Preparation process of high-toughness anti-cracking alkali-activated geopolymer cementing material

Abstract

The invention discloses a preparation process of a high-toughness anti-cracking alkali-activated geopolymer cementing material, which comprises the following steps: (1) mixing steel slag powder and a phosphoric acid solution, heating, preserving heat, reacting, drying to remove moisture, and grinding to obtain pretreated steel slag powder; and (2) uniformly mixing brucite powder, potassium silicate and water to form slurry, then adding basalt fibers into the heated slurry, standing, separating out the fibers after standing, uniformly mixing the fibers with the pretreated steel slag powder, and drying to obtain pretreated fibers. And (3) placing the pretreated fiber in a closed container containing carbon dioxide and water vapor, and carrying out heat preservation and maintenance to obtain the modified fiber. And (4) weighing the following raw materials according to the following proportion: aluminum-silicon solid waste micro powder, coarse aggregate, fine aggregate, the modified fiber, an alkali activator and a water reducing agent. The preparation method comprises the following steps: uniformly mixing the raw materials, adding water and uniformly stirring. The fiber subjected to surface treatment effectively improves the crack resistance of the geopolymer cementing material.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing geopolymers, and particularly to a preparation process of a high-toughness and crack-resistant alkali-activated geopolymer binder. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the overall understanding of the present invention, and it is not necessarily regarded as an admission or an indication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Portland cement is widely used as the main building material in the field of construction engineering, but it also brings problems of high energy consumption and high pollution. Research shows that about 0.6 - 0.8 kilograms of carbon dioxide are emitted for every 1 kilogram of ordinary Portland cement produced. The carbon dioxide emitted by the cement industry alone accounts for more than 10% of the total carbon dioxide emissions in China every year. Moreover, the production of Portland cement requires a large amount of high-quality clay resources and limestone. These non-renewable resources will continuously decrease and the prices will increase with use, resulting in a further increase in production costs. Therefore, the green and sustainable development of the cement industry is an important issue currently faced.

[0004] The concept of geopolymer was proposed by the Frenchman Davidovits in 1978. It is an inorganic polymer with a three-dimensional network structure composed of [AlO4] and [SiO4] tetrahedral structural units formed by the alkali activation of aluminosilicate materials (such as slag, coal gangue, fly ash, etc.). It can replace traditional Portland cement as a building binder, thereby reducing the high energy consumption and high pollution problems brought about during the production of Portland cement, while promoting the resource utilization of industrial solid wastes. Moreover, geopolymers also have advantages such as rich raw material sources, low prices, and simple preparation processes. Therefore, geopolymers, as a new type of high-performance building material, are more in line with the requirements and development trends of the current green transformation of the cement industry. However, due to the fast polymerization rate and large shrinkage during the formation process of geopolymers, cracks or even cracking are likely to occur, resulting in a decline in mechanical properties and being unfavorable for the application of geopolymers. Summary of the Invention

[0005] In view of the above problems, the present invention provides a preparation process of a high-toughness and crack-resistant alkali-activated geopolymer binder, which effectively improves the crack resistance of the geopolymer binder through surface-treated fibers. Specifically, the technical solution of the present invention is as follows.

[0006] A preparation process of a high-toughness and crack-resistant alkali-activated geopolymer binder includes the following steps: (1) Mix steel slag powder and phosphoric acid solution, heat and keep warm for reaction, then dry to remove moisture after completion, and obtain pretreated steel slag powder after grinding.

[0007] (2) Mix brucite powder, potassium silicate, and water evenly to form a slurry. Then add basalt fiber to the heated slurry and let it stand. After completion, separate the fiber, mix it with the pretreated steel slag powder, stir evenly, and dry to obtain pretreated fiber.

[0008] (3) Place the pretreated fiber in a sealed container containing carbon dioxide and water vapor for heat preservation and curing. After completion, obtain modified fiber.

[0009] (4) Weigh each raw material according to the following ratio: aluminosilicate solid waste fine powder, coarse aggregate, fine aggregate, the modified fiber, alkali activator, water reducer. Mix the above raw materials evenly and add water to stir evenly to obtain geopolymer cementitious material.

