Environment-friendly high-performance cementing material based on fly ash and slag and preparation method thereof

Abstract

The invention relates to the technical field of cementing materials, in particular to an environment-friendly high-performance cementing material based on fly ash and slag and a preparation method of the environment-friendly high-performance cementing material. The environment-friendly high-performance cementing material comprises the following raw materials in parts by weight: 80-100 parts of fly ash, 16-20 parts of slag, 10-14 parts of desulfurized gypsum, 4-6 parts of gasified slag and 0.6-0.8 part of a composite activator, according to the invention, the gasified slag is pretreated to form a rich pore structure, the specific surface area of the gasified slag is increased, then the desulfurized gypsum and the 3-aminopropyltriethoxysilane are combined to carry out hydrolytic condensation reaction, and through the bridging effect of the silane coupling agent, the specific surface area of the gasified slag is increased; the interface bonding force between the desulfurized gypsum and other cementing materials is remarkably enhanced, so that the strength performance of the cementing material is improved, other natural materials are replaced with solid waste, the production cost of the cementing material can be effectively reduced, meanwhile, accumulation of waste is effectively reduced, cyclic utilization of resources is achieved, and natural resources are protected.

Description

Technical Field

[0001] The present invention relates to the technical field of cementitious materials, and specifically to an environmentally friendly high-performance cementitious material based on fly ash and slag and a preparation method thereof. Background Art

[0002] A cementitious material is a material that can bond granular materials or massive materials into a whole. Through its own physical and chemical actions, it forms a bonding force between materials, enabling the bonded materials to jointly bear external forces. Cementitious materials are widely used in many fields such as construction, roads, and mining, and are key components for constructing various engineering structures.

[0003] In the prior art, cement is usually used as the base material for preparing cementitious materials. Due to the weak strength of the aggregate structure of cement, the strength performance of the cementitious material is poor. At the same time, the procurement cost of cement is high, which affects the control of the production cost of the cementitious material. Based on this, the present invention provides an environmentally friendly high-performance cementitious material based on fly ash and slag and a preparation method thereof. Summary of the Invention

[0004] The purpose of the present invention is to provide an environmentally friendly high-performance cementitious material based on fly ash and slag and a preparation method thereof. The environmentally friendly high-performance cementitious material prepared by the present invention not only has good compressive strength, but also has excellent splitting tensile strength and flexural strength, effectively improving the use performance of the environmentally friendly high-performance cementitious material.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] In the first aspect, the present invention provides an environmentally friendly high-performance cementitious material based on fly ash and slag, including the following raw materials in parts by weight: 80-100 parts of fly ash, 16-20 parts of slag, 10-14 parts of desulfurized gypsum, 4-6 parts of gasification slag, and 0.6-0.8 parts of a composite activator.

[0007] Further, the fly ash has a particle size of 10-20 mm and a moisture content of 8-10%.

[0008] Further, the slag has a particle size of 20-30 mm and is the waste residue generated by coal combustion.

[0009] Further, the desulfurized gypsum has a particle size of 10-30 mm, and the gasification slag has a particle size of 30-40 mm.

[0010] Further, the desulfurized gypsum is pretreated before preparation. The desulfurized gypsum is fed into a mixer, and an additive is added. The mass of the additive is 10-20% of the mass of the desulfurized gypsum. The mixer is set to mix at 120-160 r / min for 20-30 min to complete the pretreatment of the desulfurized gypsum.

[0011] Further, the additive is selected as 3-aminopropyltriethoxysilane.

[0012] Further, the gasification slag is pretreated before preparation. The pretreatment method of the gasification slag is as follows: The gasification slag is fed into a muffle furnace, and the heating rate is set at 10-20 °C / min to be heated to 200-300 °C and kept warm for 20-30 min. Then, the heating rate is set at 5-10 °C / min to be heated to 500-600 °C and kept warm for 2-4 h. After cooling, it is taken out to complete the pretreatment of the gasification slag.

