Infrastructure disaster reinforcement repair mortar and method of making

Abstract

The application provides a fabric repairing mortar composite material with excellent bearing capacity and excellent adhesive strength and a preparation method thereof. The fabric repairing mortar composite material comprises a tensile fabric and a polymer modified mortar which is bonded to the upper surface and the lower surface of the tensile fabric. The tensile fabric is a tensile fiber preform with a negative Poisson's ratio effect. The polymer modified mortar is composed of 1 part by weight of cement, 0.2 parts by weight of fly ash, 2.5 parts by weight of sand, 0.44 parts by weight of water, 0.1-1.0 parts by weight of a toughening polymer, 0.03 parts by weight of a water reducing agent and appropriate amounts of a curing agent and a defoaming agent. The fabric repairing mortar composite material introduces the concept of negative Poisson's ratio, improves the bearing capacity of the fabric from the energy point of view, simultaneously designs the proportioning of the mortar and the interfaces of the fabric-mortar and the mortar-matrix, significantly improves the bearing capacity of the repairing system, and inhibits the generation of secondary damage, and has important practical application value.

Description

Technical Field

[0001] This invention belongs to the field of organic composite materials and relates to a repair mortar, specifically a repair mortar with excellent load-bearing capacity and excellent bonding strength. Background Technology

[0002] By 2018, my country's infrastructure stock ranked first in the world, achieving remarkable results in transportation, energy, communications, and water conservancy. However, after prolonged use, infrastructure suffers from a gradual decline in structural durability due to external forces and internal factors, leading to defects such as microcracks and peeling on both the exterior and interior surfaces. As a result, when these defects expand to a certain extent, the overall structure loses its mechanical stability and collapses, significantly shortening the service life of components. This not only inconveniences daily life and production but also incurs substantial economic losses. Therefore, repairing damaged buildings and preventing further damage is of paramount importance.

[0003] In recent years, fiber-reinforced polymer (FRP) composites have become a research focus for reinforcing and repairing concrete structures due to their advantages such as lightweight, high strength, and strong corrosion resistance. However, epoxy resin has poor compatibility with the concrete matrix, easily leading to peeling of the repair layer; moreover, FRP materials mostly use carbon fiber cloth, which is costly and has low fiber utilization. Against this technological background, fabric-reinforced mortar (TRM) has rapidly emerged as a new material for repairing damaged structures. Compared with FRP materials, TRM has stronger impact resistance and higher fiber utilization; and because it is essentially a repair mortar, it has good compatibility with the concrete matrix. However, repair mortar suffers from insufficient interfacial bonding between the fiber fabric and the repair mortar, often ultimately leading to the destruction of the repaired structure. In general, the main failure modes are: ① slippage failure between fabric and mortar; ② separation failure caused by slippage between mortar and substrate; ③ fracture failure of the fabric inside the repair layer. The reasons can be attributed to: ① poor adhesion between fabric and mortar, easy slippage, and inability to fully utilize the advantages of fibers; ② commonly used fabric materials have low strength, poor energy absorption capacity, and are prone to brittle fracture; ③ poor adhesion of mortar and poor adhesion between mortar and substrate, resulting in overall separation failure of the repair layer.

[0004] The failure of fabric-reinforced mortar is due to the fact that it is typically subjected to tensile and bending loads during its service life. In the initial loading stage, the fiber fabric, mortar, and matrix material share the load, and the load and deflection development follows the plane section assumption. In the early to mid-loading stage, the mortar at the edge of the tension zone first exhibits brittle fracture, causing secondary cracking of the repair system. In the later loading stage, as the load increases and the neutral axis rises, insufficient interfacial bonding between the fiber fabric and mortar leads to fabric slippage. Furthermore, when the fiber fabric's load-bearing capacity is insufficient, it breaks directly, causing damage to the repair structure. In the later loading stage, as the load continues to increase, insufficient interfacial bonding between the repair layer and matrix to support the system's coordinated stress results in slippage between the repair layer and matrix, potentially leading to complete detachment of the repair layer and brittle failure. Therefore, improving the energy absorption capacity of the fabric, the bonding strength between the fabric and mortar, and the bonding strength between the mortar and matrix are pressing technical problems that need to be addressed in existing repair mortar technologies. Currently, no relevant reports have been found. Summary of the Invention

[0005] To address the problems existing in current concrete repair mortar technologies, this invention provides a fabric repair mortar composite material with excellent load-bearing capacity and superior bond strength, as well as its preparation method. The fabric repair mortar composite material introduces the concept of negative Poisson's ratio, enhancing the load-bearing capacity of the fabric from an energy perspective. Simultaneously, the mortar mix design and the interfaces between the fabric and mortar, and between the mortar and the matrix, significantly improve the load-bearing capacity of the repair system and suppress secondary damage, demonstrating significant practical application value.

[0006] The technical solution of the present invention:

[0007] A fabric repair mortar composite material with excellent load-bearing capacity and bonding strength includes a tensile fabric and a polymer-modified mortar. The polymer-modified mortar is bonded to the upper and lower surfaces of the tensile fabric. A schematic diagram of the structure is shown below. Figure 1 As shown.

[0008] The polymer-modified mortar, by weight, comprises 1 part cement, 0.2 parts fly ash, 2.5 parts sand, 0.44 parts water, 0.1-1.0 parts toughening polymer, 0.03 parts water-reducing agent, and appropriate amounts of curing agent and defoamer. The curing agent is used at half the amount of the toughening polymer, and the defoamer is used at 1% of the amount of the toughening polymer. The toughening polymer is one of polyurea, epoxy resin, polyurethane, acrylic resin, phenolic resin, urea-formaldehyde resin, and silicone resin. When the toughening polymer is added to the repair mortar according to the aforementioned proportions, it can cause the repair mortar-matrix interface to form as... Figure 2The polymer transition layer shown increases the interfacial bonding between the two through intermolecular cross-linking, which helps to passivate the stress concentration at the crack tip of the mortar specimen, effectively preventing the further propagation of the crack, thereby improving the performance of the cement mortar.

