CN-121974619-A - Waterborne epoxy resin repair mortar for constructing multistage synergistic toughening structure through interfacial chemical anchoring and preparation method thereof

Abstract

The invention discloses a waterborne epoxy resin repair mortar for constructing a multistage synergistic toughening structure through interfacial chemical anchoring and a preparation method thereof, wherein the waterborne epoxy resin repair mortar is formed by mixing a mortar matrix and nanoparticle modified waterborne epoxy resin, and the waterborne epoxy resin repair mortar comprises the following components in percentage by weight: the mortar matrix comprises cement, river sand, tap water and a water reducer, and the nanoparticle modified waterborne epoxy resin consists of waterborne epoxy resin, nanoparticles, a silane coupling agent, a curing agent and deionized water. The invention constructs a stable Si-O-C covalent bond interface between the re-doped nano alumina/silica and the water-based epoxy resin matrix by the silane coupling agent, realizes the chemical anchoring of the interface of nano scale, lays a microscopic foundation for forming a multi-level collaborative toughening structure, enables nano particles to construct a micro-nano multi-scale reinforced network together with the water-based epoxy resin matrix, and effectively solves the common technical problem of poor compatibility of epoxy resin and cement mortar.

Inventors

• LI YING
• WU TIANMIN
• LEI DONGYI
• Luan Yunjie
• LI JIN
• WANG FEITENG

Assignees

• 青岛理工大学

Dates

Publication Date

20260505

Application Date

20251226

Claims (9)

1. 1. The waterborne epoxy resin repair mortar for constructing the multistage synergistic toughening structure through interfacial chemical anchoring is characterized by being formed by mixing two parts of a mortar matrix and nanoparticle modified waterborne epoxy resin, wherein: the mortar matrix comprises, by mass, 0.3-0.5 part of cement, 0.6-0.85 part of river sand, 0.15-0.25 part of tap water and 0.003-0.005 part of water reducer; The nanoparticle modified waterborne epoxy resin consists of waterborne epoxy resin, nanoparticles, a silane coupling agent, a curing agent and deionized water, wherein the dosage of the waterborne epoxy resin is 5-10% of the mass of cement, the dosage of the curing agent is 45-55% of the mass of the waterborne epoxy resin, the dosage of the nanoparticles is 1-3% of the mass of the waterborne epoxy resin, and the dosage of the silane coupling agent is 1-3% of the mass of the waterborne epoxy resin.
2. 2. The aqueous epoxy resin repair mortar for constructing a multistage synergistic toughening structure by interfacial chemical anchoring according to claim 1, wherein the nanoparticles are one or two of nano Al 2 O 3 particles and SiO 2 particles.
3. 3. The aqueous epoxy resin repair mortar for constructing a multistage cooperative toughening structure through interfacial chemical anchoring according to claim 2, wherein the particle size of the nano Al 2 O 3 particles and the nano SiO 2 particles is not more than 200nm.
4. 4. The aqueous epoxy resin repair mortar for constructing a multistage synergistic toughening structure by interfacial chemical anchoring according to claim 1, wherein the cement is one of general Portland cement or special cement, and the compressive strength at 28d is more than 52.5MPa.
5. 5. The aqueous epoxy resin repair mortar for constructing a multistage synergistic toughening structure through interfacial chemical anchoring according to claim 1, wherein the average grain size of the river sand is 40-60 meshes, and the maximum grain size is not more than 375 μm.
6. 6. The aqueous epoxy resin repair mortar for constructing a multistage synergistic toughening structure through interfacial chemical anchoring according to claim 1, wherein the water reducing agent is a polycarboxylate water reducing agent, the water reducing rate is 16-22%, and the solid content is not less than 40%.
7. 7. The aqueous epoxy resin repair mortar for constructing a multistage cooperative toughening structure through interfacial chemical anchoring according to claim 1, wherein the silane coupling agent is one of gamma-aminopropyl triethoxysilane, gamma-glycidol ether oxypropyl trimethoxysilane and gamma-methacryloxypropyl trimethoxysilane.
8. 8. A method for preparing the aqueous epoxy resin repair mortar for constructing a multistage cooperative toughening structure by interfacial chemical anchoring according to any one of claims 1 to 7, which is characterized by comprising the following steps: Mixing nano particles and deionized water in a mass ratio of 1:15-25, placing the mixture in an ultrasonic dispersing instrument, performing ultrasonic dispersion for 10-20 min, placing the mixture on a magnetic heating stirrer, and dispersing for 100-150 min under the conditions of a rotating speed of 500-1000 r/min and a heating temperature of 50-70 ℃; Adding a silane coupling agent into the nanoparticle dispersion liquid obtained in the step one, and placing the mixture on a magnetic heating stirrer to disperse for 100-150 min under the conditions of 500-1000 r/min of rotating speed and 50-70 ℃ of heating temperature; Adding the modified nanoparticle dispersion liquid obtained in the step two into aqueous epoxy resin emulsion, and placing the aqueous epoxy resin emulsion into a magnetic stirrer to continuously stir at a rotating speed of 500-1000 r/min for 100-150 min to obtain nanoparticle modified aqueous epoxy resin emulsion for later use; adding a curing agent into the nanoparticle modified waterborne epoxy resin emulsion obtained in the step three, stirring for 1-3 min at the speed of 60-80 r/min, adding the stirring product into cement and river sand, continuously stirring for 1-3 min at the speed of 120-150 r/min, sequentially adding the mixed water of tap water and a water reducer, stirring for 1-3 min at the speed of 120-150 r/min, and then stirring for 2-5 min at the speed of 270-300 r/min; and fifthly, injecting the material obtained in the step four into a mould, vibrating for 120-150 s on a vibrating table, curing for 7d under the conditions that the temperature is 20+/-3 ℃ and the relative humidity is more than or equal to 90%, and curing for 21d under the conditions that the temperature is 23+/-2 ℃ and the relative humidity is 50+/-10% after demoulding.
9. 9. The method for preparing the aqueous epoxy resin repair mortar for constructing the multistage cooperative toughening structure through interfacial chemical anchoring according to claim 8, wherein the vibration frequency of the ultrasonic dispersion instrument is 20-40 kHz.

