Aerogel thermal-insulation waterproof mortar and preparation method thereof

Abstract

The invention discloses aerogel thermal-insulation waterproof mortar and a preparation method thereof. The mortar is prepared from cement, hydrophobic aerogel, interface modified asphalt rubber powder, a composite phase change heat conduction material, blast furnace slag micro powder, silica fume, nano montmorillonite, titanium dioxide aerogel powder, expanded vermiculite, shape memory polymer emulsion, chitosan, charcoal powder, carbon fibers, basalt fibers and the like. The preparation method comprises the following steps: carrying out plasma treatment and modification with an organosilicon waterproofing agent to obtain hydrophobic aerogel; carrying out interface modification on the asphalt rubber powder by adopting a titanate coupling agent; a phase change microcapsule-carbon nanotube heat conduction network is constructed through ball milling compounding; a basic framework is formed by adopting a graded mixing process, and then functional components are introduced; and finally, realizing cross-linking curing of the shape memory polymer and the chitosan through ultrasonic assistance and programmed temperature control. The mortar prepared by the invention realizes integration of multiple functions, and effectively solves the technical problems of single performance and poor durability of a traditional thermal insulation material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of building materials, and particularly relates to an aerogel thermal insulation waterproof mortar and a preparation method thereof. BACKGROUND

[0002] Building energy saving is the core of promoting the development of green buildings, and higher requirements are put forward for the comprehensive performance of external wall insulation systems. An ideal external wall insulation material not only needs to have excellent thermal insulation performance, but also must be firmly combined with the building base layer and have reliable waterproof and anti-permeability to cope with complex and variable external environment.

[0003] At present, traditional thermal insulation mortar is mostly based on cement, and composite light-weight aggregates such as expanded perlite and vitrified microbeads. This kind of material has many inherent defects: first, the inside of light-weight aggregate is mostly open-pore structure, and its strength is low, which is easy to be damaged in the process of mortar mixing and construction, resulting in the decline of thermal insulation performance; second, these open-pore structures will absorb and migrate a large amount of water, resulting in large dry density and high water absorption rate of finished mortar. In high humidity or freeze-thaw cycle environment, the absorbed water not only significantly increases the thermal conductivity of the material, making its thermal insulation performance sharply attenuate, but also easily causes durability problems such as hollowing, cracking and even falling. In addition, the waterproof performance of traditional mortar mostly depends on the surface spraying of silicone waterproof agent after forming. This “external application type” waterproof strategy is difficult to form a complete, continuous and durable hydrophobic barrier in the material interior and capillary channels, and its waterproof life is often not matched with the structure life.

[0004] Silica aerogel is known as one of the most potential new thermal insulation materials due to its unique nano-porous network structure and extremely low solid thermal conductivity (usually lower than 0.020 W / (m·K)). However, its direct application in cement-based mortar system faces two technical bottlenecks: first, the nano-scale skeleton structure of aerogel has low mechanical strength and is very fragile, which is easy to collapse and powder due to mechanical shear force in the process of conventional dry mixing and wet mixing, resulting in the loss of its excellent theoretical thermal insulation performance in actual products; second, the unmodified aerogel shows significant hydrophilicity and actively absorbs environmental water, which not only aggravates the potential risk of structural damage, but also fundamentally contradicts the waterproof and anti-permeability function pursued by the mortar system.

[0005] To improve the flexibility and crack resistance of the mortar, the asphalt rubber powder prepared from waste tires is concerned as a low-cost material with elasticity and inherent hydrophobicity. However, when the organic and hydrophobic asphalt rubber powder is compounded with inorganic aerogel with high specific surface area and cement hydration products with strong polarity, there is a serious challenge of interface compatibility. The physical and chemical properties of the components are greatly different, and simple physical mixing leads to weak interface bonding, which is easy to become a stress concentration point and a priority path for water penetration, not only failing to realize the synergistic effect of thermal insulation, waterproofing, flexibility and other functions, but also possibly leading to overall performance degradation due to interface defects.

[0006] Especially important is that the building envelope is subjected to periodic thermal stress in actual use due to diurnal and seasonal temperature difference fluctuations, which is an important reason for the cracking and hollowing of the thermal insulation system. The existing thermal insulation mortar has passive and single function, and lacks self-adaptive adjustment ability to temperature changes. Although phase change materials (PCM) can absorb or release latent heat through phase change process to smooth temperature fluctuations, their application in mortar has bottlenecks: PCM is easy to leak when directly introduced, has poor compatibility with cement matrix, and seriously deteriorates the mechanical strength of the material. Therefore, how to organically combine the phase change temperature control function with the thermal insulation and waterproof system and overcome its negative effects has become a key problem.

[0007] In summary, there is an urgent need in the art for an innovative systematic solution. The solution cannot be a simple superposition of existing technologies, but must start from the level of molecular interface engineering and material structure design, and through innovative pretreatment processes and precise processing procedures, it synchronously solves the core problems of aerogel structure protection and durable hydrophobicity, asphalt rubber powder interface chemical coupling, and phase change material functionalization encapsulation and efficient thermal conduction, thereby actively building a stable composite system with strong and tough combination of components, synergistic effect of functions, and finally realizing the integration breakthrough of multiple performances such as thermal insulation, waterproofing, temperature regulation, and load bearing. SUMMARY

[0008] The present application is directed to the above technical problems, and provides an aerogel thermal insulation and waterproof mortar and a preparation method thereof.

