Large-dosage industrial solid waste-based concrete and preparation method thereof

Abstract

The invention discloses high-dosage industrial solid waste-based concrete and a preparation method thereof, and the high-dosage industrial solid waste-based concrete is prepared from the following raw materials in parts by mass: a cementing material including 45-55 parts of fly ash, 30-38 parts of slag and 4-6 parts of red mud; the alkali activator comprises 2-4 parts of a solid alkali activator, 5-7 parts of carbide slag and 5-7 parts of sodium sulfate; the aggregate is prepared from 100 to 120 parts of river sand and 240 to 260 parts of gravel; and 40-50 parts of water. According to the large-dosage industrial solid waste-based concrete disclosed by the embodiment of the invention, the production cost and environmental load of the concrete are reduced, stockpiling pollution of industrial waste residues can be reduced, efficient utilization of the fly ash and the red mud is realized, and the mechanical strength of the industrial solid waste-based concrete is improved; moreover, due to the introduction of the carbide slag and the sodium sulfate, the dosage of the alkali activator can be correspondingly and properly reduced, and the cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of building materials, and in particular to a high-volume industrial solid waste-based concrete and its preparation method. Background Technology

[0002] Concrete is the most widely used building material globally. The production process of cement, its traditional binder, is energy-intensive and generates significant carbon emissions, placing immense pressure on the environment. Meanwhile, industries such as power generation, metallurgy, and chemicals produce large quantities of industrial solid waste, including fly ash, slag, red mud, and carbide slag. The accumulation of these solid wastes not only occupies land but also poses risks of environmental pollution and safety hazards.

[0003] Alkali-activated cementitious materials are a new type of green material that utilizes strong alkali to activate the reaction of silica-alumina raw materials (such as fly ash and slag) to generate cementitious products. They possess advantages such as high early strength, high temperature resistance, and corrosion resistance, and can effectively utilize large quantities of industrial solid waste, making them considered one of the ideal alternatives to traditional cement.

[0004] However, existing alkali-activated concrete formulations typically have the following problems: High raw material costs: Liquid alkaline activators such as water glass and sodium hydroxide are commonly used. These chemicals are expensive and highly corrosive, causing inconvenience in transportation, storage and construction.

[0005] Limited solid waste content: Most studies focus on the utilization of single or two types of solid waste, with insufficient research on formulations for the synergistic utilization of multiple solid wastes, resulting in room for improvement in the comprehensive utilization of solid waste.

[0006] Workability control is difficult: alkali-activated concrete sets quickly and loses its workability (flowability, slump) rapidly, making it difficult to construct and pour on-site.

[0007] Therefore, developing an alkali-activated concrete formula that can utilize multiple industrial solid wastes in large quantities at low cost and with excellent workability and mechanical properties is of great environmental and economic significance. Summary of the Invention

[0008] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one objective of this invention is to propose a high-volume industrial solid waste-based concrete that can fully utilize the potential activity of coal-based solid waste, reduce pollution from industrial waste stockpiling, and achieve efficient utilization of fly ash and red mud; furthermore, due to the introduction of carbide slag and sodium sulfate, the amount of alkali activator can be appropriately reduced, thereby lowering costs.

[0009] The present invention also proposes a method for preparing the above-mentioned high-volume industrial solid waste-based concrete.

[0010] According to a first aspect of the present invention, the high-volume industrial solid waste-based concrete is made from raw materials comprising the following components by weight: cementitious materials, including 45-55 parts fly ash, 30-38 parts slag, and 4-6 parts red mud; alkali activator, including 2-4 parts solid alkali activator, 5-7 parts calcium carbide slag, and 5-7 parts sodium sulfate; aggregates, including 100-120 parts river sand and 240-260 parts crushed stone; and 40-50 parts water.

[0011] According to embodiments of the present invention, the high-volume industrial solid waste-based concrete uses solid waste cementitious materials including fly ash, slag, and red mud as the cementitious materials for fly ash-based polymer concrete. This reduces or avoids the carbon dioxide generated during the preparation of the cementitious materials, lowers concrete production costs and environmental impact, and fully utilizes the potential activity of coal-based solid waste, reducing pollution from industrial waste stockpiling and achieving efficient utilization of fly ash and red mud. Furthermore, the Fe2O3 and Al2O3 components abundant in red mud also participate in the reaction, enhancing the mechanical strength of the industrial solid waste-based concrete. By using carbide slag and sodium sulfate as part of the composite activator, the gypsum generated by the reaction can further promote the formation of ettringite. The ettringite intertwines with the geopolymer gel, improving the workability and mechanical strength of the industrial solid waste-based concrete, achieving a "sulfate activation" effect. Moreover, due to the introduction of carbide slag and sodium sulfate, the amount of alkali activator can be appropriately reduced, lowering costs.

