Early-strength corrosion-resistant cement-thermal-shrinkage fiber three-dimensional mesh fabric composite material and preparation and construction method thereof

Abstract

The application discloses an early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material, which comprises a heat-shrinkable three-dimensional mesh spacer fabric matrix, iron aluminate cement modified magnesium phosphate cement filled in the matrix and a water-permeable and grout-resistant heat-shrinkable fiber non-woven fabric packaging layer arranged on the surface of the matrix; the spinning fiber of the three-dimensional mesh spacer fabric matrix comprises first temperature-shrinkage-induced anti-cracking fibers matched with the modified cement hydration heat release peak value and high modulus sheath layer temperature-shrinkage-core material phase change composite fibers; and the spinning fiber of the water-permeable and grout-resistant heat-shrinkable fiber non-woven fabric packaging layer comprises second temperature-shrinkage-induced fibers with low shrinkage rate. The application firstly combines the high hydration heat of the iron aluminate cement modified magnesium phosphate cement with the heat response characteristics of the heat-shrinkable fiber, and the two can synergistically act to simultaneously realize the improvement effects of self-regulation of stress, optimization of microstructure, regulation of interface transition zone and self-anti-cracking; and the construction method is simple, short in period and wide in applicability.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to an early-strength corrosion-resistant cement-thermal-shrinkable fiber three-dimensional mesh fabric composite material and its preparation and construction methods. Background Technology

[0002] Three-dimensional fabric-reinforced cementitious composites (3DTRC) are widely used in infrastructure reinforcement due to their lightweight, high strength, and good integrity. However, applying this technology to harsh environments such as the ocean still faces significant challenges: 1. Insufficient performance of traditional filler cement: Traditional silicate cement has low early strength and poor corrosion resistance, making it susceptible to erosion in marine environments, resulting in insufficient durability of 3DTRC; although magnesium phosphate cement has early strength characteristics, it has poor water resistance and significant strength loss in humid environments.

[0003] 2. Mismatch in thermal expansion coefficients: There is a significant difference in the thermal expansion coefficients between traditional polymer fibers (such as PES and PET) and cement matrix. During cement hydration, thermal stress is generated due to temperature changes, which leads to micro-cracks at the interface.

[0004] 3. Insufficient alkali resistance of fibers: Traditional polymer fibers are prone to hydrolysis and degradation in the strongly alkaline environment (pH 12-13) of cement matrix, resulting in decreased fiber strength and deterioration of interfacial properties.

[0005] 4. Insufficient interfacial bonding performance: The interfacial bonding strength between traditional fibers and cement matrix is ​​insufficient, resulting in low stress transfer efficiency and easy interfacial delamination.

[0006] Existing improved cementitious materials have demonstrated excellent early strength and water resistance in applications in cold and humid environments. However, their introduction into the 3DTRC system still presents problems such as mismatched coefficients of thermal expansion and insufficient interfacial bonding between fibers and the cement matrix, failing to achieve good stress self-regulation performance. Therefore, there is an urgent need to develop a new composite material that integrates early strength, corrosion resistance, self-stress regulation, and convenient construction. Summary of the Invention

[0007] The main objective of this invention is to address the problems and shortcomings of traditional 3DTRC by providing a heat-shrinkable fiber three-dimensional mesh fabric composite material pre-filled with early-strength corrosion-resistant cement. Under the high heat of hydration of aluminoferrite cement modified magnesium phosphate cement, the thermal shrinkage of the flexible fabric and its strong interfacial bonding coupling with the cement paste will apply compressive stress to the 3DTRC system, improve the original defects of the 3DTRC paste and regulate the microstructure of the transition zone between the fiber fabric and the paste, thereby improving the microstructure of 3DTRC, increasing its density, and fundamentally enhancing the resistance of 3DTRC to seawater erosion and abrasion.

[0008] Another objective of this invention is to provide a simple method for preparing and constructing pre-filled powder composite materials. The hydration reaction can be activated by a simple surface water spraying process, and the cycle is short. It is particularly suitable for rapid repair and reinforcement projects in the fields of marine environmental infrastructure.

[0009] To achieve the above objectives, the technical solution adopted by the present invention includes: A high-strength, corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material comprises a heat-shrinkable three-dimensional mesh spacer fabric matrix, modified cement powder filled in the matrix, and a water-permeable, slurry-resistant heat-shrinkable fiber nonwoven encapsulation layer disposed on the surface of the matrix; the modified cement is aluminoferrite cement modified magnesium phosphate cement; the spun fibers used in the three-dimensional mesh spacer fabric matrix include a first temperature-shrinkable induced crack-resistant fiber matching the peak value of the hydration exothermic reaction of the modified cement and a high-modulus sheath temperature-shrinkable-core material reinforced composite fiber; the spun fibers used in the water-permeable, slurry-resistant heat-shrinkable fiber nonwoven encapsulation layer include a second temperature-shrinkable induced crack-resistant fiber with a low shrinkage rate (3-10%). Thermo-shrinkable crack-resistant fiber has a cement-doped heat-shrinkable composite core and a polyvinyl alcohol sheath covering its surface; the sheath-thermo-shrinkable-core phase change composite fiber includes a phase change core and a heat-shrinkable sheath arranged from the inside out.

[0010] Furthermore, the second thermo-shrinkage induced fiber with low shrinkage rate is obtained by pre-treating the first thermo-shrinkage induced crack-resistant fiber with heat activation or relaxation heat setting to remove some internal stress and adjust its heat shrinkage rate to 3-10%.

[0011] Furthermore, the early-strength corrosion-resistant cement-thermal-shrinkable fiber three-dimensional mesh fabric composite material is activated by surface water spraying.

[0012] In the above scheme, the filling amount of aluminoferrite cement modified magnesium phosphate cement in the heat-shrinkable three-dimensional mesh spacer fabric matrix is ​​1800-2200 kg / m. 3 .

[0013] Furthermore, to ensure uniform powder distribution and effective stress transfer, a high-frequency vibration-assisted filling process is adopted. Specifically, the dry powder is added to the fabric in batches, and vertical vibration with a frequency of 50-100Hz and an amplitude of 0.2-1.0mm is used to ensure that the powder fully enters the gaps between the spacer yarns. After filling, micro-compaction is performed to eliminate internal macroscopic voids.

