Coal gangue coarse aggregate pumping concrete and preparation method thereof

Abstract

The present application relates to the technical field of building materials, and specifically discloses a kind of gangue coarse aggregate pumping concrete and its preparation method. A kind of gangue coarse aggregate pumping concrete, including the following mass percentage ratio raw materials: gangue wrapping material 60%-75%, cement 8%-20%, admixture 5%-10%, admixture 2.0%-4.0%, water 4.0%-8%, the sum of the mass percentages of the above raw materials is 100%. The gangue wrapping material includes: gangue coarse aggregate 25%-45%, gangue fine aggregate 30%-50%, sodium polyacrylate solution 2.7%-6.7%, admixture 0.6%-1.3%, the remainder is water, and the sum of the mass percentages of the above gangue wrapping material components is 100%. The composition of the present application can realize the resource utilization of gangue, effectively alleviate the supply pressure of natural aggregate, and it has the advantages of good fluidity and high strength.

Description

Technical Field

[0001] The present application relates to the technical field of building materials, and more specifically, to a gangue coarse aggregate pumping concrete and a preparation method thereof. Background Art

[0002] With the rapid development of the economy, the scale of my country's infrastructure continues to expand. The preparation of concrete requires the consumption of large quantities of non-renewable natural sand and gravel. The uncontrolled use of these materials has gradually highlighted the problem of my country's shortage of natural aggregates. Gangue is a solid waste that is mixed into coal seams during the mining and washing process. It has a low carbon content and is harder than coal. With the continuous exploitation of mineral resources, the output of gangue continues to increase. Coupled with the low efficiency of gangue recovery, the land area occupied by gangue mountains is increasing day by day, resulting in a significant waste of my country's land resources. Furthermore, open-air dumping can cause serious pollution to the water and soil around the mining areas. Taking advantage of the rock properties of gangue and using it as coarse aggregate to prepare concrete not only helps to realize the resource utilization of gangue but also effectively alleviates the pressure on the supply of natural aggregate.

[0003] However, in practice, the use of gangue as an aggregate in concrete production presents some challenges. Due to its high hardness, porous and rough surface, and high coefficient of friction with the mortar, the concrete slurry encounters significant resistance during mixing and transportation, ultimately reducing the fluidity of the concrete slurry and hindering its widespread use in concrete. Summary of the Invention

[0004] In order to improve the fluidity of concrete slurry when coal gangue is used as aggregate, the present application provides a coal gangue coarse aggregate pumping concrete and a preparation method thereof.

[0005] In a first aspect, the present application provides a gangue coarse aggregate pumping concrete, which adopts the following technical solution:

[0006] A gangue coarse aggregate pumping concrete comprises the following raw materials in percentage by mass:

[0007] The gangue coating material comprises 60%-75%, cement 8%-20%, admixture 5%-10%, admixture 2.0%-4.0%, and water 4.0%-8%, the total weight percentage of the above raw materials being 100%. The gangue coating material comprises: 25%-45% gangue coarse aggregate, 30%-50% gangue fine aggregate, 2.7%-6.7% sodium polyacrylate, 0.6%-1.3% admixture, and the balance being water, the total weight percentage of the above components being 100%. The sodium polyacrylate solution is prepared by mixing sodium acrylate, butyl acrylate, potassium persulfate, triethanolamine, and water, wherein the weight ratio of sodium acrylate, butyl acrylate, potassium persulfate, triethanolamine, and water is (15-20):6:1:1:100.

[0008] By adopting the above technical solution, a large amount of coal gangue is used as coarse aggregate, replacing a portion of cement and sand and gravel, easing the supply pressure of natural aggregate. The main components of coal gangue, silicates and aluminates, react with cement to form calcium silicate and calcium aluminate with high strength and durability. Furthermore, by controlling the ratio of coarse and fine aggregates in coal gangue and adding certain admixtures, the fluidity of coal gangue concrete slurry is improved. Pre-forming coal gangue into a coating material not only makes the aggregate surface smoother, reduces friction and inter-ionic interaction, and increases the fluidity of the resulting concrete slurry, but also makes the aggregate surface more dense, reduces the porosity and defects of the coal gangue itself, and improves the strength of concrete made from coal gangue. The coating material is then mixed with other components in the concrete, making the aggregate more evenly distributed in the concrete, and the interface between it and other components more solid, thereby improving the compressive strength of the concrete.

