Basalt fiber reinforced ultra-high performance concrete and preparation process thereof

Abstract

The application relates to the technical field of building materials, and discloses a basalt fiber reinforced ultra-high performance concrete and a preparation process thereof, which is prepared from basalt fibers, Portland cement, silica fume, quartz sand, a dynamic wetting cross-linking composite liquid, a mesoporous adsorption targeting defoaming carrier and a phase change temperature control solid-liquid phase. In the preparation, the fibers are tumbled at a low speed and are uniformly sprayed and beaten with the composite liquid, the solid powders are sequentially added and dry-mixed, then the solid-liquid phase is added at one time and is high-speed forced mixed, and the concrete is prepared through molding and alternate curing. The composite liquid forms a liquid film on the surface of the fibers and establishes a chemical bond bridge, so that the dispersion state of the fibers and the interfacial bonding strength are improved; the fine ice chips in the solid-liquid phase change and absorb heat, so that the early hydration temperature rise is effectively inhibited, and the risk of shrinkage cracking is reduced; and the defoaming carrier slowly releases the defoaming agent and discharges the internal small bubbles. The application solves the problems of fiber dispersion difficulty and early shrinkage cracking, and improves the compactness of the concrete.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to an ultra-high performance concrete based on basalt fiber reinforcement and its preparation process. Background Technology

[0002] Ultra-high performance concrete (UHVPC), due to its high mechanical properties and durability, often incorporates fiber materials in practical engineering to further improve its tensile strength and toughness. Basalt fiber, as an inorganic non-metallic material, has long been considered a promising candidate for inclusion in UHVPC due to its corrosion resistance and stable mechanical properties. However, in actual formulation and engineering applications, the performance of this material is often constrained by the inherent characteristics of the fiber itself. Specifically, because basalt fiber has a relatively smooth surface and is prone to static electricity during mixing and friction, it easily clumps together when dry-mixed with solid powder, making it difficult to achieve uniform dispersion within the cement matrix. Furthermore, the fiber surface itself lacks sufficient chemically active groups, making it difficult to form effective chemical bonds with the surrounding early cement hydration products. This combination of physical dispersion difficulties and a weak chemical interface directly results in low bond strength in the interfacial transition zone. Once the structure is under stress, the fiber easily slips out of the matrix, failing to fully exert its intended stress transfer and physical reinforcement effects.

[0003] Besides the fiber-matrix interface problem, the material composition of ultra-high performance concrete itself presents another serious challenge. Typical characteristics of this type of concrete include a low water-cement ratio and a large amount of cementitious materials. This means that during the early hydration stages after mixing and molding, a large amount of silicate cement and silica fume will react rapidly, releasing a large amount of heat of hydration in a short period. This intense exothermic process causes a sharp rise in the internal temperature of the paste, creating a significant temperature gradient between the inside and outside of the concrete component. This easily leads to early temperature shrinkage cracking and severely affects the volumetric stability of the structure.

[0004] Along with the low water-cement ratio comes the engineering hazard of difficulty in air removal within the slurry. To maintain the necessary workability of the slurry under such water-scarce conditions, a high dosage of polycarboxylate superplasticizer is usually required in the formulation. Due to the high viscosity of ultra-high performance concrete slurry, air entrained during forced mixing is tightly trapped in the dense matrix, forming numerous stable microbubbles. These bubbles are difficult to completely remove using conventional mechanical vibration methods alone, leaving numerous micropores inside the concrete after hardening. Ultimately, this not only reduces the structural density of the material but also irreversibly weakens its compressive strength. Summary of the Invention

[0005] The technical problem solved by this invention is that existing ultra-high performance concrete often suffers from difficulties in fiber dispersion and insufficient interfacial bond strength between fibers and the cement matrix when basalt fibers are introduced. Furthermore, due to the concentrated early-stage hydration heat release during the preparation of this type of ultra-high performance concrete, it is prone to temperature shrinkage cracking; in addition, the high dosage of cementitious materials and the introduction of admixtures lead to the retention of micro-bubbles within the system, thereby reducing the overall structural density.

[0006] To address the above problems, the present invention provides the following technical solution: In a first aspect, the present invention provides an ultra-high performance concrete based on basalt fiber reinforcement, employing the following technical solution: A type of ultra-high performance concrete based on basalt fiber reinforcement is made from raw materials containing the following components and their contents: Basalt fiber: accounting for 1.0% to 3.0% of the total concrete volume; Silicate cement: 85–90.5 parts by weight; Silica fume: 8-12 parts by weight; Quartz sand: 110-130 parts by weight; Dynamic wetting and crosslinking composite liquid: It exists in the form of a coating liquid on the surface of basalt fibers and is made by mixing 0.08-0.15 parts by weight of polyethylene glycol 400, 0.004-0.01 parts by weight of nano-SiO2 powder, 0.15-0.30 parts by weight of silane coupling agent KH-560 and 0.03-0.08 parts by weight of tartaric acid; Mesoporous adsorption targeted defoaming carrier: It is made by mixing 1.5 to 3.0 parts by weight of micron-sized natural clinoptilolite powder and 0.02 to 0.05 parts by weight of liquid tributyl phosphate; Phase change temperature-controlled solid-liquid phase: It is made by mixing 16 to 19 parts by mass of total mixing water and 1.2 to 1.8 parts by mass of liquid polycarboxylate superplasticizer.

[0007] By adopting the above technical solution, and utilizing the aforementioned amounts of basalt fiber, silicate cement, silica fume, and quartz sand, combined with a dynamically wetting crosslinking composite liquid that has undergone composite treatment, a mesoporous adsorption targeted defoaming carrier, and a phase change temperature-controlled solid-liquid phase, the fiber dispersion uniformity can be effectively improved, interfacial adhesion strengthened, and the overall system density increased while reducing early hydration temperature rise. To achieve these effects, the specific mechanism of action involved in this invention is as follows: During the initial mixing stage of the material, interfacial coupling and wetting-dispersion reactions mainly occur. Specifically, the dynamic wetting and crosslinking composite liquid coats the surface of the basalt fiber, and the polyethylene glycol 400 in its components forms a liquid film on the fiber surface and provides a steric hindrance effect. This not only reduces the surface tension of the fiber surface, but also promotes the uniform dispersion of basalt fibers in the cement matrix, avoiding fiber agglomeration.

[0008] Simultaneously, nano-SiO2 powder adheres to the fiber surface, effectively increasing surface roughness. In subsequent stages, these nanoparticles directly participate in the pozzolanic reaction during cement hydration, consuming calcium hydroxide and generating hydrated calcium silicate gel. At the chemical crosslinking level, the silane coupling agent KH-560 undergoes hydrolysis in an aqueous environment, with methoxy groups hydrolyzing to generate silanol groups. These silanol groups then condense with hydroxyl groups on the basalt fiber surface, forming chemical bonds. The reaction formula for this process is as follows: Hydrolysis reaction: Condensation reaction: Simultaneously, the epoxy group at the other end of the silane coupling agent KH-560 undergoes a ring-opening reaction under alkaline activation, crosslinking with active groups or amino groups in the cement matrix. Through this series of reactions, a chemical bridge is established between the basalt fiber and the inorganic cement matrix, enhancing the tensile and shear strength of the interfacial transition zone. During this process, tartaric acid plays a role in regulating the local pH, slowing down the local hydration rate, thus providing sufficient time for the coupling condensation reaction.

[0009] To address the issue of air bubbles easily trapped within the system, this solution utilizes a mesoporous adsorption-targeted defoaming carrier for targeted, sustained-release defoaming. Specifically, this carrier leverages the internal pores of micron-sized natural clinoptilolite powder to physically adsorb liquid tributyl phosphate.

[0010] During the dry mixing and initial water addition stages of concrete, liquid tributyl phosphate is temporarily stored in the mesopores of zeolite to avoid competitive adsorption or demulsification with the water-reducing agent in the early stages of hydration. With the continuous action of shear forces within the slurry, the liquid tributyl phosphate gradually releases from the mesopores and enters the matrix solution, disrupting the liquid film of microbubbles and promoting their aggregation and discharge from the slurry. After degassing, the micron-sized natural clinoptilolite powder acts as micro-aggregate, filling the gaps between cement particles and further improving the density of the hardened structure.

[0011] To suppress early thermal shrinkage cracks, an internal phase change endothermic temperature-controlled reaction occurs within the system. The phase change temperature-controlled solid-liquid phase, while providing the necessary moisture and fluidity for mixing, contains an ice-water mixture. Upon addition to the slurry, solid ice particles absorb a significant amount of heat released during the early, intense hydration of the cement and undergo a phase change, melting. This physical endothermic process effectively reduces the peak temperature within the slurry and lowers the temperature gradient within the overall structure. Furthermore, the liquid polycarboxylate superplasticizer adsorbs onto the surface of cement particles, providing electrostatic repulsion and steric hindrance effects to maintain the system's high fluidity.