[0014] In the above scheme, the iron aluminate cement modified magnesium phosphate cement includes magnesium phosphate cement components, iron aluminate cement, mineral admixtures, and nano-silica.

[0015] In the above scheme, the magnesium phosphate cement component includes calcined magnesium oxide and phosphate.

[0016] Furthermore, the phosphate may be selected from one or more of potassium dihydrogen phosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, etc.

[0017] In the above scheme, the aluminoferrite cement is selected as rapid-hardening aluminoferrite cement with a strength grade of 42.5 or higher and a specific surface area ≥360m². 2 / kg.

[0018] In the above scheme, the mineral admixture comprises fly ash (micro-aggregates and active components) and silica fume (pore-refining components); the mass ratio of the two is 1:0.15-0.3; wherein, the fly ash is selected as Grade I fly ash with a water demand ratio ≤95%, utilizing its microsphere effect to improve the permeability of the slurry in the fabric; the silica fume is selected with a SiO2 content ≥92% and a specific surface area ≥18000m². 2 / kg of highly active microsilica powder to strengthen the fiber-matrix interface transition zone.

[0019] In the above scheme, the nano-silica (interface enhancer) is selected with an average particle size of 15-40 nm and a specific surface area ≥200 m². 2 / g of hydrophilic nano-silica; its high specific surface area generates a nucleation effect that accelerates the hydration and exothermic reaction of the gelation system and fills the nanoscale pores at the fiber-matrix interface.

[0020] Furthermore, in the modified magnesium phosphate cement with iron aluminate cement, the components and their respective weight percentages include: 65-90 parts magnesium phosphate cement, 10-20 parts iron aluminate cement, 8-18 parts mineral admixtures, and 1-3 parts nano silica.

[0021] Furthermore, the magnesium phosphate cement component is obtained by dry mixing the weighed magnesium phosphate cement component, aluminoferrite cement, mineral admixtures, and nano-silica.

[0022] Furthermore, the magnesium phosphate cement component also includes a retarding component, which may be one or more of borax, boric acid, sodium tripolyphosphate, etc.; its weight percentage in the aluminoferrite cement modified magnesium phosphate cement is 1.5-3 parts.

[0023] The modified cement powder described in this invention is aluminoferrite cement modified magnesium phosphate cement. By introducing aluminoferrite cement and magnesium phosphate cement components to achieve synergistic effects, hydration generates amorphous hydrated calcium sulfoaluminate gel, CSH gel, and aluminoferrite gel, which can effectively encapsulate struvite crystals and fill pores, significantly improving the water resistance and seawater erosion resistance of the resulting composite material system.

[0024] In the above scheme, the mass percentage of temperature shrinkage-induced crack-resistant fibers in the three-dimensional mesh spacer fabric matrix is ​​65-75%, and the mass percentage of sheath temperature shrinkage-core phase change composite fibers is 25-35%; the water-permeable and pulp-resistant heat-shrinkable fiber nonwoven encapsulation layer mainly uses low-shrinkage temperature shrinkage-induced crack-resistant fibers.

[0025] Furthermore, the total thickness of the three-dimensional mesh spacer fabric matrix is ​​5-50 mm, and the areal density is 520-600 g / m³. 2 The porosity is >90%, and the total porosity is 78-85%.

[0026] Furthermore, the yarn density of the three-dimensional mesh spacer fabric matrix is ​​set as follows: weft yarn density 14-18 threads / 10cm, warp yarn density 12-16 threads / 10cm, and spacer yarn density 16-20 threads / cm. 2 .

[0027] In the above scheme, the core material of the first thermal shrinkage-induced crack-resistant fiber includes thermal shrinkage material and cement mixed therein, wherein the cement is ultrafine cement (average particle size 10-50μm) and the dosage is 1-5wt%.

[0028] In the above scheme, the heat-shrinkable material is polyester with a molecular weight of 23,000-27,000 and a heat shrinkage rate of 8-12%.

[0029] In the above scheme, the polyvinyl alcohol leather (heat shrinkable leather) is polyvinyl alcohol with a molecular weight of 180,000-200,000.

[0030] In the above scheme, the thickness of the polyvinyl alcohol leather is 10-30 μm.

[0031] Furthermore, an air-entraining agent is introduced into the heat-shrinkable leather material at a dosage of 0.1-1.5 wt%.

[0032] Furthermore, the air-entraining agent may be selected from one or more of rosin soap, sodium lauryl sulfate, and sodium fatty alcohol polyoxyethylene ether sulfate.

[0033] In the above scheme, the temperature range of the first thermo-shrinkage induced crack-resistant fiber is 45-85℃; which matches well with the hydration exothermic peak value of the modified cement of the present invention.

[0034] In the above scheme, the core material matrix of the sheath thermal shrinkage-core phase change composite fiber is a porous metal fiber, including one or more of porous stainless steel fiber, porous nickel fiber, and porous titanium fiber; its porosity is 30-60%, pore size is 1-50μm, and fiber diameter is 0.1-1.0mm; the phase change material loaded in the core material matrix is ​​one or more of conventional phase change materials such as paraffin, fatty acid, and hydrated salt, with a phase change temperature of 20-80℃ and a latent heat of phase change ≥150kJ / kg; the sheath is a high-modulus heat-shrinkable polymer material with an elastic modulus ≥12GPa; specifically, one or more of polyester, polypropylene, polyurethane, and high-density polyethylene can be selected; the sheath thickness is 0.1-0.5mm.

[0035] Furthermore, the shrinkage response temperature of the sheath is 30-90℃, and the shrinkage rate is 2-10%.

[0036] In the above scheme, the ratio of the equivalent diameter of the core material matrix to the thickness of the sheath layer is (2-4):1; the phase change temperature of the sheath layer thermal shrinkage-core material phase change composite fiber is 26-30℃, and the latent heat of phase change is ≥180kJ / kg.

[0037] In the above scheme, the water-permeable, anti-slurry, heat-shrinkable fiber nonwoven encapsulation layer is made entirely of low-shrinkage, temperature-shrinkage-induced, crack-resistant fibers. Its (fiber) heat shrinkage rate is 3-10% (80℃×30min), which is coordinated with the deformation of the internal three-dimensional fabric matrix to prevent the encapsulation layer from cracking due to shrinkage mismatch. The initial shrinkage temperature is 40-45℃, and the maximum shrinkage temperature is 75-85℃. To adapt to water spray activation and prevent powder leakage, the air permeability of the encapsulation layer is adjusted to 120-180mm / s, the longitudinal tensile strength is ≥120N / 5cm, and the main pore size is 10-35μm (to prevent dry powder leakage and exhibit good anti-slurry properties).