[0013] Further, the composite activator is composed of steel slag, sodium silicate and calcium lignosulfonate, and the mass ratio of the steel slag, sodium silicate and calcium lignosulfonate is 1:(0.4-0.6):(0.2-0.4).

[0014] Further, the concentration of the sodium silicate is 30-40%, and the steel slag selected has a particle size of 5-10 mm.

[0015] In the second aspect, the present invention provides a preparation method of an environment-friendly high-performance cementitious material based on fly ash and slag, including the following steps:

[0016] S1: The fly ash, slag, and the pretreated desulfurized gypsum and gasification slag are fed into a mixer, and the mixer is set to mix at 200-300 r / min for 20-30 min to obtain a mixture;

[0017] S2: The mixture and the composite activator are mixed in a mixer, and the mixer is set to mix at 400-500 r / min for 10-20 min to obtain a mixed material;

[0018] S3: The mixed material is fed into a ball mill. The ceramic balls are selected as the ball milling medium in the ball mill. The mass of the ceramic balls is 30-40% of the mass of the mixed material. The rotation speed is set at 1200-1400 r / min, and the time is 10-30 min to prepare the environment-friendly high-performance cementitious material.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. In the present invention, during the preparation process of the cementitious material, through the pretreatment of the gasification slag, after the gasification slag undergoes high-temperature pretreatment, the moisture in the gasification slag rapidly evaporates during heating, forming a rich pore structure on the surface of the gasification slag, increasing the specific surface area of the gasification slag. Subsequently, the desulfurized gypsum reacts with 3-aminopropyltriethoxysilane through hydrolysis and condensation reaction. Through the bridging effect of the silane coupling agent, the interfacial bonding force between the desulfurized gypsum and other cementitious materials is significantly enhanced, thereby improving the strength performance of the cementitious material.

[0021] 2. In the present invention, fly ash, slag, desulfurized gypsum, and gasification slag as raw materials are all solid waste products in industrial processing. Using these solid wastes to replace other natural materials can effectively reduce the production cost of the cementitious material, and at the same time effectively reduce the accumulation of waste, realize the recycling of resources, and protect natural resources.

[0022] 3. In the present invention, through the use of steel slag and water glass in the composite activator, water glass can fill the pores, making the microstructure of the cementitious material more dense, thereby improving the compressive strength and flexural strength. Utilizing the better strength and hardness of the steel slag material can enhance the density of the cementitious material, and further improve the strength performance of the cementitious material. Detailed implementation manners

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0024] To enable those in the technical field to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below.

[0025] This embodiment provides an environmentally friendly high-performance cementitious material based on fly ash and slag, including the following raw materials in parts by weight: 80 - 100 parts of fly ash, 16 - 20 parts of slag, 10 - 14 parts of desulfurized gypsum, 4 - 6 parts of gasification slag, and 0.6 - 0.8 parts of composite activator.

[0026] In some embodiments, the fly ash has a particle size of 10 - 20 mm and a moisture content of 8 - 10%.

[0027] In some embodiments, the slag has a particle size of 20 - 30 mm and is the waste residue generated by coal combustion.

[0028] In some embodiments, the desulfurized gypsum has a particle size of 10 - 30 mm, and the gasification slag has a particle size of 30 - 40 mm.

[0029] In some embodiments, the desulfurized gypsum is pretreated before preparation. The desulfurized gypsum is fed into a mixer, and an additive is added. The mass of the additive is 10-20% of the mass of the desulfurized gypsum. The mixer is set to mix at 120-160 r / min for 20-30 min to complete the pretreatment of the desulfurized gypsum.

[0030] In some embodiments, the additive is 3-aminopropyltriethoxysilane.