[0009] To achieve the above-mentioned object, the technical solutions provided by the present application are as follows: A preparation method of an aerogel thermal insulation and waterproof mortar, comprising the following steps: (1) Place 5-20 parts of hydrophilic silica aerogel in a plasma treatment device, and treat it at 500-800W power for 5-15 minutes under an argon atmosphere and a pressure of 50-100Pa. Then, spray in 10-20% of the aerogel mass of organosilicon waterproofing agent and treat it at a speed of 200-400rpm for 10-20 minutes to obtain hydrophobic aerogel. The organosilicon waterproofing agent is a mixed solution of methyltrimethoxysilane and hexamethyldisilazane in a mass ratio of 2:1. (2) Preheat 5-15 parts of 40-80 mesh waste tire asphalt powder to 70-90℃, add 2-4% of titanate coupling agent NDZ-201 by weight of the powder, and react at 400-600 rpm for 20-40 min to obtain interface modified asphalt powder. (3) Grind 5-15 parts of phase change microcapsules and 3-8 parts of carbon nanotubes together in a ball mill at a speed of 300-500 rpm for 30-60 min to obtain a composite phase change thermal conductive material; the core material of the phase change microcapsules is paraffin wax, the phase change temperature is 22-28℃, and the shell material is polymethyl methacrylate. (4) Grind 30-50 parts of cement, 15-25 parts of blast furnace slag powder, 10-20 parts of silica fume, 5-15 parts of nano montmorillonite, 5-10 parts of titanium dioxide aerogel powder, and 3-8 parts of expanded vermiculite together to 300-400 mesh to obtain inorganic composite matrix. (5) The inorganic composite matrix obtained in step (4), the interface-modified asphalt powder obtained in step (2), 2-8 parts of reinforcing fiber, and 3-9 parts of biochar powder are mixed at a speed of 400-600 rpm for 10-20 minutes to form a basic skeleton material; the reinforcing fiber is a hybrid fiber system composed of carbon fiber with a length of 2-5 mm and basalt fiber with a length of 1-3 mm in a mass ratio of (1.5-2.5):1. (6) Add the hydrophobic aerogel obtained in step (1), the composite phase change thermal conductive material obtained in step (3), 2-6 parts of redispersible latex powder, and 3-7 parts of hydroxypropyl methylcellulose ether to the basic skeleton material obtained in step (5), and mix at 100-200 rpm for 15-25 min to obtain a uniform dry mix. (7) a liquid phase is prepared by mixing 50-70 parts of water, 1-3 parts of polycarboxylic acid water reducing agent, 2-5 parts of water retention agent, 10-20 parts of shape memory polymer emulsion, and 3-8 parts of chitosan; the liquid phase is added into the dry mixture obtained in step (6) under the assistance of ultrasonic waves with a frequency of 20-40 kHz and a power of 200-400 W at a rotating speed of 40-80 rpm, and then the temperature is raised to 60-70 °C at a rate of 2-4 °C / min, and the stirring is continued at a rotating speed of 100-150 rpm for 20-40 min at the temperature, to obtain the aerogel thermal insulation waterproof mortar; the shape memory polymer emulsion is a polyurethane emulsion with a glass transition temperature of 25-35 °C.

[0010] Further, in step (1), the plasma treatment and the modification of the organosilicon waterproof agent are synergistically combined, so that the contact angle of the obtained hydrophobized aerogel is ≥150°, and the structure retention rate of the aerogel during the stirring of the mortar is ≥90%. The plasma pretreatment activates the surface of the aerogel, greatly improves the grafting density and firmness of the subsequent organosilicon waterproof agent, not only makes the aerogel obtain super-hydrophobic properties with a contact angle ≥150° to effectively block the intrusion of water, but also enhances the structure retention rate of the aerogel to more than 90% during the subsequent stirring of the mortar, thereby solving the core bottleneck in the application of the aerogel.

[0011] Further, in step (3), the mass ratio of the phase change microcapsule to the carbon nanotube is 1:(0.5-0.7); the co-grinding makes the carbon nanotubes uniformly embedded and anchored on the surface of the shell layer of the phase change microcapsule, and constructs an efficient heat conduction path. By ball milling, the carbon nanotubes are uniformly embedded and anchored on the shell layer of the phase change microcapsule, forming a local efficient heat conduction path in units of microcapsules. This not only significantly speeds up the thermal response speed of the phase change material, making the temperature adjustment more timely and efficient, but also reduces the breakage rate of the microcapsules in the stirring process due to the reinforcing effect of the carbon nanotubes, effectively preventing the leakage of the phase change core material.

[0012] Further, in step (5), the biochar powder is prepared by pyrolyzing agricultural waste under anaerobic conditions at 500-700 °C for 2-4 h, and then ball milling to a specific surface area of 200-400 m 2 / g. The biochar powder prepared from agricultural waste by a specific process has a developed porous structure (specific surface area of 200-400 m 2 / g), is light in weight and has certain thermal insulation properties, can adsorb free water and adjust the internal humidity of the mortar, and cooperates with the nano-montmorillonite to improve the density and ion exchange capacity of the system, and has the dual benefits of environmental protection and functionalization.

[0013] Further, in step (7), the mass ratio of the shape memory polymer emulsion to chitosan is (2-3):1. Controlling the mass ratio of the shape memory polymer emulsion to chitosan to be (2-3):1, the two can form an interpenetrating network structure with moderate crosslinking density in subsequent heating and stirring, which provides excellent flexibility and crack bridging ability for the mortar, avoids brittleness caused by excessive crosslinking, and realizes the best balance between material toughness and strength.

[0014] The application further provides an aerogel thermal insulation waterproof mortar prepared by the preparation method.

[0015] Further, the thermal conductivity of the mortar is ≤0.030 W / (m·K), the water absorption is ≤3%, the compressive strength is ≥5.0 MPa, and the bonding strength is ≥0.8 MPa; the phase change enthalpy of the mortar is ≥35 J / g, and after 50 freeze-thaw cycles, the mass loss rate is ≤3%, and the compressive strength loss rate is ≤8%.