[0038] Furthermore, the water-permeable, pulp-resistant, heat-shrinkable fiber nonwoven encapsulation layer is made by opening and combing a low-shrinkage second temperature-shrinkage-induced crack-resistant fiber into a web; a three-stage hydroentangling reinforcement process is used to construct a dense microporous structure (average pore size 15-45μm); and then a relaxation heat-setting treatment is performed at 100-105°C to obtain the final product.

[0039] In the above scheme, the areal density of the water-permeable, pulp-resistant, heat-shrinkable fiber nonwoven fabric encapsulation layer is 60-100 g / m². 2 .

[0040] Furthermore, the thickness ratio of the three-dimensional mesh spacer fabric matrix to the water-permeable, pulp-resistant heat-shrinkable fiber nonwoven encapsulation layer (single layer) is (30-80):1.

[0041] This invention also provides a method for preparing the above-mentioned early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material, comprising the following steps: 1) Preparation of three-dimensional mesh spacer fabric matrix: The first thermal shrinkage-induced crack-resistant fiber and the sheath thermal shrinkage-core phase change composite fiber are configured in a predetermined ratio and three-dimensionally woven (using a double needle bed Raschel warp knitting machine, etc.), and the matrix is ​​obtained by three-stage heat setting treatment; wherein, the warp yarn and the weft yarn are both prepared by thermal shrinkage-induced crack-resistant fiber and high modulus sheath thermal shrinkage-core phase change composite fiber through blending, twisting and doubling processes, and the spacer yarn is prepared by sheath thermal shrinkage-core phase change composite fiber; 2) Preparation of water-permeable and anti-slip heat-shrinkable fiber nonwoven fabric: The second temperature shrinkage-induced crack-resistant fiber is pretreated by heat activation, then carded into a web, hydroentangled and heat-shrinkable to obtain water-permeable and anti-slip heat-shrinkable fiber nonwoven fabric. 3) Composite encapsulation treatment: The substrate obtained in step 1) and the nonwoven fabric obtained in step 2) are subjected to surface plasma and coupling agent pretreatment; 4) Composite cement filling: A high-frequency vibration-assisted process is used to fill the gaps in the encapsulated three-dimensional fabric with a dry powder mixture of aluminoferrite cement and magnesium phosphate cement. 5) The pre-treated nonwoven fabric described in step 3) is laminated onto the surface of the matrix filled with composite cement through a partitioned needle punching process, and finally heat-shrinkable fiber three-dimensional mesh fabric is obtained by hot pressing.

[0042] Furthermore, the modified cement powder has a filling rate of ≥95% in the encapsulated three-dimensional fabric.

[0043] Furthermore, the high-frequency vibration-assisted process requires the use of micro-vibration + negative pressure suction process. The specific steps include: applying a micro negative pressure (-0.01~-0.03MPa) to the lower surface of the heat-shrinkable fiber three-dimensional mesh fabric, supplying powder to the upper surface and applying micro-vibration with a frequency of 30-60Hz and an amplitude of 0.3-0.8mm, so that the powder is extremely densely filled in the fiber mesh (processing time is 30-90s).

[0044] In the above scheme, the compaction treatment uses a pressure of 0.1~0.5MPa and a time of 10~60s.

[0045] In the above scheme, in step 1), the mass ratio of the first thermal shrinkage-induced crack-resistant fiber to the sheath thermal shrinkage-core phase change composite fiber in the weft yarn and the warp yarn is 6-7:3-4; all the spacer yarns are made of sheath thermal shrinkage-core phase change composite fiber.

[0046] Further, the heat setting treatment in step 1) includes three stages: the first stage (pre-relaxation), temperature 85-95℃, time 100-110s, tension 5-8cN; the second stage (structural setting), temperature 115-125℃, time 160-170s, pressure 0.06-0.08MPa; the third stage (cooling stabilization) adopts a gradient cooling process, first cooling to 75-85℃ at a rate of 1.5-2.5℃ / min, and then cooling to 35-45℃ at a rate of 2.5-3.5℃ / min (higher than the first step rate).

[0047] In the above scheme, the thermal activation pretreatment process in step 2) is as follows: the second temperature shrinkage-induced crack-resistant fiber is pre-shrinked at 60-70℃ for 10-20 minutes to remove the internal stress of spinning but without triggering large-scale thermal shrinkage.

[0048] Furthermore, the hydroentangling reinforcement described in step 2) adopts a three-level pressure control. The specific process parameters include: the production line running speed is controlled at 30-40m / min, and the corresponding hydroentangling time is 2-5s; the first-level pressure control is 65-75Bar, the second-level pressure control is 85-95Bar, and the third-level pressure control is 105-115Bar.

[0049] Further, the heat shrinking treatment in step 2) includes: the preheating zone is treated at a temperature of 90-96℃ for 35-40s; the shrinking zone is treated at a temperature of 108-112℃ for 75-85s; and the setting zone is treated at a temperature of 98-102℃ for 50-55s.

[0050] In the above scheme, the surface pretreatment in step 3) includes plasma treatment and silane coupling agent impregnation process, wherein the power of the plasma treatment process is 3.8-4.2kW ​​and the time is 70-80s; the concentration of the silane coupling agent is 2.0-5.0wt% and the impregnation time is 12-18min.

[0051] Furthermore, the acupuncture process employs a zoning strategy, with specific process parameters including: a pre-acupuncture zone density of 115-125 needles / cm². 2 Depth 2.8-3.2mm; main acupuncture zone density 145-155 needles / cm² 2 Depth 4.8-5.2mm; density in the finishing area 75-85 stitches / cm 2 The depth is 1.8-2.2mm.

[0052] Furthermore, the hot pressing and shaping parameters include: upper plate temperature 115-118℃, lower plate temperature 111-113℃, hot pressing pressure 0.65-0.075MPa, and holding time 2-5min.