[0010] Further, in step (1), the ratio of the steel slag powder to the phosphoric acid solution is 1 g: 1 - 2 ml. Optionally, the mass fraction of the phosphoric acid solution is 15 - 25%.

[0011] Further, in step (1), the heating temperature is 50 - 70 °C, and the heat preservation time is 1 - 1.5 hours.

[0012] Further, in step (1), the drying temperature is 35 - 40 °C, and dry at this temperature until the weight of the solid matter is constant to obtain the pretreated steel slag powder. Optionally, the fineness of the pretreated steel slag powder is 300 - 400 mesh.

[0013] Further, in step (2), the mass ratio of the brucite powder to the potassium silicate is 1: 0.13 - 0.18. Optionally, the fineness of the brucite powder is 400 - 500 mesh.

[0014] Further, in step (2), the solid content of the slurry is 55 - 65 wt.%.

[0015] Further, in step (2), the length of the basalt fiber is 10 - 30 mm.

[0016] Further, in step (2), the heating temperature is 50 - 70 °C, and the standing time is 0.5 - 1 hour.

[0017] Further, in step (2), the mass ratio of the pretreated steel slag powder to the basalt fiber is 0.3 - 0.4: 1.

[0018] Further, in step (2), the drying temperature is 40 - 60 °C, and the drying time is 1 - 2 hours.

[0019] Further, in step (3), the volume percentage of carbon dioxide and water vapor is 70 - 80%: 20 - 30%.

[0020] Further, in step (3), the temperature for heat preservation and curing is 90 - 110 °C, and the time is 50 - 80 min.

[0021] Further, in step (3), the proportions of the raw materials are as follows: 100 - 115 parts by weight of aluminosilicate waste micro - powder, 270 - 310 parts by weight of coarse aggregate, 140 - 160 parts by weight of fine aggregate, 12 - 15 parts by weight of the modified fiber, 6 - 7 parts by weight of alkali activator, and 0.15 - 0.23 parts by weight of water - reducing agent. Optionally, the water is added according to a water - cement ratio of 0.4 - 0.45.

[0022] Further, in step (3), the aluminosilicate waste micro - powder includes at least one of slag, fly ash, metakaolin, silica fume, coal gangue, etc. Optionally, the specific surface area of the aluminosilicate waste micro - powder is 350 - 500 m 2 / kg.

[0023] Further, in step (3), the alkali activator includes at least one of sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, etc.

[0024] Further, in step (3), the water - reducing agent includes at least one of polycarboxylate water - reducing agent, naphthalene - based water - reducing agent, melamine - based water - reducing agent, lignosulfonate water - reducing agent, etc.

[0025] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects: In view of the insufficient crack resistance of geopolymers and the problem of easy cracking during the hardening process, the present invention effectively improves the crack resistance of geopolymers by adding modified fibers. To this end, the present invention first treats steel slag with phosphoric acid, which not only helps to reduce the calcium oxide therein, thereby reducing the problem of poor volume stability of steel slag and realizing the stable utilization of steel slag. Then the present invention treats basalt fibers with a slurry formed by brucite powder and potassium silicate. On the one hand, the potassium silicate can improve the surface roughness after activating the surface of the basalt fibers, facilitating the coating of the fiber surface by the slurry. Then the present invention coats the surface of the fibers coated with the slurry with the pretreated steel slag powder again and performs heat preservation curing under the conditions of carbon dioxide and water vapor. During this process, the brucite releases magnesium ions in the acidic environment provided by carbon dioxide, and the potassium silicate provided by the fiber coating layer reacts with the phosphoric acid in the pretreated steel slag powder to form silicic acid precipitate and dihydrogen phosphate. After the magnesium carbonate releases magnesium ions in the acidic environment provided by the dihydrogen phosphate, it undergoes a hydration reaction to form struvite - MgKPO4·6H2O. This high - strength and high - adhesiveness cementitious product can significantly enhance the binding force between each particulate matter coated on the fiber surface and the fiber, thereby forming roughened fibers. When this kind of fiber is added to the geopolymer, due to the stronger binding force between the two, it can more effectively inhibit the cracking of the geopolymer and improve the crack resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] It should be noted that the specification drawings forming a part of the present invention are used to provide a further understanding of the present invention and do not unduly limit the present invention.

