Modified basalt fiber and preparation method and application thereof

Abstract

The present application relates to a modified basalt fiber and a preparation method and application thereof. The modified basalt fiber comprises a basalt fiber modified by a ketone compound, a polymer of an unsaturated amide monomer and an unsaturated carboxylic acid ester-olefin copolymer. The modified basalt fiber can be used as a geopolymer reinforcing material, and can improve the elongation and tensile strength of the geopolymer under the premise of ensuring excellent compressive strength of the geopolymer.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, and relates to a modified basalt fiber, its preparation method and its application in geopolymers. Background Technology

[0002] Geopolymers are a novel inorganic cementitious material formed by the alkaline-activated reaction of aluminosilicate precursors. They are amorphous / semi-crystalline inorganic polymers composed of [SiO4] and [AlO4] tetrahedra connected by oxygen atoms (Si-O-Al bonds). They retain the advantages of inorganic materials such as high temperature resistance and high durability, while achieving excellent mechanical properties through polymer network structure. They also have the outstanding advantages of "solid waste resource utilization and low carbon environmental protection". They are an important green alternative to traditional cement and are currently a research hotspot in the fields of materials science and civil engineering. They have been widely used in construction, environmental protection, and engineering repair.

[0003] In order to further obtain high-performance geopolymer composite materials, existing technologies have prepared geopolymer reinforced materials in the following ways: (1) reducing the particle size of the material, increasing the specific surface area, and improving the reactivity of the raw materials through mechanochemical action, thereby improving the mechanical strength of the geopolymer; (2) adding active powders rich in Si, Al and some alkali metal cations to improve the reactivity of the precursor; (3) adding organic materials, such as polyethylene glycol and polyacrylamide, to combine the functional groups of organic materials with the three-dimensional network structure of the geopolymer and change the properties of the geopolymer; (4) incorporating fibers, such as steel fibers, carbon fibers, and basalt fibers, to disperse and consume fracture energy through debonding, fracture, and pull-out behaviors, thereby alleviating stress concentration.

[0004] Basalt fiber has been widely used in cement-based materials and has achieved good application results due to its good compatibility with the chemical composition of the geopolymer matrix and its higher tensile strength than glass fiber. For example, the basalt fiber reinforced cement-based material developed by patent CN110563388A uses short basalt fibers with a length of 12-18mm and a volume content of 1.5%-2.5%, and has been successfully applied to many practical engineering scenarios such as seismic reinforcement of masonry structures and flexural reinforcement of beams and slabs.

[0005] However, the effect of blending ordinary basalt fiber with geopolymer materials on improving the tensile strength and elongation of the materials is not significant and needs further improvement. Therefore, it is necessary to modify existing basalt fibers and use them as reinforcing materials to improve the mechanical properties of geopolymer cementitious materials, especially their elongation. Summary of the Invention

[0006] To address one of the aforementioned technical problems in the prior art, this invention provides a modified basalt fiber. Adding this modified basalt fiber as a reinforcing material to geopolymers can improve the mechanical properties of the geopolymer cementitious materials, particularly its elongation and tensile strength. This invention also provides a method for preparing the modified basalt fiber and its applications.

[0007] In a first aspect, the present invention provides a modified basalt fiber comprising basalt fiber modified by a polymer of ketone compounds, unsaturated amide monomers, and an unsaturated carboxylic acid ester-olefin copolymer.

[0008] According to some embodiments of the present invention, the ketone compound is selected from C3-C6 ketone compounds, such as acetone.

[0009] 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.

[0010] According to some embodiments of the present invention, 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, the weight-average molecular weight of the polymer of the unsaturated amide monomer is 10 million to 15 million. In some embodiments, the weight-average molecular weight of the polymer of the unsaturated amide monomer is 11 million to 13 million.

[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] Secondly, the present invention provides a method for preparing modified basalt fibers, comprising the following steps:

[0016] (1) Basalt fibers were soaked in ketone compounds, removed and dried to obtain the first modified fiber;

[0017] (2) The first modified fiber is immersed in a polymer solution of unsaturated amide monomers, taken out and dried to obtain the second modified fiber;

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

[0019] According to some embodiments of the present invention, the ketone compound is selected from C3-C6 ketone compounds, such as acetone.

[0020] 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.

[0021] 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.