[0053] The present invention also provides a construction method for the above-mentioned early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material, comprising the following steps: (1) Interface treatment of the concrete structure to be repaired: roughen the interface and apply an interface agent; (2) The prefabricated early-strength corrosion-resistant cement-heat shrinkable fiber three-dimensional mesh fabric composite material is fixedly attached to the surface of the concrete structure to be repaired. The early-strength corrosion-resistant cement-heat shrinkable fiber three-dimensional mesh fabric composite material is activated by spraying water. It can be quickly hydrated and partially hardened in 5-10 minutes (the setting time is adjustable), thus completing the rapid repair work.

[0054] Furthermore, the water spraying activation step adopts an atomized spraying process; the spraying water pressure is controlled at 0.2-0.4MPa to ensure that the water penetrates the surface non-woven fabric and evenly permeates into the internal powder; the total water consumption is measured according to the water-binder ratio of 0.14-0.18; the spraying process continues until the internal temperature of the composite material reaches above 55°C to ensure that the aluminoferrite cement component is fully hydrated and releases heat, and to stimulate the fibers to generate thermal shrinkage prestress.

[0055] Furthermore, the atomized spraying process involves multiple spraying passes.

[0056] In the above scheme, the interface agent is selected from one or more of epoxy resin interface agents, water-based epoxy interface agents, styrene-acrylic emulsions, styrene-butadiene emulsions, polymer-modified cement slurries, etc.

[0057] The principles of this invention include: This invention is the first to propose combining the high heat of hydration of aluminoferrite cement modified magnesium phosphate cement with the thermal response characteristics of heat-shrinkable fibers. The synergistic effect simultaneously achieves improvements such as autonomous stress regulation, microstructure optimization, interface transition zone control, and autonomous crack resistance. The specific mechanism of action includes the following: Autonomous stress regulation: Utilizing the unique instantaneous high heat of hydration characteristics of the modified cement (unlike conventional silicate cement, which has a low hydration temperature rise and slow setting, making it unable to trigger the thermal shrinkage threshold), its hydration heat release (peak temperature can reach 75-85℃) simultaneously activates the thermal shrinkage mechanism of the internal three-dimensional fabric matrix and the external encapsulation layer fiber, with an effective thermal shrinkage rate of 8-15%. Through the strong bonding effect of the fiber-modified cement interface, compressive stress (expected to be 0.5-15MPa) is applied to the modified cement matrix inside the composite material.

[0058] Microstructure optimization: The generated compressive stress can effectively refine the pore structure of cement paste, reduce the total porosity, and especially reduce harmful pores >50nm.

[0059] Interface transition zone control: Relying on the overall topological structure of the three-dimensional fiber fabric, the "skeleton compression effect" generated by the thermal shrinkage of the fiber forms a multidimensional active constraint on the coated cement paste. The resulting radial clamping force forces the paste to adhere tightly to the fiber, which can effectively eliminate the loose and porous defects common in traditional interfaces, promote the formation of a gradient dense structure with gradually changing density from the inside to the outside, and promote the improvement of interfacial bonding strength (40-60%).

[0060] Self-resistant crack resistance: During temperature changes, the fiber’s thermal shrinkage and reversible thermal deformation (using irreversible shrinkage to establish prestress and using reversible thermal deformation to coordinate matrix size changes) form a complementary deformation mechanism with the modified cement matrix, thus autonomously inhibiting the generation of microcracks.

[0061] Furthermore, this invention achieves a triple breakthrough in ultra-early strength, high corrosion resistance, and crack-resistant self-stress, mainly based on the innovative coupling of the following two core mechanisms: 1. Synergistic hydration mechanism of aluminoferrite cement modified with magnesium phosphate cement; The hydration product of traditional magnesium phosphate cement (MPC) is mainly potassium magnesium phosphate hexahydrate (struvite, MKP), whose crystal structure is prone to decomposition under long-term water immersion, leading to a decrease in strength. This invention introduces aluminoferrite cement (SAC) for composite modification, resulting in complex synergistic reactions within the system, specifically including the following: In the initial stage of the reaction: the MPC component undergoes an acid-base reaction, rapidly generating the MKP crystal framework, providing ultra-early strength performance on the order of hours, and releasing a large amount of heat of hydration.

[0062] Mid-reaction: The SAC component utilizes the remaining moisture from the MPC reaction and the rising temperature environment to rapidly hydrate and generate a large amount of amorphous hydrated calcium sulfoaluminate gel, CSH gel, as well as iron glue and aluminum glue.

[0063] Microstructure reconstruction: The generated amorphous gel phase fills the voids in the MKP crystal framework and coats the surface of the MKP crystal; this dense structure of "gel-encapsulated crystal" not only blocks the erosion path of water molecules on the MKP crystal, but also effectively adsorbs and solidifies Cl⁻ and SO₄ in seawater by utilizing the excellent seawater erosion resistance of SAC gel. 2- The ions fundamentally solve the problem of poor water resistance in traditional MPCs.

[0064] 2. Intelligent thermomechanical coupling mechanism based on hydration heat-fiber thermal shrinkage; This invention ingeniously utilizes the "waste heat" generated by the high exothermic thermal oxidation reaction unique to aluminoferrite cement modified magnesium phosphate cement as a "trigger signal" for functional fibers to construct an active crack-resistant system: Temperature rise stage (active temperature control): In the early stage of hydration, the system temperature rises rapidly; at this time, the core material (phase change material) in the fabric spacer yarn undergoes phase change and absorbs heat, producing a "peak shaving and valley filling" effect to prevent the local temperature from being too high, which could cause the slurry to "burn" or produce thermal shock cracks.

[0065] Peak stage (active pressure): When the heat of hydration causes the internal temperature to reach the peak range of 75-85℃, it is precisely in the initial setting-final setting transition period of the modified cement paste (possessing certain structural strength but still having plasticity); at this time, the thermal shrinkage-induced crack-resistant fibers are activated, generating a high shrinkage rate of 30-40%. Since the ends of the fibers are anchored by the partially hardened matrix, the shrinkage of the fibers cannot occur freely, thus transforming into a strong radial and axial "clamping force" (i.e., three-dimensional pre-compression stress) on the matrix.

[0066] Cooling stage (permanent reinforcement): As the temperature decreases after the reaction ends, the thermally shrunken fibers retain tension and form a permanent compressive stress field inside the concrete, similar to that of prestressed steel bars. This actively counteracts the tensile stress generated by the later drying shrinkage of the concrete, thereby eliminating microcracks in their infancy.