[0027] Figure 1 It is the compressive strength test diagram of the following Example 1.

[0028] Figure 2 It is the compressive strength test diagram of the following Example 2.

[0029] Figure 3 It is the compressive strength test diagram of the following Example 3.

[0030] Figure 4 It is the compressive strength test diagram of the following Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Unless otherwise defined, all professional and scientific terms used in the present invention have the same meaning as those familiar to those skilled in the art. The preferred implementation methods and materials described in the present invention are only for demonstration purposes. The reagents or raw materials used in the present invention can be obtained through conventional channels. Unless otherwise specified, the reagents or raw materials used in the present invention are used in accordance with the conventional methods in the art or in accordance with the product instructions. The technical solutions of the present invention will be further described below in conjunction with specific embodiments.

[0032] Example 1 A preparation process of a high-toughness and crack-resistant alkali-activated geopolymer cementitious material comprises the following steps: (1) Mix 300-mesh steel slag powder and 20% by mass phosphoric acid solution in a ratio of 1 g: 1.5 ml, and then heat the mixture in a closed container to 60 °C and keep it warm for 1.0 hour. After completion, heat and dry the obtained product at 35 °C until the weight is constant, grind it, and sieve it through a 300-mesh sieve to obtain pretreated steel slag powder for standby.

[0033] (2) Mix 500-mesh brucite powder, potassium silicate, and water and stir evenly to form a slurry. Among them, the mass ratio of brucite powder to potassium silicate is 1: 0.17, and the solid content of the slurry is 65 wt.%. Then heat the slurry to 60 °C and keep it warm, then add basalt fibers with a length of 20 mm, stir evenly, and let it stand for 40 min. After completion, filter out the fibers, and then add 30% of the pretreated steel slag powder of this embodiment by the mass of the basalt fibers, mix evenly, and dry at 50 °C for 90 min to obtain pretreated fibers for standby.

[0034] (3) Place the pretreated fibers in a closed container containing CO2 and H2O vapor (the volume percentage (v: v) of the two is 80%: 20%), and then heat it to 100 °C and keep it warm for 70 min. After completion, naturally cool it to room temperature to obtain modified fibers for standby.

[0035] (4) Weigh each raw material according to the following ratio: 105 parts by weight of metakaolin (specific surface area is 468.8 m 2 / kg), 280 parts by weight of coarse aggregate of crushed stone with a particle size of 5 - 10 mm, 145 parts by weight of fine aggregate of river sand with a particle size of 0.5 - 1.5 mm, 13 parts by weight of the modified fibers of this embodiment, 6.5 parts by weight of sodium hydroxide, and 0.2 parts by weight of polycarboxylate water reducer. Mix the above raw materials and stir for 2 min, and then add clear water according to a water-cement ratio of 0.45 and stir evenly to obtain a geopolymer cementitious material.

[0036] Performance test: The geopolymer cementitious material prepared in this embodiment is poured into a mold, demolded after hardening, and then cured in a standard curing box for 28 days. Then, according to the "Standard Test Method for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), the compressive strength of the obtained specimens is tested (as Figure 1 shown). The result is: 28-day compressive strength = 106.37 MPa.

[0037] Example 2 A preparation process of a high-toughness and crack-resistant alkali-activated geopolymer cementitious material includes the following steps: (1) Mix 400-mesh steel slag powder and 25% mass fraction phosphoric acid solution in a ratio of 1 g: 1 ml, heat them in a closed container to 70 °C and keep warm for 80 min. After completion, dry the obtained product by heating at 35 °C until the weight is constant, grind it and pass through a 400-mesh sieve to obtain pretreated steel slag powder for standby.

