High-toughness solid-waste-based concrete and method for producing the same

Abstract

The application relates to the technical field of building materials, in particular to high-toughness solid-waste-based concrete and a preparation method thereof, which uses solid-waste-based cementitious materials and modified recycled aggregates as main materials, realizes the recycling of industrial solid wastes, and adds modified basalt fibers and alkali-resistant penetrants to improve the mechanical properties and crack resistance of the concrete.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a high-toughness solid waste-based concrete and a preparation method thereof. Background Art

[0002] Solid waste-based concrete is concrete made primarily from solid waste-based cementitious materials, with slag, tailings sand, and tailings waste rock used as aggregates. Solid waste-based cementitious materials generally refer to industrial and mining wastes with potential hydraulic and pozzolanic properties, such as fly ash, granulated blast furnace slag powder, steel slag, desulfurized gypsum, and alkali slag. These materials are generally used as active admixtures or active admixtures in specific dosages and proportions during cement production and concrete mixing, ensuring the workability, strength, and durability of cement concrete while reducing costs.

[0003] Conventional cement concrete is strengthened and toughened using fiber modification, sometimes combined with other modifiers to improve the interface between the cement matrix and the fiber for better adhesion. Solid waste-based concrete has similar properties to conventional concrete, with high compressive strength and low tensile strength. Therefore, improving its flexural crack toughness and tensile strength is of great engineering significance. However, research on the strengthening and toughening of all-solid waste concrete is relatively limited. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a high-toughness solid waste-based concrete, which uses solid waste-based cementitious materials and modified recycled aggregates as the main materials to achieve the recycling of industrial solid waste, and adds modified basalt fiber and alkali-resistant penetrant to improve the mechanical properties and crack resistance of concrete.

[0005] Specifically, the high-toughness solid waste-based concrete of the present invention is composed of the following raw materials in parts by weight: 200-250 parts of solid waste-based cementitious materials, 500-800 parts of modified recycled aggregates, 30-40 parts of activators, 2-4 parts of modified basalt fibers, 2-5 parts of water reducers, 0.2-0.4 parts of alkali-resistant penetrants, and 80-100 parts of water.

[0006] Preferably, the solid waste-based cementitious material is composed of steel slag powder, mineral powder, and fly ash in a mass ratio of (1-2):(6-8):(1-3).

[0007] Preferably, the mineral powder grade is S95 or S105, and the fly ash grade is grade I or grade II.

[0008] Preferably, the modified recycled aggregate preparation process comprises adding a silane coupling agent and an acrylic emulsion to a graphene dispersion, mixing uniformly, and spraying the mixture onto the surface of the recycled aggregate, wherein the mass ratio of graphene, silane coupling agent, acrylic emulsion, and recycled aggregate is (2-5):(0.4-0.6):(1-2):1000. The present invention utilizes graphene and a silane coupling agent to improve the interface of the recycled aggregate, facilitates the adhesion of gelling hydration products, reduces the water-binder ratio in the interface transition zone, improves the strength of the interface transition zone, and can enhance the strength of the concrete material.

[0009] Preferably, the recycled aggregate comprises recycled fine aggregate and recycled coarse aggregate. More preferably, the mass ratio of recycled fine aggregate to recycled coarse aggregate is 1:1-1.8. More preferably, the recycled aggregate is obtained by crushing and screening waste concrete.

[0010] Preferably, the mass concentration of the graphene dispersion is 12-20%.

[0011] Preferably, the activator is a mixture of red mud and desulfurized gypsum in a mass ratio of (4-6): (3-4). In order to treat large amounts of solid waste generated by the mining and construction industries, reduce carbon emissions and the use of natural sand and gravel materials, the present invention utilizes siliceous and aluminous active materials such as steel slag produced by converter steelmaking, blast furnace slag produced by blast furnace ironmaking, and fly ash produced by coal combustion in thermal power plants as cementitious materials, desulfurized gypsum produced by treating sulfur dioxide in coal combustion flue gas and red mud, a waste of the aluminum industry, as alkaline activators to provide an alkaline environment and sulfate ions, and recycled aggregates obtained by crushing and screening waste concrete as coarse and fine aggregates to prepare solid waste-based concrete.