[0067] Compared with the prior art, the beneficial effects of the present invention include: 1. A unique self-excited prestressing system based on a chemical heat source and physical thermal shrinkage was constructed for the first time, which can effectively achieve active reinforcement of composite materials: Unlike the cumbersome process of traditional external prestressing, this invention utilizes the concentrated heat of hydration released instantaneously by aluminoferrite cement modified magnesium phosphate cement (as an internal driving force) to effectively trigger the thermal shrinkage mechanism of the three-dimensional fabric skeleton, thereby constructing a three-dimensional prestress field in situ inside the material, which significantly improves the crack resistance and load-bearing capacity of the composite material.

[0068] 2. Achieved chemical-physical dual synergistic anchoring between fibers and the matrix, solving the problem of weak interfaces: At the microscopic level, the phosphate component of the modified cement forms a chemical bond with the fiber surface; at the macroscopic level, the radial clamping force generated by the thermal shrinkage of the fiber eliminates the interfacial micro-gap and promotes the formation of a gradient dense bond structure; this dual mechanism increases the interfacial bonding strength by more than 40% compared with ordinary cement-based composite materials.

[0069] 3. It has overcome the technological bottleneck of rapid repair in harsh environments and possesses excellent environmental adaptability: By employing a simple pre-filled powder + water spray activation process, combined with the self-heating characteristics of the material system, the construction time is not only significantly shortened (adapting to tidal windows), but also overcomes the problems of slow hardening and low strength of conventional repair materials in low-temperature environments (such as 5℃), which is conducive to achieving rapid repair in all weather conditions.

[0070] 4. It endows the structure with excellent volumetric stability and durability: Under the high heat of hydration of ferroaluminate cement-modified magnesium phosphate cement, the thermal shrinkage induced by the reconstruction of fiber molecules in the flexible fabric and the strong interfacial bonding coupling between the fiber fabric and the cement paste will apply compressive stress to the 3DTRC, effectively improving the original defects of the 3DTRC paste and regulating the microstructure of the transition zone between the fiber fabric and the paste, significantly improving the density of the matrix; combined with the excellent seawater erosion resistance of the modified cement itself, the service life of the obtained components in extreme environments such as marine splash zones can be greatly improved. Attached Figure Description

[0071] Figure 1 This is a schematic diagram of the overall structure of the heat-shrinkable three-dimensional mesh fabric composite material prefilled with early-strength corrosion-resistant cement according to an embodiment of the invention. In this diagram, a is a front view of the heat-shrinkable three-dimensional mesh fabric with a surface encapsulation layer; b is a side view of the heat-shrinkable three-dimensional mesh fabric with a surface encapsulation layer; and c is a morphological diagram of the heat-shrinkable three-dimensional mesh fabric composite material prefilled with early-strength corrosion-resistant cement powder. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0073] In the following examples, the calcined magnesium oxide (MgO) used is recalcined magnesium oxide, with a calcination temperature ≥1500℃ and a magnesium oxide content ≥90%; the average particle size (D50) is controlled between 1.0-5.0μm; if it is too fine, the reaction will be too fast and the heat release will be uncontrollable, while if it is too coarse, the early strength will be insufficient.

[0074] The potassium dihydrogen phosphate (KH2PO4) used is industrial grade with a purity of ≥98%, and is ground to an average particle size of ≤45μm (325 mesh) to ensure that the dissolution rate matches the reaction of magnesium oxide.

[0075] The preparation requirements for the first thermo-shrinkage induced crack-resistant fiber include the following steps: Core-skin structure: The core-skin structure is prepared using a composite melt spinning process; Composite core material preparation: High-shrinkage polyester chips (provided by Sinopec Yizheng Chemical Fiber, model ECDP, intrinsic viscosity 0.65-0.70 dL / g; boiling water shrinkage rate 30-45%) and ultrafine cement particles (modified with KH550 silane coupling agent) are mixed and granulated in a twin-screw extruder to prepare masterbatch, which is then melt-spun to obtain composite core material. The cement particles incorporated in the masterbatch act as "in-situ anchoring points".

[0076] Skin coating: The obtained composite core material is coated with polyvinyl alcohol (PVA) solution through an online coating tank, and after drying, a water-soluble skin layer is formed. This skin layer has excellent hydrophilicity and can effectively improve the interfacial compatibility between the hydrophobic core material and the hydrophilic cement matrix.

[0077] In the following embodiments, modified cement powder is filled into a heat-shrinkable three-dimensional mesh spacer fabric matrix using a vibration filling process. To ensure that the powder filling rate is ≥95%, a "micro-vibration + negative pressure suction" process is required: a micro negative pressure (-0.01~-0.03MPa) is applied to the lower surface of the heat-shrinkable three-dimensional mesh matrix, and powder is supplied to the upper surface and micro-vibration with a frequency of 30~60Hz and an amplitude of 0.3~0.8mm is applied to make the powder extremely densely fill the fiber mesh (processing time is 30~90s) to avoid voids. Example 1

[0078] A high-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material, the preparation method of which includes the following steps: 1. Preparation of modified cement powder: Weigh the following components by weight: 48 parts calcined magnesium oxide (made from magnesite calcined at 1600℃ for 5-6 hours and then ground, with an average particle size of 1.0μm), 30 parts potassium dihydrogen phosphate (industrial grade, purity >98%), 15 parts 42.5 grade rapid-hardening aluminoferrite cement, 7 parts fly ash, 5 parts silica fume, 2 parts nano silica, and 2 parts borax; dry mix the above components in a special mixer at a speed of 400r / min for 20 minutes to obtain modified cement powder.