[0038] (2) Mix 400-mesh brucite powder, potassium silicate and water and stir evenly to form a slurry. Among them, the mass ratio of brucite powder to potassium silicate is 1: 0.13, and the solid content of the slurry is 60 wt.%. Then heat the slurry to 50 °C and keep warm, then add basalt fibers with a length of 10 mm, stir evenly and let it stand for 30 min. After completion, filter out the fibers, and then add 35% of the pretreated steel slag powder of this embodiment based on the mass of the basalt fibers, mix evenly and dry at 40 °C for 120 min to obtain pretreated fibers for standby.

[0039] (3) Place the pretreated fibers in a closed container containing CO2 and H2O vapor (the volume percentage of the two (v: v) = 75%: 25%), then heat to 110 °C and keep warm for 50 min. After completion, naturally cool to room temperature to obtain modified fibers for standby.

[0040] (4) Weigh each raw material according to the following ratio: 115 parts by weight of slag powder (specific surface area is 347.4 m 2 / kg), 310 parts by weight of coarse aggregate of crushed stone with a particle size of 5 - 10 mm, 160 parts by weight of fine aggregate of river sand with a particle size of 0.5 - 1.5 mm, 15 parts by weight of the modified fibers of this embodiment, 7 parts by weight of sodium hydroxide, and 0.23 parts by weight of polycarboxylate water reducer. Mix the above raw materials and stir for 2 min, then add clear water according to a water-cement ratio of 0.42 and stir evenly to obtain the geopolymer cementitious material.

[0041] Performance test: The geopolymer cementitious material prepared in this example was poured into a mold, demolded after hardening, and then cured in a standard curing box for 28 days. Then, according to the "Standard Test Method for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), the compressive strength of the obtained specimens was tested (as Figure 2 shown). The result was: 28-day compressive strength = 102.79 MPa.

[0042] Example 3 A preparation process of a high-toughness and crack-resistant alkali-activated geopolymer cementitious material includes the following steps: (1) Mix 400-mesh steel slag powder and 15% phosphoric acid solution by mass ratio of 1 g: 2 ml, and heat in a closed container to 40 °C for 90 min. After completion, heat and dry the obtained product at 35 °C until the weight is constant, grind it and pass through a 400-mesh sieve to obtain pretreated steel slag powder for standby.

[0043] (2) Mix 500-mesh brucite powder, potassium silicate, and water and stir evenly to form a slurry. Among them, the mass ratio of brucite powder to potassium silicate is 1: 0.18, and the solid content of the slurry is 55 wt.%. Then heat the slurry to 70 °C for heat preservation, then add basalt fibers with a length of 30 mm, stir evenly and let stand for 60 min. After completion, filter out the fibers, and then add 40% of the pretreated steel slag powder of this example by the mass of the basalt fibers, mix evenly and dry at 60 °C for 60 min to obtain pretreated fibers for standby.

[0044] (3) Place the pretreated fibers in a closed container containing CO2 and H2O vapor (the volume percentages of the two are (v: v) = 70%: 30%), and then heat to 90 °C for heat preservation and curing for 80 min. After completion, naturally cool to room temperature to obtain modified fibers for standby.

[0045] (4) Weigh each raw material according to the following ratio: 100 parts by weight of coal gangue powder (specific surface area is 506.2 m 2 / kg), 270 parts by weight of coarse aggregate of crushed stone with a particle size of 5-10 mm, 140 parts by weight of fine aggregate of river sand with a particle size of 0.5-1.5 mm, 12 parts by weight of the modified fibers of this example, 6 parts by weight of sodium hydroxide, and 0.15 parts by weight of lignosulfonate water reducer. Mix the above raw materials and stir for 3 min, and then add clear water according to the water-cement ratio of 0.4 and stir evenly to obtain the geopolymer cementitious material.

[0046] Performance test: Pour the geopolymer cementitious material prepared in this example into a mold, demold after hardening, and then cure it in a standard curing box for 28 days. Then, according to the "Standard Test Method for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), test the compressive strength of the obtained specimens (as Figure 3 shown). The result is: 28-day compressive strength = 111.02 MPa.

