Basalt fiber reinforced geopolymer composite material and preparation method and application thereof

Abstract

The present application relates to a kind of basalt fiber reinforced geopolymer composite material and its preparation method and application.The basalt fiber reinforced geopolymer composite material preparation raw material includes geopolymer, mineral powder, silica fume, fly ash, modified basalt fiber, aggregate sand, water reducing agent and water;Wherein, the modified basalt fiber includes the basalt fiber modified by ketone compound, the polymer of unsaturated amide monomer, the copolymer of unsaturated carboxylic acid ester-olefin is collectively modified.The basalt fiber reinforced geopolymer composite material of the present application has higher elongation, stronger tensile strength and compressive strength, and can be used for building structure aseismic reinforcement, infrastructure repair, special engineering and pavement repair, and has good construction performance and high strength.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, and relates to a basalt fiber reinforced geopolymer composite material, its preparation method and application. Background Technology

[0002] Masonry structures, as a building structure with a long history of application, have a huge stock in urban and rural construction in my country. However, a large number of existing masonry buildings, especially those built in the last century, generally suffer from prominent problems such as low material strength, poor structural integrity, and insufficient seismic design measures. In recent years, the development of high-ductility cement-based composite materials has provided a new technical approach for the reinforcement of masonry structures. These materials are designed based on micromechanical principles, and through optimized interface control between fibers and the matrix, they achieve tensile strain hardening characteristics. Their ultimate tensile strain capacity can reach hundreds of times that of ordinary concrete, which can significantly improve the seismic performance and damage control capabilities of the structure. The use of thin-layer ECC surface layers to reinforce masonry structures has become an important research direction in this field, the core of which lies in developing fiber-reinforced materials that combine high mechanical properties, good workability, and economic feasibility.

[0003] In recent years, geopolymers, as a novel green cementitious material, have attracted widespread attention due to their unique high-temperature resistance, corrosion resistance, and low-carbon environmental protection characteristics. Compared with ordinary silicate cement, geopolymers form a three-dimensional network structure with -Si-O-Al-O- as the main chain by alkali-activated silica-alumina-rich materials (such as fly ash, slag, metakaolin, etc.). Their production process does not require high-temperature calcination, reducing carbon dioxide emissions by approximately 60-70%, meeting the requirements of green building and sustainable development. Geopolymer materials exhibit excellent material properties: rapid early strength development and stable later strength; acid corrosion resistance 10-100 times that of ordinary cement; fire resistance temperature exceeding 1000°C with high residual strength retention after high temperatures; good volume stability and a drying shrinkage rate more than 50% lower than cement. These characteristics make them particularly suitable for structural reinforcement applications in high-temperature and corrosive environments. Developing high-performance geopolymer composites by combining fiber-reinforced materials with geopolymer matrices has become an important research direction in the field of structural engineering materials, demonstrating enormous application potential in civil engineering reinforcement.

[0004] In existing technologies, alkali-resistant glass fiber or polypropylene fiber are mainly used as reinforcing materials for geopolymers, such as patents CN114538831A and CN112521059A.

[0005] Basalt fiber is a continuous fiber made from natural basalt ore, melted at 1450-1500℃ and rapidly drawn through a platinum-rhodium alloy spinneret. Its main chemical components are SiO2 (45-55%), Al2O3 (14-18%), and Fe2O3 (5-14%), exhibiting good compatibility with the chemical composition of geopolymer matrices and possessing higher tensile strength than glass fiber. Basalt fiber has achieved good application results in cement-based materials, as evidenced by patents CN105541209A and CN105585289A. However, the tensile strength and elongation of existing basalt fiber composites with geopolymer materials still need further improvement. In addition, the interfacial bonding strength between basalt fiber and geopolymer matrix is ​​insufficient, especially during long-term use, the interfacial performance degrades significantly, affecting the full utilization of the mechanical properties of the composite material. Due to the high surface energy of basalt fiber, it is prone to agglomeration during stirring, resulting in uneven fiber distribution in the matrix and affecting the stability of the composite material's performance. Summary of the Invention

[0006] To address one of the aforementioned technical problems in the prior art, this invention provides a basalt fiber reinforced geopolymer composite material. This material, produced by compounding geopolymer with cementitious waste materials such as mineral powder, silica fume, and fly ash, and adding modified basalt fibers, exhibits high elongation and high tensile strength, while also possessing relatively high compressive strength. This invention also provides a method for preparing and applying the basalt fiber reinforced geopolymer composite material.

[0007] In a first aspect, the present invention provides a basalt fiber reinforced geopolymer composite material, the raw materials for which include: geopolymer, mineral powder, silica fume, fly ash, modified basalt fiber, aggregate sand, water-reducing agent and water;

[0008] The modified basalt fiber includes basalt fiber modified by a polymer of ketone compounds, unsaturated amide monomers, and unsaturated carboxylic acid ester-olefin copolymer.

[0009] According to some embodiments of the present invention, the ketone compound is selected from C3-C6 ketone compounds, such as acetone.

[0010] According to some embodiments of the present invention, the unsaturated amide monomer is selected from C3-C6 unsaturated amides, such as acrylamide or methacrylamide. In some embodiments, the unsaturated amide monomer is acrylamide.

[0011] According to some embodiments of the present invention, the unsaturated carboxylic acid ester in the unsaturated carboxylic acid ester-olefin copolymer is selected from esters formed by C2-C6 unsaturated alcohols and C2-C6 carboxylic acids, such as vinyl acetate.

[0012] According to some embodiments of the present invention, the olefin in the unsaturated carboxylic acid ester-olefin copolymer is selected from C2-C6 olefins. According to some embodiments of the present invention, the olefin in the unsaturated carboxylic acid ester-olefin copolymer is selected from C2-C4 olefins, such as ethylene.

[0013] According to some embodiments of the present invention, the unsaturated carboxylic acid ester-olefin copolymer is a vinyl acetate-ethylene copolymer.

[0014] According to some embodiments of the present invention, the modified basalt fiber comprises basalt fiber modified by acetone, polyacrylamide and vinyl acetate-ethylene copolymer.

[0015] According to some embodiments of the present invention, the modified basalt fiber is prepared by a method comprising the following steps:

[0016] (1) The basalt fiber was soaked in the ketone compound, removed and dried to obtain modified fiber A;

[0017] (2) The modified fiber A is immersed in the polymer solution of the unsaturated amide monomer, taken out and dried to obtain the modified fiber B;

[0018] (3) The modified fiber B is immersed in the unsaturated carboxylic acid ester-olefin copolymer emulsion, taken out and dried to obtain the modified basalt fiber.

[0019] In some implementations, the soaking time in step (1) is 1-5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours.

[0020] In some implementations, the soaking time in step (2) is 1-5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours.

[0021] In some embodiments, in step (2), the concentration of the polymer solution of the unsaturated amide monomer is 0.1-1.0 wt%, for example, 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.7 wt%, 0.9 wt%, 1.0 wt%, etc. In some embodiments, in step (2), the concentration of the polymer solution of the unsaturated amide monomer is 0.3-0.5 wt%.

[0022] According to some embodiments of the present invention, in step (2), the weight-average molecular weight of the polymer of the unsaturated amide monomer is 5 million to 25 million, for example, 5 million, 6 million, 7 million, 8 million, 9 million, 10 million, 11 million, 12 million, 13 million, 14 million, 15 million, 16 million, 17 million, 18 million, 19 million, 20 million, 21 million, 22 million, 23 million, 24 million, 25 million, or any value between them. According to some embodiments of the present invention, in step (2), the weight-average molecular weight of the polymer of the unsaturated amide monomer is 10 million to 15 million. In some embodiments, in step (2), the weight-average molecular weight of the polymer of the unsaturated amide monomer is 11 million to 13 million.

[0023] In some implementations, the soaking time in step (3) is 20-60 minutes, for example, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, etc.