[0079] 2. Preparation of heat-shrinkable three-dimensional fabric matrix: The first thermal shrinkage-induced crack-resistant fiber (core material is high shrinkage polyester with a molecular weight of 25,000 (provided by Sinopec Yizheng Chemical Fiber, model ECDP), with 3wt% ultrafine cement particles (provided by Tangshan Arctic Bear Building Materials Co., Ltd., model UFC-800, with an average particle size of 8-12μm) is blended with sheath thermal shrinkage-core material reinforced composite fiber at a mass ratio of 7:3 as warp and weft yarns; Among them, the sheath shrinkage-core phase change composite fiber (the core material is porous nickel fiber loaded with docosane, the sheath is high modulus high shrinkage polyester PET, molecular weight 22,000-25,000, elastic modulus ≥12GPa, and the outer wrapping process is melt co-extrusion) is selected as the spacer yarn; The first heat-shrinkable induced crack-resistant fiber and the sheath heat-shrinkable-core reinforced composite fiber are woven on a double-needle bed Raschel warp knitting machine, and then subjected to a 90°C pre-relaxation, 120°C structural setting, and gradient cooling process to obtain a 20mm thick heat-shrinkable three-dimensional fabric matrix; the specific preparation steps include: Weaving: Using an E20 double-needle bed Raschel warp knitting machine; setting the weaving speed to 700 rpm, and the weaving density to be: 14 weft yarns / 10cm, 12 warp yarns / 10cm, and 16 spacer yarns / cm. 2 Tension control: ground yarn 20cN, spacer yarn 23cN.

[0080] Heat setting: The fabric passes through the heat setting machine, and the parameter settings for different areas are as follows: Pre-relaxation zone: 90℃, 105s, low tension (6.5cN), allowing initial fiber shrinkage; Setting zone: 120℃, 165s, air pressure 0.065MPa, to fix the fabric pore structure; in addition to temperature and pressure control, the hot air flow rate must be precisely controlled at 3.0±0.2m / s to ensure uniform heating inside the thick fabric; at the same time, the yarn tension control accuracy must be kept within ±1cN throughout the heat setting process. Cooling zone: Cool to 80℃ at a rate of 2℃ / min, then cool to 40℃ at a rate of 3℃ / min to prevent thermal shock deformation; The areal density of the obtained heat-shrinkable three-dimensional fabric matrix is ​​520 g / m³. 2 Porosity > 90%, total porosity 82%; 3. Encapsulation layer fabrication: The first thermo-shrinkage-induced crack-resistant fiber prepared in step 2 was opened and carded into a web; a three-stage hydroentangling reinforcement process (water pressure of 30 bar, 50 bar, and 40 bar respectively) was used to construct a dense microporous structure (average pore size 15-45 μm); subsequently, a relaxation heat setting treatment was performed at 100-105°C to eliminate some internal stress, and the heat shrinkage rate at 80°C was precisely controlled to 5%, yielding the second thermo-shrinkage-induced crack-resistant fiber; a partitioned needle punching process was used to laminate the nonwoven fabric onto the matrix surface, followed by hot pressing and setting. The specific steps include the following: Fiber pretreatment: The second type of temperature shrinkage-induced crack-resistant fiber was treated in an oven at 65℃ for 15 minutes (pre-shrinkage); Web formation: The second type of thermal shrinkage-induced crack-resistant fiber is formed into a web by a carding machine (cylinder speed 500 rpm, working roller speed 35±2 m / min), and cross-laying (7 layers, ±15° angle) is used to ensure isotropy; Hydroentangling reinforcement: Through three hydroentangling processes (70Bar / 90Bar / 110Bar), the production line speed is controlled at 35m / min, and the water needle plate aperture is 0.11mm, the fibers are tightly entangled to ensure the uniformity of the microporous structure. The selected water needle plate has a water needle arrangement density of 1400±50 holes / m, and the hydroentangling energy is strictly controlled at 0.50±0.02kWh / kg to avoid excessive energy damaging the fiber structure or insufficient energy causing weak entanglement. Relaxation heat setting treatment: The hydroentangled nonwoven fabric is fed into a heat setting machine and treated at a temperature of 102-105℃ for 50-60 seconds, with an overfeed of 3-5% to eliminate residual internal stress generated during spinning and hydroentanglement, and to precisely lock the heat shrinkage rate at 80℃ to about 5%.

[0081] The obtained nonwoven fabric was then subjected to surface plasma treatment and coupling agent impregnation pretreatment. The plasma treatment process used a power of 4kW and a time of 75s; the silane coupling agent concentration was 4wt% and the impregnation time was 15min. Performance indicators: The resulting encapsulation layer has an air permeability of 135 mm / s, a main pore size of 15-35 μm, and an areal density of 120 g / m³. 2 .

[0082] 4. Fill with composite cement: The composite cement powder obtained in step 1 was filled into the pores of the three-dimensional mesh spacer fabric matrix using a vibration filling process (filling rate 96%). The vibration filling process includes: placing the single-sided sealed semi-finished fabric on a negative pressure platform and applying a negative pressure of -0.03MPa; uniformly spreading the powder, starting a vertical vibration with a frequency of 50Hz and an amplitude of 0.5mm for 60s, and then applying a micro pressure of 0.2MPa to compact it, ensuring that the powder is densely filled.

[0083] 5. Composite Encapsulation Treatment: The non-woven fabric obtained in step 3 is applied to the lower surface of the substrate filled with composite cement, and then subjected to zoned needle punching: the density of the pre-needled area is 120 needles / cm. 2 Depth 3.0mm; main acupuncture zone density 150 needles / cm 2 Depth 5.0mm; finishing area density 80 stitches / cm 2 The depth is 2.0 mm. Then, hot pressing is performed for shaping: upper plate temperature 117℃, lower plate temperature 112℃, hot pressing pressure 0.70 MPa, holding time 3 min; the resulting encapsulation layer has an air permeability of 135 mm / s, a main pore size of 15-35 μm, and an areal density of 120 g / m³. 2 .

[0084] The composite material prepared in Example 1 was fixed in a mold, and its surface was activated by atomized spraying (the spraying water pressure was set to 0.3 MPa, the total water volume was accurately measured according to a water-cement ratio of 0.16, and the spraying was carried out in 3 cycles to ensure uniform penetration). Then, mechanical properties, water resistance, durability and other tests were performed. The specific test results are as follows: Mechanical properties: 1-hour compressive strength 28.5 MPa, 28-day compressive strength 112 MPa.

[0085] Water resistance: After 7 days of standard curing and 28 days of immersion in water, the strength retention rate is 125% (due to continuous hydration).

[0086] Freeze-thaw resistance: After 300 freeze-thaw cycles, the strength loss rate is only 2.1%.