[0009] The turbulent fabric is a turbulent fiber preform with a negative Poisson's ratio effect, and its structure and deformation process are as follows: Figure 1 As shown, the fiber fabric is obtained by weaving it into a net according to a certain mesh size and weaving method. This application applies the tensile fabric to repair mortar and adjusts the negative Poisson's ratio of the fabric by controlling the weaving method and mesh size to obtain a tensile fabric with optimal strength and energy absorption capacity. The mesh size is 5-15mm, and the weaving method is plain weave, twill weave, or satin weave, such as... Figure 3 As shown. The stretched fiber preform is obtained by spirally winding the auxiliary fibers onto the core fibers using low-modulus fiber bundles as core fibers and high-modulus fiber bundles as auxiliary fibers. The diameter of the low-modulus fiber bundles is 1500-1600 μm, and the diameter of the high-modulus fiber bundles is 500-600 μm. The tensile strength of the stretched fabric is 128.66-155.47 MPa, which is 8.30%-30.87% higher than that of woven fabrics; and 59.95%-93.27% higher than that of fabrics with a mesh size of 20 mm; the breaking energy is 4.29-5.79 kJ / m. 3 Compared to woven weaving methods, it improves by 6.50% to 43.67%, and compared to a mesh size of 20mm, it improves by 15.63% to 56.06%.

[0010] Preferably, the surface of the stretched fabric is chemically grafted with nano-SiO2 particles through a modification treatment. This application introduces the concept of negative Poisson's ratio into fiber fabrics and simultaneously controls the surface roughness of the fabric by chemically grafting nanomaterials onto the fabric surface, thereby improving its adhesion and significantly enhancing the bond strength between the fabric and the mortar. This solves the problems of insufficient fabric load-bearing capacity and fabric-mortar interface slippage. It plays a crucial role in improving the load-bearing capacity during the fabric-mortar co-stress stage of the repair system's service life.

[0011] Preferably, the low-modulus fiber is one or more selected from polyvinyl alcohol fiber, polyvinyl alcohol formal fiber, polyvinyl chloride fiber, polypropylene fiber, polyacrylonitrile fiber, polyamide fiber, polyimide fiber, polyester fiber, polyurethane fiber, cellulose fiber, polytetrafluoroethylene fiber, and phenyl sulfide fiber. The high-modulus fiber is one of aramid fiber, polybenzimidazole fiber, polybenzodioxazole fiber, polyarylate fiber, ultra-high molecular weight polyethylene fiber, glass fiber, carbon fiber, steel fiber, continuous basalt fiber, silicon carbide fiber, magnesium oxide fiber, alumina fiber, silica fiber, aluminum silicate fiber, graphene fiber, and boron fiber.

[0012] The preparation method of the fabric repair mortar composite material as described above includes the following steps:

[0013] (1) Preparation of the stretched fabric: (a) Using low-modulus fiber bundles as core fibers and high-modulus fiber bundles as auxiliary fibers, the auxiliary fibers are spirally wound onto the core fibers to obtain a stretched fiber preform with a negative Poisson's ratio effect. (b) The stretched fiber preform is woven into a net according to the mesh size and weaving method, and then bonded and shaped to obtain the stretched fabric. (c) The stretched fabric is surface-treated to chemically graft nano-SiO2 particles onto the stretched fabric. Specifically, the fabric is immersed in a 0.5wt% silane coupling agent / anhydrous ethanol solution, reacted at 80℃ for 4 hours, and then dried to achieve the purpose of modifying the fabric surface; then it is immersed in a 0.5wt% nano-SiO2 solution for 15 minutes and dried at 100℃ to graft nano-SiO2 particles onto the fabric.

[0014] (2) Preparation of polymer-modified mortar: (a) Weigh 1 part by weight of cement, 0.2 parts by weight of fly ash, 2.5 parts by weight of sand, 0.44 parts by weight of water, 0.1-1.0 parts by weight of toughening polymer, 0.03 parts by weight of water-reducing agent, and appropriate amounts of curing agent and defoamer. (b) Slowly dry mix the cement, fly ash, and sand until uniformly mixed, then add water, toughening polymer, water-reducing agent, curing agent, and defoamer, and slowly stir until uniformly mixed to obtain polymer-modified mortar. As mentioned above, the weight ratio of toughening polymer to cement / fly ash is the key to the polymer-modified mortar described in this application. After adding the toughening polymer to the repair mortar according to the aforementioned ratio, a polymer transition layer can be formed at the repair mortar-matrix interface, increasing the interfacial bonding between the two, which is beneficial for passivating the stress concentration at the crack tip of the mortar specimen, effectively preventing further crack propagation, thereby improving the performance of cement mortar.

[0015] (3) Preparation of fabric repair mortar composite material: (a) Surface treatment of the matrix to achieve a surface roughness of 0.5-1.5, and application of an interface agent. By controlling the matrix roughness and applying the interface agent, the bonding strength of the mortar-matrix interface is significantly improved. (b) A layer of polymer-modified mortar is poured onto the treated matrix, followed by the laying of a tensile fabric, and finally another layer of polymer-modified mortar is poured. The thickness of each layer of polymer-modified mortar is 5-10 mm. (c) Curing and solidification are performed to obtain the fabric repair mortar composite material. The optimized fabric repair mortar composite material uses a tensile fabric with significantly optimized performance, and the bonding strength of the fabric-mortar is achieved through surface treatment of the fabric. At the same time, the roughness of the interface is improved by adjusting the proportion of each component in the polymer-modified mortar, thereby achieving the bonding strength of the fabric-matrix interface, thus obtaining an infrastructure disaster reinforcement and repair mortar system with overall synergistic load-bearing deformation function.

