Self-compacting concrete

Abstract

The invention relates to the technical field of solid waste recycling, and discloses self-compacting concrete. The self-compacting concrete contains natural sand, 42.5 R cement, fly ash, natural sand, broken stone, water, gasified slag, ground gasified slag, coal gangue, a polycarboxylic acid water reducing component, a lignosulfonate retarding component, a tackifying component, an air entraining component and a gasified slag activating agent. The self-compacting concrete admixture and the self-compacting concrete are developed on the basis of the coal chemical industry solid wastes difficult to treat and by taking the self-compacting concrete as an application scene, so that the problem that part of raw materials of the self-compacting concrete admixture are cheap is solved while excellent vibration-free and self-compacting properties of the self-compacting concrete are maintained, the solid wastes can be utilized, and the cost is reduced. The cost of the self-compacting concrete admixture is reduced, the solid waste disposal cost of enterprises is reduced, and the cost is reduced and the benefit is increased for the enterprises.

Description

Technical Field

[0001] This invention relates to the field of solid waste recycling technology, specifically to a self-compacting concrete. Background Technology

[0002] Self-compacting concrete (SCC) is concrete that fills a mold by its own weight without the need for vibration. This type of concrete has good fluidity, excellent workability and filling properties, does not segregate aggregates, and exhibits good mechanical properties and durability after hardening.

[0003] Self-compacting concrete is characterized by its ability to self-compact without vibration. It is produced through a combination of cementitious materials, coarse and fine aggregates, and admixtures. The workability of self-compacting concrete is mainly reflected in the following four aspects: 1. High fluidity; 2. Good stability; 3. Excellent filling properties; 4. Ability to pass through gaps in reinforcing bars. The fluidity, stability, filling properties, and ability to pass through gaps in self-compacting concrete all require the use of admixtures to achieve these properties.

[0004] Traditional coal chemical industries generate solid wastes such as miscellaneous salts (mainly sodium sulfate and sodium chloride), softened sludge (mainly calcium carbonate and magnesium carbonate), desulfurization gypsum, gasification slag, fly ash, and coal gangue. These are typically disposed of via landfill, increasing the cost of solid waste disposal for enterprises and hindering their sustainable development. The large-scale, volume-reduced treatment of these industrial wastes through self-compacting concrete admixtures not only addresses a portion of the solid waste but also enables their application in self-compacting concrete, turning waste into valuable resources and reducing costs while increasing efficiency for enterprises.

[0005] Currently, self-compacting concrete admixtures consist of multiple components, all of which are commercially available products or compounded from commercially available agents, resulting in high raw material costs. Furthermore, traditional self-compacting concrete uses cement, sand, and aggregate as raw materials, adding different types of admixtures to prepare self-compacting concrete with good fluidity and filling properties, which leads to high consumption of natural resources such as sand and aggregate, and high costs. Gasification slag is also used in self-compacting concrete. Gasification slag has a particle size distribution and fineness modulus comparable to natural sand, but a low elastic modulus, making it suitable as a fine aggregate. However, its high water absorption rate significantly affects the fluidity of self-compacting concrete. Coal gasification slag can also be used as a mineral admixture, but its activity is low, requiring activation. Different activation methods significantly impact the performance of self-compacting concrete. Summary of the Invention

[0006] This invention is based on the difficult-to-treat solid waste from coal chemical industry and takes self-compacting concrete as the application scenario. It develops self-compacting concrete admixtures and self-compacting concrete. While maintaining the excellent performance of self-compacting concrete that does not require vibration and is self-compacting, it not only solves the problem of reducing the cost of some raw materials for self-compacting concrete admixtures, but also utilizes solid waste to reduce the cost of self-compacting concrete admixtures and reduce the solid waste disposal costs for enterprises, thereby reducing costs and increasing efficiency for enterprises.