[0047] Example 4 A preparation process of a high-toughness and crack-resistant alkali-activated geopolymer cementitious material includes the following steps: Weigh each raw material according to the following ratio: 105 parts by weight of metakaolin (specific surface area is 468.8 m 2 / kg), 280 parts by weight of coarse aggregate of crushed stone with a particle size of 5 - 10 mm, 145 parts by weight of fine aggregate of river sand with a particle size of 0.5 - 1.5 mm, 13 parts by weight of basalt fiber with a length of 20 mm, 6.5 parts by weight of sodium hydroxide, and 0.2 parts by weight of polycarboxylate water reducer. Mix the above raw materials and stir for 2 min, then add clear water according to the water-cement ratio of 0.45 and stir evenly to obtain the geopolymer cementitious material.

[0048] Performance test: Pour the geopolymer cementitious material prepared in this example into a mold, demold after hardening, and then cure it in a standard curing box for 28 days. Then, according to the "Standard Test Method for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), test the compressive strength of the obtained specimens (as Figure 4 shown). The result is: 28-day compressive strength = 93.59 MPa.

[0049] Example 5 A preparation process of a high-toughness and crack-resistant alkali-activated geopolymer cementitious material includes the following steps: (1) Mix 500-mesh brucite powder, potassium silicate, and water and stir evenly to form a slurry. Among them, the mass ratio of brucite powder to potassium silicate is 1:0.17, and the solid content of the slurry is 65 wt.%. Then heat the slurry to 60 °C and keep it warm, then add basalt fiber with a length of 20 mm and stir evenly, and then let it stand for 40 min. After completion, filter out the fiber, and then add 30% of the mass of the basalt fiber of unmodified steel slag powder (fineness is 300 mesh), mix evenly, and dry at 50 °C for 90 min to obtain the pretreated fiber for standby.

[0050] (2) Place the pretreated fibers in a sealed container containing CO2 and H2O vapor (the volume percentages of the two are (v:v) = 80%:20%), then heat to 100 °C for heat preservation and curing for 70 min. After completion, naturally cool to room temperature to obtain modified fibers for standby.

[0051] (3) Weigh each raw material according to the following ratio: metakaolin (specific surface area is 468.8 m 2 / kg) 105 parts by weight, crushed stone coarse aggregate with a particle size of 5 - 10 mm 280 parts by weight, river sand fine aggregate with a particle size of 0.5 - 1.5 mm 145 parts by weight, the modified fibers of this example 13 parts by weight, sodium hydroxide 6.5 parts by weight, polycarboxylate water reducer 0.2 parts by weight. Mix the above raw materials and stir for 2 min, then add clear water according to a water-cement ratio of 0.45 and stir evenly to obtain the geopolymer binder.

[0052] Performance test: Pour the geopolymer binder prepared in this example into a mold, demold after hardening, and then cure in a standard curing box for 28 days. Then, according to the "Standard Test Method for Physical and Mechanical Properties of Concrete" (GB / T50081 - 2019), test the compressive strength of the obtained specimens. The result is: 28d compressive strength = 95.52 MPa.

[0053] Example 6 A preparation process of a high-toughness and crack-resistant alkali-activated geopolymer binder, comprising the following steps: (1) Mix 400-mesh steel slag powder and 25% mass fraction phosphoric acid solution at a ratio of 1 g:1 ml, then heat in a sealed container to 70 °C for heat preservation for 80 min. After completion, dry the obtained product by heating at 35 °C until the weight is constant, grind it and pass through a 400-mesh sieve to obtain the pretreated steel slag powder for standby.

[0054] (2) Mix 400-mesh brucite powder, potassium silicate, and water and stir evenly to form a slurry. Among them: the mass ratio of brucite powder to potassium silicate is 1:0.13, and the solid content of the slurry is 60 wt.%. Then heat the slurry to 50 °C for heat preservation, then add basalt fibers with a length of 10 mm and stir evenly, then let it stand for 30 min. After completion, filter out the fibers, and then add 35% of the pretreated steel slag powder of this example based on the mass of the basalt fibers, mix evenly and dry at 40 °C for 120 min to obtain modified fibers for standby.