[0009] As part of the gangue coating material, the sodium polyacrylate solution carries a negative charge on the sodium polyacrylate molecules, while the charge on the surface of the cement particles is positive. The positive and negative charges attract each other, forming a double layer effect. The polymer molecular chains are anchored on the surface of the cement particles and extend into the aqueous solution. The molecular chains are intertwined and crossed with each other, causing steric hindrance, thereby preventing the particles from approaching each other, forming steric hindrance, and further helping to improve the fluidity of the concrete. At the same time, they are wrapped around the outside of the gangue particles to help disperse the gangue particles, fill the gaps on the surface of the gangue, improve the density of the concrete, and thus improve the strength of the concrete.

[0010] Optionally, the loose bulk density of the gangue coarse aggregate is 1100-1500 kg / m 3 , with a continuous gradation of 5-25mm and a crushing value of 10.0%; the apparent density of fine aggregate is 1400-1800kg / m 3 , with a continuous gradation of 0-4.75mm.

[0011] By adopting the above technical solution, the performance indicators of coal gangue aggregate affect the compressive strength of the final concrete, and the density and particle size of the coarse and fine aggregates of coal gangue are controlled so that the coarse and fine aggregates are graded within a reasonable range. Good gradation can not only reduce segregation, improve the workability of the slurry mixture, reduce the friction between the coarse aggregates, and improve the fluidity of the concrete slurry, but also increase the interlocking ability between the coarse and fine aggregates, enhance the internal structure of the concrete, and enable the prepared concrete to have higher compressive strength when subjected to external loads.

[0012] Optionally, the admixture is a mixture of one or more of fly ash, limestone powder, silica fume, microbeads, mineral powder, metakaolin, rice husk ash, and glass powder.

[0013] By adopting the above technical solution, the admixture has a smaller particle size and can fill the pores between the aggregate particles. On the one hand, it increases the density of the concrete and improves the strength of the concrete. On the other hand, it can reduce the internal friction between the aggregates, thereby improving the fluidity of the concrete slurry. At the same time, the addition of admixtures can replace part of the cement and reduce the hydration heat of the cement. Preferably, the specific surface area of ​​the fly ash is 300-500m 2 / kg, with a loss on ignition of no more than 2%; the CaCO3 content of limestone powder is greater than 85%; the average particle size of rice husk ash is 0.1-3μm, with a loss on ignition of 10-30%; the average particle size of glass powder is 1-5μm, and it is a white transparent powder; the specific surface area of ​​silica fume is 1800-2000m 2 / kg, loss on ignition is 2-4%; microbead specific surface area is 2200-2500m 2 / kg, activity index>100%; the slag powder used is S95 grade slag powder with a specific surface area of ​​400-450m 2 / kg.

[0014] Optionally, the gangue wrapping material is prepared by the following steps:

[0015] (1) Pre-wet the coarse and fine aggregates of coal gangue by sprinkling or spraying them at least 12 hours in advance, and gently turn the coal gangue aggregates over during the pre-wetting process;

[0016] (2) After the pre-wetted gangue aggregate is graded, sodium polyacrylate solution and admixture are added and mixed to obtain gangue coating material.

[0017] By adopting the above technical solution, coal gangue is lightweight and porous, with a high water absorption rate. Directly adding it will reduce the fluidity of the concrete mixture and increase the loss of fluidity over time. Therefore, the coal gangue must be pre-treated at least 12 hours in advance. After it is saturated with water, it is mixed with the sodium polyacrylate solution and admixtures. The sodium polyacrylate polymer and admixtures wrap the coal gangue aggregate, which improves the compatibility of the coal gangue with other raw materials in the concrete, avoids reducing the strength of the interface bonding area, and improves the strength of the concrete. The moisture absorbed by the coal gangue can be released again when the humidity inside the concrete is insufficient in the later stage, playing a role in internal curing and further improving the strength of the concrete.

[0018] Optionally, the admixture consists of 5-14% of water reducing agent, 4-10% of slump retaining agent, 0.5-5% of retarder, 0.5-2% of viscosity modifier, 0-0.03% of air entraining agent, 0-0.03% of defoaming agent and 70-85% of water.