[0024] In some embodiments, in step (3), the solid content of the unsaturated carboxylic acid ester-olefin copolymer emulsion is not less than 54.5%. In some embodiments, the solid content of the emulsion is 54.5%-60%. In some embodiments, the solid content of the emulsion is 54.5%-57%. In some embodiments, the solid content of the emulsion is 54.5%-55.5%.

[0025] According to some embodiments of the present invention, in step (3), the viscosity of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 1000 mPa·s-1500 mPa·s, for example, 1000 mPa·s, 1100 mPa·s, 1200 mPa·s, 1300 mPa·s, 1400 mPa·s, 1500 mPa·s, or any value between them. In some embodiments, the viscosity of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 1100 mPa·s-1300 mPa·s.

[0026] In this invention, the solid content of the unsaturated carboxylic acid ester-olefin copolymer emulsion is tested using a vacuum drying method, and the viscosity is measured using a Brookfield viscometer.

[0027] According to some embodiments of the present invention, the raw materials for preparing the geopolymer include: activated kaolin, blast furnace slag, red mud, and alkali activator.

[0028] In some embodiments, the activated kaolin contains more than 90 wt% amorphous SiO2 and Al2O3. In some embodiments, the activated kaolin has a particle size of less than 20 μm. In some embodiments, the activated kaolin is prepared by a method comprising the steps of calcining kaolin at 600-800°C for 3-6 hours to obtain the activated kaolin. In some embodiments, the calcination is performed using an extremely cold process.

[0029] In some embodiments, based on the total mass of activated kaolin, blast furnace slag, and red mud as 100%, the mass percentage of activated kaolin is 60-70%, for example, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, etc. In some embodiments, based on the total mass of activated kaolin, blast furnace slag, and red mud as 100%, the mass percentage of activated kaolin is 63-67%.

[0030] In some embodiments, based on the total mass of activated kaolin, blast furnace slag, and red mud as 100%, the mass percentage of blast furnace slag is 15-25%, for example, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, etc. In some embodiments, based on the total mass of activated kaolin, blast furnace slag, and red mud as 100%, the mass percentage of blast furnace slag is 18-22%.

[0031] In some embodiments, the red mud comprises gibbsite-type bauxite red mud. In some embodiments, the particle size of the red mud is less than 75 μm.

[0032] In some embodiments, based on the total mass of activated kaolin, blast furnace slag, and red mud as 100%, the mass percentage of red mud is 10-20%, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc. In some embodiments, based on the total mass of activated kaolin, blast furnace slag, and red mud as 100%, the mass percentage of red mud is 13-17%.

[0033] In some embodiments, the alkali activator comprises silicates and alkali metal hydroxides. The silicates mentioned in this invention include, but are not limited to, alkali metal silicates, such as sodium silicate and potassium silicate. The alkali metal hydroxides mentioned in this invention include, but are not limited to, sodium hydroxide and potassium hydroxide. In some embodiments, the alkali activator comprises anhydrous sodium silicate and sodium hydroxide. In some embodiments, the mass ratio of silicate to alkali metal hydroxide in the alkali activator is (1.0-2.5):1, for example, 1.0:1, 1.2:1, 1.4:1, 1.5:1, 1.6:1, 1.8:1, 2.0:1, 2.2:1, 2.5:1, etc. In some embodiments, the mass ratio of silicate to alkali metal hydroxide in the alkali activator is (1.0-2.0):1.

[0034] In some embodiments, the amount of the alkali activator is 3-15% of the total mass of the activated kaolin, blast furnace slag and red mud, for example, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc.

[0035] In the composite material system of this invention, mineral admixtures such as mineral powder, fly ash, and silica fume are used to partially replace cement. This not only optimizes the particle size distribution of the tough mortar and improves the matrix density, but also allows for secondary reactions with cement hydration products, generating new cementitious substances and continuously enhancing the mechanical properties of the matrix. Furthermore, the mineral admixtures act as a lubricant in freshly mixed mortar, significantly improving its workability. In addition, the mineral admixtures can further fill the voids between the modified basalt fibers and the matrix, reducing frictional resistance and making the mortar easier to mix and pour, thereby improving the internal structural density, construction efficiency, and durability. All mineral admixtures in this invention are derived from solid waste, meeting green and environmentally friendly requirements.

[0036] According to some embodiments of the present invention, the geopolymer in the raw materials for preparing the composite material is 250-750 parts by mass, for example, 250 parts, 275 parts, 300 parts, 325 parts, 350 parts, 375 parts, 400 parts, 425 parts, 450 parts, 475 parts, 500 parts, 525 parts, 550 parts, 575 parts, 600 parts, 625 parts, 650 parts, 675 parts, 700 parts, 725 parts, 750 parts, etc.

[0037] According to some embodiments of the present invention, the mass ratio of the geopolymer to the total mass of mineral powder, silica fume, and fly ash is 1:(0.5-3). According to some embodiments of the present invention, the mass ratio of the geopolymer to the total mass of mineral powder, silica fume, and fly ash is 1:(0.5-1.5).

[0038] According to some embodiments of the present invention, the mass ratio of the geopolymer to the fly ash is (0.5-4):1, for example, 0.5:1, 0.8:1, 1.0:1, 1.5:1, 2.0:1, 2.5:1, 3.0:1, 3.5:1, 4.0:1, etc. According to some embodiments of the present invention, the mass ratio of the geopolymer to the fly ash is (1-3.5):1.

[0039] According to some embodiments of the present invention, the mineral powder is S95 grade mineral powder.

[0040] Mineral powder, a high-fineness, high-activity powder made from water-quenched blast furnace slag through drying and grinding, is a recognized important admixture for high-performance concrete. It effectively improves the compressive strength of concrete, inhibits alkali-aggregate reaction, reduces heat of hydration, decreases early temperature cracking, and enhances impermeability and erosion resistance. Mineral powder exhibits a pozzolanic effect, enhancing compressive, tensile, flexural, and shear strength, improving workability, reducing segregation and bleeding, refining pore structure, and improving frost resistance and durability. Although mineral powder significantly contributes to strength, its toughening effect is less than that of fly ash; therefore, its dosage should be controlled within an appropriate range.

[0041] According to some embodiments of the present invention, the mass ratio of mineral powder to fly ash is 1:(1.2-5). According to some embodiments of the present invention, the mass ratio of mineral powder to fly ash is 1:(2-4).

[0042] According to some embodiments of the present invention, the raw materials for preparing the composite material contain 100-400 parts of mineral powder by mass, for example, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts, 160 parts, 170 parts, 180 parts, 190 parts, 200 parts, 220 parts, 250 parts, 280 parts, 300 parts, 320 parts, 350 parts, 380 parts, 400 parts, etc.

[0043] Silica fume is a powdery material collected during the smelting of alloys or industrial silicon, and its main component is amorphous SiO2. According to some embodiments of the present invention, the silica fume contains more than 90% silica. Adding silica fume can improve the density and water retention of the matrix, reduce mortar segregation, and exert a nucleation effect, accelerating the hydration of cementitious materials and improving the early and mid-term strength of the matrix. The combination of fly ash and silica fume can achieve better particle size classification, enhance structural density and sealing, improve durability, and simultaneously reduce heat of hydration, thermal stress, and the risk of cracking. However, because silica fume has a small particle size, excessive addition will lead to a sharp decline in workability; therefore, its dosage should be controlled within an appropriate range.

[0044] According to some embodiments of the present invention, the mass ratio of silica fume to fly ash is 1:(2-10). According to some embodiments of the present invention, the mass ratio of silica fume to fly ash is 1:(4-8).

[0045] According to some embodiments of the present invention, the silica fume in the raw materials for preparing the composite material is 50-100 parts by mass, for example, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, etc.