[0022] 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. According to some embodiments of the present invention, the unsaturated carboxylic acid ester-olefin copolymer is a vinyl acetate-ethylene copolymer.

[0023] According to some embodiments of the present invention, in step (1), the soaking time is 1-5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, etc. In some embodiments, in step (1), the soaking time is 1-2 hours.

[0024] According to some embodiments of the present invention, in step (2), the soaking time is 1-5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, etc. In some embodiments, in step (2), the soaking time is 2-3 hours.

[0025] According to some embodiments of the present invention, 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 0.1-0.5 wt%. In some embodiments, in step (2), the concentration of the polymer solution of the unsaturated amide monomer is 0.3-0.5 wt%.

[0026] 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.

[0027] According to some embodiments of the present invention, in step (3), the soaking time 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. In some embodiments, in step (3), the soaking time is 30-40 minutes.

[0028] According to some embodiments of the present invention, 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 unsaturated carboxylic acid ester-olefin copolymer emulsion is 54.5%-60%. In some embodiments, the solid content of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 54.5%-57%. In some embodiments, the solid content of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 54.5%-55.5%.

[0029] 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.

[0030] 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.

[0031] Thirdly, the present invention provides the application of modified basalt fibers as described in the first aspect or modified basalt fibers obtained by the preparation method described in the second aspect in the preparation of geopolymer cementitious materials for seismic reinforcement of building structures, infrastructure repair, special engineering, and road repair.

[0032] According to some embodiments of the present invention, the raw materials for preparing the geopolymer cementitious material include component A, component B, modified basalt fiber, aggregate sand, water-reducing agent and water; wherein component A includes activated kaolin, blast furnace slag, red mud and alkali activator; and component B includes one or more of mineral powder, silica fume and fly ash.

[0033] According to some embodiments of the present invention, component B includes mineral powder, silica fume and fly ash.

[0034] According to some embodiments of the present invention, the modified basalt fiber accounts for 1-10% of the total mass of components A and B, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc. In some embodiments, the modified basalt fiber accounts for 4%-8% of the total mass of components A and B. In 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 distribution spacing in the geopolymer 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. As a result, when the material is subjected to tension or bending, the cracks propagate rapidly and cannot be suppressed. Therefore, the toughness (i.e., fracture energy and ultimate tensile strain) decreases sharply, 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.

[0035] In some embodiments, the raw materials for preparing the geopolymer cementitious material also include one or more of fly ash microspheres, carboxypropyl methylcellulose, and latex powder.

[0036] According to some embodiments of the present invention, in component A, the content of amorphous SiO2 and Al2O3 in the activated kaolin is greater than 90 wt%. In some embodiments, the particle size of the activated kaolin is 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 carried out using an extremely cold process.

[0037] According to some embodiments of the present invention, in component A, 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%.

[0038] According to some embodiments of the present invention, in component A, 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%.

[0039] According to some embodiments of the present invention, in component A, the red mud comprises gibbsite-type bauxite red mud. In some embodiments, the particle size of the red mud is less than 75 μm.

[0040] According to some embodiments of the present invention, in component A, 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%.

[0041] According to some embodiments of the present invention, in component A, the alkaline activator comprises silicates and alkali metal hydroxides. The silicates mentioned in the present invention include, but are not limited to, alkali metal silicates, such as sodium silicate, potassium silicate, etc. The alkali metal hydroxides mentioned in the present invention include, but are not limited to, sodium hydroxide, potassium hydroxide, etc. In some embodiments, the alkaline activator comprises anhydrous sodium silicate and sodium hydroxide. In some embodiments, the mass ratio of silicate to alkali metal hydroxide in the alkaline 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 alkaline activator is (1.0-2.0):1.

[0042] According to some embodiments of the present invention, 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., preferably 8-12%.

[0043] In the geopolymer cementitious material 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.

[0044] According to some embodiments of the present invention, in the raw materials for preparing the geopolymer cementitious material, component A 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.

[0045] According to some embodiments of the present invention, the mass ratio of component A to component B is 1:(0.5-3). According to some embodiments of the present invention, the mass ratio of component A to component B is 1:(0.5-1.5).

[0046] According to some embodiments of the present invention, the mass ratio of fly ash in component A to component B 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 component A to fly ash is (1-3.5):1.

[0047] According to some embodiments of the present invention, the mineral powder is S95 grade mineral powder.