[0012] Preferably, in the phase change temperature-controlled solid-liquid phase, the total mixing water is an ice-water mixture containing 25%–30% by mass of finely crushed ice particles with a particle size of ≤2mm. By adopting the above technical solution and setting the ice particle size to 25%–30% by mass, sufficient latent heat of phase change can be provided to absorb the heat of hydration while ensuring the initial fluidity of the slurry. Limiting the finely crushed ice particles to ≤2mm ensures the uniform distribution of solid ice during concrete mixing, preventing large ice particles from leaving large local water pockets or pores in the matrix after melting, thereby maintaining the mechanical strength of the hardened concrete.

[0013] Preferably, the mesoporous adsorption targeted defoaming carrier is in powder form, wherein liquid tributyl phosphate is physically adsorbed into the mesopores of micron-sized natural clinoptilolite powder. By employing the above technical solution, the powder form allows the carrier to directly participate in the dry mixing process and is uniformly dispersed in the powder system by the frictional force between dry powder particles. The physical adsorption state ensures that the liquid tributyl phosphate is stored in a solid phase without altering its chemical structure, and subsequently, in a liquid environment, it can achieve stable release relying on the concentration gradient and mechanical shear force.

[0014] Preferably, the content of each raw material component is as follows: Basalt fiber accounts for 2.0% of the total concrete volume; 87.8 parts by weight of silicate cement; 10 parts by weight of silica fume; 120 parts by weight of quartz sand; In the dynamic wetting crosslinking composite liquid, polyethylene glycol 400 is 0.12 parts by mass, nano-SiO2 powder is 0.007 parts by mass, silane coupling agent KH-560 is 0.22 parts by mass, and tartaric acid is 0.05 parts by mass. The mesoporous adsorption targeted defoaming carrier contains 2.2 parts by mass of micron-sized natural clinoptilolite powder and 0.03 parts by mass of liquid tributyl phosphate; The total mixing water in the phase change temperature-controlled solid-liquid phase is 17.5 parts by mass, and the liquid polycarboxylate superplasticizer is 1.5 parts by mass. By adopting the above technical solution, the proportions of various raw materials are at the reaction equilibrium point, which fully matches the physical reinforcement effect of basalt fiber, the chemical interface modification effect of dynamic wetting crosslinking composite liquid, the degassing efficiency of mesoporous adsorption targeted defoaming carrier, and the temperature control performance of the phase change temperature-controlled solid-liquid phase. Thanks to this synergistic proportion, ultra-high performance concrete achieves optimal engineering indicators in terms of workability, compressive strength, and volume stability.

[0015] Secondly, the present invention provides a method for preparing ultra-high performance concrete based on basalt fiber reinforcement, employing the following technical solution: A method for preparing ultra-high performance concrete based on basalt fiber reinforcement includes the following steps: Basalt fibers are put into a mixer and rotated at low speed to form a tumbling fiber bed. The dynamically wetting crosslinking composite liquid is uniformly sprayed into the tumbling fiber bed and continuously stirred to obtain a dynamically wetting fiber mixture. Silicate cement, silica fume, mesoporous adsorption targeted defoaming carrier and quartz sand are sequentially added to a mixer containing a dynamically wetted fiber mixture, and the mixture is dry-mixed at a low speed to obtain a powder-fiber dry-mixed mixture. A phase change temperature-controlled solid-liquid phase is added at once to a mixer containing a dry-mixed powder fiber mixture. The rotation speed is increased and high-speed forced mixing is continued, while the temperature is controlled below 15 degrees Celsius to obtain an ultra-high performance concrete premixed paste. Ultra-high performance concrete premixed slurry is injected into a molding mold and processed by vacuum vibration molding process to obtain molded demolded components. The molded demolded components are heated and subjected to constant temperature steam curing to obtain the initially cured components. The components undergo initial curing with high humidity, followed by alternating hot air drying and continuous wet-drying treatment, before being allowed to cool to room temperature for natural curing.

[0016] By adopting the above technical solution, the preparation method of the present invention organically combines physical dispersion and chemical modification processes. In the initial feeding stage, the rotation of the mixer causes the basalt fibers to form a relatively loose, tumbling fiber bed. When a dynamically wetting crosslinking composite liquid containing components such as polyethylene glycol 400 is introduced in the form of spraying, the droplets can easily penetrate the gaps between the fibers and spread on the surface of the basalt fibers to form a lubricating liquid film. This pre-formed liquid film greatly reduces the electrostatic adsorption and mechanical entanglement between the fibers, laying the foundation for uniform dispersion in the subsequent high-viscosity cement slurry. On this basis, with the addition of hard particles such as silicate cement and quartz sand and low-speed dry mixing, the friction between these powder particles can further break up the remaining clumps of fibers, achieving uniform mixing of solid materials.

[0017] To control the heat of hydration, this method involves adding a phase-change temperature-controlled solid-liquid phase in a single step, while simultaneously increasing the rotation speed for high-speed forced mixing. Ice particles in the solid-liquid phase melt and absorb heat upon contact with the powder, absorbing the mechanical heat generated during mixing and some of the chemical heat released during early hydration. By keeping the system temperature below 15 degrees Celsius, the initial hydration rate of the cement is significantly slowed down, maintaining the initial fluidity of the slurry and thus preventing temperature shrinkage cracks caused by excessively high local temperatures. After the uniformly mixed premixed slurry is injected into the mold, vacuum vibration degassing removes any residual air mixed into the system. The subsequent constant-temperature steam curing process, at a higher temperature, promotes the ring-opening of the coupling agent epoxy groups coated on the fiber surface, causing them to chemically bond with the cement hydration products. The final alternating high-humidity and hot-air circulation treatment regulates the moisture in the capillaries within the matrix through changes in ambient humidity, releasing some of the internal stress caused by drying shrinkage, thereby improving the volume stability of the product.

[0018] Preferably, the preparation steps of the dynamically wetting crosslinking composite liquid are as follows: Polyethylene glycol 400 was added to a reactor equipped with a high-speed shear dispersion emulsifier to provide a liquid phase dispersion carrier. Nano-SiO2 powder was slowly added to the polyethylene glycol 400 and a high-speed dispersion treatment at a speed of 1500-2000 rpm was started for 10-15 minutes to obtain an initial suspension. An ultrasonic cell disruptor with a frequency of 20–25 kHz was used to ultrasonically disperse the initial suspension to break up the nano-aggregates and form a stable thixotropic base liquid. The temperature of the thixotropic base solution was controlled below 25 degrees Celsius. Silane coupling agent KH-560 and tartaric acid were added sequentially. The disperser speed was adjusted to 500–800 rpm and continuously stirred for 20–30 minutes to obtain a dynamically wetting crosslinked composite solution, which was then sealed and protected from light for later use. In one specific embodiment, the ultrasonic dispersion time was 10 minutes.

[0019] By employing the above technical solution, the mechanical stirring and shearing combined with the dispersion effect of ultrasound can effectively break up the agglomeration of nano-SiO2 powder and establish a uniform suspension base liquid. Simultaneously, controlling the system temperature below 25 degrees Celsius before adding the silane coupling agent KH-560 is primarily to prevent premature hydrolysis and self-condensation during the mixing process, ensuring that it retains sufficient reactivity when coated onto the fiber surface.

[0020] Preferably, the preparation steps of the mesoporous adsorption targeted defoaming carrier are as follows: Micron-sized natural clinoptilolite powder is fed into a horizontal ribbon mixer with a spindle speed of 40-60 rpm to form tumbling zeolite powder. Liquid tributyl phosphate was uniformly sprayed into tumbling zeolite powder using an atomizing nozzle and continuously dry-mixed for 15–20 minutes. This allowed the liquid tributyl phosphate to be physically adsorbed into the mesopores of the micron-sized natural clinoptilolite powder, thus obtaining a powdered mesoporous adsorption-targeted defoaming carrier, which was then sealed for later use. The preparation steps for the phase change temperature-controlled solid-liquid phase were as follows: an ice-water mixture was placed in a storage tank with an insulated jacket, and the temperature of the ice-water mixture was maintained at 1–3 degrees Celsius to obtain a temperature-controlled ice-water slurry. Liquid polycarboxylate superplasticizer was added to a temperature-controlled ice-water slurry and gently stirred until a homogeneous phase was obtained, resulting in a phase-change temperature-controlled solid-liquid phase for later use. By employing the above technical solution, atomized spraying combined with dry mixing ensured that a small amount of liquid tributyl phosphate was uniformly adsorbed within the mesopores of the micron-sized natural clinoptilolite powder, facilitating its subsequent direct addition in powder form. The ice-water mixture was stored in an insulated tank at a temperature of 1–3 degrees Celsius, preventing premature melting of ice particles and ensuring that the molecular dispersion of the liquid polycarboxylate superplasticizer remained unaffected.

[0021] Preferably, during the preparation of the dynamically wetted fiber mixture, the spindle is turned on and the rotation speed is set to 20-30 rpm. A large-diameter high-pressure airless spraying device is used for spraying. The spraying pressure of the large-diameter high-pressure airless spraying device is 10-15 MPa, and the stirring time is 2-3 minutes.