[0055] (3) Weigh each raw material according to the following ratio: slag powder (specific surface area is 347.4 m 2115 parts by weight of blast furnace slag powder with a particle size of 400 mesh, 310 parts by weight of coarse aggregate of crushed stone with a particle size of 5 - 10 mm, 160 parts by weight of fine aggregate of river sand with a particle size of 0.5 - 1.5 mm, 15 parts by weight of the modified fiber of this example, 7 parts by weight of sodium hydroxide, and 0.23 parts by weight of polycarboxylate water reducer. After mixing the above raw materials, stir for 2 min, and then add clear water according to a water-cement ratio of 0.42 and stir evenly to obtain the geopolymer binder.

[0056] Performance test: Pour the geopolymer binder prepared in this example into a mold, demold after hardening, and then cure in a standard curing box for 28 days. Then, test the compressive strength of the obtained specimens according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T 50081 - 2019). The result is: 28-day compressive strength = 94.86 MPa.

[0057] Example 7 A preparation process of a high-toughness and crack-resistant alkali-activated geopolymer binder, comprising the following steps: (1) Mix 400-mesh steel slag powder and a phosphoric acid solution with a mass fraction of 15% in a ratio of 1 g: 2 ml, and heat in a closed container to 40 °C and keep warm for 90 min. After completion, dry the obtained product by heating at 35 °C until the weight is constant, grind it, and pass through a 400-mesh sieve to obtain the pretreated steel slag powder for standby.

[0058] (2) Mix 500-mesh coal gangue powder, potassium silicate, and water and stir evenly to form a slurry. Among them: the mass ratio of coal gangue powder to potassium silicate is 1: 0.18, and the solid content of the slurry is 55 wt.%. Then heat the slurry to 70 °C and keep warm, then add basalt fibers with a length of 30 mm, stir evenly, and let it stand for 60 min. After completion, filter out the fibers, and then add 40% of the mass of the basalt fibers of the pretreated steel slag powder of this example, mix evenly, and dry at 60 °C for 60 min to obtain the pretreated fiber for standby.

[0059] (3) Place the pretreated fiber in a closed container containing CO2 and H2O vapor (the volume percentage of the two (v: v) = 70%: 30%), and then heat to 90 °C and keep warm for 80 min. After completion, cool naturally to room temperature to obtain the modified fiber for standby.

[0060] (4) Weigh each raw material according to the following ratio: coal gangue powder (specific surface area is 506.2 m 2100 parts by weight, 270 parts by weight of coarse aggregate of crushed stone with a particle size of 5 - 10 mm, 140 parts by weight of fine aggregate of river sand with a particle size of 0.5 - 1.5 mm, 12 parts by weight of the modified fiber of this embodiment, 6 parts by weight of sodium hydroxide, and 0.15 parts by weight of sodium lignosulfonate water reducer. After mixing the above raw materials, stir for 3 minutes, and then add clear water according to a water-cement ratio of 0.4 and stir evenly to obtain the geopolymer cementitious material.

[0061] Performance test: Pour the geopolymer cementitious material prepared in this embodiment into a mold, demold after hardening, and then cure in a standard curing box for 28 days. Then, test the compressive strength of the obtained specimens according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T 50081-2019). The result is: 28-day compressive strength = 96.57 MPa.

[0062] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. should be included within the protection scope of the present invention.

Claims

1. A preparation process of a highly tough and crack-resistant alkali-activated geopolymer cementitious material, characterized in that, It includes the following steps: (1) Mix steel slag powder and phosphoric acid solution, heat and keep warm for reaction. After completion, dry to remove moisture, and then grind to obtain pretreated steel slag powder; (2) Mix brucite powder, potassium silicate and water evenly to form a slurry. Then add basalt fiber to the heated slurry and let it stand. After completion, separate the fiber, mix it with the pretreated steel slag powder and stir evenly, and dry to obtain pretreated fiber; (3) Place the pretreated fiber in a closed container containing carbon dioxide and water vapor for heat preservation and curing. After completion, obtain modified fiber; (4) Weigh each raw material according to the following ratio: aluminosilicate solid waste fine powder, coarse aggregate, fine aggregate, the modified fiber, alkali activator, water reducing agent; mix the above raw materials evenly and add water and stir evenly to obtain geopolymer cementitious material.