[0031] In some embodiments, the gasification slag is pretreated before preparation. The pretreatment method of the gasification slag is as follows: The gasification slag is fed into a muffle furnace, and the heating rate is set to 10-20 °C / min to heat up to 200-300 °C, and keep warm for 20-30 min. Then the heating rate is set to 5-10 °C / min to heat up to 500-600 °C, and keep warm for 2-4 h. After cooling, it is taken out to complete the pretreatment of the gasification slag.

[0032] In this embodiment, through the pretreatment of the gasification slag, after the gasification slag is pretreated at high temperature, the moisture in the gasification slag evaporates rapidly during heating, so that a rich pore structure is formed on the surface of the gasification slag, improving the specific surface area of the gasification slag. Then, the desulfurized gypsum reacts with 3-aminopropyltriethoxysilane through hydrolysis and condensation reaction. Through the bridging action of the silane coupling agent, the interfacial bonding force between the desulfurized gypsum and other cementitious materials is significantly enhanced, thereby improving the strength performance of the cementitious material.

[0033] In some embodiments, the composite activator is composed of steel slag, water glass and calcium lignosulfonate, and the mass ratio of steel slag, water glass and calcium lignosulfonate is 1:(0.4-0.6):(0.2-0.4).

[0034] In this embodiment, through the use of steel slag and water glass in the composite activator, the water glass can fill the pores, making the microstructure of the cementitious material more dense, thereby improving the compressive strength and flexural strength. Utilizing the good strength and hardness of the steel slag material can improve the density of the cementitious material, and further improve the strength performance of the cementitious material.

[0035] In some embodiments, the concentration of water glass is 30-40%, and the steel slag selected has a particle size of 5-10 mm.

[0036] In some embodiments, the preparation method of the environmentally friendly high-performance cementitious material based on fly ash and slag includes the following steps:

[0037] S1: Fly ash, slag, and the pretreated desulfurized gypsum and gasification slag are fed into a mixer, and the mixer is set to mix at 200-300 r / min for 20-30 min to obtain a mixture.

[0038] S2: Mix the mixture material and the composite activator in a mixer. The mixer is set to mix at 400 - 500 r / min for 10 - 20 min to obtain a mixed material.

[0039] S3: Feed the mixed material into a ball mill. The ball mill uses ceramic balls as the ball milling medium. The mass of the ceramic balls is 30 - 40% of the mass of the mixed material. The rotation speed is set to 1200 - 1400 r / min and the time is 10 - 30 min to produce an environmentally friendly high-performance cementitious material.

[0040] In this embodiment, fly ash, slag, desulfurized gypsum, and gasification slag as raw materials are all solid waste products in industrial processing. Using these solid wastes to replace other natural materials can effectively reduce the production cost of the cementitious material, and at the same time effectively reduce the accumulation of waste, realize the recycling of resources, and protect natural resources.

[0041] Based on the foregoing embodiments, the inventor also conducted the following multiple groups of experiments:

[0042] It should be noted that the raw materials used in the following experiments are all commercially available raw materials.

[0043] Experiment 1:

[0044] Raw material selection: 80 parts of fly ash, 16 parts of slag, 10 parts of desulfurized gypsum, 4 parts of gasification slag, 0.6 part of composite activator;

[0045] The selected fly ash has a particle size of 10 mm and a moisture content of 8%. The selected slag has a particle size of 20 mm and is the waste residue generated by coal combustion. The selected desulfurized gypsum has a particle size of 10 mm, and the selected gasification slag has a particle size of 30 mm;

[0046] Pretreatment of desulfurized gypsum: Feed the desulfurized gypsum into a mixer, add 3-aminopropyltriethoxysilane, and the mass of 3-aminopropyltriethoxysilane is 10% of the mass of the desulfurized gypsum. The mixer is set to mix at 120 r / min for 20 min to complete the pretreatment of the desulfurized gypsum;