[0007] To achieve the above objectives, the first aspect of the present invention provides a self-compacting concrete comprising natural sand, 42.5R cement, fly ash, natural sand, crushed stone, water, gasification slag, ground gasification slag, coal gangue, polycarboxylate superplasticizer, lignosulfonate retarder, thickening agent, air-entraining agent, and gasification slag activator. The content of 42.5R cement is 20-80 parts by weight, fly ash is 2-30 parts by weight, crushed stone is 30-80 parts by weight, water is 8-60 parts by weight, and gasification slag is 10-40 parts by weight, relative to 100 parts by weight of natural sand. The composition of the gasification slag is 4-20 parts by weight, the content of coal gangue is 4-40 parts by weight, the content of polycarboxylate water-reducing component is 0.1-0.6 parts by weight, the content of lignosulfonate retarding component is 0.01-0.06 parts by weight, the content of thickening component is 0.01-0.06 parts by weight, the content of air-entraining component is 0.01-0.06 parts by weight, and the content of gasification slag activator is 2-10 parts by weight. The gasification slag activator contains miscellaneous salts, softened sludge, and desulfurized gypsum, and the weight ratio of miscellaneous salts, softened sludge, and desulfurized gypsum is (0.2-1):(0.5-2):1.

[0008] Preferably, relative to 100 parts by weight of natural sand, the content of 42.5R cement is 20-30 parts by weight, the content of fly ash is 2-5 parts by weight, the content of crushed stone is 30-40 parts by weight, the content of water is 8-12 parts by weight, the content of gasification slag is 10-15 parts by weight, the content of ground gasification slag is 4-6 parts by weight, the content of coal gangue is 4-6 parts by weight, the content of polycarboxylate superplasticizer is 0.1-0.2 parts by weight, the content of lignosulfonate retarder is 0.01-0.02 parts by weight, the content of thickening agent is 0.01-0.02 parts by weight, the content of air-entraining agent is 0.01-0.02 parts by weight, and the content of gasification slag activator is 2-3 parts by weight.

[0009] Preferably, the gasification slag is coarse gasification slag with residual carbon of less than 5 wt%.

[0010] Preferably, the ground gasification slag is prepared according to the following steps: the gasification coarse slag with less than 5% residual carbon is ball-milled and sieved, and the sieve residue rate is less than 5%, to obtain the ground gasification slag.

[0011] Preferably, the ball milling conditions include: a rotation speed of 30 to 60 rpm and a time of 10 to 30 hours.

[0012] Preferably, the sieving is performed using a 0.05-0.1 mm square hole sieve.

[0013] Preferably, the particle size of the coal gangue is 10-20 mm.

[0014] Preferably, the polycarboxylate superplasticizer is selected from at least one of polycarboxylate superplasticizer, slump-resistant superplasticizer, and high-density superplasticizer.

[0015] Preferably, the lignosulfonate retarder is selected from at least one of sodium lignosulfonate, calcium lignosulfonate, and magnesium lignosulfonate.

[0016] Preferably, the thickening component is selected from at least one of cellulose ether, xanthan gum, and redispersible latex powder.

[0017] Preferably, the air-entraining component is selected from at least one of sodium dodecylbenzenesulfonate, sodium α-olefin sulfonate, and water-soluble rosin resin.

[0018] Preferably, the gasification slag activator is prepared according to the following steps: the mixed salt, the softened sludge and the desulfurized gypsum are mixed and heated to 300-700°C at a heating rate of 1-5°C / min, held at the temperature for 30-150 min, then ball-milled and sieved, with a sieve residue rate of less than 10%, to obtain the gasification slag activator.

[0019] This invention uses solid waste generated during coal chemical production as raw material and utilizes various wastes to prepare activators for activating gasification slag and fly ash, enabling the large-scale utilization of coal chemical solid waste. The solid waste-based self-compacting concrete prepared by this invention has the characteristics of good fluidity, excellent pumpability, and low shrinkage, and can be used in flexible membrane support construction in coal mine tunnels. It has the advantages of not clogging pipes and being able to be cast in one go during construction. Detailed Implementation