[0048] 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.

[0049] 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).

[0050] According to some embodiments of the present invention, the mineral powder in the raw materials for preparing the geopolymer cementitious material is 100-400 parts 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.

[0051] 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.

[0052] 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).

[0053] According to some embodiments of the present invention, the silica fume in the raw materials for preparing the geopolymer cementitious material is 50-100 parts by mass, for example, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, etc.

[0054] 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.

[0055] According to some embodiments of the present invention, in component B, based on the total mass of mineral powder, silica fume, and fly ash (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.

[0056] According to some embodiments of the present invention, the fly ash in the raw materials for preparing the geopolymer cementitious material is 200-600 parts 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.

[0057] 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.

[0058] According to some embodiments of the present invention, the aggregate sand in the raw materials for preparing the geopolymer cementitious 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.

[0059] 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.

[0060] According to some embodiments of the present invention, the water-reducing agent in the raw materials for preparing the geopolymer cementitious material is 1-5 parts by mass, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0061] According to some embodiments of the present invention, the modified basalt fiber in the raw materials for preparing the geopolymer cementitious 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.

[0062] According to some embodiments of the present invention, the water content in the raw materials for preparing the geopolymer cementitious 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.

[0063] According to some embodiments of the present invention, the raw materials for preparing the geopolymer cementitious material include the following components in parts by weight: component A 250-750 parts, mineral powder 100-400 parts, silica fume 50-100 parts, fly ash 200-600 parts, aggregate sand 500-1000 parts, water-reducing agent 1-5 parts, modified basalt fiber 30-80 parts, and water 200-400 parts.

[0064] According to some embodiments of the present invention, the raw materials for preparing the geopolymer cementitious material include the following components in parts by weight: Component A 350-650 parts, mineral powder 100-150 parts, silica fume 50-100 parts, fly ash 200-400 parts, aggregate sand 500-1000 parts, water-reducing agent 2-4 parts, modified basalt fiber 60-80 parts, and water 200-300 parts.

[0065] According to some embodiments of the present invention, the raw materials for preparing the geopolymer cementitious material include the following components in parts by weight: Component A 250-750 parts, mineral powder 100-400 parts, silica fume 50-100 parts, fly ash 200-600 parts, aggregate sand 500-1000 parts, water-reducing agent 1-5 parts, modified basalt fiber 30-80 parts, fly ash microspheres 0-100 parts, carboxypropyl methylcellulose 0-2 parts, latex powder 0-100 parts, and water 200-400 parts.

[0066] According to some embodiments of the present invention, the raw materials for preparing the geopolymer cementitious material include the following components in parts by weight: Component A 350-650 parts, mineral powder 100-150 parts, silica fume 50-100 parts, fly ash 200-400 parts, aggregate sand 500-1000 parts, water-reducing agent 2-4 parts, modified basalt fiber 60-80 parts, fly ash microspheres 0-100 parts, carboxypropyl methylcellulose 0-2 parts, latex powder 0-100 parts, and water 200-300 parts.

[0067] According to some embodiments of the present invention, the raw materials for preparing the geopolymer cementitious material further include one or more of fly ash microspheres, carboxypropyl methylcellulose, and latex powder.

[0068] According to some embodiments of the present invention, the raw materials for preparing the geopolymer cementitious material further include carboxypropyl methylcellulose and latex powder.

[0069] According to some embodiments of the present invention, the raw materials for preparing the geopolymer cementitious material further include fly ash microspheres, carboxypropyl methylcellulose, and latex powder.

[0070] In some embodiments, the particle size of the fly ash microspheres is 0.1-10 μm;

[0071] 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.

[0072] 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 geopolymer cementitious material system of the present 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.

[0073] In some embodiments, the mass ratio of fly ash microspheres to the total mass of component A, 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 component A, mineral powder, silica fume, and fly ash is 1:(8-20).

[0074] In some embodiments, the mass ratio of latex powder to the total mass of component A, 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 component A, mineral powder, silica fume, and fly ash is 1:(9-22).

[0075] 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.

[0076] In some embodiments, the mass of carboxypropyl methylcellulose accounts for 0.05-0.25% of the total mass of component A, 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 component A, mineral powder, silica fume, and fly ash.

[0077] In some embodiments, the fly ash microspheres in the raw materials for preparing the geopolymer cementitious 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 geopolymer cementitious material are 50-100 parts by weight.