[0016] The beneficial effects of this invention are:

[0017] (1) The tensile strength of the taut fabric described in this application is 128.66–155.47 MPa, which is 8.30%–30.87% higher than that of the woven fabric and 59.95%–93.27% higher than that of the fabric with a mesh size of 20 mm; the breaking energy is 4.29–5.79 kJ / m. 3 Compared to woven fabrics, it improves efficiency by 6.50% to 43.67%, and compared to fabrics with a mesh size of 20mm, it improves efficiency by 15.63% to 56.06%.

[0018] (2) The tensile fabric composite repair mortar composite material described in this application, through the design of the fabric-mortar interface, obtains an interface structure with optimal bonding strength by grafting 0.5wt% nano SiO2. At this concentration, the grafting rate of nanoparticles reaches 5.75% to 6.78%, the bonding strength is increased by 3.10% to 36.08%, and the interfacial slippage in the middle and late stages of loading is reduced by 34.40% to 78.93%.

[0019] (3) The tensile fabric composite repair mortar composite material described in this application achieves significant improvement in performance during the mid-to-late stage of loading and the late stage of loading by designing the proportion of polymer modified mortar and the interface structure of fabric mortar-matrix; compared with ordinary fabric mortar, its splitting strength is increased by 13.40% to 49.61% and its shear strength is increased by 5.98% to 47.21%.

[0020] (4) The tensile fabric composite repair mortar composite material described in this application, through the design of the fabric structure, fabric-mortar interface and mortar-matrix interface, obtains a system with excellent load-bearing capacity and bonding performance throughout the service life of the repair mortar. Its bending strength is increased by 19.06% to 59.20%, which improves the failure mode in the middle and late stages of loading, thereby solving the problem of damage caused by the aforementioned insufficient performance of fabric mortar. Attached Figure Description

[0021] Appendix Figure 1 This is a schematic diagram of the structure of the tensile fabric composite mortar described in this application and the tensile fiber preform under tensile deformation.

[0022] Appendix Figure 2 This is a schematic diagram of the internal structure of the repair mortar described in this application and the intermolecular cross-linking effect in the transition zone of the mortar-matrix interface after treatment.

[0023] Appendix Figure 3 This is a schematic diagram of the tensile fabric structure with different weaving methods inside the repair mortar constructed in this design.

[0024] Appendix Figure 4These are SEM microscopic images of the stretched fabric before and after surface treatment in Example 4.

[0025] Among them: 1. Tensile deformation process of fiber preform; 2. Fiber-mortar interface; 3. Mortar-matrix interface; 4. Polymer modified mortar; 5. Matrix; 6. Molecular cross-linking between mortar and matrix; 7. Toughening polymer; 8. Sand; 9. Mortar-matrix interface transition zone; 10. Plain weave; 11. Twill weave; 12. Satin weave. Detailed Implementation

[0026] The present invention will be further described below with reference to the embodiments.

[0027] Example 1: Preparation of Stretch Fabric

[0028] The tensile fabric is a fiber fabric obtained by weaving a tensile fiber preform with a negative Poisson's ratio effect into a web according to a certain mesh size and weaving method. The mesh size is 5 mm, and the weaving method is plain weave. The tensile fiber preform consists of a low-modulus fiber bundle as the core fiber and a high-modulus fiber bundle as the auxiliary fiber, with the auxiliary fiber spirally wound on the core fiber. The diameter of the low-modulus fiber bundle is 1500-1600 μm, and the diameter of the high-modulus fiber bundle is 500-600 μm. The low-modulus fiber is polyvinyl alcohol fiber, and the high-modulus fiber is carbon fiber.

[0029] Example 2: Preparation of Stretch Fabric

[0030] The tensile fabric is a fiber fabric obtained by weaving a tensile fiber preform with a negative Poisson's ratio effect into a web according to a certain mesh size and weaving method. The mesh size is 10 mm, and the weaving method is twill weave. The tensile fiber preform consists of a low-modulus fiber bundle as the core fiber and a high-modulus fiber bundle as the auxiliary fiber, with the auxiliary fiber spirally wound on the core fiber. The diameter of the low-modulus fiber bundle is 1500-1600 μm, and the diameter of the high-modulus fiber bundle is 500-600 μm. The low-modulus fiber is polypropylene fiber, and the high-modulus fiber is basalt fiber.

[0031] Example 3: Preparation of Stretch Fabric

[0032] The tensile fabric is a fiber fabric obtained by weaving a tensile fiber preform with a negative Poisson's ratio effect into a web according to a certain mesh size and weaving method. The mesh size is 15mm, and the weaving method is satin weave. The tensile fiber preform consists of a low-modulus fiber bundle as the core fiber and a high-modulus fiber bundle as the auxiliary fiber, with the auxiliary fiber spirally wound on the core fiber. The diameter of the low-modulus fiber bundle is 1500-1600μm, and the diameter of the high-modulus fiber bundle is 500-600μm. The low-modulus fiber is polypropylene fiber, and the high-modulus fiber is aramid fiber.

[0033] Example 4: Fabric Repair Mortar Composite Material and its Preparation

[0034] A fabric repair mortar composite material with excellent load-bearing capacity and bonding strength includes a tensile fabric and a polymer-modified mortar, wherein the polymer-modified mortar is bonded to the upper and lower surfaces of the tensile fabric.

[0035] The polymer-modified mortar, by weight, comprises 1 part cement, 0.2 parts fly ash, 2.5 parts sand, 0.44 parts water, 1.0 part toughening polymer, 0.03 parts water-reducing agent, and appropriate amounts of curing agent and defoamer. The curing agent is used at half the amount of the toughening polymer; the defoamer is used at 1% of the amount of the toughening polymer. The toughening polymer is epoxy resin.