[0016] Further, the mortar comprises the following components in parts by weight: cement 30-40 parts, the hydrophobic aerogel 5-12 parts, the interface modified asphalt powder 6-15 parts, the composite phase change thermal conductive material 6-15 parts, blast furnace slag powder 18-22 parts, silica fume 12-18 parts, nano-montmorillonite 8-12 parts, titanium dioxide aerogel powder 6-9 parts, expanded vermiculite 4-7 parts, shape memory polymer emulsion 12-18 parts, chitosan 4-7 parts, biochar powder 4-7 parts, carbon fiber 3-6 parts, basalt fiber 1.5-3 parts, redispersible latex powder 3-5 parts, hydroxypropyl methylcellulose ether 4-6 parts, polycarboxylic acid water reducer 1.5-2.5 parts, water retaining agent 3-4 parts, and water 55-65 parts. The preferred formula range is the best synergistic interval of each component verified by a large number of experiments. Within this range, each component can fully exert its own function and produce the best synergistic effect, thereby ensuring that the final product not only achieves the top performance index, but also has the best cost-effectiveness and process feasibility.

[0017] Compared with the prior art, the application has the following beneficial effects: I. The present application constructs a stable multi-phase interface structure at the molecular level through the three-stage pretreatment process of "plasma activation-silicone hydrophobic modification", "titanate coupling agent interface bridging", and "ball milling composite construction of heat conduction path". The plasma treatment produces a large number of active sites on the surface of aerogel, significantly improves the grafting density and bonding strength of the silicone waterproof agent, and forms a durable super-hydrophobic interface; the active groups introduced by the titanate coupling agent on the surface of the asphalt rubber powder can form firm Si-O-Si and Si-O-Ca covalent bonds with the cement hydration products; ball milling composite makes carbon nanotubes and phase change microcapsules form a stable "core-shell" heat conduction structure. This multi-level functional network breaks through the performance constraints of each component in traditional materials, and realizes the synergistic optimization of thermal insulation, waterproofing, and mechanical properties.

[0018] II. The present application adopts a three-stage process system of "basic framework construction-function component introduction-smart crosslinking and curing". First, a strong and tough three-dimensional framework network is formed by inorganic binder, modified asphalt rubber powder, and hybrid fibers at an optimized rotation speed; then, the specially treated aerogel and phase change composite material are introduced at a protective rotation speed to ensure uniform dispersion of the functional components while maximizing the integrity of their microstructure; finally, through ultrasonic assisted dispersion and programmed temperature curing, in-situ crosslinking of shape memory polymer and chitosan is realized to form a three-dimensional interpenetrating network. This precise process design ensures that each functional component performs synergistically in the best state, making the material performance optimal.

[0019] III. The present application first integrates hydrophobic aerogel, interface modified asphalt rubber powder, composite phase change and heat conduction materials, and shape memory polymer into a system, constructing an intelligent material system with temperature self-adaptive regulation capability. Phase change microcapsules achieve dynamic management of thermal energy through solid-liquid phase change, effectively smoothing temperature fluctuations; shape memory polymers undergo reversible phase change at a specific temperature range, giving the material thermal stress self-adaptive function; hydrophobic aerogel provides a durable and stable thermal barrier; modified asphalt rubber powder contributes to elastic recovery and auxiliary waterproof function. This multiple intelligent response mechanism enables the material to autonomously adjust its thermal performance and mechanical state according to environmental changes, realizing the integration of building envelope insulation, waterproofing, temperature regulation, and load bearing functions. DETAILED DESCRIPTION

[0020] The specific embodiments are described in detail below, but it should be understood that the scope of protection of the present application is not limited by the specific embodiments. The raw materials and reagents used in the examples are commercially available unless otherwise specified.

[0021] Example 1 A preparation method of an aerogel thermal insulation and waterproof mortar, comprising the following steps: (1) Put 12 kg of hydrophilic silica aerogel into a plasma treatment device, treat it for 10 min at a power of 600 W under an argon atmosphere and a pressure of 80 Pa, and then spray it into 1.44 kg of silicone waterproofing agent (consisting of 0.96 kg of methyltrimethoxysilane and 0.48 kg of hexamethyldisilazane) at a speed of 300 rpm for 15 min to obtain hydrophobized aerogel; (2) Preheat 10 kg of 40-mesh waste tire asphalt rubber powder to 80°C, add 0.2 kg of titanate coupling agent NDZ-201, and react at a speed of 500 rpm for 30 min to obtain interface-modified asphalt rubber powder; (3) Grind 10 kg of phase change microcapsules (core material: paraffin wax, phase change temperature: 25°C, shell material: polymethyl methacrylate) and 5 kg of carbon nanotubes together in a ball mill at a speed of 400 rpm for 45 min to obtain a composite phase change thermal conductive material; (4) Grind 40 kg of cement, 20 kg of blast furnace slag powder, 15 kg of silica fume, 10 kg of nano-montmorillonite, 8 kg of titanium dioxide aerogel powder, and 6 kg of expanded vermiculite to 350 mesh to obtain an inorganic composite base material; (5) Mix the inorganic composite base material obtained in step 4, the interface-modified asphalt rubber powder obtained in step 2, 5 kg of reinforcing fibers (consisting of 3 kg of 3 mm long carbon fibers and 2 kg of 2 mm long basalt fibers), and 6 kg of biochar powder (obtained by pyrolyzing rice husks at 600°C under anaerobic conditions for 3 h and then ball milling to a specific surface area of 300 m 2 / g) at a speed of 500 rpm for 15 min to form a basic framework material; (6) Add the hydrophobized aerogel obtained in step 1, the composite phase change thermal conductive material obtained in step 3, 4 kg of redispersible latex powder, and 5 kg of hydroxypropyl methylcellulose ether to the basic framework material obtained in step 5, and mix at a speed of 150 rpm for 20 min to obtain a uniform dry mixture; (7) Prepare a liquid phase by mixing 60 kg of water, 2 kg of polycarboxylic acid superplasticizer, 3.5 kg of water-retaining agent, 15 kg of shape memory polymer emulsion (polyurethane emulsion with a glass transition temperature of 30°C), and 5 kg of chitosan; under the assistance of ultrasonic waves at a frequency of 30 kHz and a power of 300 W, add the liquid phase to the dry mixture obtained in step 6 at a speed of 60 rpm, then heat it to 65°C at a rate of 3°C / min, and continue stirring at a speed of 120 rpm for 30 min at this temperature to obtain the aerogel thermal insulation waterproof mortar.

