrete with excellent superhydrophobicity, active / passive synergistic anti-icing and self-cleaning functions, completely solves the industry pain points of weak interfacial bonding, easy damage to micro / nano structures, and instability in long-term service of traditional functional coatings. The integrated modification strategy of this invention provides an innovative solution with high performance, high durability, and high construction feasibility for long-term protection of concrete infrastructure in cold and high-humidity environments.

[0065] To further verify the microstructural characteristics of the functional interface layer of this invention and its structure-property relationship with the original filler, the coating obtained by this invention and the original filler were characterized by scanning electron microscopy (SEM). The results are as follows: Figure 1 As shown: Figure 1 (a) is a SEM image of the 1µm coating surface under 10,000x magnification; as shown. Figure 1 As shown in (a), the coating surface exhibits a distinct micro-nano hierarchical rough structure, which is composed of a large number of interwoven and entangled fibrous skeletons and granular protrusions attached thereto. This multi-level rough structure is the result of the uniform dispersion and synergistic stacking of multi-walled carbon nanotubes modified with silane coupling agent and nano-silica in epoxy resin as the binder matrix, providing the necessary physical roughness for constructing a superhydrophobic surface.

[0066] Figure 1 (b) SEM image of the 10µm coating surface under 500x magnification; Figure 1 (b) shows the surface texture of the coating; the coating surface is not flat, but has micro-undulations, and there are no obvious cracks or pinholes on the surface. This indicates that the stepped thermosetting process of the present invention effectively releases the interfacial stress during the curing process, so that the resin matrix and the concrete substrate achieve good interfacial fusion and form a continuous, dense and defect-free functional interface layer.

[0067] Figure 1 (c) is a SEM image of the original multi-walled carbon nanotubes (MWCNTs) at 30,000x magnification; as shown. Figure 1 As shown in (c), the original carbon nanotubes have a typical tubular linear morphology with a very high aspect ratio. Their surfaces are relatively smooth, with lengths ranging from 25 μm to 35 μm and outer diameters ranging from 10 nm to 20 nm. These original carbon nanotubes serve as the core framework material for the functional interface layer and retain their long-range continuous network structure after resin curing.

[0068] Figure 1 (d) is a SEM image of the original nano-silica (nano-SiO2) under 30,000x magnification; as shown. Figure 1 As shown in (d), the nano-silica is in the form of approximately spherical or irregular polyhedral particles with a particle size mainly distributed between 10 nm and 20 nm. The particles are relatively uniformly dispersed and do not have serious agglomeration. In the functional interface layer, these nanoparticles fill the gaps in the carbon nanotube framework and are partially exposed on the surface during the curing process, forming the roughness of the micro-nano composite.

[0069] By comparison Figure 1 (c) and Figure 1 (d) (original packing), and Figure 1 (a) and Figure 1 (b) (Final coating): The original multi-walled carbon nanotubes with extremely high aspect ratio were successfully formed into a continuous three-dimensional network framework in the resin matrix. Figure 1 (a) The interwoven fibrous structure, while nano-silica is uniformly distributed as a secondary unit in the interstices of the framework, the two work together to construct Figure 1(b) shows a macroscopic-micro-nano hierarchical rough surface; this structure meets the morphological requirements of the Cassie-Baxter wetting model and is the structural basis for achieving superhydrophobic performance.

[0070] Figure 1 No obvious filler agglomerates were observed in (a), indicating that the silane coupling agent (KH-560) effectively improved the dispersion stability of carbon nanotubes and nano-silica in epoxy resin. Furthermore, the precursor liquid spraying and thermosetting process parameters (0.5MPa spraying pressure, 80℃ / 100℃ step curing) were appropriate, ensuring the uniformity of the internal structure of the functional interface layer.

[0071] Figure 1 (b) shows a crack-free and pore-free dense surface, which proves that the stepped thermosetting regime (pre-curing at 80°C for 30 min and post-curing at 100°C for 30 min) can effectively regulate the solvent evaporation rate and resin crosslinking density, avoiding shrinkage cracking or interface debonding that may be caused by traditional high-temperature direct curing, thereby ensuring the chemical integration and anchoring effect between the functional interface layer and the concrete substrate.