[0046] According to some embodiments of the present invention, the fly ash is Grade I fly ash. Fly ash particles are mostly regularly spherical, which facilitates uniform distribution in the mixture, reduces inter-particle friction, and improves fluidity. When used as a cementitious material to partially replace cement, fly ash can optimize the particle size distribution of the cementitious system, improve density, and possess pozzolanic activity, promoting strength development through hydration reactions. With increasing fly ash content, the initial crack strength and tensile strength of the tough mortar decrease, but the ultimate tensile strain increases, and the matrix toughness is significantly improved. Therefore, the matrix strength and toughness can be coordinated by adjusting the fly ash content, achieving synergistic reinforcement with fibers.

[0047] According to some embodiments of the present invention, based on the total mass of mineral powder, silica fume, and fly ash as 100%, the mass percentage of fly ash is 40%-80%, for example, 40%, 45%, 48%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, etc. Within this range, the toughening effect of fly ash can be fully utilized.

[0048] According to some embodiments of the present invention, the raw materials for preparing the composite material contain 200-600 parts of fly ash by mass, for example, 200 parts, 225 parts, 250 parts, 275 parts, 300 parts, 325 parts, 350 parts, 375 parts, 400 parts, 425 parts, 450 parts, 475 parts, 500 parts, 525 parts, 550 parts, 575 parts, 600 parts, etc.

[0049] According to some embodiments of the present invention, the aggregate sand comprises quartz sand. According to some embodiments of the present invention, the fineness of the quartz sand is 40-120 mesh.

[0050] According to some embodiments of the present invention, the aggregate sand in the raw materials for preparing the composite material is 500-1000 parts by mass, for example, 500 parts, 525 parts, 550 parts, 575 parts, 600 parts, 625 parts, 650 parts, 675 parts, 700 parts, 725 parts, 750 parts, 775 parts, 800 parts, 825 parts, 850 parts, 875 parts, 900 parts, 925 parts, 950 parts, 975 parts, 1000 parts, etc.

[0051] According to some embodiments of the present invention, the water-reducing agent is a polycarboxylate water-reducing agent. According to some embodiments of the present invention, the polycarboxylate water-reducing agent is a liquid or a powder.

[0052] According to some embodiments of the present invention, the water-reducing agent in the raw materials for preparing the composite material is 1-5 parts by mass, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0053] According to some embodiments of the present invention, the modified basalt fiber accounts for 1-10% of the total mass of the geopolymer, mineral powder, silica fume, and fly ash. In some embodiments, the modified basalt fiber accounts for 4%-8% of the total mass of the geopolymer, mineral powder, silica fume, and fly ash. The basalt fiber has good compatibility with the chemical composition of the geopolymer matrix. In the composite material system of the present invention, the dosage of modified basalt fiber should be controlled within a suitable range. When the fiber dosage is too low, the fiber spacing in the matrix is ​​too large, and the number of fibers effectively bridging cracks per unit area is insufficient. According to composite material theory and fiber spacing theory, the "bridging effect" of fibers in preventing crack propagation is directly related to their number density. Too low a dosage means that the crack tip cannot be effectively bound by enough fibers, and the stress cannot be effectively transferred from the brittle matrix and dispersed to the fiber phase. This causes the crack to propagate rapidly and cannot be suppressed when the material is under tension or bending, thus exhibiting a sharp decrease in toughness (i.e., fracture energy and ultimate tensile strain), and the material still exhibits significant brittle fracture characteristics. When the fiber volumetric content is too high, the high specific surface area of ​​the fibers significantly increases the specific surface area of ​​the mixture system, leading to the adsorption of a large amount of free water and a sharp reduction in the amount of free water available for lubricating the slurry. Simultaneously, the large number of fibers results in an exponential increase in the probability of cross-linking and entanglement between fibers, forming a strong three-dimensional network structure in the slurry and generating significant mechanical interlocking resistance. This significantly increases the yield stress and plastic viscosity of the fresh mixture, thereby worsening its fluidity and causing a severe decline in workability (such as flowability, sprayability, and self-compacting properties), making effective construction, pouring, and compaction difficult. Therefore, a suitable dosage range is the key window for balancing the contradictory relationship between the "fiber bridging toughening effect" and the "workability of the fresh mixture system." Within the scope defined by this invention, a sufficiently dense fiber network can be formed to effectively transfer stress and restrain cracks, thereby significantly improving the toughness and post-cracking performance of the matrix, while maintaining acceptable workability of the fresh mixture to meet construction process requirements. To avoid the negative effects of high admixture, it is usually necessary to introduce high-efficiency water-reducing agents or redispersible latex powders to improve the rheological properties of the slurry.

[0054] According to some embodiments of the present invention, the modified basalt fiber in the raw materials for preparing the composite material is 30-80 parts by mass, for example, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, etc.

[0055] According to some embodiments of the present invention, the water content in the raw materials for preparing the composite material is 200-400 parts by mass, for example, 200 parts, 220 parts, 250 parts, 280 parts, 300 parts, 320 parts, 350 parts, 380 parts, 400 parts, etc.

[0056] According to some embodiments of the present invention, the raw materials for preparing the composite material include the following components in parts by mass: 250-750 parts of geopolymer, 100-400 parts of mineral powder, 50-100 parts of silica fume, 200-600 parts of fly ash, 500-1000 parts of aggregate sand, 1-5 parts of water-reducing agent, 30-80 parts of modified basalt fiber, and 200-400 parts of water.

[0057] According to some embodiments of the present invention, the raw materials for preparing the composite material include the following components in parts by mass: 350-650 parts of geopolymer, 100-150 parts of mineral powder, 50-100 parts of silica fume, 200-400 parts of fly ash, 500-1000 parts of aggregate sand, 2-4 parts of water-reducing agent, 60-80 parts of modified basalt fiber, and 200-300 parts of water.

[0058] According to some embodiments of the present invention, the raw materials for preparing the composite material also include one or more of fly ash microspheres, carboxypropyl methylcellulose, and latex powder.

[0059] According to some embodiments of the present invention, the raw materials for preparing the composite material also include carboxypropyl methylcellulose and latex powder.

[0060] According to some embodiments of the present invention, the raw materials for preparing the composite material also include fly ash microspheres, carboxypropyl methylcellulose and latex powder.

[0061] In some embodiments, the particle size of the fly ash microspheres is 0.1-10 μm;

[0062] In some embodiments, the viscosity of the carboxypropyl methylcellulose is 10-30 W Pa·s. In some embodiments, the viscosity of the carboxypropyl methylcellulose is 15-25 W Pa·s. In some embodiments, the viscosity of the carboxypropyl methylcellulose is 18-22 W Pa·s.

[0063] In some embodiments, the latex powder is one or more of an ethylene / vinyl acetate copolymer, a vinyl acetate / ethylene tert-carbonate copolymer, and an acrylic acid copolymer. In some embodiments, the latex powder is an ethylene / vinyl acetate copolymer. Redispersible latex powder serves as a key functional additive in the composite material system of this invention. By redispersing upon contact with water and forming a continuous polymer film, it interweaves with cement hydration products to form an organic-inorganic composite network structure, thereby significantly improving the material's flexibility, crack resistance, bond strength, and durability. Simultaneously, it improves the workability of fresh mortar through the ball-bearing effect and air-entraining action, and enhances impermeability by filling pores and optimizing the pore structure. Together with mineral admixtures and fibers, it forms the core technological foundation of high-performance tough mortar.

[0064] In some embodiments, the mass ratio of fly ash microspheres to the total mass of the geopolymer, mineral powder, silica fume, and fly ash is 1:(5-25), for example, 1:5, 1:8, 1:10, 1:12, 1:15, 1:18, 1:20, 1:22, 1:25, etc. In some embodiments, the mass ratio of fly ash microspheres to the total mass of the geopolymer, mineral powder, silica fume, and fly ash is 1:(8-20).