[0022] Example 2 A method for preparing an aerogel thermal insulation waterproof mortar, comprising the following steps: (1) Put 5 kg of hydrophilic silica aerogel into a plasma treatment device, treat it for 5 min at a power of 500 W under an argon atmosphere and a pressure of 50 Pa, and then spray it into 0.5 kg of silicone waterproof agent (consisting of 0.33 kg of methyltrimethoxysilane and 0.17 kg of hexamethyldisilazane) at a speed of 200 rpm for 10 min to obtain hydrophobized aerogel; (2) Preheat 5 kg of 80-mesh waste tire asphalt rubber powder to 70°C, add 0.075 kg of titanate coupling agent NDZ-201, and react at a speed of 400 rpm for 20 min to obtain interface-modified asphalt rubber powder; (3) Grind 5 kg of phase change microcapsules (core material: paraffin, phase change temperature: 22°C, shell material: polymethyl methacrylate) and 3 kg of carbon nanotubes together in a ball mill at a speed of 300 rpm for 30 min to obtain a composite phase change thermal conductive material; (4) Grind 30 kg of cement, 15 kg of blast furnace slag powder, 10 kg of silica fume, 5 kg of nano-montmorillonite, 5 kg of titanium dioxide aerogel powder, and 3 kg of expanded vermiculite to 300 mesh to obtain an inorganic composite base material; (5) Mix the inorganic composite base material obtained in step 4, the interface-modified asphalt rubber powder obtained in step 2, 2 kg of reinforcing fibers (consisting of 1.2 kg of 2 mm long carbon fibers and 0.8 kg of 1 mm long basalt fibers), and 3 kg of biochar powder (obtained by pyrolyzing wheat straw at 500°C under anaerobic conditions for 2 h and then ball milling to a specific surface area of 200 m 2 / g) at a speed of 400 rpm for 10 min to form a basic framework material; (6) Add the hydrophobized aerogel obtained in step 1, the composite phase change thermal conductive material obtained in step 3, 2 kg of redispersible latex powder, and 3 kg of hydroxypropyl methylcellulose ether to the basic framework material obtained in step 5, and mix at a speed of 100 rpm for 15 min to obtain a uniform dry mixture; (7) Prepare a liquid phase by mixing 50 kg of water, 1 kg of polycarboxylic acid superplasticizer, 2 kg of water-retaining agent, 10 kg of shape memory polymer emulsion (polyurethane emulsion with a glass transition temperature of 25°C), and 3 kg of chitosan; under the assistance of ultrasonic waves with a frequency of 20 kHz and a power of 200 W, add the liquid phase to the dry mixture obtained in step 6 at a speed of 40 rpm, then heat it to 60°C at a rate of 2°C / min, and continue stirring at a speed of 100 rpm for 20 min at this temperature to obtain the aerogel thermal insulation waterproof mortar.

[0023] Example 3 A method for preparing an aerogel thermal insulation waterproof mortar, comprising the following steps: (1) Put 20 kg of hydrophilic silica aerogel into a plasma treatment device, treat it in an argon atmosphere at a pressure of 100 Pa for 15 min at a power of 800 W, and then spray it into 4 kg of silicone waterproofing agent (consisting of 2.67 kg of methyltrimethoxysilane and 1.33 kg of hexamethyldisilazane), treat it at a speed of 400 rpm for 20 min, and obtain hydrophobized aerogel; (2) Preheat 15 kg of 40-mesh waste tire asphalt rubber powder to 90°C, add 0.6 kg of titanate coupling agent NDZ-201, and react at a speed of 600 rpm for 40 min to obtain interface-modified asphalt rubber powder; (3) Grind 15 kg of phase change microcapsules (core material: paraffin, phase change temperature: 28°C, shell material: polymethyl methacrylate) and 8 kg of carbon nanotubes together in a ball mill at a speed of 500 rpm for 60 min to obtain a composite phase change thermal conductive material; (4) Grind 50 kg of cement, 25 kg of blast furnace slag powder, 20 kg of silica fume, 15 kg of nano-montmorillonite, 10 kg of titanium dioxide aerogel powder, and 8 kg of expanded vermiculite to 400 mesh to obtain an inorganic composite base material; (5) Mix the inorganic composite base material obtained in step 4, the interface-modified asphalt rubber powder obtained in step 2, 8 kg of reinforcing fibers (consisting of 5 kg of 5 mm long carbon fibers and 3 kg of 3 mm long basalt fibers), and 9 kg of biochar powder (obtained by pyrolyzing corn stalks at 700°C under anaerobic conditions for 4 hours and then ball milling to a specific surface area of 400 m 2 / g) at a speed of 600 rpm for 20 min to form a basic framework material; (6) Add the hydrophobized aerogel obtained in step 1, the composite phase change thermal conductive material obtained in step 3, 6 kg of redispersible latex powder, and 7 kg of hydroxypropyl methylcellulose ether to the basic framework material obtained in step 5, and mix at a speed of 200 rpm for 25 min to obtain a uniform dry mixture; (7) Prepare a liquid phase by mixing 70 kg of water, 3 kg of polycarboxylic acid water reducer, 5 kg of water retaining agent, 20 kg of shape memory polymer emulsion (polyurethane emulsion with a glass transition temperature of 35°C), and 8 kg of chitosan; under the assistance of ultrasonic waves at a frequency of 40 kHz and a power of 400 W, add the liquid phase to the dry mixture obtained in step 6 at a speed of 80 rpm, then heat it to 70°C at a rate of 4°C / min, and continue stirring at a speed of 150 rpm for 40 min at this temperature to obtain the aerogel thermal insulation waterproof mortar.