[0072] In summary, the SEM characterization results directly confirm that the component formulation and process parameters described in this invention can successfully construct a functional coating with a micro-nano hierarchical rough structure, dense interior, and strong interfacial bonding on the concrete surface in situ, providing direct evidence at the microstructural level for the excellent superhydrophobic, anti-icing, self-cleaning, and durable properties described in Examples 2-4.

[0073] To quantitatively characterize the wetting properties of the integrated modified concrete surface with a photothermal superhydrophobic anti-icing interface obtained in this invention, and to verify its superhydrophobic characteristics, the static water contact angle (CA) and dynamic slip angle (SA) of the coating prepared in this invention were tested. The results are as follows: Figure 2 As shown.

[0074] Figure 2 (a) is a macroscopic morphology diagram of the static water contact angle of the coating surface; such as Figure 2 As shown in (a), the water droplets on the coating surface present a perfect spherical crown shape, which is highly full and has a very small contact area with the substrate. This visually demonstrates the strong water repulsion effect of the coating, which is consistent with the typical macroscopic visual characteristics of superhydrophobic surfaces.

[0075] Figure 2 (b) is a screenshot of the software analysis of the contact angle measuring instrument; such as Figure 2As shown in (b), the fitted curve (green arc) of the water droplet profile and the specific measurement data are clearly displayed. The test results show that the static water contact angle (CA) of the coating surface is as high as 160.935°. According to wetting theory, a contact angle greater than 150° is defined as superhydrophobic. The coating obtained by this invention far exceeds this standard, indicating that its surface has extremely low free energy, making it difficult for water droplets to spread on its surface.

[0076] Figure 2 (c) is a schematic diagram of the photothermal conversion performance testing device; as shown Figure 2 As shown in (c), the test was conducted under simulated lighting conditions. A water droplet placed on the coating surface was vertically irradiated with a light source of a specific wavelength (such as blue light or simulated solar spectrum light source) to evaluate the photothermal response characteristics of the functional layer under lighting conditions and to verify its practical application potential for photothermal-assisted anti-icing and de-icing.

[0077] Figure 2 (d) is a real-time test curve of water contact angle / slip angle. For example... Figure 2 As shown in (d), the curve records the dynamic changes of water droplets on the coating surface over time. Data shows that during the 48-minute observation period, the water contact angle (CA_AV, blue curve) remained stable at approximately 160° without significant decay; simultaneously, the sliding angle (SA, green / cyan curve) remained at an extremely low level (less than 5°). This result fully demonstrates that the functional interface layer of this invention not only possesses extremely high static superhydrophobicity but also exhibits excellent wetting stability under continuous water droplet action, without wetting reversal or surface microstructure damage, ensuring its long-term reliable anti-icing and self-cleaning performance.

[0078] Combination Figure 2 Based on the test data, the following conclusions can be drawn: The integrated modified concrete surface obtained by this invention has an extremely high static water contact angle (>160°), which far exceeds the judgment standard for superhydrophobic materials (>150°), confirming that its surface has excellent water repellency.

[0079] The extremely small sliding angle means that water droplets roll very easily on the surface. This not only helps dust, stains and other contaminants to roll off with the water droplets (self-cleaning), but also allows water droplets to quickly detach from the surface before freezing or roll off after being melted by light and heat in anti-icing scenarios, effectively preventing the adhesion and accumulation of ice.

[0080] Long-term dynamic monitoring showed that the contact angle remained stable, indicating that the structure and chemical composition of the functional interface layer have good anti-aging and anti-wetting degradation capabilities under long-term moisture exposure, meeting the durability requirements of complex service environments.

[0081] To verify the self-cleaning and antifouling performance of the integrated modified concrete with a photothermal superhydrophobic anti-icing interface of this invention under complex service environments, a comparative test of the self-cleaning ability of concrete specimens coated with different coatings was conducted in a laboratory simulated environment (dust adhesion, immersion in murky water), and compared with an untreated substrate. The test results and microstructure evolution are as follows: Figure 3 As shown.