Description

Waterborne epoxy resin repair mortar for constructing multistage synergistic toughening structure through interfacial chemical anchoring and preparation method thereof Technical Field The invention belongs to the technical field of building materials, relates to water-based epoxy resin repair mortar and a preparation method thereof, and in particular relates to water-based epoxy resin repair mortar for constructing a multistage synergistic toughening structure through interfacial chemical anchoring and a preparation method thereof. Background In recent years, concrete has played a key role in various projects as a building material with the greatest dosage and the most widely used. However, concrete is a brittle material in nature, and is subject to factors such as load, impact, temperature difference and harmful medium erosion in the long-term service process, cracks and degradation are easy to occur, so that performance degradation is caused, structural safety is seriously damaged, and service life is shortened. Concrete damage is concentrated in stress concentration areas (such as joints, corners and steps) and parts bearing cyclic deformation (such as corrosive environments, pavements under the action of freeze thawing, piers, pier foundation piles and the like), so that serious potential safety hazards are brought. Therefore, effective repair and reinforcement measures are adopted to prolong the service life of the structure. Currently, the global engineering construction emphasis is gradually changed from new construction to maintenance and reinforcement, and in the coming twenty-three years, china is expected to enter a stage mainly comprising structural maintenance and transformation, and the development of high-performance repairing materials for building structures is particularly important. In recent years, concrete repair technology has been developed continuously, and polymer repair systems, cement-polymer composite systems, steel plate bonding reinforcement systems, fiber reinforced repair systems, and the like have emerged. The aqueous epoxy resin repair mortar is used as an important branch in the system, has the advantages of good flexibility, long service life, low toxicity and the like, can form firm bonding on a wet base surface, simplifies the interface treatment process of the old concrete, and has obvious advantages in improving the tensile strength and the ductility of the concrete. However, the problem that the water-based epoxy resin repair mortar has insufficient bonding strength and poor cracking resistance on repair interfaces of most building structures under severe working conditions is particularly solved because (1) in terms of material performance, the existing water-based epoxy resin is generally low in solid content, so that the existing water-based epoxy resin is poor in film forming property and self strength, a compact and tough interpenetrating network structure is difficult to form in a cement matrix, the performance gain of the composite material is limited, the ductility and bonding strength are still to be further improved, and (2) in terms of the compatibility of a repair system, a large amount of free surfactant in the existing emulsion-type epoxy resin system can seriously obstruct the cement hydration process and weaken the final mechanical property of cement stones. CN117865554a discloses a rapid repair material of aqueous epoxy resin mortar for rapid repair of water leakage diseases of high-speed rail tunnels and a preparation process, the repair material takes magnesium phosphate cement as a matrix, and is doped with components such as epoxy resin, aqueous epoxy resin, fly ash and the like, so that grouting repair function with adjustable setting time is realized to a certain extent. However, the multi-scale toughening capacity of the material is improved in a mode of compounding and blending the epoxy resin and the water-based epoxy resin, and the problem of poor compatibility of the epoxy resin and cement mortar cannot be systematically solved, so that the further optimization of the overall performance of the mortar is limited. CN105439506a discloses a water-based epoxy resin modified cement mortar repairing material and a preparation method thereof, and the repairing material is prepared by physically compounding components such as water-based epoxy resin, a curing agent, silica fume, an expanding agent and the like, so that although the bonding strength of the material is improved to a certain extent, the method mainly relies on the combination of materials on a macroscopic level, and effective regulation and control on interface chemical action are lacking, so that the improvement on toughening is still limited. CN114538861a discloses a water-based epoxy resin modified cement mortar and a preparation method thereof, which focus on reducing viscosity and improving strength by regulating and controlling a resin structure, and although the specific perfo