[0024] Comparative Example 1 (traditional thermal insulation mortar) Preparation method: (1) Use 12 kg of ordinary expanded perlite (40-60 mesh) as a thermal insulation aggregate for later use; (2) grind 40 kg of cement, 20 kg of lime powder, 15 kg of slaked lime, and 10 kg of quartz powder to 350 mesh to obtain an inorganic base material; (3) mix the inorganic base material obtained in step (2), 12 kg of expanded perlite, 5 kg of reinforcing fiber (consisting of 3 kg of 3 mm long polypropylene fiber and 2 kg of 2 mm long glass fiber), and 6 kg of ordinary wood chip powder at a speed of 500 rpm for 15 minutes; (4) prepare a liquid phase by mixing 60 kg of water, 2 kg of polycarboxylic acid water reducer, 3.5 kg of water retaining agent, 0.5 kg of organic silicon waterproof agent (externally added), and 15 kg of styrene-acrylic emulsion, and then add the liquid phase to the mixture obtained in step (3) at a speed of 60 rpm, and continuously stir at a speed of 120 rpm for 30 minutes at room temperature to obtain a traditional thermal insulation mortar.

[0025] Comparative Example 2 (omit aerogel hydrophobization treatment) Preparation method: (1) directly use 12 kg of untreated hydrophilic silica aerogel; (2) preheat 10 kg of 40 mesh waste tire asphalt rubber powder to 80°C, add 0.2 kg of titanate coupling agent NDZ-201, and react at a speed of 500 rpm for 30 minutes to obtain interface modified asphalt rubber powder; (3) grind 10 kg of phase change microcapsules (core material: paraffin, phase change temperature: 25°C, shell material: polymethyl methacrylate) and 5 kg of carbon nanotubes in a ball mill at a speed of 400 rpm for 45 minutes to obtain a composite phase change thermal conductive material; (4) grind 40 kg of cement, 20 kg of blast furnace slag powder, 15 kg of silica fume, 10 kg of nano-montmorillonite, 8 kg of titanium dioxide aerogel powder, and 6 kg of expanded vermiculite to 350 mesh to obtain an inorganic composite base material; (5) mix the inorganic composite base material obtained in step (4), the interface modified asphalt rubber powder obtained in step (2), 5 kg of reinforcing fiber (consisting of 3 kg of 3 mm long carbon fiber and 2 kg of 2 mm long basalt fiber), and 6 kg of biochar powder at a speed of 500 rpm for 15 minutes to form a basic framework material; (6) add the untreated aerogel obtained in step (1), the composite phase change thermal conductive material obtained in step (3), 4 kg of redispersible latex powder, and 5 kg of hydroxypropyl methylcellulose ether to the basic framework material obtained in step (5) and mix at a speed of 150 rpm for 20 minutes to obtain a uniform dry mixture; (7) 60 kg water, 2 kg polycarboxylic acid water reducing agent, 3.5 kg water retaining agent, 15 kg shape memory polymer emulsion (polyurethane emulsion with a glass transition temperature of 30°C), and 5 kg chitosan were mixed to form a liquid phase; the liquid phase was added to the dry mixture obtained in step (6) under the assistance of ultrasonic waves at a frequency of 30 kHz and a power of 300 W, at a rotation speed of 60 rpm, and then heated to 65°C at a rate of 3°C / min, and stirred at a rotation speed of 120 rpm for 30 min at the temperature, to obtain a comparative mortar.

[0026] Comparative Example 3 (omitting asphalt rubber powder interface modification) Preparation method: (1) 12 kg of hydrophilic silica aerogel was placed in a plasma treatment device, treated under an argon atmosphere at a pressure of 80 Pa for 10 min at a power of 600 W, and then atomized and sprayed into 1.44 kg of silicone waterproof agent (consisting of 0.96 kg of methyltrimethoxysilane and 0.48 kg of hexamethyldisilazane), and treated at a rotation speed of 300 rpm for 15 min to obtain hydrophobicized aerogel; (2) 10 kg of untreated 40 mesh waste tire asphalt rubber powder was directly used; (3) 10 kg of phase change microcapsules (core material: paraffin wax, phase change temperature: 25°C, shell material: polymethyl methacrylate) and 5 kg of carbon nanotubes were co-milled in a ball mill at a rotation speed of 400 rpm for 45 min to obtain a composite phase change thermal conductive material; (4) 40 kg of cement, 20 kg of blast furnace slag powder, 15 kg of silica fume, 10 kg of nano-montmorillonite, 8 kg of titanium dioxide aerogel powder, and 6 kg of expanded vermiculite were co-milled to 350 mesh to obtain an inorganic composite base material; (5) The inorganic composite base material obtained in step (4), the untreated asphalt rubber powder obtained in step (2), 5 kg of reinforcing fibers (consisting of 3 kg of carbon fibers with a length of 3 mm and 2 kg of basalt fibers with a length of 2 mm), and 6 kg of biochar powder were mixed at a rotation speed of 500 rpm for 15 min to form a basic framework material; (6) The hydrophobicized aerogel obtained in step (1), the composite phase change thermal conductive material obtained in step (3), 4 kg of redispersible latex powder, and 5 kg of hydroxypropyl methylcellulose ether were added to the basic framework material obtained in step (5) and mixed at a rotation speed of 150 rpm for 20 min to obtain a uniform dry mixture; (7) A liquid phase is prepared by mixing 60 kg of water, 2 kg of polycarboxylic acid water reducing agent, 3.5 kg of water retaining agent, 15 kg of shape memory polymer emulsion (polyurethane emulsion with a glass transition temperature of 30°C), and 5 kg of chitosan. Under the assistance of ultrasonic waves with a frequency of 30 kHz and a power of 300 W, the liquid phase is added to the dry mixture obtained in step (6) at a rotating speed of 60 rpm, and then the temperature is raised to 65°C at a rate of 3°C / min. The stirring is continued at a rotating speed of 120 rpm for 30 minutes at this temperature to obtain a comparative mortar.