[0082] like Figure 3 As shown, the self-cleaning effect and anti-fouling mechanism of the three coatings on the concrete surface are compared under different pollution scenarios.

[0083] like Figure 3 As shown in (a), for unmodified concrete substrate (P mortar): when dust is initially placed on the substrate surface, a large amount of dust adheres over time and is difficult to remove, resulting in severe surface residue. This indicates that the unmodified concrete surface has extremely strong hydrophilicity, readily adsorbs dust particles, and has extremely poor self-cleaning effect.

[0084] like Figure 3 As shown in (a), the single hydrophobic treated mortar (H mortar) exhibits reduced dust residue compared to P mortar, but significant adhesion still occurs under external force. This indicates that while single hydrophobic modification can reduce surface energy, it lacks effective support from the micro-nano rough structure, resulting in limited self-cleaning ability.

[0085] like Figure 3 As shown in (a), the integrated modified mortar (CH mortar, the solution of this invention) makes it difficult for dust to adhere in the initial stage. Under the action of external force (such as water flow or air flow), the dust is quickly carried away, and the surface is restored to cleanliness. This intuitively proves that the present invention achieves excellent "roll-off" self-cleaning effect through the synergistic effect of "micro-nano hierarchical rough structure + low surface energy modification".

[0086] like Figure 3 As shown in (b), the droplet states on the surfaces of H mortar and CH mortar are compared: the droplets on the surface of H mortar are spread out with a small contact angle, exhibiting hydrophilic or weakly hydrophobic characteristics; while the droplets on the surface of CH mortar are high-gloss spherical crowns with a significantly increased contact angle, demonstrating excellent superhydrophobic properties. This difference stems from the stable Cassie-Baxter wetting state constructed by CH mortar, which provides a basis for self-cleaning and antifouling.

[0087] like Figure 3 (c) shows a schematic diagram of the self-cleaning mechanism of CH mortar surface: The micro-nano hierarchical rough structure of the CH mortar surface (such as multi-walled carbon nanotube framework + nano-silica filling) effectively traps the air layer, and the droplets form a "suspended" state on the air layer. When subjected to external force, the droplets easily roll off and carry away the dust particles attached to the surface, thus achieving self-cleaning.

[0088] like Figure 3 As shown in (d), the photos of CH mortar before, during, and after soaking in turbid water are as follows: Before soaking, the surface of CH mortar is clean; during soaking, solid particles in the turbid water do not adhere to the surface; after soaking, there is still no mud residue on the surface. This indicates that CH mortar has extremely strong anti-fouling ability and can effectively prevent pollutants from remaining on the surface.

[0089] like Figure 3 As shown in (e), the antifouling mechanism of CH mortar is illustrated: the micro-nano rough structure on the surface of CH mortar forms a stable air layer at the solid-liquid interface, which hinders the direct contact between solid particles in the mud-water mixture and the surface. This "air cushion" effect effectively prevents the adhesion and penetration of pollutants, ensuring the long-term cleanliness of the surface.

[0090] based on Figure 3 The self-cleaning and anti-fouling performance tests yielded the following conclusions: The integrated modified concrete surface obtained by this invention can significantly inhibit the adhesion of dust and mud-water mixtures, achieving efficient self-cleaning and anti-fouling. Even when unmodified concrete surfaces have severe dust residue and single hydrophobic mortar still adheres, CH mortar can quickly remove dust under external force and maintain a clean, mud-free surface after soaking in murky water. This provides an effective means for the long-term maintenance-free operation of concrete infrastructure such as building exterior walls and road bridges in harsh environments.

[0091] Dust and mud mixtures are difficult to adhere to the modified surface, partly due to the superhydrophobic properties resulting from the extremely low surface energy, and partly due to the effective trapping of air by the micro-nano rough structure, forming a stable Cassie-Baxter wetting state. This "structure-chemistry" synergy makes droplets and contaminants roll off or detach easily from the surface, avoiding the adsorption and retention of traditional hydrophilic surfaces.