[0012] The modified basalt fiber preparation process comprises etching the basalt fiber with an alkali solution, washing, and drying. The present invention strengthens and toughens the basalt fiber in concrete, improving its mechanical properties. Alkali etching of the basalt fiber surface increases its surface roughness, improves the interface, and enhances its bonding with the solid waste-based concrete matrix.

[0013] Preferably, the alkali solution is sodium hydroxide solution.

[0014] The preparation process of the alkali-resistant penetrant is as follows: adding caprolactam and a solvent into a reaction kettle, uniformly mixing, introducing nitrogen, heating, adding carboxymethyl cellulose, sodium hydroxide and acyl chloride, and heating and stirring to obtain the alkali-resistant penetrant, wherein the mass ratio of caprolactam, the solvent, carboxymethyl cellulose, sodium hydroxide and acyl chloride is (10-12):(45-50):(1-2):(0.02-0.05):(0.04-0.05). Through graft copolymerization of carboxymethyl cellulose and caprolactam, the capillary pore pressure of the recycled aggregate can be reduced, the solution containing cementitious material and activator can enter the inside of the pores, the hydration reaction can occur, the voids can be filled, the recycled aggregate can be strengthened, and the toughness of the solid waste-based concrete can be improved.

[0015] Preferably, the solvent is water. It should be noted that the water here is the solvent added for the preparation of the alkali-resistant penetrant, and is not counted in the water amount in the concrete formula, and the two are unrelated.

[0016] Preferably, in the preparation process of the alkali-resistant penetrant, the temperature is increased to 70-80 DEG C after nitrogen is introduced, and the heating is performed to 120-150 DEG C for 5-6 h.

[0017] Preferably, the water reducing agent is a polycarboxylic acid water reducing agent, and the water reducing rate is greater than or equal to 25%.

[0018] The application also relates to a preparation method of the high-toughness solid waste-based concrete.

[0019] 1) weighing each raw material according to the mass fraction,

[0020] 2) uniformly mixing the raw materials, shaping, and curing to obtain the high-toughness solid waste-based concrete.

[0021] Preferably, the curing is standard curing. Specific embodiments

[0022] To prove the technical effect of the application, the high-toughness solid waste-based concrete is prepared, and the mechanical property is detected after standard curing to the specified age. The raw materials are S95 grade mineral powder, grade II fly ash, a polycarboxylic acid water reducing agent with a water reducing rate of 28%, recycled aggregate from waste concrete, a mixture of recycled fine aggregate and recycled coarse aggregate with a mass ratio of 1:1.5, and a graphene dispersion liquid with a mass concentration of 15%.

[0023] Example 1

[0024] The high-toughness solid waste-based concrete is composed of the following raw materials in parts by weight: solid waste-based cementitious material 240 parts, modified recycled aggregate 780 parts, activator 40 parts, modified basalt fiber 4 parts, water reducing agent 4 parts, alkali-resistant penetrant 0.3 parts, and water 95 parts.

[0025] The solid waste-based cementitious material is composed of steel slag micro powder, mineral powder and fly ash with a mass ratio of 1:8:2,

[0026] The modified recycled aggregate preparation process is as follows: adding silane coupling agent and acrylic emulsion to graphene dispersion, mixing evenly and spraying the mixture onto the surface of recycled aggregate, wherein the mass ratio of graphene, silane coupling agent, acrylic emulsion and recycled aggregate is 2:0.5:1:1000.

[0027] The activator is a mixture of red mud and desulfurized gypsum in a mass ratio of 4:4.

[0028] The modified basalt fiber preparation process is as follows: etching the basalt fiber with a sodium hydroxide solution, washing and drying the basalt fiber to obtain the modified basalt fiber.

[0029] The preparation process of the alkali-resistant penetrant is as follows: caprolactam and water are added to a reactor, mixed evenly, introduced with nitrogen, and heated to 70°C, carboxymethyl cellulose, sodium hydroxide and acyl chloride are added, and heated to 130°C and stirred for 5 hours to obtain the alkali-resistant penetrant, wherein the mass ratio of caprolactam, water, carboxymethyl cellulose, sodium hydroxide and acyl chloride is 11:46:2:0.03:0.05.