[0027] Comparative Example 4 (changing the mixing process sequence) Preparation method: (1) 12 kg of hydrophilic silica aerogel is placed in a plasma treatment device and treated under an argon atmosphere at a pressure of 80 Pa for 10 minutes at a power of 600 W, and then atomized and sprayed into 1.44 kg of silicone waterproof agent (composed of 0.96 kg of methyltrimethoxysilane and 0.48 kg of hexamethyldisilazane), and treated at a rotating speed of 300 rpm for 15 minutes to obtain hydrophobized aerogel; (2) 10 kg of 40 mesh waste tire asphalt gum powder is preheated to 80°C, and 0.2 kg of titanate coupling agent NDZ-201 is added, and reacted at a rotating speed of 500 rpm for 30 minutes to obtain interface modified asphalt gum powder; (3) 10 kg of phase change microcapsules (core material: paraffin, phase change temperature: 25°C, shell material: polymethyl methacrylate) and 5 kg of carbon nanotubes are co-ground in a ball mill at a rotating speed of 400 rpm for 45 minutes to obtain a composite phase change thermal conductive material; (4) 40 kg of cement, 20 kg of blast furnace slag powder, 15 kg of silica fume, 10 kg of nano-montmorillonite, 8 kg of titanium dioxide aerogel powder, and 6 kg of expanded vermiculite are co-ground to 350 mesh to obtain an inorganic composite base material; (5) All raw materials are mixed at one time: the inorganic composite base material obtained in step (4), the interface modified asphalt gum powder obtained in step (2), the hydrophobized aerogel obtained in step (1), the composite phase change thermal conductive material obtained in step (3), 5 kg of reinforcing fibers, 6 kg of biochar powder, 4 kg of redispersible latex powder, and 5 kg of hydroxypropyl methylcellulose ether are mixed at a rotating speed of 500 rpm for 20 minutes to obtain a mixture; (6) A liquid phase is prepared by mixing 60 kg of water, 2 kg of polycarboxylic acid water reducing agent, 3.5 kg of water retaining agent, 15 kg of shape memory polymer emulsion (polyurethane emulsion with a glass transition temperature of 30°C), and 5 kg of chitosan. Under the assistance of ultrasonic waves with a frequency of 30 kHz and a power of 300 W, the liquid phase is added to the dry mixture obtained in step (6) at a rotating speed of 60 rpm, and then the temperature is raised to 65°C at a rate of 3°C / min. The stirring is continued at a rotating speed of 120 rpm for 30 minutes at this temperature to obtain a comparative mortar.

[0028] Comparative Example 5 (using conventional materials instead) Preparation method: (1) use 12 kg of ordinary vitrified microbeads (instead of aerogel) as thermal insulation aggregate; (2) use 10 kg of ordinary rubber powder (instead of asphalt rubber powder); (3) grind 40 kg of cement, 20 kg of blast furnace slag powder, 15 kg of silica fume, 10 kg of fly ash (instead of nano-montmorillonite), 8 kg of ordinary silica fume (instead of titanium dioxide aerogel powder), and 6 kg of expanded perlite (instead of expanded vermiculite) to 350 mesh to obtain an inorganic base; (4) mix the inorganic base obtained in step (3), the ordinary rubber powder obtained in step (2), 5 kg of ordinary polypropylene fiber (single type of fiber), and 6 kg of ordinary wood powder at a speed of 500 rpm for 15 minutes; (5) add the vitrified microbeads obtained in step (1), 4 kg of redispersible latex powder, and 5 kg of hydroxypropyl methylcellulose ether to the mixture obtained in step (4) and mix at a speed of 150 rpm for 20 minutes to obtain a mixture; (6) prepare a liquid phase by mixing 60 kg of water, 2 kg of polycarboxylic acid water reducer, 3.5 kg of water retaining agent, 15 kg of ordinary acrylic emulsion (instead of shape memory polymer emulsion), and 5 kg of ordinary starch (instead of chitosan), and then add the liquid phase to the mixture obtained in step (5) at a speed of 60 rpm. Stir at a speed of 120 rpm for 30 minutes at room temperature to obtain a comparative mortar.

[0029] Performance comparison tests were conducted on Examples 1-3 and Comparative Examples 1-5, and the test items are as follows: 1. Thermal conductivity Test standard: GB / T 10294 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials - Guarded Hot Plate Method" Brief description of method: The sample is prepared into a size of 300 mm x 300 mm x 30 mm, and the heat flow through the sample and the temperature difference between the two sides are measured under stable heat flow conditions to calculate the thermal conductivity. The test temperature is 25±2℃.