[0092] In complex environments such as urban dust and muddy roads, concrete infrastructure such as buildings, bridges, and roads are highly susceptible to contamination, increasing maintenance costs. The self-cleaning and anti-fouling interface layer provided by this invention can effectively reduce the adhesion of pollutants, decrease the frequency of cleaning, and extend the service life of facilities, thus possessing extremely high engineering application value.

[0093] To evaluate the durability and service life of the integrated modified concrete with a photothermal superhydrophobic anti-icing interface obtained in this invention in practical outdoor use, a systematic tribological test was conducted on the coating. The focus was on investigating the evolution of its surface wetting properties under mechanical wear. The results are as follows: Figure 4 As shown.

[0094] Figure 4The curves showing the changes in water contact angle (WCA) and sliding angle (WSA) of the coating under different wear cycles are presented. The test used the standard sandpaper friction method to simulate natural weathering and physical wear. The horizontal axis represents the wear cycle, the left vertical axis represents the water contact angle (orange curve), and the right vertical axis represents the sliding angle (pink curve). Figure 4 As shown, the surface microstructure of the coating is gradually damaged with increasing wear cycles. In the initial stage (0 cycles), the coating exhibits excellent superhydrophobic properties, with a contact angle close to 160° and an extremely low sliding angle. As the wear cycles lengthen (from 0 to 50 cycles), due to the continuous wear and failure of the surface micro-nano rough structure, the water contact angle of the coating gradually decreases, while the sliding angle gradually increases.

[0095] Figure 4 (a) is a schematic diagram of the tape peel test. Figure 4 (b) is a schematic diagram of a 200g load friction test. These test conditions simulate more severe physical damage scenarios that may be encountered in real-world applications, such as performance under strong winds carrying sand and gravel impacts or heavy object friction. Despite undergoing up to 50 wear cycles, the water contact angle of the coating remained above 148°, and although the slip angle increased slightly, it remained at a low level. This indicates that the functional interface layer of the present invention can still maintain good superhydrophobic properties after experiencing a certain degree of mechanical wear, without a sharp reversal of wettability.

[0096] Combination Figure 4 Based on the test data and analysis, the following conclusions can be drawn: The integrated modified concrete surface obtained by this invention, after undergoing multiple friction and wear cycles, although its micro-nano hierarchical rough structure is damaged to some extent, the overall skeleton network is not completely destroyed, exhibiting good wear resistance.

[0097] Even after 50 wear cycles, the coating maintains a high contact angle and a low slip angle, demonstrating its excellent long-term superhydrophobic stability. This stability ensures that the coating will not quickly lose its anti-icing and self-cleaning functions due to wind, sun exposure, or slight friction during long-term outdoor use.

[0098] The gradual change in the wear curve indicates that the chemical bonding network between the epoxy resin binder matrix and the silane coupling agent modified filler effectively enhances the mechanical strength of the coating, making the functional layer superior to traditional physical blend coatings in resisting physical wear, thus providing reliable performance assurance for practical applications.

[0099] To verify the anti-icing and freeze-thaw resistance of the integrated modified concrete with a photothermal superhydrophobic anti-icing interface of this invention under extreme cold environments, static water droplet freezing delay tests were conducted on concrete specimens coated with different coatings in a simulated laboratory environment (temperature -20°C), and compared with the untreated substrate. The test results and microstructure evolution are as follows: Figure 5 As shown.

[0100] Figure 5 The study demonstrates the antifreeze effect of three coatings on concrete surfaces and the static anti-icing performance of water droplets under a low temperature of -20°C.

[0101] like Figure 5 (a)- Figure 5 As shown in (c), for unmodified concrete substrate: when a water droplet is placed on the substrate surface at the initial moment (0 min), the water droplet begins to lose heat and gradually loses its fluidity in a very short time. By 1 min, it has basically frozen into solid ice, and by 3 min, it is completely frozen to the surface, forming a dense ice layer. This indicates that the unmodified concrete surface has extremely high thermal conductivity and cannot delay the formation of ice crystals.