[0065] In some embodiments, the mass ratio of latex powder to the total mass of the geopolymer, mineral powder, silica fume, and fly ash is 1:(5-25), for example, 1:5, 1:8, 1:9, 1:10, 1:12, 1:15, 1:18, 1:20, 1:22, 1:25, etc. In some embodiments, the mass ratio of latex powder to the total mass of the geopolymer, mineral powder, silica fume, and fly ash is 1:(9-22).

[0066] In some embodiments, the mass ratio of latex powder to the modified basalt fiber is (0.2-4):1, for example, 0.2:1, 0.4:1, 0.6:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, etc. In some embodiments, the mass ratio of latex powder to the modified basalt fiber is (0.6-3):1.

[0067] In some embodiments, the mass of carboxypropyl methylcellulose accounts for 0.05-0.25% of the total mass of the geopolymer, mineral powder, silica fume, and fly ash, for example, 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25%, etc. In some embodiments, the mass of carboxypropyl methylcellulose accounts for 0.1-0.25% of the total mass of the geopolymer, mineral powder, silica fume, and fly ash.

[0068] In some embodiments, the fly ash microspheres in the raw materials for preparing the composite material are 1-100 parts by weight, for example, 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, etc. In some embodiments, the fly ash microspheres in the raw materials for preparing the composite material are 50-100 parts by weight.

[0069] In some embodiments, the amount of carboxypropyl methylcellulose in the raw materials for preparing the composite material is 0.1-2 parts by weight, for example, 0.1 parts, 0.5 parts, 0.8 parts, 1.0 parts, 1.2 parts, 1.5 parts, 1.8 parts, 2.0 parts, etc. In some embodiments, the amount of carboxypropyl methylcellulose in the raw materials for preparing the composite material is 1-2 parts by weight.

[0070] In some embodiments, the latex powder in the raw materials for preparing the composite material is 1-100 parts by weight, for example, 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, etc. In some embodiments, the latex powder in the raw materials for preparing the composite material is 45-100 parts by weight.

[0071] In some embodiments, the raw materials for preparing the composite material, by mass parts, include 1-100 parts of fly ash microspheres, 0.1-2 parts of carboxypropyl methylcellulose, and 1-100 parts of latex powder.

[0072] In some embodiments, the raw materials for preparing the composite material, by mass parts, include 50-100 parts of fly ash microspheres, 1-2 parts of carboxypropyl methylcellulose, and 45-100 parts of latex powder.

[0073] In a second aspect, the present invention provides a method for preparing a basalt fiber reinforced geopolymer composite material as described in the first aspect of the present invention, comprising the following steps:

[0074] (1) The geopolymer, mineral powder, silica fume, fly ash and aggregate sand are mixed to obtain a first mixture;

[0075] (2) The dry mixture is mixed with a water-reducing agent and water to obtain a second mixture;

[0076] (3) The second mixture is mixed with the modified basalt fiber and cured to obtain the basalt fiber reinforced geopolymer composite material.

[0077] According to some embodiments of the present invention, fly ash microspheres are also added during the mixing process in step (1).

[0078] According to some embodiments of the present invention, carboxypropyl methylcellulose is also added during the mixing process in step (1).

[0079] According to some embodiments of the present invention, latex powder is also added during the mixing process in step (3).

[0080] According to some embodiments of the present invention, stirring is also performed during the mixing process in steps (1), (2), and (3). According to some embodiments of the present invention, the stirring time is 1-5 minutes.

[0081] Thirdly, the present invention provides the application of basalt fiber reinforced geopolymer composite materials as described in the first aspect in seismic reinforcement of building structures, infrastructure repair, special engineering, and road repair.

[0082] Compared with the prior art, the present invention has the following beneficial technical effects:

[0083] This invention modifies basalt fibers using ketone compounds, polymers of unsaturated amide monomers, and unsaturated carboxylic acid ester-olefin copolymers, resulting in fibers with high alkali corrosion resistance and better bonding with mortar interfaces. When used as a reinforcing material, it is compounded with geopolymers, mineral powder, silica fume, fly ash, etc., to obtain composite materials with elongation rates as high as 0.45% to 0.96%, tensile strengths higher than 5.5 to 10.4 MPa, and high compressive strength. It can be used for seismic reinforcement projects, exhibiting good construction performance and high strength. Attached Figure Description

[0084] Figure 1 The fiber pull-out force elongation test results of the composite materials of Example 1 and Comparative Examples 1 to 6 are shown.

[0085] Figure 2 A cross-sectional view of the fiber specimen of Example 1 is shown.

[0086] Figure 3 The results of alkali corrosion resistance tests on the modified basalt fibers of Preparation Example 2, Preparation Example 2A, and Preparation Example 2B, as well as the unmodified basalt fibers, are shown. Detailed Implementation

[0087] 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. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

[0088] Unless otherwise defined, the technical terms used in the following experiments have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0089] Unless otherwise specified, all reagents used in the following experiments are conventional biochemical reagents; all raw materials, instruments and equipment used in the following experiments can be obtained by purchasing them from the market or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, all experimental methods are conventional methods.

[0090] The raw materials used in the following experiments of this invention are as follows: mineral powder is S95 grade mineral powder; silica fume has a silica content greater than 90%; fly ash is grade I fly ash; quartz sand has a fineness of 40-120 mesh; latex powder is Wacker 5010 latex powder; water-reducing agent is powdered polycarboxylate water-reducing agent; microspheres are fly ash microspheres with a particle size of 0.1-10μm; the viscosity of carboxypropyl methylcellulose is 20W Pa·s; blast furnace slag is S88 blast furnace slag powder; kaolin (unactivated) has a particle size of 1-2μm and an Al2O3 content greater than 35%; red mud is monohydrate gibbsite-type bauxite red mud; basalt fiber (unmodified) was purchased from Sichuan Aerospace Tuoxin, with a diameter of 15μm and a length of 6mm; TXCS-15 (monofilament) was purchased from Aerospace Tuoxin; CBF13-6 was purchased from Zhejiang Shijin.

[0091] Preparation Example 1: Preparation of Geopolymer Powder

[0092] Kaolin was activated by calcination at 700°C for 5 hours using an ultra-cold process. After calcination, the amorphous SiO2+Al2O3 content was greater than 90%, and the particle size was controlled below 20μm, thus obtaining activated kaolin.

[0093] Red mud ore powder: Red mud ore is dried at 100°C for 6 hours and ground to below 75μm to obtain red mud ore powder;

[0094] Anhydrous sodium silicate and sodium hydroxide were mixed at a mass ratio of 1.5:1 to obtain a dry powder alkali activator;

[0095] 65 parts activated kaolin, 20 parts blast furnace slag, and 15 parts red mud powder were mixed and 10 parts dry powder alkali activator were added to obtain geopolymer powder.

[0096] Preparation Example 1A: Preparation of Geopolymer Powder

[0097] Kaolin was activated by calcination at 700°C for 5 hours using an ultra-cold process. After calcination, the amorphous SiO2+Al2O3 content was greater than 90%, and the particle size was controlled below 20μm, thus obtaining activated kaolin.

[0098] Red mud ore powder: Red mud ore is dried at 100°C for 6 hours and ground to below 75μm to obtain red mud ore powder;

[0099] Anhydrous sodium silicate and sodium hydroxide were mixed at a mass ratio of 1.5:1 to obtain a dry powder alkali activator;

[0100] 85 parts of blast furnace slag and 15 parts of red mud ore were mixed and 10 parts of dry powder alkali activator were added to obtain geopolymer powder.

[0101] Preparation Example 1B: Preparation of Geopolymer Powder

[0102] Kaolin was activated by calcination at 700°C for 5 hours using an ultra-cold process. After calcination, the amorphous SiO2+Al2O3 content was greater than 90%, and the particle size was controlled below 20μm, thus obtaining activated kaolin.