[0030] 2. Water absorption Test standard: GB / T 5486 "Test Methods for Inorganic Rigid Thermal Insulation Products" Brief description of method: The sample is dried to constant weight, then the initial mass is measured, immersed in water at 20±5℃ for 72 hours, then the surface water is wiped off and weighed, and the mass increase percentage is calculated.

[0031] 3. Compressive strength Test standard: GB / T 17671 "Cement Mortar Strength Test Method (ISO Method)" Method: Prepare 40mm x 40mm x 160mm prism specimens, standard curing for 28 days, load by pressure testing machine at a rate of 2400±200N / s, record the maximum load when the specimen is destroyed.

[0032] 4. Adhesion strength Test standard: JG / T 24 "Synthetic resin emulsion sand wall-like architectural coatings" Method: Prepare the adhesion specimen of mortar and concrete substrate, use tensile testing machine to stretch at a rate of 5±1mm / min, measure the maximum tensile force when the adhesion interface is destroyed.

[0033] 5. Phase change enthalpy Test standard: GB / T 19466.3 "Plastics - Differential scanning calorimetry (DSC) - Part 3" Method: Use differential scanning calorimeter, perform temperature scanning at a rate of 5℃ / min under nitrogen atmosphere, calculate the phase change enthalpy by analyzing the DSC curve.

[0034] 6. Contact angle Test standard: GB / T 30447 "Nano-film contact angle measurement method" Method: Use contact angle measuring instrument, drop 2μL distilled water on the surface of the sample, measure the liquid-solid interface angle by image analysis system.

[0035] 7. Freeze-thaw cycle performance Test standard: GB / T 50082 "Standard for testing durability and long-term performance of ordinary concrete" Method: After the specimen is immersed in water for 48 hours, freeze at -20±2℃ for 4 hours, then melt in water at 20±2℃ for 4 hours, constitute a cycle. Record the mass loss and strength change after a specified number of cycles.

[0036] 8. Aerogel structure retention rate Test method: Use scanning electron microscope (SEM) to observe the microstructure of aerogel in mortar, calculate the proportion of complete aerogel particles by image analysis software, compare with the original aerogel structure to obtain the retention rate.

[0037] All tests are carried out in standard laboratory environment (temperature 23±2℃, relative humidity 50±5%), each group of data is the average value of 5 specimens.

[0038] Test data is shown in the following table: Test item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Thermal conductivity (W / (m·K)) 0.026 0.029 0.024 0.068 0.045 0.042 0.038 0.062 Water absorption (%) 2.5 3.2 2.1 21.3 15.8 9.6 6.8 18.5 Compressive strength (MPa) 5.8 5.1 6.2 2.3 3.5 3.1 4.2 2.8 Bonding strength (MPa) 0.85 0.78 0.89 0.32 0.51 0.45 0.63 0.41 Phase change enthalpy (J / g) 38.2 35.8 39.5 - 36.5 37.1 36.8 - Contact angle (°) 162 155 165 95 108 145 152 102 Mass loss rate after 50 freeze-thaw cycles (%) 2.1 2.8 1.8 18.5 12.3 8.7 5.6 15.2 Strength loss rate after 50 freeze-thaw cycles (%) 6.8 8.2 5.9 42.3 28.5 22.1 15.3 35.8 Aerogel structure retention rate (%) 92 88 94 - 65 88 78 - Analysis of table data shows that: 1. The thermal conductivity of the examples (0.024~0.029 W / (m·K)) is much lower than that of all comparative examples, especially Comparative Example 1 (0.068) and Comparative Example 5 (0.062), proving that aerogel can significantly improve the thermal insulation effect when replacing traditional insulating aggregates. Comparative Example 2, because its aerogel was not hydrophobically treated, has a significantly higher thermal conductivity (0.045) than Example 1, indicating that hydrophobic treatment is crucial for maintaining the thermal insulation performance of aerogel.

[0039] 2. The water absorption rate of the examples (2.1~3.2%) was much lower than that of all comparative examples, especially Comparative Example 1 (21.3%) and Comparative Example 5 (18.5%). Comparative Example 2, due to its untreated aerogel, had a water absorption rate as high as 15.8%, demonstrating the necessity of hydrophobic treatment. Comparative Example 3, due to its unmodified asphalt powder and poor interfacial bonding, also had a significantly higher water absorption rate (9.6%) than Example 1.

[0040] 3. The compressive strength (5.1~6.2MPa) and bond strength (0.78~0.89MPa) of the examples were significantly higher than those of the comparative examples. The mechanical properties of Comparative Example 3 (without asphalt powder modification) decreased significantly, demonstrating the importance of interface modification. The performance of Comparative Example 4 (with a changed mixing order) was also lower than that of Example 1, demonstrating that the staged mixing process plays a crucial role in protecting the aerogel structure and achieving component synergy.

[0041] 4. After 50 freeze-thaw cycles, the mass loss rate (1.8~2.8%) and strength loss rate (5.9~8.2%) of the examples were much lower than those of the comparative examples. The traditional mortar in Comparative Example 1 suffered a strength loss of up to 42.3% after freeze-thaw cycles, which completely failed to meet the durability requirements.

[0042] 5. Although Comparative Examples 2, 3, and 4 have phase change temperature regulation function (phase change enthalpy 36-37 J / g), they are significantly inferior to the Examples in other key performance aspects due to their respective technical defects, which proves the necessity of the systematic solution of the present invention.

[0043] In summary, through systematic comparative experiments, the innovativeness of this invention in terms of component selection, material modification, and process design, as well as the resulting breakthrough in overall performance, have been fully demonstrated. The synergistic effect among the various technical features is significant; the absence or alteration of any single feature will lead to a significant decrease in overall performance.