[0020] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] The self-compacting concrete of this invention contains natural sand, 42.5R cement, fly ash, natural sand, crushed stone, water, gasification slag, ground gasification slag, coal gangue, polycarboxylate superplasticizer, lignosulfonate retarder, thickening agent, air-entraining agent, and gasification slag activator. Relative to 100 parts by weight of natural sand, the content of 42.5R cement is 20-80 parts by weight, the content of fly ash is 2-30 parts by weight, the content of crushed stone is 30-80 parts by weight, the content of water is 8-60 parts by weight, the content of gasification slag is 10-40 parts by weight, and the content of ground gasification slag is 4... The composition comprises 20 parts by weight of coal gangue, 4 to 40 parts by weight of polycarboxylate superplasticizer, 0.1 to 0.6 parts by weight of lignosulfonate retarder, 0.01 to 0.06 parts by weight of thickening agent, 0.01 to 0.06 parts by weight of air-entraining agent, and 2 to 10 parts by weight of gasification slag activator. The gasification slag activator contains miscellaneous salts, softened sludge, and desulfurized gypsum, and the weight ratio of miscellaneous salts, softened sludge, and desulfurized gypsum is (0.2 to 1): (0.5 to 2): 1.

[0023] In preferred embodiments, relative to 100 parts by weight of natural sand, the content of 42.5R cement is 20-30 parts by weight, fly ash is 2-5 parts by weight, crushed stone is 30-40 parts by weight, water is 8-12 parts by weight, gasification slag is 10-15 parts by weight, ground gasification slag is 4-6 parts by weight, coal gangue is 4-6 parts by weight, polycarboxylate superplasticizer is 0.1-0.2 parts by weight, lignosulfonate retarder is 0.01-0.02 parts by weight, thickening agent is 0.01-0.02 parts by weight, air-entraining agent is 0.01-0.02 parts by weight, and gasification slag activator is 2-3 parts by weight. In these preferred embodiments, when the content of each component in the self-compacting concrete is within the above ranges, the self-compacting concrete exhibits superior fluidity, drying shrinkage, and mechanical properties.

[0024] In this invention, the gasification slag can be coarse gasification slag with less than 5 wt% residual carbon.

[0025] In some embodiments, the ground gasification slag can be prepared by the following steps: ball milling coarse gasification slag with less than 5% residual carbon and sieving it, with a sieve residue of less than 5%, to obtain ground gasification slag. Preparing the ground gasification slag according to this embodiment helps to improve the activity of the gasification slag, thereby increasing the density and later-stage strength of self-compacting concrete.

[0026] In a preferred embodiment, the ball milling conditions include: a rotation speed of 30–60 rpm and a time of 10–30 h.

[0027] In a preferred embodiment, the sieving is performed using a 0.05-0.1 mm square hole sieve.

[0028] In this invention, the particle size of the coal gangue can be 10-20 mm. The coal gangue can be obtained by crushing it into small pieces using a crusher and then sieving it through a square-hole sieve. In this invention, when the particle size of the coal gangue is within the above range, the porosity of the self-compacting concrete can be effectively reduced and its compactness improved.

[0029] In this invention, the polycarboxylate superplasticizer can be at least one of a polycarboxylate high-efficiency superplasticizer, a slump-retaining superplasticizer, and a high-density superplasticizer. In this invention, when the polycarboxylate superplasticizer is one of the above types, it can effectively achieve the effects of water reduction, dispersion, and slump retention.

[0030] In this invention, the lignosulfonate retarding component can be at least one of sodium lignosulfonate, calcium lignosulfonate, and magnesium lignosulfonate. When the lignosulfonate retarding component is one of the above types, high water reduction performance, low slump loss, high strength, and retarding effect can be achieved.

[0031] In this invention, the thickening component can be at least one selected from cellulose ether, xanthan gum, and redispersible latex powder. In this invention, when the thickening component is of the above types, the bond strength and workability of the self-compacting concrete can be improved.

[0032] In this invention, the air-entraining component can be at least one of sodium dodecylbenzenesulfonate, sodium α-olefin sulfonate, and water-soluble rosin resin. In this invention, when the air-entraining component is of the above types, the freeze-thaw resistance, impermeability, and pumpability of the self-compacting concrete can be improved.

[0033] In some embodiments, the gasification slag activator can be prepared according to the following steps: mixing the mixed salts, the softened sludge, and the desulfurized gypsum, heating the mixture to 300-700°C at a heating rate of 1-5°C / min, holding the temperature at 30-150 min, then ball-milling and sieving, with a residue rate of less than 10%, to obtain the gasification slag activator. When the gasification slag activator is prepared according to this embodiment, it can improve the activity index of the gasification slag, increase early strength, and improve the resistance of self-compacting concrete to carbonation and sulfate attack.