[0078] In some embodiments, the raw materials for preparing the geopolymer gelling material contain 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 raw materials for preparing the geopolymer gelling material contain 1-2 parts by weight.

[0079] In some embodiments, the latex powder in the raw materials for preparing the geopolymer cementitious 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 geopolymer cementitious material is 45-100 parts by weight.

[0080] In some embodiments, the raw materials for preparing the geopolymer cementitious 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.

[0081] In some embodiments, the raw materials for preparing the geopolymer cementitious 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.

[0082] According to some embodiments of the present invention, the raw materials for preparing the geopolymer cementitious material include the following components in parts by weight: Component A 350-650 parts, mineral powder 100-150 parts, silica fume 50-100 parts, fly ash 200-400 parts, aggregate sand 500-1000 parts, water-reducing agent 2-4 parts, modified basalt fiber 60-80 parts, fly ash microspheres 50-100 parts, carboxypropyl methylcellulose 1-2 parts, latex powder 45-100 parts, and water 200-300 parts.

[0083] According to some embodiments of the present invention, the preparation method of the geopolymer cementitious material includes the following steps:

[0084] (1) Mix the components A, mineral powder, silica fume, fly ash and aggregate sand to obtain a first mixture;

[0085] (2) The dry mixture is mixed with a water-reducing agent and water to obtain a second mixture;

[0086] (3) The second mixture is mixed with the modified basalt fiber and cured to obtain the geopolymer cementitious material.

[0087] According to some embodiments of the present invention, fly ash microspheres are also added during the mixing process in step (1).

[0088] According to some embodiments of the present invention, carboxypropyl methyl cellulose is also added during the mixing process in step (1).

[0089] According to some embodiments of the present invention, latex powder is also added during the mixing process in step (3).

[0090] 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.

[0091] Compared with the prior art, the present invention has the following beneficial technical effects:

[0092] This invention modifies basalt fibers using ketone compounds, polymers of unsaturated amide monomers, and unsaturated carboxylic acid ester-olefin copolymers. The addition of ketone compounds and polymers of unsaturated amide monomers improves the bonding between the unsaturated carboxylic acid ester-olefin copolymer and the fiber. The modified basalt fibers of this invention exhibit high alkali corrosion resistance and better bonding with mortar interfaces. When used as a reinforcing material for geopolymers, they enable geopolymer cementitious materials to achieve high compressive strength, elongation of up to 0.45% to 0.96%, and tensile strength exceeding 5.5 to 10.4 MPa. They can be used in seismic reinforcement projects, infrastructure repair, special engineering, road repair, and other fields, exhibiting good workability and high strength. Attached Figure Description

[0093] Figure 1 The fiber pull-out force elongation test results of the composite materials in Application Example 1 and Comparative Application Examples 1 to 6 are shown.

[0094] Figure 2 A cross-sectional view of the fiber specimen prepared from the composite material of Application Example 1 is shown.

[0095] Figure 3 The results of alkali corrosion resistance tests are shown for the modified basalt fibers of Example 1, Comparative Example 1, and Comparative Example 2, as well as the unmodified basalt fibers. Detailed Implementation

[0096] 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.

[0097] 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.

[0098] Unless otherwise specified, all reagents used in the following experiments are conventional biochemical reagents; all raw materials, instruments and equipment used can be purchased from the market or obtained through existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, all experimental methods are conventional methods.

[0099] 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.

[0100] Example 1: Preparation of modified basalt fibers

[0101] 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.

[0102] Comparative Example 1: Preparation of Modified Basalt Fibers

[0103] 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.

[0104] Comparative Example 2: Preparation of Modified Basalt Fibers

[0105] 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.

[0106] Comparative Example 3: Preparation of Modified Basalt Fibers

[0107] 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.

[0108] Comparative Example 4: Preparation of Modified Basalt Fibers

[0109] Soak basalt fibers in acetone solution for 1-2 hours, then remove and dry.

[0110] Comparative Example 5: Preparation of Modified Basalt Fibers

[0111] 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.

[0112] Comparative Example 6: Preparation of Modified Basalt Fibers

[0113] 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.

[0114] Preparation Example 1: Preparation of Geopolymer Powder

[0115] 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.