[0102] like Figure 5 (d)- Figure 5 As shown in (f), modified coating 1: In contrast, the specimen coated with the functional interface of this invention exhibits a highly glossy, spherical shape in the initial stage (0 min), demonstrating excellent hydrophobicity. As time progresses to 12 min, the water droplets maintain a good hemispherical shape, without significant spreading or freezing; only faint, fine ice crystals begin to precipitate at the bottom. Until 20 min, the water droplets remain in a liquid or semi-liquid state, without overall freezing, exhibiting excellent delayed-freezing performance.

[0103] like Figure 5 (g)- Figure 5 As shown in (i), modified coating 2 / optimal group: another coating group (or a further optimized formulation) performed even better. During the observation period from 0 min to 26 min, the water droplets maintained a near-perfect spherical shape, and even at the longest observation time (26 min), the water droplets remained suspended without freezing. This intuitively demonstrates that the coating not only has superhydrophobicity at low temperatures, but also possesses an extremely long anti-icing time, and can even achieve long-term liquid retention in a supercooled state under certain conditions.

[0104] based on Figure 5 The anti-icing performance test yielded the following conclusions: The integrated modified concrete surface obtained by this invention can significantly extend the freezing time of water droplets. At extreme low temperatures of -20°C, unmodified concrete freezes completely within 1 minute, while the modified coating can significantly delay the freezing time to more than 20 minutes, with a maximum of 26 minutes. This provides a valuable time window for winter road de-icing operations or natural ice removal.

[0105] The water droplets remain spherical on the modified surface for a long time without freezing, which is attributed to the superhydrophobic properties brought about by the extremely low surface energy, and also to the hindering effect of the micro-nano rough structure and the coating material itself on heat transfer (or potential photothermal conversion assistance), effectively isolating the formation and growth of ice crystal nuclei.

[0106] In frigid regions, concrete infrastructure such as buildings, bridges, and roads are highly susceptible to damage from freeze-thaw cycles. The anti-icing interface layer provided by this invention effectively prevents ice from adhering to the surface, avoiding damage to the internal pore structure of concrete caused by ice expansion, thereby significantly extending the service life of infrastructure and possessing extremely high engineering application value.

[0107] To quantitatively evaluate the interfacial bonding strength between the functional interface layer obtained in this invention and the concrete substrate, and to verify the long-term durability and peel resistance of the coating, a portable electric pull-out tester was used to conduct standard pull-out tests on concrete specimens coated with KB group coating (P mortar, ordinary reference mortar) and S8 group coating (CH mortar, integrated modified mortar with multi-walled carbon nanotubes, the scheme of this invention).

[0108] Test instruments and methods: This test used a portable electric pull-out apparatus (model SH-DS10, made in China). A prepared standard concrete specimen (coated with either KB or S8 group coating) was fixed on the test bench. A standard pull-out head (50mm in diameter) was brought into full contact with the coating surface, and a tensile force perpendicular to the surface was applied at a constant rate until the coating peeled off from the substrate. The maximum tensile force (force value, unit: kN) at the moment of peeling was recorded, and the pull-out strength (unit: MPa) was calculated using the formula: Strength = Pull-out head area + Force value.

[0109] The test results are shown in Table 1:

[0110] Data Analysis: 1. Performance of the KB coating: Its maximum pull-out force is 0.519 kN, which translates to a pull-out strength of 1.654 MPa. This indicates that the KB coating forms a strong chemical and physical bond with the concrete substrate, and can withstand certain external impacts without detaching.

[0111] 2. Performance of the S8 coating group: Its maximum pull-out force is 0.511 kN, which translates to a pull-out strength of 1.755 MPa. Although its absolute peel force is slightly lower than that of the KB coating group (difference approximately 0.008 kN), its calculated pull-out strength is actually higher than that of the KB coating group, reaching 1.755 MPa, under the same pull-out area. This reflects slight differences in the interfacial bonding state under different formulations or application processes, but both are generally within the same order of magnitude.

[0112] Based on the above tensile strength test data, the following conclusions can be drawn: 1. Excellent interfacial bonding strength: The pull-out strength of the KB group coating and the S8 group coating obtained by this invention both exceed 1.6 MPa, which is significantly higher than the conventional standard requirements of general building waterproof coatings or interface agents (usually above 1.0 MPa is considered good). This fully demonstrates that the coating has extremely strong interfacial adhesion to the concrete substrate.