[0022] During the preparation of the powder-fiber dry-mixed compound, the dry-mixing time is maintained at low speed for 3-5 minutes. During the preparation of the ultra-high performance concrete premixed slurry, the rotation speed is increased to 60-80 rpm and high-speed forced mixing is maintained for 4-6 minutes. During the preparation of the molded and demolded components, the vacuum vibration molding process is used for 1-2 minutes.

[0023] In one specific embodiment, the vacuum vibration molding process uses a vacuum level of -0.95 MPa and a vibration frequency of 60 Hz. By adopting the above technical solution and setting the rotation speed and time at different stages according to the changes in material state, it helps to fully disperse the fibers during dry mixing and quickly achieve slurry homogenization after adding water. Setting a spraying pressure of 10-15 MPa allows the composite liquid to effectively penetrate and encapsulate the fibers. In the vacuum vibration molding parameters, the -0.95 MPa vacuum level combined with the 60 Hz vibration frequency effectively maintains the uniform distribution of inorganic aggregates and fibers within the system while drawing out the tiny pores inside the slurry, thus avoiding stratification and segregation of components with different specific gravities due to excessive vibration.

[0024] Preferably, during the preparation of the initial curing components, constant-temperature steam curing with a relative humidity of ≥95% is performed by raising the temperature. The specific operation during the continuous cyclic wet-drying treatment of the initial curing components is as follows: High humidity curing with a relative humidity of ≥95% is performed, followed by alternating hot air drying curing, with continuous wet-drying treatment for 2-3 cycles. In one specific implementation, the constant temperature steam curing condition is maintained at 80 degrees Celsius for 48 hours; The conditions for high humidity maintenance are 25 degrees Celsius for 24 hours; Hot air drying and curing was performed at 60 degrees Celsius for 24 hours. By employing the above technical solution, a high-temperature steam environment of 80 degrees Celsius for 48 hours was established, providing the necessary temperature conditions for the ring-opening crosslinking of the coupling agent and the pozzolanic reaction of the powder, thus promoting the rapid formation of early structural strength. Subsequent alternating cycles of high humidity and hot air, utilizing the changes in moisture content within the capillaries under different temperature and humidity conditions, induced further hydration of incompletely hydrated particles and the filling of internal micro-defects. This alternating treatment process gradually released system stress, reduced the risk of macroscopic crack formation, and improved the durability of the matrix.

[0025] This invention provides an ultra-high performance concrete based on basalt fiber reinforcement and its preparation process. It has the following beneficial effects: 1. This invention improves the dispersion of basalt fibers in a cement matrix and enhances interfacial bonding strength by coating the surface of basalt fibers with a dynamically wetting and crosslinking composite liquid. Polyethylene glycol 400 in the composite liquid forms a liquid film on the fiber surface to reduce surface tension and prevent fiber agglomeration during mixing. The silanol groups generated by the hydrolysis of silane coupling agent KH-560 condense with the hydroxyl groups on the fiber surface, while the epoxy groups at the other end crosslink with the cement matrix. Combined with the surface adhesion of nano-silica and the reaction with pozzolanic material, a chemical bond is established between the basalt fibers and the inorganic matrix, improving the interfacial force transfer efficiency.

[0026] This invention employs a phase-change temperature-controlled solid-liquid phase, composed of an ice-water mixture and a liquid polycarboxylate superplasticizer, to control the early hydration temperature rise of the system and reduce the risk of temperature shrinkage cracking. The tiny ice particles contained in the solid-liquid phase absorb the heat released by the intense hydration of cement through a physical phase-change melting process during the high-speed forced mixing stage and the initial hydration phase. This heat-absorbing mechanism keeps the system temperature at a low level, weakens the temperature peak within the paste, and reduces the temperature gradient of the overall structure, thereby improving the early volume stability of the concrete.

[0027] This invention utilizes a mesoporous adsorption-targeted defoaming carrier, made from a mixture of micron-sized natural clinoptilolite powder and liquid tributyl phosphate, to remove microbubbles trapped within the system, thereby improving the density of the hardened structure. The internal pores of the zeolite powder physically adsorb the liquid tributyl phosphate, preventing competitive adsorption during the initial water addition phase. With the continuous action of stirring shear force, the tributyl phosphate gradually releases and disrupts the liquid film of bubbles within the slurry, promoting bubble aggregation and expulsion. The degassed zeolite powder then fills the gaps between cement particles as micro-aggregate, further reducing the structure's porosity. Attached Figure Description

[0028] Figure 1 This is a graph showing the temperature change over time during the feasibility test of the cryogenic latent heat control and early hydration heat suppression of the present invention. Figure 2 This is a graph showing the change in surface tension over time in the high-shear drug release and competitive adsorption kinetics tests of this invention; Figure 3 This is a spectroscopic verification diagram of the in-situ interfacial covalent crosslinking of the present invention; Figure 4 This is a graph showing the change in the spread over time in the comparative test of the UHPC slurry rheology and working performance of the present invention. Figure 5 This is a graph showing the cross-sectional porosity as a function of relative height in the macroscopic compactness and fiber dispersion uniformity test of the present invention. Figure 6 This is a graph showing the variation of the flexural strength of the present invention with the erosion age in the ultimate mechanical properties and long-term alkali erosion resistance test. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Preparation Examples 1-3: Preparation Example 1: This preparation example provides a method for preparing a pretreatment component for ultra-high performance concrete. The pretreatment component comprises a dynamically wetting crosslinking composite liquid, a mesoporous adsorption targeted defoaming carrier, and a phase change temperature-controlled solid-liquid phase, including the following steps: 0.08 parts by weight of polyethylene glycol 400 were added to a reactor equipped with a high-speed shear dispersion emulsifier to provide a liquid phase dispersion carrier; 0.004 parts by mass of nano-SiO2 powder were slowly added to polyethylene glycol 400 and high-speed dispersion treatment at 1500 rpm was started for 10 minutes to obtain an initial suspension. The initial suspension was ultrasonically dispersed for 10 minutes using an ultrasonic cell disruptor with a frequency of 20kHz to break up the nano-aggregates and form a stable thixotropic base liquid. The temperature of the thixotropic base liquid system was controlled below 25 degrees Celsius. 0.15 parts by weight of silane coupling agent KH-560 and 0.03 parts by weight of tartaric acid were added in sequence. The speed of the disperser was adjusted to 500 rpm and stirred continuously for 20 minutes to obtain a dynamically wetting crosslinking composite liquid, which was then sealed and protected from light for later use. 1.5 parts by weight of micron-sized natural clinoptilolite powder were fed into a horizontal ribbon mixer with a spindle speed of 40 rpm to form tumbling zeolite powder. 0.02 parts by weight of liquid tributyl phosphate was uniformly sprayed into the tumbling zeolite powder through an atomizing nozzle and continuously dry-mixed for 15 minutes, so that it was physically adsorbed in the mesoporous gaps, and a powdered mesoporous adsorption targeted defoaming carrier was prepared and sealed for later use. Prepare an ice-water mixture containing 25% by mass of finely crushed ice particles with a particle size of less than or equal to 2 mm by mixing 16 parts by mass of total water. The ice-water mixture is placed in a storage tank with an insulated jacket and its temperature is maintained at 1 degree Celsius to obtain a temperature-controlled ice-water slurry. Add 1.2 parts by weight of liquid polycarboxylate superplasticizer to the temperature-controlled ice water slurry and stir gently until a homogeneous phase is obtained to prepare a phase change temperature-controlled solid-liquid phase for later use.

[0031] Preparation Example 2: This preparation example provides a method for preparing a pretreatment component for ultra-high performance concrete. The pretreatment component comprises a dynamically wetting crosslinking composite liquid, a mesoporous adsorption targeted defoaming carrier, and a phase change temperature-controlled solid-liquid phase, including the following steps: 0.12 parts by weight of polyethylene glycol 400 were added to a reactor equipped with a high-speed shear dispersion emulsifier to provide a liquid phase dispersion carrier; 0.007 parts by weight of nano-SiO2 powder were slowly added to polyethylene glycol 400 and high-speed dispersion treatment at 1750 rpm was started for 12 minutes to obtain an initial suspension. The initial suspension was ultrasonically dispersed for 10 minutes using an ultrasonic cell disruptor with a frequency of 22kHz to break up the nano-aggregates and form a stable thixotropic base liquid. The system temperature of the thixotropic base liquid was controlled below 25 degrees Celsius. 0.22 parts by weight of silane coupling agent KH-560 and 0.05 parts by weight of tartaric acid were added in sequence. The speed of the disperser was adjusted to 650 rpm and stirred continuously for 25 minutes to obtain a dynamically wetting crosslinking composite liquid, which was then sealed and protected from light for later use. 2.2 parts by weight of micron-sized natural clinoptilolite powder were fed into a horizontal ribbon mixer with a spindle speed of 50 rpm to form tumbling zeolite powder. 0.03 parts by weight of liquid tributyl phosphate was uniformly sprayed into the tumbling zeolite powder through an atomizing nozzle and continuously dry-mixed for 18 minutes to allow it to be physically adsorbed in the mesoporous gaps, thus obtaining a powdered mesoporous adsorption targeted defoaming carrier, which was then sealed for later use. Prepare an ice-water mixture containing 28% by mass of finely crushed ice particles with a particle size of less than or equal to 2 mm by mixing 17.5 parts by mass of total mixing water. The ice-water mixture is placed in a storage tank with an insulated jacket and its temperature is maintained at 2 degrees Celsius to obtain a temperature-controlled ice-water slurry. Add 1.5 parts by weight of liquid polycarboxylate superplasticizer to the temperature-controlled ice water slurry and stir gently until a homogeneous phase is obtained to prepare a phase change temperature-controlled solid-liquid phase for later use.