[0116] 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;

[0117] Anhydrous sodium silicate and sodium hydroxide were mixed at a mass ratio of 1.5:1 to obtain a dry powder alkali activator;

[0118] 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.

[0119] Preparation Example 1A: Preparation of Geopolymer Powder

[0120] 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.

[0121] Red mud ore powder: Red mud ore is dried at 100°C for 6 hours and then ground to below 75μm to obtain red mud ore powder;

[0122] Anhydrous sodium silicate and sodium hydroxide were mixed at a mass ratio of 1.5:1 to obtain a dry powder alkali activator;

[0123] 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.

[0124] Preparation Example 1B: Preparation of Geopolymer Powder

[0125] 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.

[0126] 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;

[0127] Anhydrous sodium silicate and sodium hydroxide were mixed at a mass ratio of 1.5:1 to obtain a dry powder alkali activator;

[0128] 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.

[0129] Preparation Example 1C: Preparation of Geopolymer Powder

[0130] 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.

[0131] 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;

[0132] Anhydrous sodium silicate and sodium hydroxide were mixed at a mass ratio of 3:1 to obtain a dry powder alkali activator.

[0133] 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.

[0134] Application Example 1

[0135] This application example provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0136] 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 Example 1, and 250 parts of water.

[0137] 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.

[0138] Application Example 2

[0139] This application example provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0140] 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 Example 1, and 200 parts of water.

[0141] 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.

[0142] Application Example 3

[0143] This application example provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0144] Materials: 300 parts of the geopolymer of 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 Example 1, and 200 parts of water.

[0145] 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.

[0146] Application Example 4

[0147] This application example provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0148] 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 Example 1, and 240 parts of water.

[0149] 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.

[0150] Application Example 5

[0151] This application example provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0152] Materials: 400 parts of the geopolymer of 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 Example 1, and 200 parts of water.

[0153] 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.

[0154] Application Example 6

[0155] This application example provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0156] 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 Example 1, and 200 parts of water.

[0157] 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.

[0158] Application Example 7

[0159] This application example provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0160] Materials: 500 parts of the geopolymer of 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 Example 1, and 200 parts of water.

[0161] 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.

[0162] Application Example 8

[0163] This application example provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0164] 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 Example 1, and 200 parts of water.

[0165] 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.

[0166] Application Example 9

[0167] This application example provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0168] 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 Example 1, and 200 parts of water.

[0169] 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.

[0170] Application Example 10

[0171] This application example provides a basalt fiber reinforced geopolymer composite material, the preparation steps of which are as follows:

[0172] 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 Example 1, and 300 parts of water.

[0173] 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.

[0174] The mass fractions of each component in the composite materials used in Examples 1 to 10 are shown in Table 1.

[0175] Table 1 Application Examples 1-10 Component Mass Parts

[0176]

[0177] Comparative Application Example 1

[0178] The only difference from Application Example 1 is that the "modified basalt fiber" is replaced with an equal mass fraction of "unmodified basalt fiber".

[0179] Comparative Application Example 2

[0180] The only difference from Application Example 1 is that "modified basalt fiber" is replaced with an equal mass fraction of "modified basalt fiber of Comparative Example 1".

[0181] Comparative Application Example 3

[0182] The only difference from Application Example 1 is that "modified basalt fiber" is replaced with an equal mass fraction of "modified basalt fiber of Comparative Example 2".

[0183] Comparative Application Example 4

[0184] The only difference from Application Example 1 is that "modified basalt fiber" is replaced with an equal mass fraction of "modified basalt fiber of Comparative Example 3".

[0185] Comparative Application Example 5

[0186] The only difference from Application Example 1 is that "modified basalt fiber" is replaced with an equal mass fraction of "modified basalt fiber of Comparative Example 4".

[0187] Comparative Application Example 6

[0188] The only difference from Application Example 1 is that "modified basalt fiber" is replaced with an equal mass fraction of "modified basalt fiber of Comparative Example 5".

[0189] Comparative Application Example 7

[0190] The only difference from Application Example 1 is that "modified basalt fiber" is replaced with an equal mass fraction of "modified basalt fiber of Comparative Example 6".

[0191] Comparative Application Example 8

[0192] The only difference from Application Example 1 is that “geopolymer” is replaced with an equal mass fraction of “Jinyu 42.5 ordinary Portland cement”.