[0047] Pretreatment of gasification slag: Feed the gasification slag into a muffle furnace, set the heating rate to 10 °C / min and heat up to 200 °C, keep it warm for 30 min, then set the heating rate to 10 °C / min and heat up to 600 °C, keep it warm for 4 h, and take it out after cooling to complete the pretreatment of the gasification slag;

[0048] The composite activator is composed of steel slag, sodium silicate, and calcium lignosulfonate. The mass ratio of steel slag, sodium silicate, and calcium lignosulfonate is 1:0.4:0.2. The concentration of sodium silicate is 30%, and the selected steel slag has a particle size of 5 mm;

[0049] Preparation of cementitious material:

[0050] S1: Fly ash, slag, and the pre-treated desulfurized gypsum and gasification slag are fed into a mixer. The mixer is set to mix at 200 r / min for 20 min to obtain a blended material.

[0051] S2: The blended material is mixed with a composite activator in the mixer. The mixer is set to mix at 400 r / min for 10 min to obtain a mixed material.

[0052] S3: The mixed material is fed into a ball mill. The ball mill uses ceramic balls as the grinding medium. The mass of the ceramic balls is 30% of the mass of the mixed material. The rotation speed is set to 1200 r / min and the time is 10 min to produce an environmentally friendly high-performance cementitious material.

[0053] Experiment 2:

[0054] Raw material selection: 90 parts of fly ash, 18 parts of slag, 12 parts of desulfurized gypsum, 5 parts of gasification slag, 0.7 part of composite activator;

[0055] The fly ash has a particle size of 15 mm and a moisture content of 9%. The slag has a particle size of 25 mm and is the waste residue produced by coal combustion. The desulfurized gypsum has a particle size of 20 mm, and the gasification slag has a particle size of 35 mm;

[0056] Pre-treatment of desulfurized gypsum: The desulfurized gypsum is fed into a mixer, and 3-aminopropyltriethoxysilane is added. The mass of 3-aminopropyltriethoxysilane is 15% of the mass of the desulfurized gypsum. The mixer is set to mix at 140 r / min for 25 min to complete the pre-treatment of the desulfurized gypsum;

[0057] Pre-treatment of gasification slag: The gasification slag is fed into a muffle furnace. The heating rate is set to 15 °C / min and heated to 250 °C, and held for 25 min. Then the heating rate is set to 7 °C / min and heated to 550 °C, and held for 3 h. After cooling, it is taken out to complete the pre-treatment of the gasification slag;

[0058] The composite activator is composed of steel slag, water glass, and calcium lignosulfonate. The mass ratio of steel slag, water glass, and calcium lignosulfonate is 1:0.5:0.3. The concentration of water glass is 35%. The steel slag has a particle size of 7 mm;

[0059] Preparation of cementitious material:

[0060] S1: Fly ash, slag, and the pre-treated desulfurized gypsum and gasification slag are fed into a mixer. The mixer is set to mix at 250 r / min for 25 min to obtain a blended material.

[0061] S2: The blended material is mixed with a composite activator in the mixer. The mixer is set to mix at 450 r / min for 15 min to obtain a mixed material.

[0062] S3: Feed the mixture into a ball mill. Select ceramic balls as the ball milling medium. The mass of the ceramic balls is 35% of the mass of the mixture. Set the rotation speed at 1300 r / min and the time at 20 min to produce an environmentally friendly high-performance cementitious material.

[0063] Experiment 3:

[0064] Raw material selection: 100 parts of fly ash, 20 parts of slag, 14 parts of desulfurized gypsum, 6 parts of gasification slag, 0.8 part of composite activator;

[0065] The selected fly ash has a particle size of 20 mm and a moisture content of 10%. The selected slag has a particle size of 30 mm and is the waste residue produced by coal combustion. The selected desulfurized gypsum has a particle size of 30 mm, and the selected gasification slag has a particle size of 40 mm;