[0113] 2. Good durability and anti-peel properties: The high tensile strength means that the coating is not prone to hollowing, peeling or flaking in actual use environments (such as being subjected to pedestrian trampling, vehicle rolling, wind and sand abrasion or stress generated by freeze-thaw cycles), which can effectively protect the concrete substrate and ensure the long-term effectiveness of the protective function.

[0114] 3. Formulation stability and reliability: Both coatings with different formulations (KB and S8) exhibited stable high bonding strength, indicating that the coating system of the present invention has good process repeatability and engineering applicability in terms of interfacial bonding.

[0115] In summary, although the pull-out strength of the S8 group coating is at the same level as the KB benchmark group (1.755 MPa and 1.654 MPa), and even higher (1.755 MPa), it indicates that the S8 group coating of this invention did not suffer from adhesion degradation due to the introduction of multi-walled carbon nanotubes and hydrophobic components. This demonstrates that the integrated functional modification of this invention does not affect the interfacial bonding performance between the coating and the concrete matrix. Combined with the subsequent hydrophobicity, impermeability, and weather resistance test results, it can be seen that the S8 group coating of this invention maintains excellent interfacial bonding ability while achieving multiple protective functions, meeting the requirements of engineering applications.

[0116] To verify the active anti-icing and de-icing capabilities of the integrated modified concrete described in this invention in outdoor environments, the photothermal conversion and temperature rise performance of its functional interface layer under simulated sunlight irradiation were tested. In this experiment, a halogen tungsten lamp (HL10420, China) was used to simulate the solar spectrum and illumination conditions. Modified concrete specimens coated with the S8 layer were continuously irradiated, and their surface temperature changes were recorded in real time. The results are shown in Table 2.

[0117] Test conditions and data recording:

[0118] Data Analysis: 1. Under continuous high-intensity halogen tungsten lamp irradiation, the S8 coating exhibited a significant transient photothermal conversion effect. Within just one minute of irradiation, the surface temperature of the specimen rapidly increased from an initial 22.2℃ to 30.3℃, a rise of 8.1℃. As the irradiation time prolonged, heat continuously accumulated in the micro-nano rough structure, resulting in a sustained and rapid temperature increase. By the end of irradiation (10 minutes), the surface temperature had soared to 74.6℃, exceeding the ambient temperature by more than 52℃.

[0119] 2. This temperature rise performance far exceeds that of ordinary concrete (which usually struggles to exceed 40°C under sunlight) or conventional hydrophobic coatings (which are mostly passive heat insulation). This is mainly due to the special micro-nano composite structure constructed in the S8 coating and its efficient absorption of the solar spectrum and low thermal conductivity, which allows light energy to be rapidly converted into heat energy and retained on the surface.

[0120] Based on the above photothermal performance test data, the following conclusions can be drawn: 1. The integrated modified concrete (S8 group coating) obtained by this invention has extremely high photothermal conversion efficiency. Under simulated sunlight irradiation, it can achieve a significant increase in surface temperature in a very short time (1 min), proving that the coating has excellent active heating potential.

[0121] 2. Combining its superhydrophobic properties with a surface temperature rise of over 70°C, this coating can actively maintain a surface temperature above the freezing point through its own heat generation in cold environments (such as morning frost or snowfall), thus achieving not only... Figure 5 The extended-delay icing process demonstrated here has the capability to achieve "zero icing" or accelerate the melting and shedding of ice and snow in practical applications.

[0122] 3. The S8 coating integrates both passive anti-icing (superhydrophobic, low adhesion) and active anti-icing (photothermal heating) mechanisms, making it more adaptable and reliable than single-function coatings when facing complex and changeable natural climates. It provides an efficient and innovative solution for anti-icing and de-icing of roads, bridges and building exteriors in frigid regions.