[0044] It should be understood that the above embodiments are only to illustrate the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and it cannot be considered that the specific implementation of the present application is limited to these descriptions. For ordinary skilled in the art to which the present application belongs, without departing from the concept of the present application, some simple deductions or substitutions can be made, and any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A method for preparing aerogel thermal insulation and waterproof mortar, characterized in that, Includes the following steps: (1) Place 5-20 parts of hydrophilic silica aerogel in a plasma treatment device, and treat it at 500-800W power for 5-15 minutes under an argon atmosphere and a pressure of 50-100Pa. Then, spray in 10-20% of the aerogel mass of organosilicon waterproofing agent and treat it at a speed of 200-400rpm for 10-20 minutes to obtain hydrophobic aerogel. The organosilicon waterproofing agent is a mixed solution of methyltrimethoxysilane and hexamethyldisilazane in a mass ratio of 2:

1. (2) Preheat 5-15 parts of 40-80 mesh waste tire asphalt powder to 70-90℃, add 2-4% of titanate coupling agent NDZ-201 by weight of the powder, and react at 400-600 rpm for 20-40 min to obtain interface modified asphalt powder. (3) Grind 5-15 parts of phase change microcapsules and 3-8 parts of carbon nanotubes together in a ball mill at a speed of 300-500 rpm for 30-60 min to obtain a composite phase change thermal conductive material; the core material of the phase change microcapsules is paraffin wax, the phase change temperature is 22-28℃, and the shell material is polymethyl methacrylate. (4) Grind 30-50 parts of cement, 15-25 parts of blast furnace slag powder, 10-20 parts of silica fume, 5-15 parts of nano montmorillonite, 5-10 parts of titanium dioxide aerogel powder, and 3-8 parts of expanded vermiculite together to 300-400 mesh to obtain inorganic composite matrix. (5) The inorganic composite matrix obtained in step (4), the interface-modified asphalt powder obtained in step (2), 2-8 parts of reinforcing fiber, and 3-9 parts of biochar powder are mixed at a speed of 400-600 rpm for 10-20 minutes to form a basic skeleton material; the reinforcing fiber is a hybrid fiber system composed of carbon fiber with a length of 2-5 mm and basalt fiber with a length of 1-3 mm in a mass ratio of (1.5-2.5):

1. (6) Add the hydrophobic aerogel obtained in step (1), the composite phase change thermal conductive material obtained in step (3), 2-6 parts of redispersible latex powder, and 3-7 parts of hydroxypropyl methylcellulose ether to the basic skeleton material obtained in step (5), and mix at 100-200 rpm for 15-25 min to obtain a uniform dry mix. (7) Prepare a liquid phase by mixing 50-70 parts of water, 1-3 parts of polycarboxylate superplasticizer, 2-5 parts of water-retaining agent, 10-20 parts of shape memory polymer emulsion, and 3-8 parts of chitosan; add the liquid phase to the dry mixture obtained in step (6) at a speed of 40-80 rpm under the assistance of ultrasound at a frequency of 20-40 kHz and a power of 200-400 W, and then heat it to 60-70 ℃ at a speed of 2-4 ℃ / min, and stir it continuously at a speed of 100-150 rpm for 20-40 min at this temperature to obtain the aerogel thermal insulation and waterproof mortar; the shape memory polymer emulsion is a polyurethane emulsion with a glass transition temperature of 25-35 ℃.

2. The preparation method according to claim 1, characterized in that: In step (1), the plasma treatment and the modification of the organosilicon waterproofing agent work synergistically to make the contact angle of the resulting hydrophobic aerogel ≥150° and its structure retention rate ≥90% during the mortar mixing process.

3. The preparation method according to claim 1, characterized in that: In step (3), the mass ratio of the phase change microcapsule to the carbon nanotube is 1:(0.5~0.7); the co-grinding makes the carbon nanotube uniformly embedded and anchored on the surface of the phase change microcapsule shell, thus constructing an efficient heat conduction pathway.

4. The preparation method according to claim 1, characterized in that: In step (5), the biochar powder is obtained by pyrolyzing agricultural waste at 500-700℃ for 2-4 hours in an anaerobic environment, followed by ball milling until the specific surface area reaches 200-400 m². 2 / g is prepared.

5. The preparation method according to claim 1, characterized in that: In step (7), the mass ratio of the shape memory polymer emulsion to chitosan is (2~3):

1.

6. An aerogel thermal insulation and waterproof mortar prepared by any one of claims 1 to 5.

7. The aerogel thermal insulation and waterproof mortar according to claim 6, characterized in that: The mortar has a thermal conductivity ≤0.030W / (m·K), a water absorption rate ≤3%, a compressive strength ≥5.0MPa, and a bond strength ≥0.8MPa.

8. The aerogel thermal insulation and waterproof mortar according to claim 6, characterized in that: The mortar has a phase change enthalpy of ≥35J / g, and after 50 freeze-thaw cycles, its mass loss rate is ≤3% and its compressive strength loss rate is ≤8%.

9. The aerogel thermal insulation and waterproof mortar according to claims 6 to 8, characterized in that, The product comprises the following components in parts by weight: 30-40 parts cement, 5-12 parts hydrophobic aerogel, 6-15 parts interface-modified asphalt powder, 6-15 parts composite phase change thermal conductive material, 18-22 parts blast furnace slag powder, 12-18 parts silica fume, 8-12 parts nano-montmorillonite, 6-9 parts titanium dioxide aerogel powder, 4-7 parts expanded vermiculite, 12-18 parts shape memory polymer emulsion, 4-7 parts chitosan, 4-7 parts biochar powder, 3-6 parts carbon fiber, 1.5-3 parts basalt fiber, 3-5 parts redispersible latex powder, 4-6 parts hydroxypropyl methylcellulose ether, 1.5-2.5 parts polycarboxylate superplasticizer, 3-4 parts water-retaining agent, and 55-65 parts water.