[0193] Comparative Application Example 9

[0194] The only difference from Application Example 1 is that “geopolymer” is replaced with an equal mass fraction of “geopolymer of Preparation Example 1A”.

[0195] Comparative Application Example 10

[0196] The only difference from Application Example 1 is that “geopolymer” is replaced with an equal mass fraction of “geopolymer of Preparation Example 1B”.

[0197] Comparative Application Example 11

[0198] The only difference from Application Example 1 is that “geopolymer” is replaced with an equal mass fraction of “geopolymer of Preparation Example 1C”.

[0199] Comparative Application Example 12

[0200] The difference from Application Example 1 is that "200 parts mineral powder, 100 parts silica fume, and 400 parts fly ash" are replaced with "700 parts mineral powder".

[0201] Comparative Application Example 13

[0202] The difference from Application Example 1 is that "200 parts mineral powder, 100 parts silica fume, and 400 parts fly ash" are replaced with "700 parts silica fume".

[0203] Comparative Application Example 14

[0204] The difference from Application Example 1 is that "200 parts mineral powder, 100 parts silica fume, and 400 parts fly ash" are replaced with "700 parts fly ash".

[0205] Comparative Application Example 15

[0206] The difference from Application Example 1 is that "200 parts mineral powder, 100 parts silica fume, and 400 parts fly ash" is replaced with "300 parts mineral powder and 400 parts fly ash".

[0207] Comparative Application Example 16

[0208] The only difference from Application Example 1 is that "modified basalt fiber" is replaced with an equal mass fraction of "basalt fiber TXCS-15 (monofilament)".

[0209] Comparative Application Example 17

[0210] The only difference from Application Example 1 is that "modified basalt fiber" is replaced with an equal mass fraction of "basalt fiber CBF13-6".

[0211] Compare and contrast examples 18-1 to 18-8

[0212] The only difference from Application 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.

[0213] Test Example 1: Mechanical Property Test

[0214] The composite materials provided in each application example and comparative application 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.

[0215] The test results of the composite materials used in Examples 1 to 10 are shown in Table 2 below.

[0216] Table 2

[0217]

[0218] 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.

[0219] The test results of the composite materials compared with Application Examples 1 to 7 and Application Examples 16 and 17 are shown in Table 3 below.

[0220] Table 3

[0221]

[0222] As can be seen from Table 3, compared with Comparative Application Examples 1 to 7, the composite material prepared by Application Example 1 using the modified basalt fiber of Example 1 has significantly improved elongation and tensile strength.

[0223] The test results of the composite materials used in Examples 8 to 11 are shown in Table 4 below.

[0224] Table 4

[0225]

[0226] As can be seen from Table 4, compared with comparative application examples 8 to 11, the composite material prepared by application example 1 using the geopolymer of preparation example 1 has significantly improved elongation and tensile strength.

[0227] The test results of the composite materials used in Application Examples 12 to 15 are shown in Table 5 below.

[0228] Table 5

[0229]

[0230] As can be seen from Table 5, compared with comparative application examples 12 to 15, the composite material prepared by application example 1, which combines mineral powder, silica fume and fly ash as three cementing materials and adds other components, has significantly improved elongation and tensile strength.

[0231] The test results of the composite materials in comparative application examples 18-1 to 18-8 are shown in Table 6 below.

[0232] Table 6

[0233]

[0234] Test Example 2: Fiber Pull-out Experiment

[0235] The composite materials of Application Example 1 and Comparative Application Examples 1 to 6 were subjected to fiber pull-out tests, and the test methods are as follows:

[0236] 1. Material preparation:

[0237] Composite materials used in application example 1 and comparative application examples 1 to 6;

[0238] 2. Specimen design and fabrication:

[0239] Determine the burial depth: 3mm;

[0240] 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;

[0241] 3. Install test specimens:

[0242] Install the cured or hardened specimens onto the mechanical testing machine;

[0243] Precise clamping: The free end of the fiber must be firmly clamped to ensure good alignment during loading and avoid eccentricity;

[0244] 4. Perform a pull-out test:

[0245] Start the testing machine and apply a continuous and uniform tensile force to the fiber monofilament to pull it out of the matrix;

[0246] Real-time recording of tensile 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.

[0247] 5. Plotting curves and extracting parameters:

[0248] 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.