[0036] The turbulent fabric is a fiber fabric obtained by weaving a turbulent fiber preform with a negative Poisson's ratio effect into a web according to a certain mesh size and weaving method. The surface of the turbulent fabric is chemically grafted with nano-SiO2 particles after modification treatment. The mesh size is 5 mm, and the weaving method is plain weave. The turbulent fiber preform consists of low-modulus fiber bundles as core fibers and high-modulus fiber bundles as auxiliary fibers, with the auxiliary fibers spirally wound on the core fibers. The diameter of the low-modulus fiber bundles is 1500-1600 μm, and the diameter of the high-modulus fiber bundles is 500-600 μm. The low-modulus fiber is polyvinyl alcohol fiber, and the high-modulus fiber is carbon fiber.

[0037] Preparation of the fabric repair mortar composite material:

[0038] (1) Preparation of stretchable fabric:

[0039] (1) Low-modulus fiber is selected as the core fiber and high-modulus fiber as the auxiliary fiber. The core fiber and auxiliary fiber are fixed on a fiber twisting machine and twisted separately to obtain a tight fiber bundle; then the core fiber is fixed on a fiber winding machine and the auxiliary fiber is spirally wound on the core fiber to obtain a tensile fiber preform with a negative Poisson's ratio effect.

[0040] (2) The preform of the tensile fiber is woven into a net according to a certain grid size and weaving method, and the nodes are impregnated with glue and bonded to shape it, so as to obtain the tensile fabric.

[0041] (3) Fabric surface treatment (fabric-mortar interface design):

[0042] The fabric was immersed in a 0.5% wt silane coupling agent / anhydrous ethanol solution, refluxed at 80°C for 4 hours, and then air-dried to achieve the purpose of modifying the fabric surface. Subsequently, the fabric was immersed in a 0.5% wt nano SiO2 solution for 15 minutes and then placed in an oven to dry at 100°C for 8 hours, so that the nano SiO2 particles were grafted onto the fabric.

[0043] 2. Preparation of polymer-modified mortar:

[0044] Weigh out cement, fly ash, sand, water, toughening polymer, water-reducing agent, curing agent, and defoamer. Slowly dry mix cement, fly ash, and sand until uniformly mixed. Then add water, toughening polymer, water-reducing agent, curing agent, and defoamer, and slowly stir until uniformly mixed to obtain polymer-modified mortar.

[0045] (3) Preparation of fabric repair mortar composite material:

[0046] (a) Preparation and treatment of the matrix:

[0047] (1) Matrix preparation: Dry mix the weighed cement and sand for 1 minute until uniform; add the weighed water and admixtures to the uniformly mixed dry material and stir for 3 minutes. To reduce air bubbles, the mixer is manually operated at low speed throughout the process. After pouring into the mold, demold after 1 day and cure for 28 days to obtain the matrix.

[0048] (2) Surface treatment of the substrate (design of the substrate-mortar interface)

[0049] ① Matrix moisture content: Place the matrix in an oven and dry at 85±5℃ for 48 hours until the quality stabilizes, which is considered the dry state. Record the mass of the specimen after drying and cooling. Then, immerse the specimen in a seawater tank. After the specimen reaches the required moisture content (8%), take it out and seal the specimens with different moisture contents with plastic wrap for 5 days to allow the internal moisture to fully diffuse.

[0050] ② Interface roughness:

[0051] The substrate is surface treated to achieve a surface roughness of 1.5, and then coated with an organic interface agent, epoxy resin.

[0052] (b) A layer of polymer-modified mortar is poured onto the treated substrate, followed by the laying of a tensile fabric, and finally another layer of polymer-modified mortar is poured. The thickness of each layer of polymer-modified mortar is 5 mm. (c) Curing and hardening are performed to obtain the fabric repair mortar composite material.

[0053] Example 5: Fabric Repair Mortar Composite Material and its Preparation

[0054] Unlike Example 4,

[0055] The polymer-modified mortar, by weight, consists of 1 part cement, 0.2 parts fly ash, 2.5 parts sand, 0.44 parts water, 0.8 parts toughening polymer, 0.03 parts water-reducing agent, and appropriate amounts of curing agent and defoamer. The toughening polymer is epoxy resin.

[0056] The tensioned fabric has a mesh size of 10mm and is twill woven. The low-modulus fiber bundles in the tensioned fiber preform have a diameter of 1500-1600μm, and the high-modulus fiber bundles have a diameter of 500-600μm. The low-modulus fiber is polyvinyl alcohol fiber, and the high-modulus fiber is carbon fiber.

[0057] Preparation of the fabric repair mortar composite material:

[0058] 1. Preparation of the stretch fabric: Same as in Example 1.

[0059] 2. Preparation of polymer-modified mortar: Same as in Example 1.

[0060] 3. Preparation of fabric repair mortar composite material:

[0061] (a) Preparation and treatment of the matrix:

[0062] (1) Matrix preparation: Same as in Example 1.

[0063] (2) Surface treatment of the substrate (design of the substrate-mortar interface)

[0064] ① Matrix moisture content: The matrix was placed in an oven and dried at 85±5℃ for 48 hours until the quality stabilized, which was considered the dry state. The mass of the specimen after drying and cooling was recorded. Then, the specimen was immersed in a seawater tank. After the specimen reached the required moisture content (8%), it was taken out and sealed with plastic wrap for 5 days to allow the internal moisture to fully diffuse. ② Interface roughness: The matrix was surface treated to achieve a surface roughness of 1.5 and coated with an organic interface agent, epoxy resin.

[0065] (b) A layer of polymer-modified mortar is poured onto the treated substrate, followed by the laying of a tensile fabric, and finally another layer of polymer-modified mortar is poured. The thickness of each layer of polymer-modified mortar is 5 mm. (c) Curing and hardening are performed to obtain the fabric repair mortar composite material.

[0066] Example 6: Fabric Repair Mortar Composite Material and its Preparation

[0067] Unlike Example 4,

[0068] The polymer-modified mortar, by weight, consists of 1 part cement, 0.2 parts fly ash, 2.5 parts sand, 0.44 parts water, 0.6 parts toughening polymer, 0.03 parts water-reducing agent, and appropriate amounts of curing agent and defoamer. The toughening polymer is polyurea.