[0034] The self-compacting concrete of the present invention will be further illustrated below through embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0035] Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods in the art.

[0036] Unless otherwise specified, all experimental materials used in the following examples are commercially available.

[0037] Example 1

[0038] Preparation of gasification slag activator:

[0039] (1) Take 20 parts by weight of miscellaneous salt, 40 parts by weight of softened sludge and 40 parts by weight of desulfurized gypsum, mix them and place them in a muffle furnace, raise the temperature to 300°C at a heating rate of 1°C / min, keep the temperature constant for 150 min and then let it cool naturally to room temperature, take out the sample and ball mill it in a ball mill, and then pass it through a 0.08 mm square hole sieve. The sieve residue rate is less than 10%, and the gasification slag activator is obtained.

[0040] Pretreatment of coal gangue:

[0041] (2) Use a jaw crusher to crush the coal gangue into small pieces, and use a square hole screen to screen the coal gangue in the range of 10-20mm.

[0042] Preparation of ground gasification slag:

[0043] (3) Grind the gasification slag with less than 5% residual carbon in a ball mill, and pass it through a 0.08 mm square hole sieve. The residue rate is less than 5%. Grind gasification slag is obtained.

[0044] Preparation of self-compacting concrete:

[0045] (4) Take 100 parts by weight of natural sand, 20 parts by weight of 42.5R cement, 2 parts by weight of fly ash, 30 parts by weight of crushed stone, 8 parts by weight of water, 10 parts by weight of gasification slag, 4 parts by weight of the ground gasification slag prepared in step (3), 4 parts by weight of the coal gangue obtained in step (2), 0.1 parts by weight of polycarboxylate superplasticizer, 0.01 parts by weight of lignosulfonate retarder, 0.01 parts by weight of thickening agent, 0.01 parts by weight of air-entraining agent, and 2 parts by weight of gasification slag activator prepared in step (1) and mix them together to prepare self-compacting concrete.

[0046] Example 2

[0047] Preparation of gasification slag activator:

[0048] (1) Take 20 parts by weight of miscellaneous salt, 80 parts by weight of softened sludge and 80 parts by weight of desulfurized gypsum, mix them and place them in a muffle furnace. Heat the mixture to 700°C at a heating rate of 5°C / min, keep it at a constant temperature for 30 minutes and then let it cool naturally to room temperature. Take out the sample and ball mill it in a ball mill. Then pass it through a 0.08 mm square hole sieve. The sieve residue rate is less than 10%, and the gasification slag activator is obtained.

[0049] Pretreatment of coal gangue:

[0050] (2) Use a jaw crusher to crush the coal gangue into small pieces, and use a square hole screen to screen the coal gangue in the range of 10-20mm.

[0051] Preparation of ground gasification slag:

[0052] (3) Grind the gasification slag with less than 5% residual carbon in a ball mill, and pass it through a 0.08 mm square hole sieve. The residue rate is less than 5%. Grind gasification slag is obtained.

[0053] Preparation of self-compacting concrete:

[0054] (4) Take 100 parts by weight of natural sand, 80 parts by weight of 42.5R cement, 30 parts by weight of fly ash, 80 parts by weight of crushed stone, 60 parts by weight of water, 40 parts by weight of gasification slag, 20 parts by weight of the ground gasification slag prepared in step (3), 40 parts by weight of coal gangue obtained in step (2), 0.6 parts by weight of polycarboxylate superplasticizer, 0.06 parts by weight of lignosulfonate retarder, 0.06 parts by weight of thickening agent, 0.06 parts by weight of air-entraining agent, and 10 parts by weight of gasification slag activator prepared in step (1) and mix them together to prepare self-compacting concrete.

[0055] Example 3

[0056] Preparation of gasification slag activator:

[0057] (1) Take 40 parts by weight of miscellaneous salt, 40 parts by weight of softened sludge and 40 parts by weight of desulfurized gypsum, mix them and place them in a muffle furnace, raise the temperature to 500°C at a heating rate of 3°C / min, keep the temperature constant for 100 min and then let it cool naturally to room temperature, take out the sample and ball mill it in a ball mill, and then pass it through a 0.08 mm square hole sieve. The sieve residue rate is less than 10%, and the gasification slag activator is obtained.