2. The preparation process of the high-toughness and crack-resistant alkali-activated geopolymer cementitious material according to claim 1, characterized in that, In step (1), the ratio of the steel slag powder to the phosphoric acid solution is 1 g: 1 - 2 ml; optionally, the mass fraction of the phosphoric acid solution is 15 - 25%.

3. The preparation process of the high-toughness and crack-resistant alkali-activated geopolymer cementitious material according to claim 1, characterized in that, In step (1), the heating temperature is 50 - 70 °C, and the heat preservation time is 1 - 1.5 hours; Optionally, in step (1), the drying temperature is 35 - 40 °C, and dry at this temperature until the weight of the solid matter is constant to obtain the pretreated steel slag powder; Optionally, in step (1), the fineness of the pretreated steel slag powder is 300 - 400 mesh.

4. The preparation process of the high-toughness and crack-resistant alkali-activated geopolymer cementitious material according to claim 1, characterized in that, In step (2), the mass ratio of the brucite powder to the potassium silicate is 1: 0.13 - 0.18; Optionally, the fineness of the brucite powder is 400 - 500 mesh; Optionally, in step (2), the solid content of the slurry is 55 - 65 wt.%.

5. The preparation process of the high-toughness and crack-resistant alkali-activated geopolymer cementitious material according to claim 1, characterized in that, In step (2), the length of the basalt fiber is 10 - 30 mm; Optionally, in step (2), the heating temperature is 50 - 70 °C, and the standing time is 0.5 - 1 hour.

6. The preparation process of the high-toughness and crack-resistant alkali-activated geopolymer cementitious material according to claim 1, characterized in that, In step (2), the mass ratio of the pretreated steel slag powder to the basalt fiber is 0.3 - 0.4: 1; Optionally, in step (2), the drying temperature is 40 - 60 °C, and the drying time is 1 - 2 hours.

7. The preparation process of the high-toughness and crack-resistant alkali-activated geopolymer cementitious material according to claim 1, characterized in that, In step (3), the volume percentage of the carbon dioxide and the water vapor is 70 - 80%: 20 - 30%; Optionally, in step (3), the temperature of the heat preservation and curing is 90 - 110 °C, and the time is 50 - 80 min.

8. The preparation process of the high-toughness and crack-resistant alkali-activated geopolymer cementitious material according to any one of claims 1-7, characterized in that, In step (3), the ratio of each raw material is: 100 - 115 parts by weight of aluminosilicate solid waste fine powder, 270 - 310 parts by weight of coarse aggregate, 140 - 160 parts by weight of fine aggregate, 12 - 15 parts by weight of the modified fiber, 6 - 7 parts by weight of alkali activator, 0.15 - 0.23 parts by weight of water reducing agent; optionally, add the water according to the water - cement ratio of 0.4 - 0.

45.

9. The preparation process of the high-toughness and crack-resistant alkali-activated geopolymer cementitious material according to any one of claims 1-7, characterized in that, In step (3), the aluminosilicate solid waste fine powder includes at least one of slag, fly ash, metakaolin, silica fume, coal gangue; Optionally, in step (3), the specific surface area of the aluminosilicate solid waste fine powder is 350 to 500 m 2 / kg.

10. The preparation process of the high-toughness and crack-resistant alkali-activated geopolymer cementitious material according to any one of claims 1-7, characterized in that, In step (3), the alkali activator includes at least one of sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide; Optionally, in step (3), the water reducing agent includes at least one of polycarboxylate water reducing agent, naphthalene series water reducing agent, melamine series water reducing agent, and lignosulfonate water reducing agent.

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