[0030] After testing, the 28d compressive strength of concrete is 43.4MPa, the 28d flexural strength is 6.8MPa, the 56d compressive strength is 46.3MPa, and the fracture energy is 354.7N / m.

[0031] Example 2

[0032] High-toughness solid waste-based concrete is composed of the following raw materials in parts by weight: 220 parts of solid waste-based cementitious materials, 800 parts of modified recycled aggregates, 34 parts of activators, 4 parts of modified basalt fibers, 3 parts of water reducers, 0.3 parts of alkali-resistant penetrants, and 90 parts of water.

[0033] The solid waste-based cementitious material is composed of steel slag powder, mineral powder and fly ash in a mass ratio of 2:8:1.

[0034] The modified recycled aggregate preparation process is as follows: adding silane coupling agent and acrylic emulsion to graphene dispersion, mixing evenly and then spraying the mixture onto the surface of recycled aggregate to obtain the modified recycled aggregate, wherein the mass ratio of graphene, silane coupling agent, acrylic emulsion and recycled aggregate is 4:0.6:1:1000.

[0035] The activator is a mixture of red mud and desulfurized gypsum in a mass ratio of 6:3.

[0036] The modified basalt fiber preparation process is as follows: etching the basalt fiber with a sodium hydroxide solution, washing and drying the basalt fiber to obtain the modified basalt fiber.

[0037] The preparation process of the alkali-resistant penetrant is as follows: caprolactam and water are added to a reactor, mixed evenly, introduced with nitrogen, and heated to 70°C, carboxymethyl cellulose, sodium hydroxide and acyl chloride are added, and heated to 130°C and stirred for 5 hours to obtain the alkali-resistant penetrant, wherein the mass ratio of caprolactam, water, carboxymethyl cellulose, sodium hydroxide and acyl chloride is 12:44:1.5:0.03:0.05.

[0038] After testing, the 28d compressive strength of concrete is 42.3MPa, the 28d flexural strength is 6.6MPa, the 56d compressive strength is 45.8MPa, and the fracture energy is 351.5N / m.

[0039] Comparative Example 1

[0040] Concrete is composed of the following raw materials in parts by weight: 240 parts of solid waste-based cementitious materials, 780 parts of recycled aggregate, 40 parts of activator, 4 parts of modified basalt fiber, 4 parts of water reducer, 0.3 parts of alkali-resistant penetrant, and 95 parts of water.

[0041] The solid waste-based cementitious material is composed of steel slag powder, mineral powder and fly ash in a mass ratio of 1:8:2.

[0042] The activator is a mixture of red mud and desulfurized gypsum in a mass ratio of 4:4.

[0043] The modified basalt fiber preparation process is as follows: etching the basalt fiber with a sodium hydroxide solution, washing and drying the basalt fiber to obtain the modified basalt fiber.

[0044] The preparation process of the alkali-resistant penetrant is as follows: caprolactam and water are added to a reactor, mixed evenly, introduced with nitrogen, and heated to 70°C, carboxymethyl cellulose, sodium hydroxide and acyl chloride are added, and heated to 130°C and stirred for 5 hours to obtain the alkali-resistant penetrant, wherein the mass ratio of caprolactam, water, carboxymethyl cellulose, sodium hydroxide and acyl chloride is 11:46:2:0.03:0.05.

[0045] After testing, the 28d compressive strength of concrete is 37.5MPa, the 28d flexural strength is 5.4MPa, the 56d compressive strength is 40.3MPa, and the fracture energy is 341.0N / m.

[0046] Comparative Example 2

[0047] Concrete is composed of the following raw materials in parts by weight: 240 parts of solid waste-based cementitious materials, 780 parts of modified recycled aggregate, 40 parts of activator, 4 parts of modified basalt fiber, 4 parts of water reducer, 0.3 parts of alkali-resistant penetrant, and 95 parts of water.

[0048] The solid waste-based cementitious material is composed of steel slag powder, mineral powder and fly ash in a mass ratio of 1:8:2.

[0049] The modified recycled aggregate preparation process is as follows: adding a silane coupling agent to a graphene dispersion, mixing the mixture evenly, and then spraying the mixture onto the surface of the recycled aggregate to obtain the modified recycled aggregate, wherein the mass ratio of graphene, silane coupling agent, and recycled aggregate is 2:0.5:1000.