[0058] Pretreatment of coal gangue:

[0059] (2) Use a jaw crusher to crush the coal gangue into small pieces, and use a square hole screen to screen the coal gangue in the range of 10-20mm.

[0060] Preparation of ground gasification slag:

[0061] (3) Grind the gasification slag with less than 5% residual carbon in a ball mill, and pass it through a 0.08 mm square hole sieve. The residue rate is less than 5%. Grind gasification slag is obtained.

[0062] Preparation of self-compacting concrete:

[0063] (4) Take 100 parts by weight of natural sand, 60 parts by weight of 42.5R cement, 20 parts by weight of fly ash, 60 parts by weight of crushed stone, 40 parts by weight of water, 30 parts by weight of gasification slag, 15 parts by weight of the ground gasification slag prepared in step (3), 30 parts by weight of coal gangue obtained in step (2), 0.4 parts by weight of polycarboxylate superplasticizer, 0.04 parts by weight of lignosulfonate retarder, 0.04 parts by weight of thickening agent, 0.04 parts by weight of air-entraining agent, and 5 parts by weight of gasification slag activator prepared in step (1) and mix them together to prepare self-compacting concrete.

[0064] Example 4

[0065] This embodiment is implemented according to the method described in Embodiment 1, except that in step (1), after the mixture is placed in a muffle furnace, it is heated to 900°C at a heating rate of 10°C / min.

[0066] Example 5

[0067] This embodiment is implemented according to the method described in Embodiment 1. The difference is that in step (1), after the mixture is placed in a muffle furnace, it is heated to 300°C at a heating rate of 1°C / min, held at the temperature for 20 minutes, and then naturally cooled to room temperature.

[0068] Comparative Example 1

[0069] This comparative example was carried out according to the method described in Example 1, except that no mixed salts were added in step (1).

[0070] Comparative Example 2

[0071] This comparative example is carried out according to the method described in Example 1, except that softened sludge is not added in step (1).

[0072] Comparative Example 3

[0073] This comparative example is carried out according to the method described in Example 1, except that in step (1), the amount of the mixed salt is 20 parts by weight, the amount of the softened sludge is 40 parts by weight, and the amount of the desulfurized gypsum is 10 parts by weight.

[0074] Comparative Example 4

[0075] This comparative example is carried out according to the method described in Example 1, except that no gasification slag activator is added in step (4).

[0076] Comparative Example 5

[0077] This comparative example is implemented according to the method described in Example 1, except that in step (4), the amount of 42.5R cement is 10 parts by weight, the amount of fly ash is 1 part by weight, the amount of crushed stone is 20 parts by weight, the amount of water is 5 parts by weight, the amount of gasification slag is 5 parts by weight, the amount of ground gasification slag is 1 part by weight, the amount of coal gangue is 1 part by weight, the amount of polycarboxylate superplasticizer is 0.05 parts by weight, the amount of lignosulfonate retarder is 0.005 parts by weight, the amount of thickening agent is 0.005 parts by weight, the amount of air-entraining agent is 0.005 parts by weight, and the amount of gasification slag activator is 1 part by weight.

[0078] Comparative Example 6

[0079] This comparative example is implemented according to the method described in Example 1, except that in step (4), the amount of 42.5R cement is 90 parts by weight, the amount of fly ash is 40 parts by weight, the amount of crushed stone is 90 parts by weight, the amount of water is 80 parts by weight, the amount of gasification slag is 50 parts by weight, the amount of ground gasification slag is 30 parts by weight, the amount of coal gangue is 50 parts by weight, the amount of polycarboxylate superplasticizer is 1 part by weight, the amount of lignosulfonate retarder is 0.1 parts by weight, the amount of thickening agent is 0.1 parts by weight, the amount of air-entraining agent is 0.1 parts by weight, and the amount of gasification slag activator is 20 parts by weight.

[0080] Test Example 1

[0081] This test example examines the flowability, drying shrinkage, compressive strength, and bond strength of the self-compacting concrete prepared in Examples 1-5 and Comparative Examples 1-6. Specifically, the spread was tested according to JGJ / T 283-2012 "Technical Specification for Application of Self-Compacting Concrete," the shrinkage rate was tested according to GB / T 50082-2024 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete," and the strength was tested according to GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete."

[0082] The results are shown in Table 1.