[0103] Red mud ore powder: Red mud ore is dried at 100°C for 6 hours and ground to below 75μm to obtain red mud ore powder;

[0104] Anhydrous sodium silicate and sodium hydroxide were mixed at a mass ratio of 1.5:1 to obtain a dry powder alkali activator;

[0105] 20 parts of blast furnace slag and 80 parts of red mud ore were mixed and 10 parts of dry powder alkali activator were added to obtain geopolymer powder.

[0106] Preparation Example 1C: Preparation of Geopolymer Powder

[0107] Kaolin was activated by calcination at 700°C for 5 hours using an ultra-cold process. After calcination, the amorphous SiO2+Al2O3 content was greater than 90%, and the particle size was controlled below 20μm, thus obtaining activated kaolin.

[0108] Red mud ore powder: Red mud ore is dried at 100°C for 6 hours and ground to below 75μm to obtain red mud ore powder;

[0109] Anhydrous sodium silicate and sodium hydroxide were mixed at a mass ratio of 3:1 to obtain a dry powder alkali activator.

[0110] 65 parts activated kaolin, 20 parts blast furnace slag, and 15 parts red mud were mixed and 10 parts dry powder alkali activator were added to obtain geopolymer powder.

[0111] Preparation Example 2: Preparation of Modified Basalt Fibers

[0112] Basalt fibers were soaked in acetone solution for 1-2 hours, then removed and dried. They were then soaked in an aqueous solution of polyacrylamide (weight average molecular weight 12 million) with a total PAM concentration of 0.4 wt.% for 2 hours, washed and dried, and then immersed in a vinyl acetate-ethylene copolymer emulsion with a solid content of 55% (viscosity of about 1200 mPa·s) for 30 minutes. After removal, washing and drying, modified basalt fibers were obtained.

[0113] Preparation Example 2A: Preparation of Modified Basalt Fibers

[0114] Basalt fibers were immersed in 3 mol / L hydrochloric acid for 6 hours, then removed, cleaned, and dried to obtain hydrochloric acid-etched basalt fibers.

[0115] Preparation Example 2B: Preparation of Modified Basalt Fibers

[0116] Basalt fibers were soaked in silane coupling agent KH550 (silane content 5 wt%) for 1 hour, then removed, washed and dried to obtain modified basalt fibers.

[0117] Preparation Example 2C: Preparation of Modified Basalt Fibers

[0118] Basalt fibers were immersed in a 1.6% nano-SiO2 dispersion (with an average particle size of 150 nm) for 2 hours, then removed, washed, and dried to obtain nano-SiO2 modified basalt fibers.

[0119] Preparation Example 2D: Preparation of Modified Basalt Fibers

[0120] Soak basalt fibers in acetone solution for 1-2 hours, then remove and dry.

[0121] Preparation Example 2E: Preparation of Modified Basalt Fibers

[0122] Basalt fibers were immersed in a vinyl acetate-ethylene copolymer emulsion with a solid content of 55% for 30 minutes, then removed, washed, and dried to obtain modified basalt fibers.

[0123] Preparation Example 2F: Preparation of Modified Basalt Fibers

[0124] Basalt fibers were soaked in a polyacrylamide solution with a total PAM concentration of 0.4 wt.% for 2 hours, then washed and dried to obtain modified basalt fibers.

[0125] Example 1

[0126] This embodiment provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0127] Materials: 250 parts of the geopolymer of Preparation Example 1, 200 parts of mineral powder, 100 parts of silica fume, 50 parts of microspheres, 400 parts of fly ash, 0.5 parts of carboxypropyl methylcellulose, 100 parts of latex powder, 800 parts of quartz sand, 3 parts of powder water-reducing agent, 40 parts of modified basalt fiber of Preparation Example 2, and 250 parts of water.

[0128] Preparation of cementitious materials: Weigh the raw materials by weight and then add geopolymer, mineral powder, silica fume, microspheres, fly ash, carboxypropyl methylcellulose and quartz sand in sequence. Stir to obtain a dry mixture: Add water-reducing agent and water to the dry mixture and stir for 3 minutes. Then add latex powder and modified basalt fiber and stir again for 2 minutes to obtain a mixed slurry.

[0129] Example 2

[0130] This embodiment provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0131] Materials: 300 parts of the geopolymer of Preparation Example 1, 100 parts of mineral powder, 50 parts of silica fume, 50 parts of microspheres, 500 parts of fly ash, 1 part of carboxypropyl methylcellulose, 50 parts of latex powder, 500 parts of quartz sand, 2 parts of powder water-reducing agent, 45 parts of modified basalt fiber of Preparation Example 2, and 200 parts of water.

[0132] Preparation of cementitious materials: Weigh the raw materials by weight and then add geopolymer, mineral powder, silica fume, microspheres, fly ash, carboxypropyl methylcellulose and quartz sand in sequence. Stir to obtain a dry mixture: Add water-reducing agent and water to the dry mixture and stir for 3 minutes. Then add latex powder and modified basalt fiber and stir again for 2 minutes to obtain a mixed slurry.

[0133] Example 3

[0134] This embodiment provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0135] Materials: 300 parts of the geopolymer of Preparation Example 1, 200 parts of mineral powder, 50 parts of silica fume, 50 parts of microspheres, 400 parts of fly ash, 1 part of carboxypropyl methylcellulose, 50 parts of latex powder, 600 parts of quartz sand, 3 parts of powder water-reducing agent, 50 parts of modified basalt fiber of Preparation Example 2, and 200 parts of water.

[0136] Preparation of cementitious materials: Weigh the raw materials by weight and then add geopolymer, mineral powder, silica fume, microspheres, fly ash, carboxypropyl methylcellulose and quartz sand in sequence. Stir to obtain a dry mixture: Add water-reducing agent and water to the dry mixture and stir for 3 minutes. Then add latex powder and modified basalt fiber and stir again for 2 minutes to obtain a mixed slurry.

[0137] Example 4

[0138] This embodiment provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0139] Materials: 350 parts of the geopolymer of Preparation Example 1, 150 parts of mineral powder, 100 parts of silica fume, 50 parts of microspheres, 350 parts of fly ash, 1 part of carboxypropyl methylcellulose, 45 parts of latex powder, 1000 parts of quartz sand, 4 parts of powder water-reducing agent, 65 parts of modified basalt fiber of Preparation Example 2, and 240 parts of water.

[0140] Preparation of cementitious materials: Weigh the raw materials by weight and then add geopolymer, mineral powder, silica fume, microspheres, fly ash, carboxypropyl methylcellulose and quartz sand in sequence. Stir to obtain a dry mixture: Add water-reducing agent and water to the dry mixture and stir for 3 minutes. Then add latex powder and modified basalt fiber and stir again for 2 minutes to obtain a mixed slurry.

[0141] Example 5

[0142] This embodiment provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0143] Materials: 400 parts of the geopolymer of Preparation Example 1, 100 parts of mineral powder, 50 parts of silica fume, 50 parts of microspheres, 400 parts of fly ash, 1 part of carboxypropyl methylcellulose, 70 parts of latex powder, 500 parts of quartz sand, 3 parts of powder water-reducing agent, 60 parts of modified basalt fiber of Preparation Example 2, and 200 parts of water.

[0144] Preparation of cementitious materials: Weigh the raw materials by weight and then add geopolymer, mineral powder, silica fume, microspheres, fly ash, carboxypropyl methylcellulose and quartz sand in sequence. Stir to obtain a dry mixture: Add water-reducing agent and water to the dry mixture and stir for 3 minutes. Then add latex powder and modified basalt fiber and stir again for 2 minutes to obtain a mixed slurry.

[0145] Example 6

[0146] This embodiment provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0147] Materials: 500 parts of the geopolymer of Preparation Example 1, 100 parts of mineral powder, 50 parts of silica fume, 50 parts of microspheres, 300 parts of fly ash, 2 parts of carboxypropyl methylcellulose, 80 parts of latex powder, 500 parts of quartz sand, 2 parts of powder water-reducing agent, 60 parts of modified basalt fiber of Preparation Example 2, and 200 parts of water.