[0087] Crack resistance: The density of early-stage microcracks is extremely low (<0.1 m / m). 2 This confirms the effectiveness of the self-stress regulation mechanism. Example 2

[0088] A high-strength, corrosion-resistant cement-thermal-shrinkable fiber three-dimensional mesh fabric composite material is designed for deep-sea high-pressure environments. The specific preparation method is largely the same as in Example 1, with the only difference being: 1. Adjustment of modified cement powder mix proportions: In order to further improve the density of the matrix, the components and their weight proportions were adjusted as follows: 55 parts magnesium oxide, 25 parts potassium dihydrogen phosphate, 10 parts aluminoferrite cement, 10 parts fly ash, 3 parts silica fume, 1 part nano silica, and 3 parts borax.

[0089] 2. Fabric matrix adjustment: The areal density of the three-dimensional mesh spacer fabric matrix was increased to 550 g / m². 2 The proportion of spacer yarn (sheath shrinkage-core phase change composite fiber) is increased to 40% to enhance compressive strength.

[0090] 3. Encapsulation layer adjustment: The air permeability of the heat-shrinkable fiber nonwoven fabric is adjusted to 120mm / s to meet the encapsulation requirements of finer powder particles. Example 3

[0091] A high-strength, corrosion-resistant cement-thermal-shrinkable fiber three-dimensional mesh fabric composite material is designed for freeze-thaw resistance in cold sea areas. The specific preparation method is largely the same as in Example 1, with the only difference being: 1. Modified cement powder mix proportion adjustment: The focus is on increasing the amount of ferroaluminate cement to improve frost resistance; the components and their weight percentages are as follows: 40 parts magnesium oxide, 35 parts potassium dihydrogen phosphate, 20 parts ferroaluminate cement, 5 parts fly ash, 8 parts silica fume, 3 parts nano silica, and 1.5 parts borax.

[0092] 2. Fiber treatment: 0.5wt% of air-entraining agent (sodium dodecyl sulfate) is introduced into the PVA layer of the thermo-shrinkage induced crack-resistant fiber. When it comes into contact with water and dissolves, it introduces micro-bubbles at the interface, which further enhances the freeze-thaw resistance. Comparative Example 1

[0093] The same heat-shrinkable three-dimensional mesh spacer fabric matrix and non-woven encapsulation layer as in Example 1 were used, but the prefilled powder was replaced with ordinary fast-hardening silicate cement (42.5R). Comparative Example 2

[0094] Using the same fabric structure as in Example 1, the pre-filled powder is ordinary magnesium phosphate cement (MPC), which does not contain aluminoferrite cement, fly ash and silica fume components, but consists only of magnesium oxide, potassium dihydrogen phosphate and borax. Comparative Example 3

[0095] The same modified cement powder as in Example 1 was used, but the three-dimensional mesh fabric matrix was woven from ordinary high-strength polyester (PET) fibers, which does not have thermal shrinkage induction properties and does not contain phase change material core material; the surface encapsulation layer is ordinary PET nonwoven fabric. Comparative Example 4

[0096] The same modified cement powder and three-dimensional mesh spacer fabric matrix as in Example 1 were used. The only difference was that when preparing the heat-shrinkable fiber nonwoven fabric encapsulation layer on the surface, the temperature-shrinkable crack-resistant fiber was not subjected to relaxation heat setting treatment (i.e., the step of "relaxation heat setting at 100-105℃" in preparation step 2 was omitted), and the first temperature-shrinkable crack-resistant fiber was directly used for composite after carding and hydroentangling. Performance Testing and Result Analysis

[0097] The samples prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to standardized tests, and the test methods were in accordance with relevant building materials industry standards and the test conditions defined in this specification. The test results are shown in Table 1.

[0098] Table 1. Test results of mechanical properties and durability of composite materials

[0099] Results analysis: 1. Early strength and water resistance analysis: Compared to Comparative Example 2, although Comparative Example 2 (pure magnesium phosphate cement) also had high early strength, its strength retention rate was only 65% ​​after 28 days of immersion in water, and it experienced severe shrinkage in the later stages. In contrast, this invention, by introducing aluminoferrite cement modification and utilizing its hydration products (amorphous colloids) to encapsulate struvite crystals, not only did it not shrink, but also achieved a strength retention rate exceeding 120% due to continuous hydration, effectively solving the problem of poor water resistance in traditional MPC. The early strength of Comparative Example 1 (ordinary rapid-hardening silicate cement) was far lower than that of this invention, failing to meet the needs of rapid emergency repairs.

[0100] 2. Analysis of crack resistance and self-stress mechanism: The microcrack density of Examples 1-3 was significantly lower than that of Comparative Example 3 (ordinary fiber). This is because Comparative Example 3 lacked a "hydration heat-thermal shrinkage" coupling mechanism, and the fiber shrank back after expanding due to the heat of hydration, leading to interfacial debonding. In contrast, the present invention actively activates the shrinkage of the skeleton fiber by utilizing the high hydration heat peak value (approximately 80°C) of the modified cement, generating three-dimensional pre-compression stress. This is also confirmed by the huge difference in interfacial bond strength (9.8 MPa vs 4.2 MPa).

[0101] 3. The key role of the heat-shrinkable properties of the encapsulation layer: Although Comparative Example 4 used the same high-performance matrix and framework as Example 1, its surface encapsulation layer did not undergo relaxation heat setting treatment, resulting in a high shrinkage rate. Under hydration heat activation, the over-shrinked encapsulation layer easily over-compresses the incompletely hardened slurry inside, leading to board curling deformation and slurry segregation, and inducing a large number of early cracks (microcrack density as high as 0.78 m / m). 2 This structural damage directly caused its impact and abrasion resistance to drop sharply to 58.5 h / (kg / m). 2 (Even lower than the comparative example 1 of ordinary cement), and its resistance to chloride ion penetration and freeze-thaw resistance are significantly deteriorated.

[0102] 4. Freeze-thaw resistance and durability: Example 3 achieved the lowest freeze-thaw loss rate (1.5%) by optimizing the formulation and introducing an air-entraining mechanism in the fiber skin, demonstrating the excellent durability of the material in extreme cold environments.

[0103] This invention provides a revolutionary marine engineering repair material that enables deep integration of fibers and cement matrices at the chemical (synergistic hydration) and physical (thermomechanical coupling) levels. It effectively solves the problems of poor seawater corrosion resistance and easy cracking of existing materials, and provides key technical support for important projects such as island and reef construction and cross-sea bridge repair with its extremely simple construction method of "sprinkling water and it's ready to use".