[0069] The mesh size of the stretch fabric is 15mm, and the weaving method is satin weave. The diameter of the low-modulus fiber bundles in the stretch fiber preform is 1500-1600μm, and the diameter of the high-modulus fiber bundles is 500-600μm. The low-modulus fiber is polyvinyl alcohol fiber, and the high-modulus fiber is ultra-high molecular weight polyvinyl alcohol fiber.

[0070] Preparation of the fabric repair mortar composite material:

[0071] 1. Preparation of the stretch fabric: Same as in Example 1.

[0072] 2. Preparation of polymer-modified mortar: Same as in Example 1.

[0073] 3. Preparation of fabric repair mortar composite material:

[0074] (a) Preparation and treatment of the matrix:

[0075] (1) Matrix preparation: Same as in Example 1.

[0076] (2) Surface treatment of the substrate (design of the substrate-mortar interface)

[0077] ① Matrix moisture content: The matrix was placed in an oven and dried at 85±5℃ for 48 hours until the quality stabilized, which was considered the dry state. The mass of the specimen after drying and cooling was recorded. Then, the specimen was immersed in a seawater tank. After the specimen reached the required moisture content (6%), it was taken out and sealed with plastic wrap for 5 days to allow the internal moisture to fully diffuse. ② Interface roughness: The matrix was surface treated to achieve a surface roughness of 1.0 and coated with an organic interface agent, epoxy resin.

[0078] (b) A layer of polymer-modified mortar is poured onto the treated substrate, followed by the laying of a tensile fabric, and finally another layer of polymer-modified mortar is poured. The thickness of each layer of polymer-modified mortar is 5 mm. (c) Curing and hardening are performed to obtain the fabric repair mortar composite material.

[0079] Example 7: Fabric Repair Mortar Composite Material and its Preparation

[0080] Unlike Example 4,

[0081] The polymer-modified mortar, by weight, consists of 1 part cement, 0.2 parts fly ash, 2.5 parts sand, 0.44 parts water, 0.3 parts toughening polymer, 0.03 parts water-reducing agent, and appropriate amounts of curing agent and defoamer. The toughening polymer is polyurethane.

[0082] The mesh size of the stretch fabric is 5mm, and the weaving method is plain weave. The diameter of the low-modulus fiber bundles in the stretch fiber preform is 1500-1600μm, and the diameter of the high-modulus fiber bundles is 500-600μm. The low-modulus fiber is polyvinyl alcohol formal fiber, and the high-modulus fiber is ultra-high molecular weight polyvinyl alcohol fiber.

[0083] Preparation of the fabric repair mortar composite material:

[0084] 1. Preparation of the stretch fabric: Same as in Example 1.

[0085] 2. Preparation of polymer-modified mortar: Same as in Example 1.

[0086] 3. Preparation of fabric repair mortar composite material:

[0087] (a) Preparation and treatment of the matrix:

[0088] (1) Matrix preparation: Same as in Example 1.

[0089] (2) Surface treatment of the substrate (design of the substrate-mortar interface)

[0090] ① Matrix moisture content: The matrix was placed in an oven and dried at 85±5℃ for 48 hours until the quality stabilized, which was considered the dry state. The mass of the specimen after drying and cooling was recorded. Then, the specimen was immersed in a seawater tank. After the specimen reached the required moisture content (5%), it was taken out and sealed with plastic wrap for 5 days to allow the internal moisture to fully diffuse. ② Interface roughness: The matrix was surface treated to achieve a surface roughness of 1.0 and coated with an organic interface agent, epoxy resin.

[0091] (b) A layer of polymer-modified mortar is poured onto the treated substrate, followed by the laying of a tensile fabric, and finally another layer of polymer-modified mortar is poured. The thickness of each layer of polymer-modified mortar is 5 mm. (c) Curing and hardening are performed to obtain the fabric repair mortar composite material.

[0092] Example 8: Fabric Repair Mortar Composite Material and its Preparation

[0093] Unlike Example 4,

[0094] The polymer-modified mortar, by weight, consists of 1 part cement, 0.2 parts fly ash, 2.5 parts sand, 0.44 parts water, 0.1 parts toughening polymer, 0.03 parts water-reducing agent, and appropriate amounts of curing agent and defoamer. The toughening polymer is phenolic resin.

[0095] The mesh size of the stretch fabric is 10mm, and the weaving method is twill weave. The diameter of the low-modulus fiber bundles in the stretch fiber preform is 1500-1600μm, and the diameter of the high-modulus fiber bundles is 500-600μm. The low-modulus fiber is cellulose fiber, and the high-modulus fiber is ultra-high molecular weight polyvinyl alcohol fiber.

[0096] Preparation of the fabric repair mortar composite material:

[0097] 1. Preparation of the stretch fabric: Same as in Example 1.

[0098] 2. Preparation of polymer-modified mortar: Same as in Example 1.

[0099] 3. Preparation of fabric repair mortar composite material:

[0100] (a) Preparation and treatment of the matrix:

[0101] (1) Matrix preparation: Same as in Example 1.

[0102] (2) Surface treatment of the substrate (design of the substrate-mortar interface)

[0103] ① Matrix moisture content: The matrix was placed in an oven and dried at 85±5℃ for 48 hours until the quality stabilized, which was considered the dry state. The mass of the specimen after drying and cooling was recorded. Then, the specimen was immersed in a seawater tank. After the specimen reached the required moisture content (3%), it was taken out and sealed with plastic wrap for 5 days to allow the internal moisture to fully diffuse. ② Interface roughness: The matrix was surface treated to achieve a surface roughness of 0.5 and coated with an organic interface agent, epoxy resin.

[0104] (b) A layer of polymer-modified mortar is poured onto the treated substrate, followed by the laying of a tensile fabric, and finally another layer of polymer-modified mortar is poured. The thickness of each layer of polymer-modified mortar is 5 mm. (c) Curing and hardening are performed to obtain the fabric repair mortar composite material.