[0050] The activator is a mixture of red mud and desulfurized gypsum in a mass ratio of 4:4.

[0051] The modified basalt fiber preparation process is as follows: etching the basalt fiber with a sodium hydroxide solution, washing and drying the basalt fiber to obtain the modified basalt fiber.

[0052] The preparation process of the alkali-resistant penetrant is as follows: caprolactam and water are added to a reactor, mixed evenly, introduced with nitrogen, and heated to 70°C, carboxymethyl cellulose, sodium hydroxide and acyl chloride are added, and heated to 130°C and stirred for 5 hours to obtain the alkali-resistant penetrant, wherein the mass ratio of caprolactam, water, carboxymethyl cellulose, sodium hydroxide and acyl chloride is 11:46:2:0.03:0.05.

[0053] After testing, the 28d compressive strength of concrete is 38.2MPa, the 28d flexural strength is 5.1MPa, the 56d compressive strength is 41.7MPa, and the fracture energy is 345.3N / m.

[0054] Comparative Example 3

[0055] Concrete is composed of the following raw materials in parts by weight: 240 parts of solid waste-based cementitious materials, 780 parts of modified recycled aggregate, 40 parts of activator, 4 parts of polyvinyl alcohol fiber, 4 parts of water reducer, 0.3 parts of alkali-resistant penetrant, and 95 parts of water.

[0056] The solid waste-based cementitious material is composed of steel slag powder, mineral powder and fly ash in a mass ratio of 1:8:2.

[0057] The modified recycled aggregate preparation process is as follows: adding silane coupling agent and acrylic emulsion to graphene dispersion, mixing evenly and spraying the mixture onto the surface of recycled aggregate, wherein the mass ratio of graphene, silane coupling agent, acrylic emulsion and recycled aggregate is 2:0.5:1:1000.

[0058] The activator is a mixture of red mud and desulfurized gypsum in a mass ratio of 4:4.

[0059] The preparation process of the alkali-resistant penetrant is as follows: caprolactam and water are added to a reactor, mixed evenly, introduced with nitrogen, and heated to 70°C, carboxymethyl cellulose, sodium hydroxide and acyl chloride are added, and heated to 130°C and stirred for 5 hours to obtain the alkali-resistant penetrant, wherein the mass ratio of caprolactam, water, carboxymethyl cellulose, sodium hydroxide and acyl chloride is 11:46:2:0.03:0.05.

[0060] After testing, the 28d compressive strength of the concrete was 35.6MPa, the 28d flexural strength was 4.9MPa, the fibers were pulled out when the specimen broke, the 56d compressive strength was 38.1MPa, and the fracture energy was 330.4N / m.

[0061] Comparative Example 4

[0062] Concrete is composed of the following raw materials in parts by weight: 240 parts of solid waste-based cementitious materials, 780 parts of modified recycled aggregate, 40 parts of activator, 4 parts of modified basalt fiber, 4 parts of water reducer, and 95 parts of water.

[0063] The solid waste-based cementitious material is composed of steel slag powder, mineral powder and fly ash in a mass ratio of 1:8:2.

[0064] The modified recycled aggregate preparation process is as follows: adding silane coupling agent and acrylic emulsion to graphene dispersion, mixing evenly and spraying the mixture onto the surface of recycled aggregate, wherein the mass ratio of graphene, silane coupling agent, acrylic emulsion and recycled aggregate is 2:0.5:1:1000.

[0065] The activator is a mixture of red mud and desulfurized gypsum in a mass ratio of 4:4.

[0066] The modified basalt fiber preparation process comprises the following steps: etching the basalt fiber with a sodium hydroxide solution, washing, and drying the basalt fiber.

[0067] After testing, the 28d compressive strength of concrete is 31.8MPa, the 28d flexural strength is 4.2MPa, the 56d compressive strength is 35.3MPa, and the fracture energy is 307.5N / m.

[0068] Comparative Example 5

[0069] Concrete is composed of the following raw materials in parts by weight: 240 parts of solid waste-based cementitious materials, 780 parts of modified recycled aggregate, 40 parts of activator, 4 parts of modified basalt fiber, 4 parts of water reducer, 0.3 parts of alkali-resistant penetrant, and 95 parts of water.