[0104] It should be understood that the above description is merely a detailed description of the present invention, and the scope of protection of the present invention should not be limited to the specific embodiments described above. Any modifications, equivalent substitutions, or improvements made by those skilled in the art based on the present invention without departing from the essential concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A composite material of early-strength corrosion-resistant cement and heat-shrinkable fiber three-dimensional mesh fabric, characterized in that, It includes a heat-shrinkable three-dimensional mesh spacer fabric matrix, modified cement powder filled in the matrix, and a water-permeable, slurry-resistant heat-shrinkable fiber nonwoven encapsulation layer disposed on the surface of the matrix; the modified cement is aluminoferrite cement modified magnesium phosphate cement; the spinning fibers used in the three-dimensional mesh spacer fabric matrix include a first temperature-shrinkable induced crack-resistant fiber and a high-modulus sheath temperature-shrinkable-core phase change composite fiber; the spinning fibers used in the water-permeable, slurry-resistant heat-shrinkable fiber nonwoven encapsulation layer include a second temperature-shrinkable induced fiber with a low shrinkage rate; The first thermo-shrinkable crack-resistant fiber has a cement-doped heat-shrinkable composite core and a polyvinyl alcohol sheath covering its surface; the sheath thermo-shrinkable-core phase change composite fiber includes a phase change core and a heat-shrinkable sheath arranged from the inside out.

2. The early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material according to claim 1, characterized in that, The second thermo-shrinkage induced fiber with low shrinkage rate is obtained by pre-treating the first thermo-shrinkage induced crack-resistant fiber with heat activation or relaxation heat setting to remove some internal stress and adjust its heat shrinkage rate to 3-10%.

3. The early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material according to claim 1, characterized in that, The early-strength corrosion-resistant cement-thermal shrinkable fiber three-dimensional mesh fabric composite material is activated by surface water spraying.

4. The early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material according to claim 1, characterized in that, In the three-dimensional mesh spacer fabric matrix, the first thermo-shrinkage induced crack-resistant fiber accounts for 65-75% by mass, and the sheath thermo-shrinkage-core phase change composite fiber accounts for 25-35% by mass; the water-permeable and pulp-resistant heat-shrinkable fiber nonwoven encapsulation layer mainly uses the second thermo-shrinkage induced crack-resistant fiber with low shrinkage rate.

5. The early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material according to claim 1, characterized in that, The total thickness of the three-dimensional mesh spacer fabric matrix is ​​5-50 mm, and the areal density is 520-600 g / m³. 2 The open area ratio is >90%, and the total porosity is 78-85%. The yarn density is set as follows: weft yarn density 14-18 threads / 10cm, warp yarn density 12-16 threads / 10cm, and spacer yarn density 16-20 threads / cm. 2 .

6. The early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material according to claim 1, characterized in that, In the first thermal shrinkage-induced crack-resistant fiber, the thermal shrinkage material in the thermal shrinkage composite core material, excluding cement, is polyester with a molecular weight of 23,000-27,000 and a thermal shrinkage rate of 8-12%; the molecular weight of the polyvinyl alcohol skin is 180,000-200,000.

7. The early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material according to claim 1, characterized in that, In the sheath-core phase change composite fiber, the core matrix is ​​a porous metal fiber with a porosity of 30-60%, a pore size of 1-50 μm, and a fiber diameter of 0.1-1.0 mm; the phase change material loaded in the core matrix is ​​one or more of paraffin, fatty acids, and hydrated salts, with a phase change temperature of 20-80℃ and a latent heat of phase change ≥150 kJ / kg; the sheath is made of a high-modulus heat-shrinkable polymer material with an elastic modulus ≥12 GPa.

8. The early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material according to claim 1, characterized in that, The water-permeable, pulp-resistant, heat-shrinkable fiber nonwoven encapsulation layer is made by opening and combing a low-shrinkage second temperature-shrinkage-induced crack-resistant fiber into a web; a three-stage hydroentangling reinforcement process is used to construct a dense microporous structure; and then a relaxation heat-setting treatment is performed to obtain the final product. Its surface density is 60-100 g / m³ 2 .

9. The method for preparing the early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material according to any one of claims 1 to 8, characterized in that, Includes the following steps: 1) Preparation of three-dimensional mesh spacer fabric matrix: The first thermal shrinkage-induced crack-resistant fiber and the sheath thermal shrinkage-core phase change composite fiber are configured in a predetermined ratio, three-dimensionally woven, and heat-set to obtain the matrix; wherein, the warp yarn and the weft yarn are both prepared by the thermal shrinkage-induced crack-resistant fiber and the high modulus sheath thermal shrinkage-core phase change composite fiber through blending, twisting and doubling processes, and the spacer yarn is made of sheath thermal shrinkage-core phase change composite fiber; 2) Preparation of water-permeable and anti-slip heat-shrinkable fiber nonwoven fabric: The second temperature shrinkage-induced crack-resistant fiber with low shrinkage rate is pretreated by heat activation, and then carded into a web, hydroentangled and heat-shrink treated to obtain water-permeable and anti-slip heat-shrinkable fiber nonwoven fabric. 3) Composite encapsulation treatment: The substrate obtained in step 1) and the nonwoven fabric obtained in step 2) are subjected to surface plasma and coupling agent pretreatment; 4) Composite cement filling: The dry powder of aluminoferrite cement modified magnesium phosphate cement is filled into the voids of the heat-shrinkable fiber three-dimensional mesh fabric obtained in step 3) using a high-frequency vibration assisted process. 5) The pretreated nonwoven fabric obtained in step 3) is composited onto the matrix surface of the composite cement filled in step 4) by a partitioned needle punching process, and finally heat-shrinkable fiber three-dimensional mesh fabric is obtained by hot pressing.

10. A construction method for the early-strength corrosion-resistant cement-heat-shrinkable fiber three-dimensional mesh fabric composite material according to any one of claims 1 to 8, comprising the following steps: (1) Interface treatment of the concrete structure to be repaired: roughen the interface and apply an interface agent; (2) The prefabricated early-strength corrosion-resistant cement-heat shrinkable fiber three-dimensional mesh fabric composite material is fixedly attached to the surface of the concrete structure to be repaired, and the early-strength corrosion-resistant cement-heat shrinkable fiber three-dimensional mesh fabric composite material is activated by water spraying and hardened to complete the rapid repair work.

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