[0019] By adopting the above technical solution, a multi-component concrete admixture exhibits excellent properties, helping to improve the fluidity of concrete slurry, enhance concrete strength, and achieve optimal concrete performance. The water reducer and slump retainer can adsorb onto the surface of concrete aggregate to form a film, reducing water surface tension, improving concrete fluidity, and preventing slump. The retarder and viscosity modifier can extend the initial and final setting times of concrete, facilitating its transportation and placement, while also reducing slump loss and improving concrete pumpability.

[0020] Optionally, the water reducer is a polycarboxylate water reducer.

[0021] By adopting the above technical solution, the water released from the water reducer and coal gangue is used to maintain the later strength of the concrete. The polycarboxylate water reducer's dispersion effect on fine particles enables more complete cement hydration and more uniform distribution. The microstructure of the hardened concrete is improved, the grid structure is denser, and the slump loss of the concrete is prevented without causing obvious retarding of setting. The fluidity of the concrete slurry is ensured, and the later strength of the concrete is improved.

[0022] Optionally, the collapse-preserving agent is sodium gluconate.

[0023] By adopting the above technical solution, sodium gluconate can significantly improve the later strength of concrete compared with other slump retaining agents, and the selection of sodium gluconate as a slump retaining agent has good compatibility with the system composed of coal gangue, cement and admixtures, which can improve the reinforcement effect of concrete, enhance the auxiliary plasticizing effect of the water reducer, and further improve the fluidity of the slurry.

[0024] In a second aspect, the present application provides a method for preparing coal gangue coarse aggregate pumping concrete, which adopts the following technical solution:

[0025] A method for preparing coal gangue coarse aggregate pumping concrete comprises the following steps:

[0026] Cement, admixture, water and additives are sequentially added to the gangue wrapping material and stirred for at least 120 seconds to obtain a uniform mixture, that is, the gangue coarse aggregate pumping concrete.

[0027] By adopting the above technical solution, the wrapping material made from the coarse and fine aggregates of coal gangue is stirred with other raw materials in the concrete for at least 120 seconds to fully mix the components. The transportation time is controlled within 2 hours. After arriving at the site, the pump pipe should be wetted with a special pumping lubricant, and samples should be taken to measure the setting time, slump value and expansion value of the on-site concrete at the same time. After confirming that the pumping conditions are met, continuous pouring should be carried out, and the pouring of the same construction site should be completed at one time.

[0028] In summary, this application has the following beneficial effects:

[0029] 1. Since this application uses coal gangue as the main component of concrete, the supply pressure of natural aggregate is alleviated. By controlling the addition ratio of coarse and fine coal gangue aggregates and combining them with other raw materials, the fluidity of the coal gangue concrete slurry is improved. The coal gangue aggregates are pre-made into wrapping materials to reduce the natural defects of the coal gangue aggregates, further reduce the friction between the aggregates, and increase the fluidity of the concrete slurry.

[0030] 2. In this application, a composite formula admixture is preferably used. The mutual coordination of the components in the admixture helps to improve the fluidity of the concrete, is beneficial to the transportation and pouring of the concrete, improves the internal microstructure of the concrete, ensures that the concrete slurry has good fluidity in the initial stage, and helps to enhance the later strength of the concrete in the later stage.

[0031] 3. This application involves coating the surface of coal gangue with calcium polyacrylate polymer and polymerizing it with cement. The sodium acrylate solution undergoes an addition polymerization reaction under the free radicals released by the initiator to generate a linear polymer, which is then bonded and cross-linked into a network structure under the bridging action of the cross-linking agent. On the one hand, this fills the gaps on the surface of the coal gangue and enhances the density of the concrete. On the other hand, it helps improve the compatibility of the coal gangue with other raw materials in the concrete and enhances the strength of the concrete. DETAILED DESCRIPTION

[0032] The present application is further described in detail below with reference to the embodiments.

[0033] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0034] Viscosity modifier was purchased from Nanjing Chuhai New Material Technology Co., Ltd., RH-420; polycarboxylate water reducer was purchased from Shanghai Kaiyin Chemical, brand RHEOPLUS412; naphthalene water reducer was purchased from Shenyang Xingzhenghe Chemical Co., Ltd., SNF-A; the loose bulk density of the coal gangue coarse aggregate selected in this application was 1100-1500 kg / m 3 , with a continuous gradation of 5-25mm and a crushing value of 10.0%; the apparent density of fine aggregate is 1400-1800kg / m 3 , with a continuous gradation of 0-4.75mm.