[0070] The solid waste-based cementitious material is composed of steel slag powder, mineral powder and fly ash in a mass ratio of 1:8:2.

[0071] The modified recycled aggregate preparation process is as follows: adding silane coupling agent and acrylic emulsion to graphene dispersion, mixing evenly and spraying the mixture onto the surface of recycled aggregate, wherein the mass ratio of graphene, silane coupling agent, acrylic emulsion and recycled aggregate is 2:0.5:1:1000.

[0072] The activator is a mixture of red mud and desulfurized gypsum in a mass ratio of 4:4.

[0073] The modified basalt fiber preparation process is as follows: etching the basalt fiber with a sodium hydroxide solution, washing and drying the basalt fiber to obtain the modified basalt fiber.

[0074] The alkali-resistant penetrant is potassium methyl silicate.

[0075] After testing, the 28d compressive strength of concrete is 33.4MPa, the 28d flexural strength is 3.9MPa, the 56d compressive strength is 36.1MPa, and the fracture energy is 320.7N / m.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-toughness solid waste-based concrete, characterized in that: It is composed of the following raw materials in parts by weight: 200-250 parts of solid waste-based cementitious materials, 500-800 parts of modified recycled aggregates, 30-40 parts of activators, 2-4 parts of modified basalt fibers, 2-5 parts of water reducers, 0.2-0.4 parts of alkali-resistant penetrants, and 80-100 parts of water. The solid waste-based cementitious material is composed of steel slag powder, mineral powder, and fly ash in a mass ratio of (1-2): (6-8): (1-3). The modified recycled aggregate preparation process comprises: adding a silane coupling agent and an acrylic emulsion to a graphene dispersion, mixing the mixture evenly, and then spraying the mixture onto the surface of the recycled aggregate to obtain the modified recycled aggregate, wherein the mass ratio of the graphene, the silane coupling agent, the acrylic emulsion, and the recycled aggregate is (2-5):(0.4-0.6):(1-2):1000. The activator is a mixture of red mud and desulfurized gypsum in a mass ratio of (4-6): (3-4), The modified basalt fiber preparation process is as follows: basalt fiber is etched with alkali solution, cleaned and dried to obtain the modified basalt fiber. The preparation process of the alkali-resistant penetrant is as follows: caprolactam and a solvent are added to a reaction kettle, mixed evenly, introduced with nitrogen and heated, carboxymethyl cellulose, sodium hydroxide and acyl chloride are added, heated and stirred, and the obtained product is obtained, wherein the mass ratio of caprolactam, solvent, carboxymethyl cellulose, sodium hydroxide and acyl chloride is (10-12):(45-50):(1-2):(0.02-0.05):(0.04-0.05).

2. The high-toughness solid waste-based concrete according to claim 1, characterized in that: The mineral powder grade is S95 or S105, and the fly ash grade is grade I or grade II.

3. The high-toughness solid waste-based concrete according to claim 1, characterized in that: The recycled aggregate includes recycled fine aggregate and recycled coarse aggregate.

4. The high-toughness solid waste-based concrete according to claim 3, characterized in that: The mass ratio of recycled fine aggregate to recycled coarse aggregate is 1:1-1.

8.

5. The high-toughness solid waste-based concrete according to claim 1, characterized in that: The alkali solution is sodium hydroxide solution.

6. The high-toughness solid waste-based concrete according to claim 1, characterized in that: The solvent is water.

7. The high-toughness solid waste-based concrete according to claim 1, characterized in that: In the preparation process of the alkali-resistant penetrant, nitrogen is introduced and the temperature is raised to 70-80°C, then heated to 120-150°C and stirred for 5-6 hours.

8. The high-toughness solid waste-based concrete according to claim 1, characterized in that: The water reducer is a polycarboxylic acid water reducer with a water reduction rate of ≥25%.

9. The method for preparing high-toughness solid waste-based concrete according to any one of claims 1 to 8, characterized in that: The steps include: 1) Weigh each raw material by mass, 2) Mix all the raw materials evenly, shape them, and cure them to obtain the product.

10. The preparation method according to claim 9, characterized in that: The curing adopts standard curing.