[0249] Application Example 1: Comparison of the pull-out load-displacement curves (stress-strain curves) of composite materials in Application Examples 1 to 6 is as follows: Figure 1 As shown. Figure 1 The results show that, compared with comparative application examples 1 to 6, the composite material of application example 1 has higher pull-out strength and elongation.

[0250] Test Example 3: Acid and Alkali Resistance Test

[0251] Alkali resistance tests were conducted on the modified basalt fibers of Example 1, Comparative Example 1, and Comparative Example 2, as well as the unmodified basalt fibers, in accordance with GB / T 23265-2023 (Chopted Basalt Fibers for Cement Concrete and Mortar). The specific details are as follows:

[0252] 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).

[0253] 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.

[0254] 3.23 Sample preparation for electron microscopy observation.

[0255] The results are as follows Figure 3 As shown, the modified basalt fiber surface in Example 1 was basically not corroded, while the unmodified basalt fiber surface was basically corroded and a large area of ​​the surface peeled off. The modified basalt fiber surfaces in Comparative Examples 1 and 2 were severely corroded and partially peeled off.

[0256] 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 modified basalt fiber, comprising basalt fiber modified by a polymer of ketone compounds, unsaturated amide monomers, and an unsaturated carboxylic acid ester-olefin copolymer; The ketone compounds are selected from C3-C6 ketone compounds; The unsaturated amide monomer is selected from C3-C6 unsaturated amides, and the weight-average molecular weight of the polymer of the unsaturated amide monomer is 5 million to 25 million. 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, and the olefin in the unsaturated carboxylic acid ester-olefin copolymer is selected from C2-C6 olefins. The preparation method of the modified basalt fiber includes the following steps: (1) Basalt fibers were soaked in ketone compounds, removed and dried to obtain the first modified fiber; (2) The first modified fiber is immersed in a polymer solution of unsaturated amide monomers, taken out and dried to obtain the second modified fiber; (3) The second modified fiber is immersed in an unsaturated carboxylic acid ester-olefin copolymer emulsion, removed and dried to obtain the modified basalt fiber.

2. The modified basalt fiber according to claim 1, 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.

3. The modified basalt fiber according to claim 2, characterized in that, The olefin in the unsaturated carboxylic acid ester-olefin copolymer is ethylene.

4. The modified basalt fiber according to any one of claims 1-3, characterized in that, The weight-average molecular weight of the polymer of the unsaturated amide monomer is 10 million to 15 million; and / or The modified basalt fiber comprises basalt fiber modified by acetone, polyacrylamide, and vinyl acetate-ethylene copolymer.

5. The modified basalt fiber according to claim 4, characterized in that, The weight-average molecular weight of the polymer of the unsaturated amide monomer is 11 million to 13 million.

6. A method for preparing modified basalt fiber, comprising the following steps: (1) Basalt fibers were soaked in ketone compounds, removed and dried to obtain the first modified fiber; (2) The first modified fiber is immersed in a polymer solution of unsaturated amide monomers, taken out and dried to obtain the second modified fiber; (3) The second modified fiber is immersed in an unsaturated carboxylic acid ester-olefin copolymer emulsion, taken out and dried to obtain the modified basalt fiber; The ketone compounds are selected from C3-C6 ketone compounds; The unsaturated amide monomer is selected from C3-C6 unsaturated amides, and the weight-average molecular weight of the polymer of the unsaturated amide monomer is 5 million to 25 million. 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, and the olefin in the unsaturated carboxylic acid ester-olefin copolymer is selected from C2-C6 olefins.

7. The preparation method according to claim 6, 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-olefin copolymer is a vinyl acetate-ethylene copolymer.

8. The preparation method according to claim 6 or 7, characterized in that, In step (1), the soaking time is 1-5 hours; and / or In step (2), the soaking time is 1-5 hours; and / or In step (2), the concentration of the polymer solution of the unsaturated amide monomer is 0.1-1.0 wt%; and / or In step (2), the weight-average molecular weight of the polymer of the unsaturated amide monomer is 10 million to 15 million.

9. The preparation method according to claim 8, characterized in that, In step (1), the soaking time is 1-2 hours; and / or In step (2), the soaking time is 2-3 hours; and / or In step (2), the concentration of the polymer solution of the unsaturated amide monomer is 0.1-0.5 wt%; and / or In step (2), the weight-average molecular weight of the polymer of the unsaturated amide monomer is 11 million to 13 million.