[0012] According to some embodiments of the present invention, the fly ash is Class F, Grade II or above fly ash; and / or, the slag is S95 grade or above granulated blast furnace slag powder.

[0013] According to some embodiments of the present invention, the solid alkali activator comprises at least one of solid sodium metasilicate and anhydrous sodium silicate.

[0014] According to some embodiments of the present invention, the carbide slag includes calcium oxide, and the mass percentage of calcium oxide in the carbide slag is ≥60%.

[0015] According to some embodiments of the present invention, the fineness modulus of the river sand is in the range of 2.3-3.0; and / or, the crushed stone is continuously graded crushed stone, and the particle size of the crushed stone is in the range of 5mm-25mm.

[0016] According to a second aspect of the present invention, a method for preparing high-volume industrial solid waste-based concrete is provided, wherein the high-volume industrial solid waste-based concrete is the high-volume industrial solid waste-based concrete according to a first aspect of the present invention, and the method for preparing the high-volume industrial solid waste-based concrete includes: Step (1): After drying and grinding the red mud, mix it evenly with fly ash, slag, carbide slag, sodium sulfate and solid alkali activator to obtain composite cementitious powder. Step (2): The composite gelling powder and the aggregate are put into a mixer and dry-mixed evenly to form the first intermediate product; Step (3): Add water to the first intermediate product and mix until uniform to obtain concrete mixture; Step (4): Pour and cure the concrete mixture.

[0017] The method for preparing high-volume industrial solid waste-based concrete according to embodiments of the present invention reduces pollution from industrial waste stockpiling by mixing and stirring solid waste cementitious materials, carbide slag, and solid alkali activators, fully utilizes the potential activity of coal-based solid waste, achieves efficient utilization of fly ash and red mud, reduces concrete production costs and environmental impact, and increases the mechanical strength of concrete.

[0018] According to some embodiments of the present invention, in step (1), the drying temperature of the red mud is 105±5℃, the stirring speed is 25-40 r / min, and the stirring time is 4-6 min.

[0019] According to some embodiments of the present invention, in step (2), the stirring speed is 35-55 r / min and the stirring time is 2-4 min.

[0020] According to some embodiments of the present invention, in step (3), the stirring speed is 50-80 r / min and the stirring time is 4-6 min.

[0021] According to some embodiments of the present invention, in step (4), the curing temperature is 20±2℃, the relative humidity is ≥95%, and the curing time is not less than 28 days.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart of a method for preparing high-volume industrial solid waste-based concrete according to some embodiments of the present invention. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0025] The following is for reference. Figure 1 This invention describes high-volume industrial solid waste-based concrete according to embodiments of the present invention.

[0026] According to the first aspect of the present invention, the raw materials for producing high-volume industrial solid waste-based concrete include the following components in parts by weight: cementitious materials, including 45-55 parts fly ash, 30-38 parts slag, and 4-6 parts red mud; alkali activator, including 2-4 parts solid alkali activator, 5-7 parts calcium carbide slag, and 5-7 parts sodium sulfate; aggregates, including 100-120 parts river sand and 240-260 parts crushed stone; and 40-50 parts water.

[0027] Each of these portions contains materials of the same weight.

[0028] By including 45-55 parts fly ash in the solid waste cementitious material, the potential activity of coal-based solid waste can be fully utilized, fly ash can be fully utilized, secondary problems such as land occupation and environmental pollution caused by fly ash storage can be alleviated, and the comprehensive utilization rate of solid waste resources can be improved. In addition, carbon dioxide generated during the preparation of cementitious materials can be reduced or avoided, thus reducing carbon emissions, concrete production costs and environmental impact.

[0029] By including 4-6 parts of red mud in the solid waste cementitious material, the difficult-to-treat red mud can be fully utilized, alleviating the pollution problem of red mud. Furthermore, the Fe2O3 and Al2O3 components rich in red mud also participate in the reaction, helping to improve the strength of the concrete. For example, the red mud used is red mud that has undergone drying and grinding.

[0030] The cementitious system is composed entirely of industrial solid waste (fly ash, slag, red mud, and carbide slag). Without considering aggregates, the total amount of solid waste accounts for more than 90% of the cementitious material, which greatly improves resource utilization efficiency and reduces environmental impact.