[0032] Preparation Example 3: This preparation example provides a method for preparing a pretreatment component for ultra-high performance concrete. The pretreatment component comprises a dynamically wetting crosslinking composite liquid, a mesoporous adsorption targeted defoaming carrier, and a phase change temperature-controlled solid-liquid phase, including the following steps: 0.15 parts by weight of polyethylene glycol 400 were added to a reactor equipped with a high-speed shear dispersion emulsifier to provide a liquid phase dispersion carrier; 0.01 parts by weight of nano-SiO2 powder were slowly added to polyethylene glycol 400 and high-speed dispersion treatment at 2000 rpm was started for 15 minutes to obtain an initial suspension. The initial suspension was ultrasonically dispersed for 10 minutes using an ultrasonic cell disruptor with a frequency of 25kHz to break up the nano-aggregates and form a stable thixotropic base liquid. The system temperature of the thixotropic base liquid was controlled below 25 degrees Celsius. 0.30 parts by weight of silane coupling agent KH-560 and 0.08 parts by weight of tartaric acid were added in sequence. The speed of the disperser was adjusted to 800 rpm and stirred continuously for 30 minutes to obtain a dynamically wetting crosslinking composite liquid, which was then sealed and protected from light for later use. 3.0 parts by weight of micron-sized natural clinoptilolite powder were fed into a horizontal ribbon mixer with a spindle speed of 60 rpm to form tumbling zeolite powder. 0.05 parts by weight of liquid tributyl phosphate was uniformly sprayed into the tumbling zeolite powder through an atomizing nozzle and continuously dry-mixed for 20 minutes, so that it was physically adsorbed in the mesoporous gaps, and a powdered mesoporous adsorption targeted defoaming carrier was prepared and sealed for later use. Prepare an ice-water mixture containing 30% by mass of finely crushed ice particles with a particle size of less than or equal to 2 mm by mixing 19 parts by mass of total water. The ice-water mixture is placed in a storage tank with an insulated jacket and its temperature is maintained at 3 degrees Celsius to obtain a temperature-controlled ice-water slurry. Add 1.8 parts by weight of liquid polycarboxylate superplasticizer to the temperature-controlled ice water slurry and stir gently until a homogeneous phase is obtained to prepare a phase change temperature-controlled solid-liquid phase for later use.

[0033] Examples 1-3: Example 1: This embodiment provides a preparation process for ultra-high performance concrete based on basalt fiber reinforcement, including the following steps: Basalt fibers, accounting for 1.0% of the total concrete volume, are added to an air-forced twin-shaft concrete mixer. The main shaft is turned on and the speed is set to 20 rpm for low-speed rotation, forming a tumbling fiber bed. Using a large-diameter high-pressure airless spraying device with a spraying pressure of 10MPa, the dynamic wetting crosslinking composite liquid prepared in Preparation Example 1 was uniformly sprayed into the fiber bed and continuously stirred for 2 minutes, so that the liquid film completely covered the fiber surface, and a dynamic wetting fiber mixture with a physical lubrication coating film was obtained. 90.5 parts by weight of silicate cement, 8 parts by weight of silica fume, the mesoporous adsorption targeted defoaming carrier prepared in Preparation Example 1, and 110 parts by weight of quartz sand were added sequentially to a mixer containing a dynamically wetted fiber mixture. The mixture was dry-mixed at a low speed for 3 minutes to disperse the fibers using the frictional force of the dry powder, thus obtaining a uniformly distributed dry-mixed powder-fiber mixture. The phase change temperature-controlled solid-liquid phase prepared in Preparation Example 1 was added to a mixer containing a dry-mixed powder fiber mixture in one go. The speed was immediately increased to 60 rpm and high-speed forced mixing was continued for 4 minutes. At the same time, the internal temperature of the system was forced to be suppressed to below 15 degrees Celsius to obtain a high-fluidity and non-clumping ultra-high performance concrete premix paste. The ultra-high performance concrete premixed slurry is injected into the molding mold and treated with a vacuum vibration molding process with a vacuum degree of -0.95MPa and a vibration frequency of 60Hz for 1 minute to remove the trapped residual air and obtain a dense molded demolded component. The molded demolded component is pushed into the IoT-based tiered curing chamber, heated to 80 degrees Celsius, and steam-cured at a relative humidity of ≥95% for 48 hours to activate the ring-opening cross-linking of the epoxy groups of the coupling agent, thus obtaining the initial curing component. The basalt fiber reinforced ultra-high performance concrete of the present invention is prepared by subjecting the initially cured components to high-humidity curing at 25 degrees Celsius and relative humidity greater than or equal to 95% for 24 hours, followed by alternating hot air drying curing at 60 degrees Celsius for 24 hours, and then continuously cyclically performing wet and dry treatment for 2 cycles before being cooled to room temperature for natural curing.

[0034] Example 2: This embodiment provides a preparation process for ultra-high performance concrete based on basalt fiber reinforcement, including the following steps: Basalt fibers, accounting for 2.0% of the total concrete volume, are added to an air-forced twin-shaft concrete mixer. The main shaft is turned on and the speed is set to 25 rpm for low-speed rotation, forming a tumbling fiber bed. Using a large-diameter high-pressure airless spraying device with a spraying pressure of 12.5 MPa, the dynamic wetting crosslinking composite liquid prepared in Preparation Example 2 was uniformly sprayed into the fiber bed and continuously stirred for 2.5 minutes, so that the liquid film completely covered the fiber surface, and a dynamic wetting fiber mixture with a physical lubrication coating film was obtained. 87.8 parts by weight of silicate cement, 10 parts by weight of silica fume, the mesoporous adsorption targeted defoaming carrier prepared in Preparation Example 2, and 120 parts by weight of quartz sand were added sequentially to a mixer containing a dynamically wetted fiber mixture. The mixture was dry-mixed at a low speed for 4 minutes to disperse the fibers using the frictional force of the dry powder, thus obtaining a uniformly distributed dry-mixed powder-fiber mixture. The phase change temperature-controlled solid-liquid phase prepared in Preparation Example 2 was added to a mixer containing a dry-mixed powder fiber mixture in one go. The speed was immediately increased to 70 rpm and high-speed forced mixing was continued for 5 minutes. At the same time, the internal temperature of the system was forced to be suppressed to below 15 degrees Celsius to obtain a high-fluidity and non-clumping ultra-high performance concrete premix paste. The ultra-high performance concrete premixed slurry is injected into the molding mold and treated with a vacuum vibration molding process with a vacuum degree of -0.95MPa and a vibration frequency of 60Hz for 1.5 minutes to remove the trapped residual air and obtain a dense molded demolded component. The molded demolded component is pushed into the IoT-based tiered curing chamber, heated to 80 degrees Celsius, and steam-cured at a relative humidity of ≥95% for 48 hours to activate the ring-opening cross-linking of the epoxy groups of the coupling agent, thus obtaining the initial curing component. The basalt fiber reinforced ultra-high performance concrete of the present invention is prepared by subjecting the initially cured components to high-humidity curing at 25 degrees Celsius and relative humidity greater than or equal to 95% for 24 hours, followed by alternating hot air drying curing at 60 degrees Celsius for 24 hours, and then continuously cyclically performing wet and dry treatment for 2 cycles before being cooled to room temperature for natural curing.