[0105] Comparative Example 1: Stretch fabric using other weaving methods

[0106] The difference from Example 1 is:

[0107] The tensile fabric is a fiber fabric obtained by weaving a tensile fiber preform with a negative Poisson's ratio effect into a web according to a certain mesh size and weaving method. The mesh size is 15mm, and the weaving method is woven. The tensile fiber preform consists of a low-modulus fiber bundle as the core fiber and a high-modulus fiber bundle as the auxiliary fiber, with the auxiliary fiber spirally wound on the core fiber. The diameter of the low-modulus fiber bundle is 1500-1600μm, and the diameter of the high-modulus fiber bundle is 500-600μm. The low-modulus fiber is polyvinyl alcohol fiber, and the high-modulus fiber is carbon fiber.

[0108] Comparative Example 2: Using stretch fabrics with other mesh sizes

[0109] The difference from Example 1 is:

[0110] The tensile fabric is a fiber fabric obtained by weaving a tensile fiber preform with a negative Poisson's ratio effect into a web according to a certain mesh size and weaving method. The mesh size is 20 mm, and the weaving method is plain weave. The tensile fiber preform consists of a low-modulus fiber bundle as the core fiber and a high-modulus fiber bundle as the auxiliary fiber, with the auxiliary fiber spirally wound on the core fiber. The diameter of the low-modulus fiber bundle is 1500-1600 μm, and the diameter of the high-modulus fiber bundle is 500-600 μm. The low-modulus fiber is polyvinyl alcohol fiber, and the high-modulus fiber is carbon fiber.

[0111] Comparative Example 3: Preparation of Fabric Repair Mortar Composite Material Using Ordinary Fabrics

[0112] Unlike Example 4,

[0113] The fabric is a commercially available fiberglass fabric. The mesh size is 5mm, and the weaving method is plain weave. The diameter of the fiber bundle is 2000-2100μm.

[0114] Preparation of the fabric repair mortar composite material:

[0115] 1. Preparation of polymer-modified mortar: Same as in Example 1.

[0116] 2. Preparation of fabric repair mortar composite material: Same as in Example 1.

[0117] Comparative Example 4: Preparation of Fabric Repair Mortar Composite Material Using Ordinary Mortar

[0118] Unlike Example 4,

[0119] The mortar was not modified and, by weight, consisted of 1 part cement, 0.2 parts fly ash, 2.5 parts sand, 0.44 parts water, and 0.03 parts water-reducing agent.

[0120] Preparation of the fabric repair mortar composite material:

[0121] 1. Preparation of the stretch fabric: Same as in Example 1.

[0122] 2. Preparation of polymer-modified mortar: Same as in Example 1.

[0123] 3. Preparation of fabric repair mortar composite material: Same as in Example 1.

[0124] Comparative Example 5: Fabric Repair Mortar Composite Material with Untreated Substrate Surface

[0125] Unlike Example 4,

[0126] Preparation of the fabric repair mortar composite material:

[0127] 1. Preparation of the stretch fabric: Same as in Example 1.

[0128] 2. Preparation of polymer-modified mortar: Same as in Example 1.

[0129] 3. Preparation of fabric repair mortar composite material:

[0130] (a) Preparation and treatment of the matrix:

[0131] (1) Matrix preparation: Same as in Example 1.

[0132] (2) Surface treatment of substrate (substrate-mortar interface design): No treatment was performed.

[0133] (b) A layer of polymer-modified mortar is poured onto the treated substrate, followed by the laying of a tensile fabric, and finally another layer of polymer-modified mortar is poured. The thickness of each layer of polymer-modified mortar is 5 mm. (c) Curing and hardening are performed to obtain the fabric repair mortar composite material.

[0134] Comparative Example 6: Using the fabric repair mortar composite material in an anhydrous matrix

[0135] Unlike Example 4,

[0136] Preparation of the fabric repair mortar composite material:

[0137] 1. Preparation of the stretch fabric: Same as in Example 1.

[0138] 2. Preparation of polymer-modified mortar: Same as in Example 1.

[0139] 3. Preparation of fabric repair mortar composite material:

[0140] (a) Preparation and treatment of the matrix:

[0141] (1) Matrix preparation: Same as in Example 1.

[0142] (2) Surface treatment of the substrate (substrate-mortar interface design): ① Moisture content of the substrate: Place the substrate in an oven and dry it at 85±5℃ for 48 hours until the quality stabilizes. This is considered a dry state with a moisture content of 0%. Seal the specimens with plastic wrap and store them for 5 days. ② Interface roughness: Perform surface treatment on the substrate to achieve a surface roughness of 1.5, and coat it with an organic interface agent, epoxy resin.

[0143] (b) A layer of polymer-modified mortar is poured onto the treated substrate, followed by the laying of a tensile fabric, and finally another layer of polymer-modified mortar is poured. The thickness of each layer of polymer-modified mortar is 5 mm. (c) Curing and hardening are performed to obtain the fabric repair mortar composite material.

[0144] Example 9: Characterization of fabrics prepared in Examples 1-3 and Comparative Examples 1-2

[0145] The stretched fabrics prepared in Examples 1-3 and the ordinary fabrics in Comparative Examples 1-2 were characterized. The specific characterization methods are as follows: (1) The fabrics described in Examples 1-3 and Comparative Examples 1-2 were subjected to tensile tests using the wide strip stretching method. The results are detailed in Table 1. (2) The maximum negative Poisson's ratio that occurred during the stretching process was calculated according to the definition of Poisson's ratio. The results are detailed in Table 1.