[0066] Pretreatment of desulfurized gypsum: Feed the desulfurized gypsum into a mixer, add 3-aminopropyltriethoxysilane. The mass of 3-aminopropyltriethoxysilane is 20% of the mass of the desulfurized gypsum. Set the mixer at 160 r / min for mixing treatment for 30 min to complete the pretreatment of the desulfurized gypsum;

[0067] Pretreatment of gasification slag: Feed the gasification slag into a muffle furnace. Set the heating rate at 20 °C / min and heat up to 300 °C, then hold for 30 min. After that, set the heating rate at 10 °C / min and heat up to 600 °C, hold for 4 h, and take it out after cooling to complete the pretreatment of the gasification slag;

[0068] The composite activator is composed of steel slag, sodium silicate and calcium lignosulfonate. The mass ratio of steel slag, sodium silicate and calcium lignosulfonate is 1:0.6:0.4. The concentration of sodium silicate is 40%. The selected steel slag has a particle size of 10 mm;

[0069] Preparation of cementitious material:

[0070] S1: Feed fly ash, slag, and the pretreated desulfurized gypsum and gasification slag into a mixer. Set the mixer at 300 r / min for mixing treatment for 30 min to obtain a mixture;

[0071] S2: Mix the mixture with the composite activator in a mixer. Set the mixer at 500 r / min for mixing treatment for 20 min to obtain a mixed material;

[0072] S3: Feed the mixed material into a ball mill. Select ceramic balls as the ball milling medium. The mass of the ceramic balls is 40% of the mass of the mixed material. Set the rotation speed at 1400 r / min and the time at 30 min to produce an environmentally friendly high-performance cementitious material.

[0073] Comparative Example 1. The difference between this comparative example and Experiment 1 is:

[0074] This comparative example does not contain a composite activator.

[0075] Comparative Example 2: The difference between this comparative example and Experiment 1 is as follows:

[0076] In this comparative example, an equal amount of water glass is used to replace the composite activator.

[0077] Comparative Example 3: The difference between this comparative example and Experiment 1 is as follows:

[0078] In this comparative example, the gasification slag is not pretreated.

[0079] Comparative Example 4: The difference between this comparative example and Experiment 1 is as follows:

[0080] In this comparative example, the desulfurized gypsum is not pretreated.

[0081] Performance test: Perform performance tests on the environmentally friendly high-performance cementitious materials prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4.

[0082] In the performance test, using the test methods in the "Standard Test Methods for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), test the compressive strength, splitting tensile strength, and flexural strength of the environmentally friendly high-performance cementitious materials prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. The obtained test data are recorded in the following table:

[0083]

[0084] Among them, the compressive strengths of the environmentally friendly high-performance cementitious materials prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are 61 MPa, 58 MPa, 59 MPa, 42 MPa, 38 MPa, 33 MPa, and 37 MPa respectively;

[0085] The splitting tensile strengths of the environmentally friendly high-performance cementitious materials prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are 2.9 MPa, 2.8 MPa, 2.9 MPa, 2.1 MPa, 1.8 MPa, 1.5 MPa, and 1.6 MPa respectively;

[0086] The flexural strengths of the environmentally friendly high-performance cementitious materials prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are 7.6 MPa, 7.4 MPa, 6.9 MPa, 5.1 MPa, 4.8 MPa, 4.5 MPa, and 4.3 MPa respectively.

[0087] It can be seen that the data of the compressive strength, splitting tensile strength and flexural strength of the environmentally friendly high-performance cementitious materials prepared in Comparative Examples 1, 2, 3 and 4 are all lower than those in Experiments 1, 2 and 3. This shows that through the pretreatment of gasification slag, after the gasification slag is pretreated at high temperature, the moisture in the gasification slag rapidly evaporates during heating, forming a rich pore structure on the surface of the gasification slag, increasing the specific surface area of the gasification slag. Then, the desulfurized gypsum reacts with 3-aminopropyltriethoxysilane through hydrolysis and condensation reaction. Through the bridging action of the silane coupling agent, the interfacial bonding force between the desulfurized gypsum and other cementitious materials is significantly enhanced, thereby improving the strength performance of the cementitious material.