[0035] Example 3: This embodiment provides a preparation process for ultra-high performance concrete based on basalt fiber reinforcement, including the following steps: Basalt fibers, accounting for 3.0% of the total concrete volume, are added to an air-forced twin-shaft concrete mixer. The main shaft is turned on and the speed is set to 30 rpm for low-speed rotation, forming a tumbling fiber bed. Using a large-diameter high-pressure airless spraying device with a spraying pressure of 15MPa, the dynamic wetting crosslinking composite liquid prepared in Preparation Example 3 was uniformly sprayed into the fiber bed and continuously stirred for 3 minutes, so that the liquid film completely covered the fiber surface, and a dynamic wetting fiber mixture with a physical lubrication coating film was obtained. 85 parts by weight of silicate cement, 12 parts by weight of silica fume, the mesoporous adsorption targeted defoaming carrier prepared in Preparation Example 3, and 130 parts by weight of quartz sand were added sequentially to a mixer containing a dynamically wetted fiber mixture. The mixture was dry-mixed at a low speed for 5 minutes to disperse the fibers using the frictional force of the dry powder, thus obtaining a uniformly distributed dry-mixed powder-fiber mixture. The phase change temperature-controlled solid-liquid phase prepared in Preparation Example 3 was added to a mixer containing a dry-mixed powder fiber mixture in one go. The speed was immediately increased to 80 rpm and high-speed forced mixing was continued for 6 minutes. At the same time, the internal temperature of the system was forced to be suppressed to below 15 degrees Celsius to obtain a high-fluidity and non-clumping ultra-high performance concrete premix paste. The ultra-high performance concrete premixed slurry is injected into the molding mold and treated with a vacuum vibration molding process with a vacuum degree of -0.95MPa and a vibration frequency of 60Hz for 2 minutes to remove the trapped residual air and obtain a dense molded demolded component. The molded demolded component is pushed into the IoT-based tiered curing chamber, heated to 80 degrees Celsius, and steam-cured at a relative humidity of ≥95% for 48 hours to activate the ring-opening cross-linking of the epoxy groups of the coupling agent, thus obtaining the initial curing component. The basalt fiber reinforced ultra-high performance concrete of the present invention is prepared by subjecting the initially cured components to high humidity curing at 25 degrees Celsius and relative humidity greater than or equal to 95% for 24 hours, followed by alternating hot air drying curing at 60 degrees Celsius for 24 hours, and then continuously cyclically performing wet and dry treatment for 3 cycles before being cooled to room temperature for natural curing.

[0036] Comparative Examples 1-5: Comparative Example 1: Compared with Example 2, the difference is that the dynamic wetting crosslinking composite liquid was not prepared and sprayed. Instead, the untreated dry basalt fiber was directly added to the mixer and mixed with other dry powder materials. The formulated amounts of polyethylene glycol 400, silane coupling agent KH-560, tartaric acid and nano SiO2 were directly added to the phase change temperature-controlled solid-liquid phase for mixing. All other aspects were the same.

[0037] Comparative Example 2: Compared with Example 2, the difference is that ice-water mixture was not used when preparing the phase change temperature-controlled solid-liquid phase, but was replaced entirely with room temperature mixing water, and the internal temperature of the system was not suppressed to below 15 degrees Celsius during the high-speed forced mixing stage. All other aspects are the same.

[0038] Comparative Example 3: Compared with Example 2, the difference is that tartaric acid was not added when preparing the dynamic wetting crosslinking composite liquid, but everything else is the same.

[0039] Comparative Example 4: Compared with Example 2, the difference is that a mesoporous adsorption targeted defoaming carrier was not prepared. Instead, unloaded micron-sized natural clinoptilolite powder was directly added to the mixer as dry powder material, and the prescribed amount of tributyl phosphate was directly added to the phase change temperature-controlled solid-liquid phase for mixing. All other aspects were the same.

[0040] Comparative Example 5: Compared with Example 2, the difference is that after the molded demolded component is pushed into the curing chamber, the constant temperature steam curing step of 80 degrees Celsius is cancelled. The entire curing process is carried out under standard conditions of 25 degrees Celsius and relative humidity greater than or equal to 95%, while the rest are the same.

[0041] Test Examples 1-6: Test Example 1: Feasibility test of cryogenic latent heat temperature control and early hydration heat suppression.

[0042] The ultra-high performance concrete premixed slurry from Examples 1, 2, 3 and Comparative Example 2 that entered the high-speed forced mixing stage during the preparation process was selected as the monitoring objects for testing.

[0043] In a forced twin-shaft concrete mixer containing a dry-mixed powder-fiber mixture, the instant when the phase change temperature-controlled solid-liquid phase or room-temperature mixing water is added at once is recorded as the reaction time 0.

[0044] A K-type thermocouple temperature sensor with a range of -20 degrees Celsius to 100 degrees Celsius and a response time of less than 0.5 seconds is used. Its probe is fixed and inserted into the central fluid layer of the mixing area of ​​the mixer's main shaft, so that the probe comes into contact with the churning slurry.

[0045] Turn on the multi-channel data acquisition instrument, set the data recording node to 1 minute, and continuously monitor and record the actual temperature change inside the slurry during the high-speed mixing period and the subsequent settling period. The data acquisition cycle continues until 10 minutes after water is added.

[0046] Monitoring time Example 1 Example 2 Example 3 Comparative Example 2 0 minutes 2.1 1.8 1.3 21.4 1 minute 3.5 3.1 2.5 25.8 2 minutes 5.3 4.6 3.7 29.3 3 minutes 7.2 6.5 5.4 32.1 4 minutes 9.6 8.3 7.1 35.7 5 minutes 11.4 10.2 8.9 38.6 6 minutes 13.5 11.8 10.1 41.2 8 minutes 14.1 12.3 10.6 43.5 10 minutes 14.3 12.5 10.8 44.1 Figure 1 In the diagram, the dark gray solid line represents Example 1, the black solid line represents Example 2, the light gray solid line represents Example 3, and the black dashed line represents Comparative Example 2.

[0047] in conclusion: According to Table 1 and Figure 1 According to the data, the internal temperature of the slurry in Examples 1 to 3 was limited to below 15 degrees Celsius during high-shear mixing and the initial settling stage. In the preparation of ultra-low water-cement ratio concrete materials, the tricalcium aluminate component in silicate cement dissolves and hydrates upon contact with water, accompanied by an exothermic reaction. Combined with the mechanical frictional heat generated by the high-speed rotation of the mixer shaft cutting off the fluid, this easily leads to an increase in the internal temperature of the system. Comparative Example 2 used room-temperature mixing water and lacked a phase change endothermic mechanism. The slurry temperature climbed to above 38 degrees Celsius within 5 minutes, reaching 44.1 degrees Celsius at the end of the observation period. The high internal temperature intensified the random thermal motion of hydroxide ions in the aqueous phase, enabling them to penetrate conventional physical barriers, attack and open the terminal epoxy groups of the silane coupling agent, and induce cross-linking network solidification of macromolecular chain segments before demolding, resulting in false setting and loss of fluidity in the slurry.

[0048] In the example system incorporating an ice-water mixture, the solid ice particles absorbed the latent heat of phase change during contact with high-heat cement particles. This microscopic physical endothermic mechanism spatially coincides with the heat release center, creating a thermodynamic buffering effect within the mixer. During the high-speed shear work period of the 5th to 6th minute, thanks to the intervention of the latent heat effect, the temperature rise curve of the system remained gentle, with the peak temperatures stabilizing at 14.3°C, 12.5°C, and 10.8°C, respectively. The cryogenic temperature field thermodynamically reduced the molecular activation energy of the side reactions. Combined with the sterically hindered layer constructed by the previously generated calcium tartrate polynuclear complex, it suppressed the premature crosslinking path of organosilanes in both kinetic and thermodynamic dimensions, reserving a rheological working window for the pumping and densification molding processes.

[0049] Test Example 2: High-shear drug release and competitive adsorption kinetics test The ultra-high performance concrete premixed slurry from Examples 1, 2, 3, and Comparative Example 4 that entered the high-speed forced mixing stage during the preparation process was selected as the monitoring object.

[0050] In a forced twin-shaft concrete mixer containing a dry-mixed powder-fiber mixture, the instant when the solid-liquid phase system is added at once and the high-speed rotation is started is recorded as the reaction time 0.

[0051] At the 1st minute, 3rd minute, 5th minute of stirring, and 10th minute of settling, 50g slurry samples were randomly taken from multiple points at different depths of the mixer.

[0052] The extracted slurry sample was placed in a high-pressure microporous filter press and centrifuged under a constant pressure of 0.5 MPa to collect the separated transparent to semi-transparent porous aqueous solution.

[0053] A platinum ring surface tension meter, which had been calibrated in a constant temperature room at 20 degrees Celsius, was used to measure the surface tension of the porous aqueous solution collected at each time point. Before each measurement, the platinum ring was cleaned by burning with alcohol, and the final tension value after the instrument stabilized was recorded.

[0054] Monitoring time Example 1 Example 2 Example 3 Comparative Example 4 0 minutes - - - - 1 minute 52.4 50.8 48.3 55.6 3 minutes 41.1 38.6 35.2 54.2 5 minutes 32.8 29.4 26.9 53.7 10 minutes 31.5 28.7 26.1 54.1 Note: "-" indicates that the solid-liquid mixture has not yet formed a continuous free aqueous phase within this extremely short time and is in a semi-dry, hard state, making it impossible to extract sufficient porous aqueous solution for surface tension testing by centrifugation and pressure filtration.

[0055] Figure 2 In the diagram, the dark gray solid line represents Example 1, the black solid line represents Example 2, the light gray solid line represents Example 3, and the dark gray dashed line represents Comparative Example 4.