[0031] By using carbide slag and sodium sulfate as part of the composite activator, the main component of carbide slag is calcium hydroxide, which reacts to form gypsum, i.e. calcium sulfate. Calcium sulfate further promotes the formation of ettringite. The ettringite and geopolymer gel intertwine and jointly contribute to the structural strength, achieving the effect of "sulfate activation" and improving the strength of concrete. Furthermore, due to the introduction of carbide slag and sodium sulfate, the amount of alkali activator can be appropriately reduced, thus lowering costs.

[0032] By using solid alkali activators, the use of highly corrosive and inconvenient-to-transport and store liquid alkali is avoided, thus reducing safety risks and costs.

[0033] By combining various solid wastes, the silicon-aluminum components and calcium components complement each other, the alkalinity is moderate, and the reaction products are more stable, making the concrete easier to mix and pour, with good workability, high later compressive strength and excellent durability.

[0034] According to embodiments of the present invention, the high-volume industrial solid waste-based concrete uses solid waste cementitious materials including fly ash, slag, and red mud as the cementitious materials for fly ash-based polymer concrete. This reduces or avoids the carbon dioxide generated during the preparation of the cementitious materials, lowers concrete production costs and environmental impact, and fully utilizes the potential activity of coal-based solid waste, reducing pollution from industrial waste stockpiling and achieving efficient utilization of fly ash and red mud. Furthermore, the Fe2O3 and Al2O3 components abundant in red mud also participate in the reaction, enhancing the mechanical strength of the industrial solid waste-based concrete. By using carbide slag and sodium sulfate as part of the composite activator, the gypsum generated by the reaction can further promote the formation of ettringite. The ettringite intertwines with the geopolymer gel, improving the workability and mechanical strength of the industrial solid waste-based concrete, achieving a "sulfate activation" effect. Moreover, due to the introduction of carbide slag and sodium sulfate, the amount of alkali activator can be appropriately reduced, lowering costs.

[0035] According to some embodiments of the present invention, the fly ash is Class F, Grade II or higher. By using Class II or higher fly ash, the quality of solid waste cementitious materials can be improved.

[0036] According to some embodiments of the present invention, the slag is granulated blast furnace slag powder of grade S95 or higher. By using granulated blast furnace slag powder of grade S95 or higher, the quality of solid waste cementitious materials can be improved.

[0037] According to some embodiments of the present invention, the solid alkali activator includes at least one of solid sodium metasilicate and anhydrous sodium silicate. By including at least one of sodium metasilicate and anhydrous sodium silicate in the solid alkali activator, an alkaline environment can be provided, causing the active SiO2 and Al2O3 in fly ash to undergo hydration reactions, continuously generating hydration products such as CSH gel, resulting in more stable long-term performance of concrete. Furthermore, by using a solid form of alkali activator, the use of highly corrosive and inconveniently transported and stored liquid alkali is avoided, reducing safety risks and costs.

[0038] According to some embodiments of the present invention, the carbide slag includes calcium oxide, and the mass percentage of calcium oxide in the carbide slag is ≥60%. Calcium oxide can provide calcium ions for the reaction and can also provide an alkaline environment to promote the hydration reaction of SiO2 and Al2O3 in fly ash to form a gel.

[0039] According to some embodiments of the present invention, the fineness modulus of the river sand is in the range of 2.3-3.0. By making the fineness modulus of the river sand in the range of 2.3-3.0, the performance of the concrete can be improved.

[0040] According to some embodiments of the present invention, the crushed stone is continuously graded crushed stone with a particle size range of 5mm-25mm. By using continuously graded crushed stone with a particle size range of 5mm-25mm, the performance of the concrete can be improved.

[0041] Reference Figure 1 According to a second aspect of the present invention, a method for preparing high-volume industrial solid waste-based concrete is provided, wherein the high-volume industrial solid waste-based concrete is the same as that described in the first aspect of the present invention. The method for preparing the high-volume industrial solid waste-based concrete includes: Step (1): After drying and grinding the red mud, mix it evenly with fly ash, slag, carbide slag, sodium sulfate and solid alkali activator to obtain composite cementitious powder. Step (2): The composite cementitious powder and aggregate are put into the mixer and dry-mixed evenly to form the first intermediate product; Step (3): Add water to the first intermediate product and mix until uniform to obtain concrete mixture; Step (4): Pour and cure the concrete mixture.