10. The preparation method according to claim 6 or 7, characterized in that, In step (3), the soaking time is 20-60 minutes; and / or In step (3), the solid content of the unsaturated carboxylic acid ester-olefin copolymer emulsion is not less than 54.5%; and / or In step (3), the viscosity of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 1000 mPa·s-1500 mPa·s.

11. The preparation method according to claim 10, characterized in that, In step (3), the soaking time is 30-40 minutes; and / or In step (3), the solid content of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 54.5%-60%; and / or In step (3), the viscosity of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 1100 mPa·s-1300 mPa·s.

12. The preparation method according to claim 10, characterized in that, In step (3), the solid content of the unsaturated carboxylic acid ester-olefin copolymer emulsion is 54.5%-55.5%.

13. The application of the modified basalt fiber as described in any one of claims 1-5 or the modified basalt fiber obtained by the preparation method of any one of claims 6-12 in the preparation of geopolymer cementitious materials for seismic reinforcement of building structures, infrastructure repair, special engineering, and road repair.

14. The application according to claim 13, characterized in that, The raw materials for preparing the geopolymer cementitious material include component A, component B, modified basalt fiber, aggregate sand, water-reducing agent and water; wherein component A includes activated kaolin, blast furnace slag, red mud and alkali activator; and component B includes one or more of mineral powder, silica fume and fly ash.

15. The application according to claim 14, characterized in that, The modified basalt fiber accounts for 1%-10% of the total mass of components A and B.

16. The application according to claim 14, characterized in that, The modified basalt fiber accounts for 4%-8% of the total mass of components A and B.

17. The application according to claim 14, characterized in that, The raw materials for preparing the geopolymer cementitious material also include one or more of fly ash microspheres, carboxypropyl methylcellulose, and latex powder.

18. The application according to claim 14, characterized in that, The raw materials for preparing the geopolymer cementitious material include the following components in parts by weight: Component A 250-750 parts, mineral powder 100-400 parts, silica fume 50-100 parts, fly ash 200-600 parts, aggregate sand 500-1000 parts, water-reducing agent 1-5 parts, modified basalt fiber 30-80 parts, fly ash microspheres 0-100 parts, carboxypropyl methylcellulose 0-2 parts, latex powder 0-100 parts, and water 200-400 parts.

19. The application according to claim 14, characterized in that, The raw materials for preparing the geopolymer cementitious material include the following components in parts by weight: Component A 350-650 parts, mineral powder 100-150 parts, silica fume 50-100 parts, fly ash 200-400 parts, aggregate sand 500-1000 parts, water-reducing agent 2-4 parts, modified basalt fiber 60-80 parts, fly ash microspheres 0-100 parts, carboxypropyl methylcellulose 0-2 parts, latex powder 0-100 parts, and water 200-300 parts.

20. The application according to claim 14, characterized in that, The raw materials for preparing the geopolymer cementitious material include the following components in parts by weight: Component A 350-650 parts, mineral powder 100-150 parts, silica fume 50-100 parts, fly ash 200-400 parts, aggregate sand 500-1000 parts, water-reducing agent 2-4 parts, modified basalt fiber 60-80 parts, fly ash microspheres 50-100 parts, carboxypropyl methylcellulose 1-2 parts, latex powder 45-100 parts, and water 200-300 parts.

21. The application according to claim 14, characterized in that, In component A, 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%; the mass percentage of red mud is 10%-20%; and the amount of alkali activator is 3%-15% of the total mass of activated kaolin, blast furnace slag, and red mud.

22. The application according to claim 14, characterized in that, In component A, 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%; the mass percentage of red mud is 13%-17%; and the amount of alkali activator is 8%-12% of the total mass of activated kaolin, blast furnace slag, and red mud.

23. The application according to claim 14, characterized in that, The alkaline activator includes silicates and alkali metal hydroxides.

24. The application according to claim 23, characterized in that, The alkaline activator includes anhydrous sodium silicate and sodium hydroxide.

25. The application according to claim 23, characterized in that, In the alkaline activator, the mass ratio of silicate to alkali metal hydroxide is (1.0-2.5):

1.

26. The application according to claim 23, characterized in that, In the alkaline activator, the mass ratio of silicate to alkali metal hydroxide is (1.0-2.0):1.

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