[0056] in conclusion: According to Table 2 and Figure 2 The data shows that the surface tension of the porous aqueous solutions in Examples 1 to 3 exhibited a stepwise decrease trend from the initial stirring stage to the 5th minute. In the preparation of ultra-high performance concrete, a low water-cement ratio imparts high apparent viscosity and yield stress to the matrix, and the highly viscous fluid environment makes it easy for added hydrophobic chemicals to be physically encapsulated by polymers and unhydrated cement particles. In Comparative Example 4, tributyl phosphate was directly added to the solid-liquid phase system, and the surface tension of the pore aqueous solution filtered by pressure remained in the range of 53.7 to 55.6 mN / m within a 10-minute monitoring period. This data confirms that the defoamer without mesoporous carrier shielding undergoes local aggregation and physical isolation in multiphase high-viscosity fluids, failing to effectively desorb into the free aqueous phase and losing its function of reducing free energy at the gas-liquid interface.

[0057] The mesoporous targeted competitive adsorption system constructed in this invention exhibits different interfacial drug release behaviors in a mixing flow field. Tributyl phosphate, pre-loaded into the internal pores of natural clinoptilolite, is physically shielded during the initial water addition, avoiding the risk of being encapsulated by high-viscosity cement slurry. As mechanical shear work is input into the system along the stirring axis, the agglomerated zeolite micron powder is disaggregated by fluid shear stress. Negatively charged polycarboxylate superplasticizer comb-like molecules in the aqueous phase migrate to the newly exposed zeolite surface, occupying adsorption sites around the zeolite micropores due to the lower adsorption potential energy of polymer segments at the aluminosilicate interface. The in-situ competitive adsorption mechanism forcibly displaces and elutes tributyl phosphate into the free aqueous phase. In Example 2, the surface tension decreased from 50.8 mN / m at minute 1 to 29.4 mN / m at minute 5, indicating that the defoaming component was introduced into the pore fluid network. The defoamer diffuses and accumulates inside the slurry at the interface of the liquid film containing the air bubbles, disrupting the mechanical balance of the liquid phase film layer. During the stirring kinetic window, in-situ defoaming is achieved inside the slurry, eliminating the potential for interface defects in the formation of dense components.

[0058] Test Example 3: Spectroscopic Verification of In-situ Interfacial Covalent Crosslinking Basalt fiber-reinforced ultra-high performance concrete specimens from Examples 1, 2, 3, and Comparative Example 5 after a complete curing cycle were selected as the sampling objects for spectral characterization.

[0059] Using anhydrous ethanol ultrasonic cleaning and cutting tools, blocks containing fiber pull-out sections were randomly split from the inside of the specimen. With the assistance of a stereomicroscope, a micro probe was used to scrape off the powdery solid material in the interface transition zone attached to the surface of the basalt fibers.

[0060] The collected interface powder was placed in an agate mortar and mixed with dry high-purity potassium bromide powder at a mass ratio of 1:100. The mixture was then ground under infrared light until the particle size was less than 2 micrometers. The powder was then transferred to a mold and pressed into a translucent test sheet under a pressure of 15 MPa.

[0061] The thin slice was fixed in the sample chamber of the Fourier transform infrared spectrometer. The scanning wavenumber range was set to 4000 to 400, the resolution was 4, and the cumulative number of scans was 32. Infrared transmittance data in the 850 to 1200 band range were extracted and recorded.

[0062] Wavenumber (cm⁻¹) Example 1 Example 2 Example 3 Comparative Example 5 850 92.1 91.5 93.2 90.8 880 91.8 90.7 92.4 88.5 910 88.4 87.2 89.1 64.3 940 90.5 89.8 91.3 81.2 980 85.2 84.1 86.6 82.5 1020 72.3 70.8 74.1 78.4 1050 58.7 55.4 61.2 - 1080 45.6 41.2 48.3 71.5 1120 52.8 49.5 55.4 74.2 1180 78.4 76.9 80.1 85.3 1200 83.1 81.5 84.6 88.2 Note: "-" indicates that at this wavenumber, the transmittance data is distorted due to baseline drift caused by instrument background noise, and is therefore removed and treated as blank.

[0063] Figure 3 In the diagram, the dark gray solid line represents Example 1, the black solid line represents Example 2, the light gray solid line represents Example 3, and the black dotted line represents Comparative Example 5.

[0064] in conclusion: According to Table 3 and Figure 3 The data, specifically the peak-valley distribution characteristics of the examples and comparative examples in the infrared transmission spectra, reflect the differences in the microscopic chemical evolution state of the interface. In the mechanical characterization experience of cement-based composite materials, it has been observed that the physical interpenetration of the polymer and inorganic phases is difficult to resist the etching in the strongly alkaline environment during the later stages of component service. Comparative Example 5 retains a low transmittance absorption valley near wavenumber 910, corresponding to the asymmetric stretching vibration of unreacted ternary epoxy groups. Test results show that under standard wet-dry curing conditions lacking external high-temperature thermal activation, the calcium tartrate polynuclear complex chelate layer surrounding the silane coupling agent during the initial stirring stage maintains thermodynamic stability. The dual physical and chemical barriers prevent the dormant epoxy groups from contacting the hydrated calcium silicate gel, with the coupling agent acting as a coating adhering to the fiber surface.

[0065] The spectral trajectories of Examples 1 to 3 show that the absorption valley in the 910 wavenumber band is smoothed out, the transmittance data rebounds and stabilizes above 87%, and a broadband absorption band emerges near the 1080 wavenumber band. The region of decreased transmittance originates from the antisymmetric tensile vibration of the silicon-containing covalent network. The 80°C constant-temperature steam curing process introduces activation energy across the reaction energy barrier into the molded demolded component, and the molecular thermal motion causes structural relaxation due to the situ lock-in of the calcium tartrate complex. Hydroxide ions free in the pore-forming strong alkaline solution penetrate the barrier, opening the released epoxy ring groups and promoting in-situ condensation of the epoxy ring groups with the free silanol groups on the surface of the surrounding newly formed hydrated calcium silicate products. The microscopic covalent bonding reaction and the macroscopic stepped heating curing process correspond in time and space, transforming the van der Waals force physical adhesion of the basalt fiber-cement matrix interface transition zone into a three-dimensional inorganic-organic covalent network connection, eliminating the risk of later mechanical degradation of concrete caused by interfacial slip at the molecular scale.

[0066] Test Example 4: Comparative Test of UHPC Slurry Rheology and Performance The ultra-high performance concrete premixed slurry after high-speed forced mixing during the preparation process of Examples 1, 2, 3, and Comparative Examples 2 and 3 was selected as the test object.

[0067] The slurry from the machine is loaded into an inverted standard slump cylinder. After smoothing the surface, the slump cylinder is lifted vertically upwards. A stopwatch is started to record the time required for the slurry to spread to a diameter of 500 mm, which is recorded as the initial T50 flow time.

[0068] After the slurry stops flowing, the maximum diameter in two mutually perpendicular directions is measured using a standard steel ruler, and the average value is taken as the initial expansion at 0 minutes.

[0069] The remaining untested slurry samples were sealed and stored in an indoor environment at 20 degrees Celsius and 60% relative humidity. The slurry was removed after standing for 15 minutes, 30 minutes and 45 minutes, and the spread test was repeated. The time-dependent decay data of the rheological properties were recorded.

[0070] Monitoring parameters Monitoring time Example 1 Example 2 Example 3 Comparative Example 2 Comparative Example 3 Initial T50 flow time (s) 0 minutes 4.3 3.8 3.2 16.5 19.1 Slurry spread (mm) 0 minutes 768 785 802 612 594 Slurry spread (mm) 15 minutes 741 762 788 395 315 Slurry spread (mm) 30 minutes 712 734 751 - - Slurry spread (mm) 45 minutes 684 708 722 - - Note: "-" indicates that at this time point the slurry has undergone severe false coagulation and lost its fluidity, and cannot spread into a continuous disk under its own weight, so the degree of spread cannot be measured.

[0071] Figure 4 In the diagram, the dark gray solid line represents Example 1, the black solid line represents Example 2, the light gray solid line represents Example 3, the black dashed line represents Comparative Example 2, and the black dotted line represents Comparative Example 3.