[0042] By drying and grinding red mud, it is then uniformly mixed with fly ash, slag, carbide slag, sodium sulfate, and a solid alkali activator to obtain a composite cementitious powder. The solid alkali activator provides an alkaline environment for the solid waste cementitious material, causing the active SiO2 and Al2O3 in the fly ash to undergo hydration reactions, continuously generating hydration products such as CSH gel, resulting in more stable long-term concrete performance. Furthermore, the Fe2O3 and Al2O3 components abundant in the red mud also participate in the reaction, enhancing the mechanical strength of industrial solid waste-based concrete. Carbide slag, in conjunction with the solid alkali activator, activates the activity of fly ash and slag, improving the cementitious capacity of the solid waste cementitious material. Due to the introduction of carbide slag and sodium sulfate, the amount of alkali activator can be appropriately reduced, lowering costs.

[0043] For example, tools can be used to mix and stir solid alkaline activators with solid waste cementitious materials and carbide slag. Compared with the direct dumping of liquid alkaline chemicals in related technologies, this can reduce the risk of alkaline chemicals harming people or other facilities during the dumping process and improve safety.

[0044] The method for preparing high-volume industrial solid waste-based concrete according to embodiments of the present invention reduces pollution from industrial waste stockpiling by mixing and stirring solid waste cementitious materials, carbide slag, and solid alkali activators, fully utilizes the potential activity of coal-based solid waste, achieves efficient utilization of fly ash and red mud, reduces concrete production costs and environmental impact, and increases the mechanical strength of concrete.

[0045] According to some embodiments of the present invention, in step (1), the drying temperature of the red mud is 105±5℃, the stirring speed is 25-40 r / min, and the stirring time is 4-6 min. By drying and pulverizing the red mud, the contact area between the red mud and other substances can be increased, making it easier to mix and stir. By setting the stirring speed to 25-40 r / min and the stirring time to 4-6 min, the stirring can be more thorough.

[0046] According to some embodiments of the present invention, in step (2), the stirring speed is 35-55 r / min and the stirring time is 2-4 min. By setting the stirring speed in step (2) to 35-55 r / min and the stirring time to 2-4 min, the mixing between the composite cementitious powder and the aggregate can be more thorough.

[0047] According to some embodiments of the present invention, in step (3), the stirring speed is 50-80 r / min and the stirring time is 4-6 min. By setting the stirring speed in step (3) to 50-80 r / min and the stirring time to 4-6 min, the mixing between the first intermediate product and water can be more thorough.

[0048] According to some embodiments of the present invention, in step (4), the curing temperature is 20±2℃, the relative humidity is ≥95%, and the curing time is not less than 28 days. By setting the curing conditions to a temperature of 20±2℃, a relative humidity of ≥95%, and a curing time of not less than 28 days, the normal hardening of the concrete can be guaranteed.

[0049] The following describes high-volume industrial solid waste-based concrete according to embodiments of the present invention with reference to some specific examples.

[0050] Example 1 Weigh the raw materials according to the following proportions (unit: kg): Fly ash: 50, Slag: 34, Red mud: 5, Solid alkali activator: 3, Calcium carbide slag: 6, Sodium sulfate: 2, River sand: 110, Crushed stone: 250, Water: 46.

[0051] Preparation method: Step (1): Dry and grind the red mud at 105℃, mix it with fly ash, slag, carbide slag, sodium sulfate and solid alkali activator, dry mix for 5 minutes, and mix evenly to form a composite cementitious powder.

[0052] Step (2): Add the composite cementitious powder, river sand, and crushed stone into the mixer and dry mix for 3 minutes to form the first intermediate product.

[0053] Step (3): Add water to the first intermediate product and continue wet mixing for 5 minutes to obtain a uniform concrete mixture.

[0054] Step (4): Pour the concrete into the mold and cure it for 28 days to obtain the concrete.

[0055] Example 2 Weigh the raw materials according to the following proportions (unit: kg): Fly ash: 50, Slag: 36, Red mud: 5, Solid alkali activator: 3, Calcium carbide slag: 4, Sodium sulfate: 2, River sand: 110, Crushed stone: 250, Water: 47.

[0056] Preparation method: Step (1): Dry and grind the red mud at 105℃, mix it with fly ash, slag, carbide slag, sodium sulfate and solid alkali activator, dry mix for 5 minutes, and mix evenly to form a composite cementitious powder.

[0057] Step (2): Add the composite cementitious powder, river sand, and crushed stone into the mixer and dry mix for 3 minutes to form the first intermediate product.

[0058] Step (3): Add water to the first intermediate product and continue wet mixing for 5 minutes to obtain a uniform concrete mixture.

[0059] Step (4): Pour the concrete into the mold and cure it for 28 days to obtain the concrete.