[0123] Acid and alkali solution immersion corrosion resistance test: To verify the interfacial stability and durability of the integrated modified concrete of this invention under strong acid and alkali environments, referring to the method in GB / T9274-1988 "Determination of Resistance to Liquid Media for Paints and Varnishes", the integrated modified concrete specimen (No. S8) and the control specimen (No. S7) with a traditional superhydrophobic coating without integrated modification were completely immersed in acid and alkali solutions with pH values ​​of 2, 4, 6, 8, 10, 12, and 14, respectively, for 72 hours (3 days). After immersion, the specimens were removed, gently rinsed with deionized water, and allowed to air dry. The water contact angle of each specimen was then measured. The test results are shown in Table 3.

[0124]

[0125] After acid and alkali immersion, the contact angle of the conventionally coated specimen S7 decreased significantly with acid and alkali corrosion, especially under strong acid (pH=2) and strong alkali (pH=14) conditions, where the contact angle dropped to 148° and 141°, respectively. This indicates that its surface micro-nano structure and low surface energy modification layer were damaged due to the weak physical interface. In contrast, the integrated modified concrete specimen S8 of this invention maintained excellent hydrophobic properties under all pH conditions, with the contact angle stably maintained above 151°. After immersion in strong acid (pH=2) and strong alkali (pH=14), it still reached 153° and 157°, respectively, without significant attenuation.

[0126] The above results fully demonstrate that the "four-in-one" chemical anchoring network constructed by the silane coupling agent KH-560 between the concrete substrate and the functional interface layer in this invention not only firmly anchors the micro-nano hierarchical rough structure to the concrete surface, but also effectively blocks the path of corrosive ions to penetrate along the interface. This chemically bonded integrated structure significantly improves the resistance of the modified layer to acid and alkali erosion, avoids the protective failure caused by interface peeling of traditional physical coatings, and ensures the long-term superhydrophobic and anti-icing stability of concrete components under complex corrosive service conditions such as industrial acidic environments, saline-alkali land, and marine environments.

[0127] Matters not covered in this invention are common knowledge.

[0128] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0129] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

[0130] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An integrated modified concrete with a photothermal superhydrophobic anti-icing interface, characterized in that, It includes a concrete substrate and a functional interface layer that is in situ hybridized on the surface of the concrete substrate and in the surface opening pores. The functional interface layer forms a seamless connection structure with the surface hydration products of the concrete substrate through chemical bonding. The functional interface layer uses epoxy resin as the in-situ crosslinking matrix and nano-silica and multi-walled carbon nanotubes as interface co-construction units. A three-dimensional interpenetrating network is established between the construction units, the crosslinking matrix and the concrete hydrated calcium silicate gel through silane coupling agent. Then, it is modified in-situ with low surface energy fluorosilane to construct a micro / nano-level rough superhydrophobic interface on the concrete surface. Multi-walled carbon nanotubes construct a continuous conductive and heat-transferring framework within a cross-linked matrix. Nano-silica fills the gaps in the continuous conductive and heat-transferring framework and anchors to the surface of the framework to form nanoscale protrusions. Together, they form a framework-filling hierarchical rough structure. The functional interface modification layer forms an inseparable integrated whole with the concrete substrate through the synergistic effect of physical interlocking and chemical bonding.

2. The integrated modified concrete with a photothermal superhydrophobic anti-icing interface according to claim 1, characterized in that, The silane coupling agent is 3-glycidyloxypropyltrimethoxysilane, which acts as an interfacial bridge to simultaneously achieve multiple bonding. After the alkoxy group of 3-glycidoxypropyltrimethoxysilane is hydrolyzed, it condenses with the silanol groups on the concrete surface and the nano silica surface to form Si-O-Si bonds. Furthermore, the epoxy group of 3-glycidoxypropyltrimethoxysilane copolymerizes with the curing agent in the system and embeds into the resin crosslinking network during the epoxy resin curing process, thereby forming an integrated structure without macroscopic interlayer delamination on the concrete surface.

3. The integrated modified concrete with a photothermal superhydrophobic anti-icing interface according to claim 1, characterized in that, Multi-walled carbon nanotubes with an aspect ratio of not less than 1000 are assembled in situ in epoxy resin to form a three-dimensional interconnected conductive network. The particle size distribution of nano-silica is in the range of 1 to 10 times the outer diameter of multi-walled carbon nanotubes. It is fixed on the surface of multi-walled carbon nanotubes through interfacial bridging of silane coupling agent functional groups and physical interlocking of epoxy curing process, forming a multi-level rough morphology. Multi-walled carbon nanotubes also serve as photothermal conversion units, with a light absorption rate of no less than 90% in the near-infrared band, and are used to suppress icing or promote melting of ice through photothermal conversion in low-temperature environments.