[0072] in conclusion: According to Table 4 and Figure 4 The data from the examples and comparative examples show drastically different evolution patterns in the working performance and rheological state of the slurry after exiting the mixer. In practical engineering, maintaining rheological stability for a relatively long working window is a prerequisite for achieving pumping and densification casting in ultra-low water-cement ratio systems containing highly active inorganic powders and polymer additives. Observing the data from comparative examples 2 and 3, it can be found that the initial T50 flow times of both are extended to 16.5 seconds and 19.1 seconds, respectively, and the initial spread hovers around 600 mm; when the settling time is extended to 15 minutes, the slurry spread drops sharply to below 400 mm, and finally completely loses its fluidity within 30 minutes. The physicochemical root cause of this phenomenon lies in the lack of a single-factor protection mechanism. In Comparative Example 2, the removal of the ice phase from the phase-change temperature-controlled solid-liquid phase prevented the effective dissipation of mechanical frictional heat accumulated during high-speed stirring and the early-stage hydration heat of cement. The high ambient temperature directly provided the necessary activation energy for the ring-opening reaction of the silane coupling agent molecular chain segments. In Comparative Example 3, the lack of tartaric acid prevented the in-situ formation of polynuclear complexes in the strongly alkaline aqueous phase, resulting in the inability to establish an effective steric hindrance layer around the silane coupling agent. The premature exposure of the polymer end groups to the alkaline solution and their attack by hydroxide ions induced irreversible three-dimensional network cross-linking and solidification, macroscopically manifesting as large-area false setting of the slurry.

[0073] In contrast, the dual-locking system of deep cryogenic latent heat and chelate steric hindrance constructed in Examples 1 to 3 effectively reshaped the early setting process of the slurry. Test data objectively reflects that the initial spread of each example exceeded 760 mm, and the initial T50 time was controlled within 4.5 seconds, demonstrating thixotropy and post-yield flowability that meet engineering injection molding standards. During a monitoring period of up to 45 minutes, the rheological decay trend of the slurry in the examples was relatively gradual, with the final spread consistently remaining above 680 mm. This long-term rheological retention capability is attributed to the absorption of residual heat from the system by phase change ice chips during the initial stirring stage, suppressing the slurry temperature below the reaction threshold; simultaneously, the calcium tartrate complex attached to the fiber surface synergistically constructs a physical coating barrier, jointly blocking the premature cross-linking path of epoxy groups from both thermodynamic and kinetic dimensions. The dormant coupling agent molecules maintain a uniform fluid distribution with the slurry, eliminating the dramatic increase in rheological resistance caused by interweaving and aggregation at the microscale, thus reserving ample time for subsequent molding operations of the highly dense components.

[0074] Test Example 5: Macroscopic Compactness and Fiber Dispersion Uniformity Test Rectangular ultra-high performance concrete specimens from Examples 1, 2, and 3, as well as Comparative Examples 2 and 4, after being cured under standard conditions for 28 days were selected as test objects.

[0075] Along the casting height direction of the specimen, set the relative height positions of 10%, 30%, 50%, 70% and 90% of the bottom as the cutting reference plane.

[0076] An automated CNC water-cooled diamond wire saw was used to slice horizontally layer by layer to obtain cross-sectional samples.

[0077] X-ray computed tomography (CT) system combined with image processing software was used to perform non-destructive scanning and binarization analysis on each cross-sectional sample. The proportion of macroscopic defects with a diameter greater than 0.2 mm on the cross-section was calculated and recorded as the cross-sectional porosity.

[0078] Ten observation grids with a side length of 20 mm were randomly selected from the same cross section. The number of exposed basalt fibers in each grid was counted using a high-definition stereomicroscope. The coefficient of variation of fiber number between grids was calculated to characterize the uniformity of fiber dispersion in the matrix.

[0079] relative height Example 1 Example 2 Example 3 Comparative Example 2 Comparative Example 4 10% 0.82 0.95 1.14 3.42 2.15 30% 0.91 1.03 1.25 3.68 2.84 50% 0.96 1.15 1.41 3.85 3.52 70% 1.12 1.28 1.55 4.12 4.63 90% 1.35 1.44 1.62 4.45 5.81 relative height Example 1 Example 2 Example 3 Comparative Example 2 Comparative Example 4 10% 4.3 4.8 5.1 22.4 14.2 30% 4.5 5.2 5.5 24.1 15.6 50% 4.9 5.7 6.2 26.5 16.8 70% 5.4 6.1 6.8 28.3 18.1 90% 5.8 6.5 7.4 31.2 19.5 Figure 5 In the diagram, the dark gray solid line represents Example 1, the black solid line represents Example 2, the light gray solid line represents Example 3, the black dashed line represents Comparative Example 2, and the dark gray dashed line represents Comparative Example 4.

[0080] According to Table 5, Table 6 and Figure 5The data show differences in the density of the matrix spatial structure and the dispersion state of the reinforcing phase after hardening between the examples and the comparative examples. In the study of concrete forming process, the entrainment of micro-bubbles and the interweaving of high specific surface area fibers during the mixing stage leads to increased exhaust resistance, affecting the density of the formed components. The porosity of the cross-section of Comparative Example 4 increased from 2.15% at the bottom to 5.81% at the top. The gravity gradient distribution indicates that without the use of a mesoporous targeted carrier, the defoamer free in the aqueous phase is locally encapsulated by a non-Newtonian fluid with high shear yield stress, failing to break through the gas-liquid interface to reduce surface tension. The advancement of the hydration reaction and the increase in viscosity in the system cause unexpelled bubbles to remain in the upper region of the matrix. Comparative Example 2 lacks a latent heat of phase change temperature control mechanism, and the slurry undergoes thermodynamic runaway and false setting reaction in the later stages of mixing. The rheological properties decayed, locking the channels for bubble escape, and the porosity of the entire cross section remained above 3.42%; the three-dimensional rearrangement path of basalt fibers in the flow field was cut off, and the fiber variation coefficient at each height level was as high as 22.4% to 31.2%, showing a state of coexistence of local clustering and depletion areas.

[0081] Improved flow dynamics play a decisive role in eliminating structural defects. In Examples 1 to 3, the cross-sectional porosity was controlled below 1.62% in the longitudinal height, and the fiber distribution variation coefficient was maintained between 4.3% and 7.4%. Tributyl phosphate preloaded in natural clinoptilolite was released and enriched at the gas-solid-liquid multiphase interface under the competitive adsorption of the water-reducing agent. The eluted defoamer molecules acted on the defects in the liquid film encapsulating the fibers, puncturing and fusing microbubbles, reducing the resistance of microscopic air pockets attached to the fiber surface. The phase change ice phase continuously absorbed residual heat from the system, maintaining the slurry system in a thixotropic flow state during the injection molding window. The synergistic effect of low viscosity and low interfacial free energy endowed the basalt fibers with displacement freedom, allowing the fibers to achieve uniform three-dimensional spatial distribution under their own weight and mechanical vibration. Multidimensional rheological control eliminated internal weak interfaces, ensuring the mechanical isotropy and molding quality of the composite material.

[0082] Test Example 6: Ultimate Mechanical Properties and Long-Term Alkali Resistance Test 40 mm × 40 mm × 160 mm prism specimens from Examples 1, 2, 3, Comparative Examples 1 and 5, after being molded and subjected to 28 days of standard curing, were selected as the test objects for long-term alkali corrosion resistance.

[0083] A portion of the specimens were placed in a standard constant temperature and humidity chamber at 20 degrees Celsius and a relative humidity of over 95% as a reference. The remaining specimens were completely immersed in a pre-prepared mixed alkaline solution of sodium hydroxide and potassium hydroxide with an equivalent concentration of 1 mol / L.

[0084] The sealed polytetrafluoroethylene container containing the alkaline solution and the immersed specimen was placed in a 60°C water bath circulating heating chamber for accelerated aging and etching treatment. At etching ages of 30, 60, 90, and 120 days, the specimens were removed from the strong alkaline solution, and the surface was repeatedly rinsed with deionized water to remove residual alkaline solution until the rinsing solution was neutral. The specimens were then placed in a vacuum drying oven and dried to constant weight.

[0085] A microcomputer-controlled electronic universal testing machine was used to perform three-point bending load tests on dried specimens of various ages. The loading rate was controlled at 50 Newtons per second, and the ultimate flexural strength data at the time of specimen failure was recorded.

[0086] Erosion Age Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 5 0 days 34.2 35.8 33.6 24.8 30.4 30 days 33.1 34.9 32.1 20.1 28.2 60 days 31.8 33.4 30.5 15.6 24.2 90 days 30.5 32.2 29.3 11.5 19.8 120 days 29.4 31.5 27.8 - 16.3 Note: "-" indicates that the specimen underwent dissolution and structural loosening under long-term immersion in high-temperature alkaline solution, and brittle fracture occurred during the clamping or preloading stage of the testing machine, making it impossible to obtain ultimate flexural strength data.

[0087] Figure 6 In the diagram, the dark gray solid line represents Example 1, the black solid line represents Example 2, the light gray solid line represents Example 3, the dark gray dotted line represents Comparative Example 1, and the black dotted line represents Comparative Example 5.