[0146] Table 1. Tensile test results and Poisson's ratio of the fabrics

[0147] Sample number Tensile strength / MPa <![CDATA[Fracture energy absorption / (kJ / m 3 )]]> Maximum negative Poisson's ratio Example 1 155.47 5.79 -2.54 Example 2 133.25 4.94 -2.05 Example 3 128.66 4.29 -1.47 Comparative Example 1 118.8 4.03 -1.62 Comparative Example 2 80.44 3.71 -1.59

[0148] Results analysis:

[0149] As shown in Table 1, the tensile fabrics prepared in Examples 1-3 and Comparative Examples 1-2 all exhibited negative Poisson's ratios. The tensile strength of the tensile fabrics prepared in Examples 1-3 ranged from 128.66 to 155.47 MPa, and the breaking energy ranged from 4.29 to 5.79 kJ / m. 3 Compared to ordinary woven tensile fabrics (tensile strength 118.8 MPa, breaking energy 4.03 kJ / m),... 3 And a tensile fabric with a mesh size of 20mm (tensile strength 80.44MPa, breaking energy 3.71kJ / m²). 3 In contrast, the fabrics prepared in Examples 1-3 of this application have significantly improved mechanical properties by designing the fabric with a negative Poisson's ratio, thus solving the problem of failure of the fabric composite repair mortar in the early stage of loading due to insufficient load-bearing capacity of the fabric.

[0150] Example 10: Characterization of the fabric repair mortar composite materials prepared in Examples 4-8 and Comparative Examples 3-6

[0151] The fabric repair mortar composite materials prepared in Examples 4-8 and Comparative Examples 3-6 were characterized using the following methods:

[0152] (1) The stretched fabrics in Examples 4-8 were tested using SEM before and after surface treatment, and their microstructure images are shown below. Figure 4 As shown.

[0153] (2) The grafting rate of nano-SiO2 on the surface of the stretched fabric described in Examples 4-6 was tested by mass method. The results are detailed in Table 2.

[0154] (3) Pull-out test and axial tensile test were performed on the fabric composite repair mortar described in Examples 4-8 and Comparative Example 3. The results are detailed in Table 3.

[0155] (4) The splitting tensile and shear strength of the fabric composite repair mortars described in Examples 4-8 and Comparative Examples 4-6 were tested using the splitting method and the direct shear method. The results are detailed in Table 4.

[0156] (5) The three-point bending method was used to test the fabric composite repair mortar described in Examples 4-8 and Comparative Examples 4-6. The results are detailed in Table 5.

[0157] Table 2. Test results of the grafting rate of nano-SiO2 on the surface of the stretched fabric.

[0158] Sample number <![CDATA[Initial mass m1 / g]]> <![CDATA[Final mass (m2) / g]]> Grafting rate / % Example 4 2.32 2.48 6.05 Example 5 1.62 1.67 6.78 Example 6 1.29 1.38 5.75

[0159] Table 3. Pull-out and tensile test results of fabric composite repair mortar

[0160] Sample number Bond strength / MPa Interface sliding / mm Tensile strength / MPa Example 4 2.64 1.06 5.12 Example 5 2.40 2.16 4.83 Example 6 2.00 3.30 4.42 Example 7 2.53 1.44 5.07 Example 8 2.25 1.25 4.99 Comparative Example 3 1.94 5.03 3.03

[0161] Table 4. Splitting and shear test results of fabric composite repair mortar

[0162] Sample number Splitting tensile strength / MPa Shear strength / MPa Example 4 5.76 3.43 Example 5 5.53 3.15 Example 6 5.37 2.94 Example 7 5.15 2.72 Example 8 4.88 2.66 Comparative Example 4 3.85 2.33 Comparative Example 5 4.30 2.51 Comparative Example 6 4.03 2.43

[0163] Table 5. Bending test results of fabric composite repair mortar

[0164]

[0165] Results analysis:

[0166] Depend on Figure 4The characterization results show that before surface treatment, the fiber surface is smooth and has poor wettability. After treatment, grooves appear on the fiber surface, and the wettability with inorganic minerals is improved. In addition, a large amount of nano-SiO2 is grafted onto the surface. As shown in Table 2, the grafting rate of nano-SiO2 reaches 5.75-6.78%, and the roughness of the fiber surface is greatly increased, which plays a role in improving the slippage and damage between the fabric and the mortar.

[0167] As shown in Table 3, the fabric composite repair mortars prepared in Examples 4-8 exhibit an interfacial bond strength of 2.00-2.64 MPa, an interfacial slip of 1.06-3.30 mm, and a tensile strength of 4.42-5.12 MPa. Compared with existing fabric composite repair mortars (interfacial bond strength 1.94 MPa, interfacial slip 5.03 mm, tensile strength 3.03 MPa), this application, through negative Poisson's ratio design of the fiber fabric and interfacial treatment of the fabric-mortar interface, can significantly improve the mechanical properties of the fabric composite mortar system in the early stage of loading, suppress the generation and development of interfacial slip, and fully utilize the synergistic stress-bearing effect of the fabric and mortar.

[0168] As shown in Table 4, the fabric composite repair mortars prepared in Examples 4-8 exhibit a splitting strength of 4.88-5.76 MPa and a shear strength of 2.66-3.43 MPa at the mortar-matrix interface. In contrast, in Comparative Example 2 (ordinary mortar), the splitting strength at the mortar-matrix interface was 3.85 MPa and the shear strength was 2.33 MPa; in Comparative Example 3 (untreated matrix surface), the splitting strength was 4.30 MPa and the shear strength was 2.51 MPa; and in Comparative Example 4 (matrix without water), the splitting strength was 4.03 MPa and the shear strength was 2.43 MPa. This demonstrates that, compared to existing fabric composite repair mortars, this invention, through the design of the mortar formulation and the mortar-matrix interface, effectively enhances the interfacial bonding performance and improves the mortar's ability to delaminate during the early stages of loading and to prevent slippage at the mortar-fabric interface during the later stages of loading. It is important to emphasize that the fabric composite repair mortars prepared in Examples 4-8 exhibit superior parameters compared to anhydrous matrices when the matrix moisture content is 3-8%, indicating that they are suitable not only for ordinary environments but also for high-moisture environments. This solves the repair problems of coastal infrastructure in existing technologies, significantly extends their service life, and has significant practical application value.