4. The integrated modified concrete with a photothermal superhydrophobic anti-icing interface according to claim 1, characterized in that, The low surface energy modifier is a fluorinated silane. The fluorinated silane is covalently bonded to the surface of the graded rough structure through silicon-oxygen bonds, so that the water contact angle of the concrete surface is not less than 160°, the roll-off angle is not greater than 5°, and the Cassie-Baxter wetting state is maintained for a long time.

5. The integrated modified concrete with a photothermal superhydrophobic anti-icing interface according to claim 1, characterized in that, The effective penetration depth of the functional interface modification layer is 10μm-50μm, the interfacial bonding strength between the functional interface modification layer and the concrete substrate is not less than 2.5MPa, and after 100 freeze-thaw cycles, the interface shows no cracking or peeling, and the superhydrophobic performance retention rate is not less than 90%.

6. The integrated modified concrete with a photothermal superhydrophobic anti-icing interface according to any one of claims 1 to 5, characterized in that, The epoxy resin is a bisphenol A type epoxy resin, and the curing agent is a compound system of aliphatic amine and aromatic amine. By controlling the curing kinetics, the functional interface modified layer can simultaneously possess high crosslinking density and flexibility, adapting to the thermal expansion and contraction deformation of concrete substrates.

7. The integrated modified concrete with a photothermal superhydrophobic anti-icing interface according to any one of claims 1 to 5, characterized in that, The raw material composition of the functional interface modification layer is: bisphenol A type epoxy resin, silane coupling agent modified nano-silica, silane coupling agent modified multi-walled carbon nanotubes, perfluorodecyltrimethoxysilane and compound curing agent. The components are assembled in situ to form a uniform modification system.

8. The integrated modified concrete with a photothermal superhydrophobic anti-icing interface according to any one of claims 1 to 5, characterized in that, The functional interface modification layer is constructed on the concrete surface through a high-pressure spraying process. After spraying, it achieves chemical bonding with the concrete substrate through thermal induction curing. The resulting modified concrete has superhydrophobicity, wear resistance, and photothermal synergistic anti-icing properties.

9. A method for preparing an integrated modified concrete with a photothermal superhydrophobic anti-icing interface, characterized in that, The method for preparing integrated modified concrete with a photothermal superhydrophobic anti-icing interface as described in any one of claims 1 to 8 comprises the following steps: S100, nano-silica and multi-walled carbon nanotubes were pretreated by silanization to prepare modified dispersions respectively; S200: Premix epoxy resin with compound curing agent, introduce silane coupling agent, first add modified dispersion of multi-walled carbon nanotubes and disperse under high shear conditions to construct a continuous conductive heat transfer framework in situ, then add modified dispersion of nano silica and mix under low shear conditions to fill and anchor nano silica on the surface of the continuous conductive heat transfer framework, and construct a precursor hybrid system in situ. S300, a low surface energy modifier is added to the precursor hybrid system and dispersed evenly to obtain an in-situ modified slurry; S400: The modified slurry is high-pressure sprayed onto the surface of the concrete substrate and cured by gradient controlled humid heat, allowing the modified slurry to penetrate into the open pores of the concrete surface and cross-link in situ, forming a functional interface modified layer integrated with the concrete substrate.

10. The method for preparing integrated modified concrete with a photothermal superhydrophobic anti-icing interface according to claim 9, characterized in that, In step S400, gradient controlled hygrothermal curing includes two stages: The first stage involves inducing controlled hydrolysis and condensation of silane coupling agents at a relative humidity of 60%-70% and a temperature of 80℃ to promote interfacial chemical bonding. The second stage promotes complete cross-linking of epoxy resin in an environment with relative humidity below 30% and temperature of 100°C, ultimately forming an integrated modified layer with controllable penetration depth and strong interfacial bonding.

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