[0088] in conclusion: According to Table 7 and Figure 6 The data shows that the evolution trajectories of the ultimate mechanical properties of the examples and comparative specimens under high temperature and strong alkaline conditions exhibit differences in corrosion resistance. In the study of silicate-based composite systems, basalt fiber, as a reinforcing phase, possesses high initial mechanical properties. However, the amorphous aluminosilicate network is prone to depolymerization under long-term immersion in high-pH solutions with porous structures, leading to brittle degradation of the composite material in the later stages of service. Data from Comparative Example 1 shows that the flexural strength of unmodified precursor fibers decreased sharply from 24.8 MPa to 11.5 MPa within a 90-day accelerated aging cycle, and it lost its load-bearing capacity at 120 days. The rapid loss of mechanical properties confirms the structural disintegration of the exposed silicon-oxygen skeleton under continuous etching by hydroxide ions. Comparative Example 5 introduced a conventional silane coupling agent for surface treatment, which had a delaying effect on degradation in the early stages of corrosion, and the flexural strength remained at 24.2 MPa after 60 days of testing. As the erosion time progresses, the physical adhesion and hydrogen bond network cannot withstand the penetration and peeling of high-temperature alkaline solution for a long time, and the failure of the interface coating layer causes the strength to drop to 16.3 MPa after 120 days.

[0089] Failure modes at single-layer or weakly bonded interfaces were suppressed in the embodiment systems. In Examples 1 to 3, the flexural strength remained stable above 27.8 MPa during a 120-day alkali erosion period. During the high-temperature steam curing stage, the released epoxy groups underwent in-situ condensation with the matrix hydrated calcium silicate gel, resulting in the fiber surface being encapsulated in a three-dimensional covalently cross-linked network. The inorganic-organic hybrid isolation zone deeply embedded in the interfacial transition zone possesses low ion permeability, effectively cutting off the diffusion path of corrosive hydroxide ions to the fiber matrix from both physical barrier and chemical anchoring perspectives. The interfacial covalent bonding mechanism locks the matrix and reinforcing phase into a unified stress-bearing structure, preventing interfacial slippage and debonding caused by alkali erosion, thus ensuring the toughness retention and structural continuity of the ultra-high performance concrete during long-term service in harsh water and soil environments.

Claims

1. A type of ultra-high performance concrete based on basalt fiber reinforcement, characterized in that, Made from raw materials containing the following components and amounts: Basalt fiber: accounting for 1.0% to 3.0% of the total concrete volume; Silicate cement: 85–90.5 parts by weight; Silica fume: 8-12 parts by weight; Quartz sand: 110-130 parts by weight; Dynamic wetting and crosslinking composite liquid: It exists in the form of a coating liquid on the surface of basalt fibers and is made by mixing 0.08-0.15 parts by weight of polyethylene glycol 400, 0.004-0.01 parts by weight of nano-SiO2 powder, 0.15-0.30 parts by weight of silane coupling agent KH-560 and 0.03-0.08 parts by weight of tartaric acid; Mesoporous adsorption targeted defoaming carrier: It is made by mixing 1.5 to 3.0 parts by weight of micron-sized natural clinoptilolite powder and 0.02 to 0.05 parts by weight of liquid tributyl phosphate; Phase change temperature-controlled solid-liquid phase: It is made by mixing 16 to 19 parts by mass of total mixing water and 1.2 to 1.8 parts by mass of liquid polycarboxylate superplasticizer.

2. The ultra-high performance concrete according to claim 1, characterized in that, In the phase change temperature-controlled solid-liquid phase, the total mixing water is an ice-water mixture containing 25% to 30% by mass and fine ice chips with a particle size of less than or equal to 2 mm.

3. The ultra-high performance concrete according to claim 1, characterized in that, The mesoporous adsorption targeted defoaming carrier is in powder form, wherein the liquid tributyl phosphate is physically adsorbed into the mesoporous gaps of the micron-sized natural clinoptilolite powder.

4. The ultra-high performance concrete according to claim 1, characterized in that, The content of each raw material component is as follows: Basalt fiber accounts for 2.0% of the total concrete volume; 87.8 parts by weight of silicate cement; 10 parts by weight of silica fume; 120 parts by weight of quartz sand; In the dynamic wetting crosslinking composite liquid, polyethylene glycol 400 is 0.12 parts by mass, nano-SiO2 powder is 0.007 parts by mass, silane coupling agent KH-560 is 0.22 parts by mass, and tartaric acid is 0.05 parts by mass. The mesoporous adsorption targeted defoaming carrier contains 2.2 parts by mass of micron-sized natural clinoptilolite powder and 0.03 parts by mass of liquid tributyl phosphate; The total mixing water in the phase change temperature-controlled solid-liquid phase is 17.5 parts by mass, and the liquid polycarboxylate superplasticizer is 1.5 parts by mass.

5. A method for preparing ultra-high performance concrete as described in any one of claims 1-4, characterized in that, Includes the following steps: Basalt fibers are put into a mixer and rotated at low speed to form a tumbling fiber bed. The dynamically wetting crosslinking composite liquid is uniformly sprayed into the tumbling fiber bed and continuously stirred to obtain a dynamically wetting fiber mixture. Silicate cement, silica fume, mesoporous adsorption targeted defoaming carrier and quartz sand are sequentially added to a mixer containing the dynamically wetted fiber mixture, and the mixture is dry-mixed at a low speed to obtain the powder-fiber dry-mixed mixture. A phase change temperature-controlled solid-liquid phase is added at once to a mixer containing the powder fiber dry-mixed mixture, the rotation speed is increased and high-speed forced mixing is continued, while the temperature is controlled below 15 degrees Celsius to obtain an ultra-high performance concrete premixed paste. The ultra-high performance concrete premixed slurry is injected into a molding mold and processed by a vacuum vibration molding process to obtain a molded demolded component. The molded demolded component is heated and subjected to constant temperature steam curing to obtain a pre-cured component. The initial curing components are subjected to high humidity curing, alternating hot air drying curing, and continuous cyclic wet-drying treatment before being cooled to room temperature for natural curing.

6. The method for preparing ultra-high performance concrete according to claim 5, characterized in that, The preparation steps of the dynamically wetting crosslinking composite liquid are as follows: Polyethylene glycol 400 is added to a reactor equipped with a high-speed shear dispersion emulsifier to provide a liquid phase dispersion carrier. Nano-SiO2 powder is slowly added to the polyethylene glycol 400 and a high-speed dispersion treatment at a speed of 1500-2000 rpm is started for 10-15 minutes to obtain an initial suspension. The initial suspension was ultrasonically dispersed using an ultrasonic cell disruptor with a frequency of 20–25 kHz to break up the nano-aggregates and form a stable thixotropic base liquid. The temperature of the thixotropic base liquid was controlled below 25 degrees Celsius. Silane coupling agent KH-560 and tartaric acid were added sequentially. The speed of the disperser was adjusted to 500-800 rpm and the mixture was continuously stirred for 20-30 minutes to obtain the dynamically wetting crosslinking composite liquid, which was then sealed and protected from light for later use.

7. The method for preparing ultra-high performance concrete according to claim 5, characterized in that, The preparation steps of the mesoporous adsorption targeted defoaming carrier are as follows: micron-sized natural clinoptilolite powder is put into a horizontal ribbon mixer with a spindle speed of 40-60 rpm to form tumbling zeolite powder. Liquid tributyl phosphate is uniformly sprayed into the tumbling zeolite powder through an atomizing nozzle and continuously dry-mixed for 15-20 minutes, so that the liquid tributyl phosphate is physically adsorbed into the mesopores of the micron-sized natural clinoptilolite powder, thus obtaining a powdered mesopore adsorption targeted defoaming carrier, which is then sealed for later use. The preparation steps of the phase change temperature-controlled solid-liquid phase are as follows: place the ice-water mixture in a storage tank with a heat insulation jacket and maintain the temperature of the ice-water mixture at 1 to 3 degrees Celsius to obtain a temperature-controlled ice-water slurry; Liquid polycarboxylate superplasticizer was added to the temperature-controlled ice-water slurry and stirred gently until a homogeneous phase was obtained to prepare a phase change temperature-controlled solid-liquid phase for later use.

8. The method for preparing ultra-high performance concrete according to claim 5, characterized in that, During the preparation of the dynamically wetted fiber mixture, the spindle is turned on and the rotation speed is set to 20-30 rpm. A large-diameter high-pressure airless spraying device is used for spraying. The spraying pressure of the large-diameter high-pressure airless spraying device is 10-15 MPa, and the stirring time is 2-3 minutes. During the preparation of the powder-fiber dry-mixed mixture, the dry-mixing time is maintained at low speed for 3-5 minutes.

9. The method for preparing ultra-high performance concrete according to claim 5, characterized in that, During the preparation of the ultra-high performance concrete premixed slurry, the rotation speed is increased to 60-80 rpm and high-speed forced mixing is continued for 4-6 minutes; during the preparation of the molded demolding component, the vacuum vibration molding process is used for 1-2 minutes.

10. The method for preparing ultra-high performance concrete according to claim 5, characterized in that, During the preparation of the initial curing component, constant temperature steam curing with a relative humidity of ≥95% is performed by raising the temperature; during the continuous cyclic wet-drying treatment of the initial curing component, the specific operation is as follows: high humidity curing with a relative humidity of ≥95% is performed, followed by alternating hot air drying curing, and continuous cyclic wet-drying treatment for 2 to 3 cycles.

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