[0148] Preparation of cementitious materials: Weigh the raw materials by weight and then add geopolymer, mineral powder, silica fume, microspheres, fly ash, carboxypropyl methylcellulose and quartz sand in sequence. Stir to obtain a dry mixture: Add water-reducing agent and water to the dry mixture and stir for 3 minutes. Then add latex powder and modified basalt fiber and stir again for 2 minutes to obtain a mixed slurry.

[0149] Example 7

[0150] This embodiment provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0151] Materials: 500 parts of the geopolymer of Preparation Example 1, 100 parts of mineral powder, 50 parts of silica fume, 100 parts of microspheres, 250 parts of fly ash, 1 part of carboxypropyl methylcellulose, 50 parts of latex powder, 500 parts of quartz sand, 2 parts of powder water-reducing agent, 60 parts of modified basalt fiber of Preparation Example 2, and 200 parts of water.

[0152] Preparation of cementitious materials: Weigh the raw materials by weight and then add geopolymer, mineral powder, silica fume, microspheres, fly ash, carboxypropyl methylcellulose and quartz sand in sequence. Stir to obtain a dry mixture: Add water-reducing agent and water to the dry mixture and stir for 3 minutes. Then add latex powder and modified basalt fiber and stir again for 2 minutes to obtain a mixed slurry.

[0153] Example 8

[0154] This embodiment provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0155] Materials: 550 parts of the geopolymer of Preparation Example 1, 150 parts of mineral powder, 100 parts of silica fume, 200 parts of fly ash, 2 parts of carboxypropyl methylcellulose, 50 parts of latex powder, 500 parts of quartz sand, 2 parts of powder water-reducing agent, 60 parts of modified basalt fiber of Preparation Example 2, and 200 parts of water.

[0156] Preparation of cementitious materials: Weigh the raw materials by weight and then add geopolymer, mineral powder, silica fume, fly ash, carboxypropyl methylcellulose and quartz sand in sequence. Stir to obtain a dry mixture: Add water-reducing agent and water to the dry mixture and stir for 3 minutes. Then add latex powder and modified basalt fiber and stir again for 2 minutes to obtain a mixed slurry.

[0157] Example 9

[0158] This embodiment provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0159] Materials: 650 parts of the geopolymer of Preparation Example 1, 100 parts of mineral powder, 50 parts of silica fume, 200 parts of fly ash, 1 part of carboxypropyl methylcellulose, 100 parts of latex powder, 500 parts of quartz sand, 4 parts of powder water-reducing agent, 80 parts of modified basalt fiber of Preparation Example 2, and 200 parts of water.

[0160] Preparation of cementitious materials: Weigh the raw materials by weight and then add geopolymer, mineral powder, silica fume, fly ash, carboxypropyl methylcellulose and quartz sand in sequence. Stir to obtain a dry mixture: Add water-reducing agent and water to the dry mixture and stir for 3 minutes. Then add latex powder and modified basalt fiber and stir again for 2 minutes to obtain a mixed slurry.

[0161] Example 10

[0162] This embodiment provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0163] Materials: 650 parts of the geopolymer of Preparation Example 1, 100 parts of mineral powder, 50 parts of silica fume, 200 parts of fly ash, 1 part of carboxypropyl methylcellulose, 100 parts of latex powder, 500 parts of quartz sand, 4 parts of powder water-reducing agent, 80 parts of modified basalt fiber of Preparation Example 2, and 300 parts of water.

[0164] Preparation of cementitious materials: Weigh the raw materials by weight and then add geopolymer, mineral powder, silica fume, fly ash, carboxypropyl methylcellulose and quartz sand in sequence. Stir to obtain a dry mixture: Add water-reducing agent and water to the dry mixture and stir for 3 minutes. Then add latex powder and modified basalt fiber and stir again for 2 minutes to obtain a mixed slurry.

[0165] The mass fractions of each component in the composite materials in Examples 1 to 10 are shown in Table 1.

[0166] Table 1. Mass parts of components in Examples 1-10

[0167]

[0168] Comparative Example 1

[0169] The only difference from Example 1 is that the "modified basalt fiber" is replaced with an equal number of parts by weight of "unmodified basalt fiber".

[0170] Comparative Example 2

[0171] The only difference from Example 1 is that the "modified basalt fiber" is replaced with the same mass fraction of "modified basalt fiber of Preparation Example 2A".

[0172] Comparative Example 3

[0173] The only difference from Example 1 is that the "modified basalt fiber" is replaced with the same mass fraction of "modified basalt fiber of Preparation Example 2B".

[0174] Comparative Example 4

[0175] The only difference from Example 1 is that the "modified basalt fiber" is replaced with the same mass fraction of "modified basalt fiber of Preparation Example 2C".

[0176] Comparative Example 5

[0177] The only difference from Example 1 is that the "modified basalt fiber" is replaced with the same mass fraction of "modified basalt fiber of Preparation Example 2D".

[0178] Comparative Example 6

[0179] The only difference from Example 1 is that the "modified basalt fiber" is replaced with the same mass fraction of "modified basalt fiber of Preparation Example 2E".

[0180] Comparative Example 7

[0181] The only difference from Example 1 is that the "modified basalt fiber" is replaced with the same mass fraction of "modified basalt fiber of Preparation Example 2F".

[0182] Comparative Example 8

[0183] The only difference from Example 1 is that the "geopolymer" is replaced with the same number of parts by weight of "Jinyu 42.5 ordinary Portland cement".

[0184] Comparative Example 9

[0185] The only difference from Example 1 is that “geopolymer” is replaced with an equal mass fraction of “geopolymer of Preparation Example 1A”.

[0186] Comparative Example 10

[0187] The only difference from Example 1 is that “geopolymer” is replaced with an equal mass fraction of “geopolymer of Preparation Example 1B”.

[0188] Comparative Example 11

[0189] The only difference from Example 1 is that “geopolymer” is replaced with an equal mass fraction of “geopolymer of Preparation Example 1C”.

[0190] Comparative Example 12

[0191] The difference from Example 1 is that "200 parts mineral powder, 100 parts silica fume, and 400 parts fly ash" are replaced with "700 parts mineral powder".

[0192] Comparative Example 13

[0193] The difference from Example 1 is that "200 parts mineral powder, 100 parts silica fume, and 400 parts fly ash" are replaced with "700 parts silica fume".

[0194] Comparative Example 14

[0195] The difference from Example 1 is that "200 parts mineral powder, 100 parts silica fume, and 400 parts fly ash" are replaced with "700 parts fly ash".

[0196] Comparative Example 15

[0197] The difference from Example 1 is that "200 parts mineral powder, 100 parts silica fume, and 400 parts fly ash" are replaced with "300 parts mineral powder and 400 parts fly ash".

[0198] Comparative Example 16

[0199] The only difference from Example 1 is that the "modified basalt fiber" is replaced with the same mass fraction of "basalt fiber TXCS-15 (monofilament)".

[0200] Comparative Example 17

[0201] The only difference from Example 1 is that the "modified basalt fiber" is replaced with an equal number of "basalt fiber CBF13-6" by mass.

[0202] Comparative Examples 18-1 to 18-8

[0203] The only difference from Example 1 is that the mass ratio of latex powder to modified basalt fiber was adjusted from 2.5:1 to 4:1, 3:1, 2:1, 1:1, 1:1.5, 1:2, 1:3, and 1:5, respectively.

[0204] Test Example 1: Mechanical Property Test

[0205] The composite materials provided in each embodiment and comparative example were cured, and their compressive strength, flexural strength, and elongation were tested at 28 days of age. The testing methods were in accordance with JC / T 2461-2018 Test Method for Mechanical Properties of High-Ductility Fiber Reinforced Cement-Based Composite Materials.