[0169] As shown in Table 5, the flexural strength of the fabric composite mortars prepared in Examples 4-8 of this application is 3.96-4.76 MPa, and in all cases, the fabric and mortar failed simultaneously in the later stages of loading, with the fabric partially breaking. In contrast, in Comparative Example 1 (ordinary fabric), the flexural strength was 2.99 MPa, and slippage occurred at the interface between the fabric and mortar in the middle and later stages of loading; in Comparative Example 2 (ordinary mortar), the flexural strength was 3.34 MPa, and the mortar peeled off in the early and middle stages of loading, and slipped with the matrix in the later stages of loading; in Comparative Example 3 (untreated matrix surface), the flexural strength was 3.16 MPa, and peeling occurred between the mortar and the matrix in the later stages of loading; in Comparative Example 4 (matrix without water), the flexural strength was 3.01 MPa, and shrinkage cracks existed between the mortar and the matrix in the later stages of loading. This shows that, compared with existing fabric composite repair mortars, the fabric composite mortars prepared in Examples 4-8 of this application not only have significantly improved flexural strength, but also have improved failure modes at each stage of bending load, thus solving the problems caused by the aforementioned deficiencies of fabric composite repair mortars.

Claims

1. A fabric repair mortar composite having excellent load bearing capacity and bond strength, characterized by: The invention comprises a tensile fabric and a polymer-modified mortar, wherein the polymer-modified mortar is bonded to the upper and lower surfaces of the tensile fabric; the polymer-modified mortar, by weight, consists of 1 part cement, 0.2 parts fly ash, 2.5 parts sand, 0.44 parts water, 0.1-1.0 parts toughening polymer, 0.03 parts water-reducing agent, and appropriate amounts of curing agent and defoamer; the amount of curing agent is 1 / 2 of the amount of toughening polymer; the amount of defoamer is 1% of the amount of toughening polymer; the tensile fabric is a fiber fabric obtained by weaving a preform of tensile fibers with a negative Poisson's ratio effect into a web according to a certain mesh size and weaving method; wherein the mesh size is 5-15mm, and the weaving method is plain weave, twill weave, or satin weave.

2. The fabric restoration mortar composite of claim 1, wherein: The toughening polymer is one of polyurea, epoxy resin, polyurethane, acrylic resin, phenolic resin, urea-formaldehyde resin, and silicone resin.

3. The fabric restoration mortar composite of claim 1 or 2, wherein: The tensile fiber preform is obtained by using low-modulus fiber bundles as core fibers and high-modulus fiber bundles as auxiliary fibers, with the auxiliary fibers spirally wound around the core fibers.

4. The fabric restoration mortar composite of claim 3, wherein: The low-modulus fiber bundle has a diameter of 1500-1600 μm, and the high-modulus fiber bundle has a diameter of 500-600 μm.

5. The fabric restoration mortar composite of claim 3, wherein: The low-modulus fiber is one or more of the following: polyvinyl alcohol fiber, polyvinyl alcohol formal fiber, polyvinyl chloride fiber, polypropylene fiber, polyacrylonitrile fiber, polyamide fiber, polyimide fiber, polyester fiber, polyurethane fiber, cellulose fiber, polytetrafluoroethylene fiber, and phenyl sulfide fiber; the high-modulus fiber is one of the following: aramid fiber, polybenzimidazole fiber, polybenzodioxazole fiber, polyarylate fiber, ultra-high molecular weight polyethylene fiber, glass fiber, carbon fiber, steel fiber, continuous basalt fiber, silicon carbide fiber, magnesium oxide fiber, alumina fiber, silica fiber, aluminum silicate fiber, graphene fiber, and boron fiber.

6. The fabric restoration mortar composite of claim 3, wherein: The surface of the stretched fabric is modified by chemical grafting of nano-SiO2 particles.

7. The method of making a fabric restorative grout composite of any of claims 1-6, wherein: Includes the following steps: (1) Preparation of auxetic fabric: (a) taking low modulus fiber bundle as core fiber and high modulus fiber bundle as auxiliary fiber, the auxiliary fiber is spirally wound on the core fiber, and an auxetic fiber preform with negative Poisson's ratio effect is obtained; (b) the auxetic fiber preform is woven into a net according to the grid size and weaving method, and is bonded and shaped to obtain an auxetic fabric; (c) surface treatment is performed on the auxetic fabric, and nano-SiO2 particles are chemically grafted on the surface of the auxetic fabric; (2) Preparation of polymer modified mortar: (a) weighing 1 part by weight of cement, 0.2 parts by weight of fly ash, 2.5 parts by weight of sand, 0.44 parts by weight of water, 0.1-1.0 parts by weight of toughening polymer, 0.03 parts by weight of water reducing agent and appropriate amount of curing agent and defoaming agent; (b) the cement, fly ash and sand are slowly mixed and dried until uniform, then the water, toughening polymer, water reducing agent, curing agent and defoaming agent are added and slowly stirred until uniform, and the polymer modified mortar is prepared; (3) Preparation of fabric repaired mortar composite material: (a) surface treatment is performed on the substrate to make the surface roughness reach 0.5~1.5, and an interface agent is coated; (b) a layer of polymer modified mortar is poured on the treated substrate, then the auxetic fabric is laid, and finally another layer of polymer modified mortar is poured; (c) curing, to obtain a fabric repaired mortar composite material.

8. The method of claim 7, wherein the fabric repair mastic composite is prepared by: The interface agent in step (3) is an organic interface agent; the thickness of each layer of polymer modified mortar is 5-10mm.

9. The method of claim 7, wherein the fabric repair mastic composite is prepared by: Step (1c) is specifically: soaking the fabric in a 0.5%wt silane coupling agent / anhydrous ethanol solution, reacting at 80℃ for 4h and drying; then soaking in a 0.5%wt nano-SiO2 solution for 15min and drying at 100℃, so that the nano-SiO2 particles are grafted on the fabric.

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