[0088] By comparing and analyzing the relevant data in the table, it can be seen that the environmentally friendly high-performance cementitious material prepared by the present invention not only has good compressive strength, but also has excellent splitting tensile strength and flexural strength. This shows that the environmentally friendly high-performance cementitious material based on fly ash and slag provided by the present invention and its preparation method have a broader market prospect and are more suitable for popularization.

[0089] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0090] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. An environmentally friendly high-performance cementitious material based on fly ash and slag, characterized in that: The invention comprises the following raw materials in parts by weight: 80 to 100 parts of fly ash, 16 to 20 parts of slag, 10 to 14 parts of desulfurized gypsum, 4 to 6 parts of gasified slag and 0.6 to 0.8 parts of composite activator.

2. The environmentally friendly high-performance cementitious material based on fly ash and slag according to claim 1, characterized in that: The fly ash has a particle size of 10 to 20 mm and a moisture content of 8 to 10%.

3. The environmentally friendly high-performance cementitious material based on fly ash and slag according to claim 1, characterized in that: The slag has a particle size of 20 to 30 mm and is waste slag produced by coal combustion.

4. The environmentally friendly high-performance cementitious material based on fly ash and slag according to claim 1, characterized in that: The desulfurized gypsum has a particle size of 10 to 30 mm, and the gasified slag has a particle size of 30 to 40 mm.

5. The environmentally friendly high-performance cementitious material based on fly ash and slag according to claim 1, characterized in that: The desulfurized gypsum is pretreated before preparation. The desulfurized gypsum is fed into a mixer and an additive is added. The mass of the additive is 10-20% of the mass of the desulfurized gypsum. The mixer is set at 120-160r / min for mixing for 20-30min to complete the pretreatment of the desulfurized gypsum.

6. The environmentally friendly high-performance cementitious material based on fly ash and slag according to claim 5, characterized in that: The additive is 3-aminopropyltriethoxysilane.

7. The environmentally friendly high-performance cementitious material based on fly ash and slag according to claim 1, characterized in that: The gasified slag is pretreated before preparation, and the pretreatment method of the gasified slag is as follows: the gasified slag is fed into a muffle furnace, the heating rate is set to 10-20°C / min to heat the slag to 200-300°C, and the temperature is kept for 20-30 minutes, then the heating rate is set to 5-10°C / min to heat the slag to 500-600°C, and the temperature is kept for 2-4 hours. After cooling, the slag is taken out to complete the pretreatment of the gasified slag.

8. The environmentally friendly high-performance cementitious material based on fly ash and slag according to claim 1, characterized in that: The composite activator is composed of steel slag, water glass and calcium lignin sulfonate, and the mass ratio of the steel slag, water glass and calcium lignin sulfonate is 1: (0.4-0.6): (0.2-0.4).

9. The environmentally friendly high-performance cementitious material based on fly ash and slag according to claim 8, characterized in that: The water glass concentration is 30-40%, and the steel slag particle size is 5-10 mm.

10. The method for preparing an environmentally friendly high-performance cementitious material based on fly ash and slag according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: The fly ash and slag as well as the pre-treated desulfurized gypsum and gasified slag are fed into a mixer, and the mixer is set at 200-300 r / min for mixing for 20-30 min to obtain a mixed material; S2: The mixing material and the composite activator are mixed in a mixer, and the mixer is set at 400-500 r / min for 10-20 min to obtain a mixture; S3: The mixed material is sent to a ball mill, and ceramic balls are used as the grinding media. The mass of the ceramic balls is 30-40% of the mass of the mixed material. The rotation speed is set to 1200-1400 r / min, and the time is 10-30 min to obtain an environmentally friendly high-performance cementitious material.

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