[0083] Table 1

[0084]

[0085] As shown in Table 1, the self-compacting concrete prepared by the method described in this invention has excellent properties such as large solid waste content, low cost, good fluidity, and low drying shrinkage, which meets the construction requirements of self-compacting concrete.

[0086] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A self-compacting concrete, characterized in that, This self-compacting concrete contains natural sand, 42.5R cement, fly ash, crushed stone, water, gasification slag, ground gasification slag, coal gangue, polycarboxylate superplasticizer, lignosulfonate retarder, thickening agent, air-entraining agent, and gasification slag activator. Relative to 100 parts by weight of natural sand, the content of 42.5R cement is 20–80 parts by weight, fly ash is 2–30 parts by weight, crushed stone is 30–80 parts by weight, water is 8–60 parts by weight, gasification slag is 10–40 parts by weight, and ground gasification slag is 4–20 parts by weight. The composition comprises 0 parts by weight, 4-40 parts by weight of coal gangue, 0.1-0.6 parts by weight of polycarboxylate superplasticizer, 0.01-0.06 parts by weight of lignosulfonate retarder, 0.01-0.06 parts by weight of thickening agent, 0.01-0.06 parts by weight of air-entraining agent, and 2-10 parts by weight of gasification slag activator. The gasification slag activator contains miscellaneous salts, softened sludge, and desulfurized gypsum, and the weight ratio of miscellaneous salts, softened sludge, and desulfurized gypsum is (0.2-1):(0.5-2):

1.

2. The self-compacting concrete according to claim 1, characterized in that, Relative to 100 parts by weight of natural sand, the content of 42.5R cement is 20-30 parts by weight, the content of fly ash is 2-5 parts by weight, the content of crushed stone is 30-40 parts by weight, the content of water is 8-12 parts by weight, the content of gasification slag is 10-15 parts by weight, the content of ground gasification slag is 4-6 parts by weight, the content of coal gangue is 4-6 parts by weight, the content of polycarboxylate superplasticizer is 0.1-0.2 parts by weight, the content of lignosulfonate retarder is 0.01-0.02 parts by weight, the content of thickening agent is 0.01-0.02 parts by weight, the content of air-entraining agent is 0.01-0.02 parts by weight, and the content of gasification slag activator is 2-3 parts by weight.

3. The self-compacting concrete according to claim 1 or 2, characterized in that, The gasification slag is coarse gasification slag with a residual carbon content of less than 5 wt%.

4. The self-compacting concrete according to claim 1 or 2, characterized in that, The ground gasification slag is prepared according to the following steps: the gasification coarse slag with less than 5% residual carbon is ball-milled and sieved, and the sieve residue rate is less than 5%, to obtain the ground gasification slag. Preferably, the ball milling conditions include: a rotation speed of 30–60 rpm and a time of 10–30 min; Preferably, the sieving is performed using a 0.05-0.1 mm square hole sieve.

5. The self-compacting concrete according to claim 1 or 2, characterized in that, The particle size of the coal gangue is 10-20 mm.

6. The self-compacting concrete according to claim 1 or 2, characterized in that, The polycarboxylate superplasticizer is selected from at least one of polycarboxylate superplasticizer, slump-resistant superplasticizer, and high-density superplasticizer.

7. The self-compacting concrete according to claim 1 or 2, characterized in that, The lignosulfonate retarding component is selected from at least one of sodium lignosulfonate, calcium lignosulfonate, and magnesium lignosulfonate.

8. The self-compacting concrete according to claim 1 or 2, characterized in that, The thickening component is selected from at least one of cellulose ether, xanthan gum, and redispersible latex powder.

9. The self-compacting concrete according to claim 1 or 2, characterized in that, The air-entraining component is selected from at least one of sodium dodecylbenzenesulfonate, sodium α-olefin sulfonate, and water-soluble rosin resin.

10. The self-compacting concrete according to claim 1 or 2, characterized in that, The gasification slag activator is prepared according to the following steps: the mixed salt, the softened sludge and the desulfurized gypsum are mixed and heated to 300-700°C at a heating rate of 1-5°C / min, held at the temperature for 30-150 min, then ball-milled and sieved, with a sieve residue rate of less than 10%, to obtain the gasification slag activator.

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