[0060] Comparative Example 1 Weigh the raw materials according to the following proportions (unit: kg): Fly ash: 50, Slag: 36, Red mud: 5, Solid alkali activator: 3, Calcium carbide slag: 6, River sand: 110, Crushed stone: 250, Water: 48.

[0061] Preparation method: Step (1): Dry and grind the red mud at 105℃, mix it with fly ash, slag, carbide slag and solid alkali activator, dry mix for 5 minutes, and mix evenly to form a composite cementitious powder.

[0062] Step (2): Add the composite cementitious powder, river sand, and crushed stone into the mixer and dry mix for 3 minutes to form the first intermediate product.

[0063] Step (3): Add water to the first intermediate product and continue wet mixing for 5 minutes to obtain a uniform concrete mixture.

[0064] Step (4): Pour the concrete into the mold and cure it for 28 days to obtain the concrete.

[0065] The slump of the concrete mixtures formed in step (3) of Examples 1, 2 and Comparative Example 1 was tested. The slump of the fresh concrete was 180 mm, which showed that it had good workability.

[0066] The compressive strength of the concrete in Examples 1, 2, and Comparative Example 1 was tested. The compressive strength of the concrete obtained in Example 1 was 32.3 MPa, the compressive strength of the concrete obtained in Example 2 was 31.7 MPa, and the compressive strength of the concrete obtained in Comparative Example 1 was 19.9 MPa. The compressive strength of the concrete obtained in Examples 1 and 2 was significantly higher than that in Comparative Example 1. The above experiments show that the formula and preparation method provided by the present invention successfully achieves the efficient synergistic utilization of various industrial solid wastes, and the prepared concrete has excellent workability and mechanical properties, with significant environmental and economic benefits.

[0067] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0068] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0069] In the description of this invention, "a plurality of" means two or more.

[0070] In the description of this invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0071] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0072] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0073] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A type of concrete with high industrial solid waste content, characterized in that, The raw materials for producing the high-volume industrial solid waste-based concrete include the following components in parts by weight: Cementitious materials include 45-55 parts fly ash, 30-38 parts slag, and 4-6 parts red mud; Alkali activator, including 2-4 parts solid alkali activator, 5-7 parts calcium carbide slag, and 5-7 parts sodium sulfate; Aggregates, including 100-120 parts river sand and 240-260 parts crushed stone; 40-50 parts water.

2. The high-volume industrial solid waste-based concrete according to claim 1, characterized in that, The fly ash is Class F, Grade II or above; and / or, the slag is S95 grade or above granulated blast furnace slag powder.

3. The high-volume industrial solid waste-based concrete according to claim 1, characterized in that, The solid alkali activator includes at least one of solid sodium metasilicate and anhydrous sodium silicate.

4. The high-volume industrial solid waste-based concrete according to claim 1, characterized in that, The carbide slag includes calcium oxide, and the mass percentage of calcium oxide in the carbide slag is ≥60%.

5. The high-volume industrial solid waste-based concrete according to claim 1, characterized in that, The fineness modulus of the river sand is in the range of 2.3-3.0; and / or, the crushed stone is continuously graded crushed stone, and the particle size of the crushed stone is in the range of 5mm-25mm.

6. A method for preparing high-volume industrial solid waste-based concrete, characterized in that, The high-volume industrial solid waste-based concrete is the high-volume industrial solid waste-based concrete according to any one of claims 1-5, and the preparation method of the high-volume industrial solid waste-based concrete includes: Step (1): After drying and grinding the red mud, mix it evenly with fly ash, slag, carbide slag, sodium sulfate and solid alkali activator to obtain composite cementitious powder. Step (2): The composite gelling powder and the aggregate are put into a mixer and dry-mixed evenly to form the first intermediate product; Step (3): Add water to the first intermediate product and mix until uniform to obtain concrete mixture; Step (4): Pour and cure the concrete mixture.

7. The method for preparing high-volume industrial solid waste-based concrete according to claim 6, characterized in that, In step (1), the drying temperature of the red mud is 105±5℃, the stirring speed is 25-40 r / min, and the stirring time is 4-6 min.

8. The method for preparing high-volume industrial solid waste-based concrete according to claim 6, characterized in that, In step (2), the stirring speed is 35-55 r / min and the stirring time is 2-4 min.

9. The method for preparing high-volume industrial solid waste-based concrete according to claim 6, characterized in that, In step (3), the stirring speed is 50-80 r / min and the stirring time is 4-6 min.

10. The method for preparing high-volume industrial solid waste-based concrete according to claim 6, characterized in that, In step (4), the curing temperature is 20±2℃, the relative humidity is ≥95%, and the curing time is no less than 28 days.

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