[0206] The test results of the composite materials in Examples 1 to 10 are shown in Table 2 below.

[0207] Table 2

[0208]

[0209] The test results show that the basalt fiber reinforced geopolymer composites provided in Examples 1 to 10 have a high elongation rate, which can reach 0.45% to 0.96%; at the same time, they also have high tensile strength and compressive strength.

[0210] The test results of the composite materials of Comparative Examples 1 to 7, and Comparative Examples 16 and 17 are shown in Table 3 below.

[0211] Table 3

[0212]

[0213] As can be seen from Table 3, compared with Comparative Examples 1 to 7, the composite material prepared by using the modified basalt fiber of Preparation Example 2 in Example 1 has significantly improved elongation and tensile strength.

[0214] The test results of the composite materials of Comparative Examples 8 to 11 are shown in Table 4 below.

[0215] Table 4

[0216]

[0217] As can be seen from Table 4, compared with Comparative Examples 8 to 11, the composite material prepared by using the geopolymer of Preparation Example 1 in Example 1 has significantly improved elongation and tensile strength.

[0218] The test results of the composite materials in Comparative Examples 12 to 15 are shown in Table 5 below.

[0219] Table 5

[0220]

[0221] As can be seen from Table 5, compared with Comparative Examples 12 to 15, the composite material prepared by combining mineral powder, silica fume and fly ash, and adding other components in Example 1 has significantly improved elongation and tensile strength.

[0222] The test results of the composite materials of Comparative Examples 18-1 to 18-8 are shown in Table 6 below.

[0223] Table 6

[0224]

[0225] Test Example 2: Fiber Pull-out Experiment

[0226] The composite materials of Example 1 and Comparative Examples 1 to 6 were subjected to fiber pull-out tests, and the test methods are as follows:

[0227] 1. Material preparation:

[0228] The matrix material used was the composite material of Example 1 and Comparative Examples 1 to 6;

[0229] 2. Specimen design and fabrication:

[0230] Determine the burial depth: 3mm;

[0231] Preparation of specimens: (1) Fix the fiber monofilament (ordinary basalt fiber) vertically and centrally in a specific mold; (2) Pour the matrix material; (3) Control the embedment length to a predetermined value; (4) Cure the matrix to ensure that the matrix achieves the expected performance;

[0232] 3. Install test specimens:

[0233] Install the cured or hardened specimens onto the mechanical testing machine;

[0234] Precise clamping: The free end of the fiber must be firmly clamped to ensure good alignment during loading and avoid eccentricity;

[0235] 4. Perform a pull-out test:

[0236] Start the testing machine and apply a continuous and uniform tensile force to the fiber monofilament to pull it out of the matrix;

[0237] Real-time recording of pull-out load and fiber pull-out displacement data continues until the fiber is completely pulled out or broken. The cross-sectional view of the fiber specimen in Example 1 is shown below. Figure 2 As shown, it can be seen that the basalt fibers under this ratio undergo pull-out failure (the specific characteristic of pull-out failure is that dense fibers can be seen in the cross-section), and the pull-out length is 2-3 mm.

[0238] 5. Plotting curves and extracting parameters:

[0239] Plot the pull-out load-displacement curve. From the curve, parameters such as the initial debonding load (the first inflection point of the curve) and the maximum pull-out load (the maximum value of the ordinate) can be analyzed. These parameters can reflect the bond-slip behavior of the interface.

[0240] Example 1: The pull-out load-displacement curves (stress-strain curves) of the composite materials of Comparative Examples 1 to 6 are as follows: Figure 1 As shown. Figure 1 The results showed that the composite material of Example 1 had higher pull-out strength and elongation compared with Comparative Examples 1 to 6.

[0241] Test Example 3: Acid and Alkali Resistance Test

[0242] The modified basalt fibers from Preparation Examples 2, 2A, and 2B, as well as the unmodified basalt fibers, were subjected to alkali resistance tests. The tests were conducted in accordance with GB / T 23265-2023 (Chopped Basalt Fibers for Cement Concrete and Mortar), as detailed below:

[0243] 3.1 Prepare 150g of 1mol / L sodium hydroxide solution for each group and store it in a wide-mouthed glass bottle (with a lid that can be sealed).

[0244] 3.2 Prepare several basalt monofilaments with a length of at least 40 mm, wash them with pure water to remove surface impurities, and immerse them in the solution for 7 days. After the 7-day aging period, remove all the fibers and wash them with plenty of pure water to remove surface impurities.

[0245] 3.23 Sample preparation for electron microscopy observation.

[0246] The results are as follows Figure 3 As shown, the modified basalt fiber surface in Preparation Example 2 was basically not corroded, while the unmodified basalt fiber surface was basically corroded and a large area of ​​the surface was peeled off. The modified basalt fiber surfaces in Preparation Examples 2A and 2B were severely corroded and partially peeled off.

[0247] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing a basalt fiber reinforced geopolymer composite material, comprising the following steps: (1) The geopolymer, mineral powder, silica fume, fly ash and aggregate sand are mixed to obtain the first mixture; (2) The first mixture is mixed with a water-reducing agent and water to obtain a second mixture; (3) The second mixture is mixed with modified basalt fiber and cured to obtain the basalt fiber reinforced geopolymer composite material; In step (1), fly ash microspheres and / or carboxypropyl methylcellulose and / or latex powder are also added during the mixing process; Stirring is also performed during the mixing process in steps (1), (2) and (3), and the stirring time is 1-5 minutes; The modified basalt fiber includes basalt fiber modified by a polymer of ketone compounds, unsaturated amide monomers, and unsaturated carboxylic acid ester-olefin copolymer. The modified basalt fiber is prepared by a method comprising the following steps: (S1) The basalt fiber is soaked in the ketone compound, removed and dried to obtain modified fiber A; (S2) The modified fiber A is immersed in the polymer solution of the unsaturated amide monomer, taken out and dried to obtain the modified fiber B; (S3) The modified fiber B is immersed in the unsaturated carboxylic acid ester-olefin copolymer emulsion, removed and dried to obtain the modified basalt fiber.

2. The preparation method according to claim 1, characterized in that, The ketone compounds are selected from C3-C6 ketone compounds; and / or The unsaturated amide monomer is selected from C3-C6 unsaturated amides; and / or The unsaturated carboxylic acid ester in the unsaturated carboxylic acid ester-olefin copolymer is selected from esters formed by C2-C6 unsaturated alcohols and C2-C6 carboxylic acids; the olefin in the unsaturated carboxylic acid ester-olefin copolymer is selected from C2-C6 olefins.

3. The preparation method according to claim 2, characterized in that, The ketone compound is acetone; and / or The unsaturated amide monomer is acrylamide or methacrylamide; and / or The unsaturated carboxylic acid ester in the unsaturated carboxylic acid ester-olefin copolymer is vinyl acetate; the olefin in the unsaturated carboxylic acid ester-olefin copolymer is selected from C2-C4 olefins.

4. The preparation method according to claim 2, characterized in that, The olefin in the unsaturated carboxylic acid ester-olefin copolymer is ethylene.

5. The preparation method according to claim 2, characterized in that, The modified basalt fiber comprises basalt fiber modified by acetone, polyacrylamide, and vinyl acetate-ethylene copolymer.

6. The preparation method according to claim 1, characterized in that, In step (S1), the soaking time is 1-5 hours.

7. The preparation method according to claim 1, characterized in that, In step (S2), the soaking time is 1-5 hours.

8. The preparation method according to claim 1, characterized in that, In step (S2), the concentration of the polymer solution of the unsaturated amide monomer is 0.1-1.0 wt%.

9. The preparation method according to claim 1, characterized in that, In step (S2), the concentration of the polymer solution of the unsaturated amide monomer is 0.3-0.5 wt%.

10. The preparation method according to claim 1, characterized in that, In step (S2), the weight-average molecular weight of the polymer of the unsaturated amide monomer is 5 million to 25 million.

11. The preparation method according to claim 1, characterized in that, In step (S2), the weight-average molecular weight of the polymer of the unsaturated amide monomer is 10 million to 15 million.

12. The preparation method according to claim 1, characterized in that, In step (S2), the weight-average molecular weight of the polymer of the unsaturated amide monomer is 11 million to 13 million.

13. The preparation method according to claim 1, characterized in that, In step (S3), the soaking time is 20-60 minutes.

14. The preparation method according to claim 1, characterized in that, In step (S3), the solid content of the unsaturated carboxylic acid ester-olefin copolymer emulsion is not less than 54.5%.

15. The preparation method according to claim 1, characterized in that, In step (S3), the solid content of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 54.5-60%.

16. The preparation method according to claim 1, characterized in that, In step (S3), the solid content of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 54.5-55.5%.

17. The preparation method according to claim 1, characterized in that, In step (S3), the viscosity of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 1000 mPa·s-1500 mPa·s.

18. The preparation method according to claim 1, characterized in that, In step (S3), the viscosity of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 1100 mPa·s-1300 mPa·s.

19. The preparation method according to any one of claims 1-18, characterized in that, The raw materials for preparing the geopolymer include: activated kaolin, blast furnace slag, red mud, and alkali activator.

20. The preparation method according to claim 19, characterized in that, Based on the total mass of activated kaolin, blast furnace slag and red mud as 100%, the mass percentage of activated kaolin is 60-70%; the mass percentage of blast furnace slag is 15-25%; and the mass percentage of red mud is 10-20%.

21. The preparation method according to claim 19, characterized in that, Based on the total mass of activated kaolin, blast furnace slag and red mud as 100%, the mass percentage of activated kaolin is 63-67%; the mass percentage of blast furnace slag is 18-22%; and the mass percentage of red mud is 13-17%.

22. The preparation method according to claim 19, characterized in that, The amount of the alkali activator is 3-15% of the total mass of the activated kaolin, blast furnace slag and red mud.

23. The preparation method according to claim 19, characterized in that, The amount of the alkali activator is 8-12% of the total mass of the activated kaolin, blast furnace slag and red mud.

24. The preparation method according to claim 19, characterized in that, The activated kaolin contains more than 90 wt% amorphous SiO2 and Al2O3.

25. The preparation method according to claim 19, characterized in that, The activated kaolin has a particle size of less than 20 μm.

26. The preparation method according to claim 19, characterized in that, The activated kaolin is prepared by a method comprising the following steps: calcining kaolin at 600-800°C for 3-6 hours to obtain the activated kaolin.

27. The preparation method according to claim 19, characterized in that, The red mud includes monohydrate gibbsite-type bauxite red mud; the particle size of the red mud is less than 75 μm.

28. The preparation method according to claim 19, characterized in that, The alkaline activator includes silicates and alkali metal hydroxides.

29. The preparation method according to claim 19, characterized in that, The alkaline activator includes anhydrous sodium silicate and sodium hydroxide.

30. The preparation method according to claim 19, characterized in that, In the alkaline activator, the mass ratio of silicate to alkali metal hydroxide is (1.0-2.5):

1.

31. The preparation method according to claim 19, characterized in that, In the alkaline activator, the mass ratio of silicate to alkali metal hydroxide is (1.0-2.0):

1.

32. The preparation method according to any one of claims 1-18, characterized in that, The mass ratio of the geopolymer to the fly ash is (0.5-4):1; and / or The mass ratio of mineral powder to fly ash is 1:(1.2-5); and / or The mass ratio of silica fume to fly ash is 1:(2-10); and / or The modified basalt fiber accounts for 1-10% of the total mass of the geopolymer, mineral powder, silica fume and fly ash.

33. The preparation method according to claim 32, characterized in that, The mass ratio of the geopolymer to the fly ash is (1-3.5):1; and / or The mass ratio of mineral powder to fly ash is 1:(2-4); and / or The mass ratio of silica fume to fly ash is 1:(4-8); and / or The modified basalt fiber accounts for 4%-8% of the total mass of the geopolymer, mineral powder, silica fume and fly ash.

34. The preparation method according to any one of claims 1-18, characterized in that, The raw materials for preparing the composite material include the following components in parts by weight: 250-750 parts of geopolymer, 100-400 parts of mineral powder, 50-100 parts of silica fume, 200-600 parts of fly ash, 500-1000 parts of aggregate sand, 1-5 parts of water-reducing agent, 30-80 parts of modified basalt fiber, and 200-400 parts of water.

35. The preparation method according to any one of claims 1-18, characterized in that, The raw materials for preparing the composite material include the following components in parts by weight: 350-650 parts of geopolymer, 100-150 parts of mineral powder, 50-100 parts of silica fume, 200-400 parts of fly ash, 500-1000 parts of aggregate sand, 2-4 parts of water-reducing agent, 60-80 parts of modified basalt fiber, and 200-300 parts of water.

36. The preparation method according to any one of claims 1-18, characterized in that, The fly ash microspheres have a particle size of 0.1-10 μm; The latex powder is one or more of the following: ethylene / vinyl acetate copolymer, vinyl acetate / ethylene tert-carbonate copolymer, and acrylic acid copolymer.

37. The preparation method according to any one of claims 1-18, characterized in that, The latex powder is a copolymer of ethylene and vinyl acetate.

38. The preparation method according to any one of claims 1-18, characterized in that, The mass ratio of fly ash microspheres to the total mass of the geopolymer, mineral powder, silica fume and fly ash is 1:(5-25).

39. The preparation method according to any one of claims 1-18, characterized in that, The mass ratio of fly ash microspheres to the total mass of the geopolymer, mineral powder, silica fume and fly ash is 1:(8-20).

40. The preparation method according to any one of claims 1-18, characterized in that, The mass ratio of latex powder to the total mass of the aforementioned geopolymer, mineral powder, silica fume, and fly ash is 1:(5-25).

41. The preparation method according to any one of claims 1-18, characterized in that, The mass ratio of latex powder to the total mass of the aforementioned geopolymer, mineral powder, silica fume and fly ash is 1:(9-22).

42. The preparation method according to any one of claims 1-18, characterized in that, The mass of carboxypropyl methylcellulose accounts for 0.05-0.25% of the total mass of the geopolymer, mineral powder, silica fume and fly ash.

43. The preparation method according to any one of claims 1-18, characterized in that, The mass of carboxypropyl methylcellulose accounts for 0.1-0.2% of the total mass of the geopolymer, mineral powder, silica fume and fly ash.

44. The preparation method according to any one of claims 1-18, characterized in that, By mass, the raw materials for preparing the composite material contain 1-100 parts of fly ash microspheres, 0.1-2 parts of carboxypropyl methylcellulose, and 1-100 parts of latex powder.

45. The preparation method according to any one of claims 1-18, characterized in that, By mass, the raw materials for preparing the composite material contain 50-100 parts fly ash microspheres, 1-2 parts carboxypropyl methylcellulose, and 45-100 parts latex powder.

46. ​​The preparation method according to any one of claims 1-18, characterized in that, The mineral powder is S95 grade mineral powder; and / or The silica content of the silica fume is greater than 90%; and / or The fly ash is Grade I fly ash, and / or The aggregate sand includes quartz sand; and / or The water-reducing agent is a polycarboxylate water-reducing agent.

47. The preparation method according to claim 46, characterized in that, The fineness of the quartz sand is 40-120 mesh; and / or The polycarboxylate superplasticizer is in the form of liquid or powder.

48. The application of basalt fiber reinforced geopolymer composite materials obtained by the preparation method according to any one of claims 1-47 in seismic reinforcement of building structures, infrastructure repair, special engineering, and road repair.

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