[0035] Preparation example of admixture

[0036] Preparation Example 1

[0037] An admixture comprising the following components:

[0038] 5% polycarboxylate water-reducing agent, 10% sodium gluconate (slump-preventing agent), 5% boric acid (retarder), 0.5% viscosity modifier, 0.03% sodium alkylbenzene sulfonate (air-entraining agent), 0.03% aluminum silicate (defoaming agent), and 79.44% water are used to prepare 10 kg of admixture, which is obtained by taking the above-mentioned mass percentage components and stirring and mixing them.

[0039] Preparation Example 2

[0040] An admixture comprising the following components:

[0041] 10 kg of admixture is prepared by mixing 14% polycarboxylate water reducer, 4% sodium gluconate (slump retaining agent), 0.5% boric acid (retarder), 2% viscosity modifier and 79.5% water. The mixture is stirred and evenly mixed.

[0042] Preparation Example 3

[0043] An admixture comprising the following components:

[0044] 10 kg of admixture is prepared by mixing 14% naphthalene-based water reducer, 4% sodium gluconate (slump retaining agent), 0.5% boric acid (retarder), 2% viscosity modifier, and 79.5% water. The mixture is stirred and evenly mixed.

[0045] Preparation Example 4

[0046] An admixture comprising the following components:

[0047] 10 kg of admixture is prepared by mixing 14% polycarboxylate water-reducing agent, 4% sodium hexametaphosphate (slump-retaining agent), 0.5% boric acid (retarder), 2% viscosity modifier and 79.5% water. The mixture is stirred and evenly mixed with the above-mentioned components in the above-mentioned mass percentages.

[0048] Preparation Example of Sodium Polyacrylate Solution

[0049] Preparation Example 5

[0050] A sodium polyacrylate solution, the preparation of which comprises the following steps:

[0051] 7.5 kg of sodium acrylate was dissolved in 50 kg of water, and 3 kg of butyl acrylate, 0.5 kg of potassium persulfate and 0.5 kg of triethanolamine were added in sequence and stirred evenly to prepare a sodium polyacrylate solution.

[0052] Preparation Example 6

[0053] A sodium polyacrylate solution, the preparation of which comprises the following steps:

[0054] 10 kg of sodium acrylate was dissolved in 50 kg of water, and 3 kg of butyl acrylate, 0.5 kg of potassium persulfate and 0.5 kg of triethanolamine were added in sequence and stirred evenly to prepare a sodium polyacrylate solution.

[0055] Example

[0056] Example 1

[0057] A method for preparing coal gangue coarse aggregate pumping concrete comprises the following steps:

[0058] Step 1: Preparation of coal gangue wrapping material:

[0059] (1) Take 15 kg of gangue coarse aggregate and 30 kg of gangue fine aggregate and sprinkle or spray them 12 hours in advance to pre-wet them. During the pre-wetting process, turn the gangue aggregate over gently to ensure the uniformity of the aggregate pre-wetting.

[0060] (2) After the pre-wetted gangue aggregate is graded, 4.02 kg of the sodium polyacrylate solution prepared in Preparation Example 5, 0.36 kg of the admixture prepared in Preparation Example 1, and 10.62 kg of tap water are added and mixed to obtain a gangue coating material;

[0061] Step 2: Add 20kg of cement, 10kg of fly ash, 8kg of water and 2kg of admixture into the gangue wrapping material in sequence and stir and mix them for at least 120s to obtain a uniform mixture, namely the gangue coarse aggregate pumping concrete.

[0062] Example 2

[0063] A method for preparing coal gangue coarse aggregate pumping concrete comprises the following steps:

[0064] Step 1: Preparation of coal gangue wrapping material:

[0065] (1) Take 27 kg of gangue coarse aggregate and 18 kg of gangue fine aggregate and sprinkle or spray them 12 hours in advance to pre-wet them. During the pre-wetting process, gently turn the gangue aggregate over to ensure the uniformity of the aggregate pre-wetting.

[0066] (2) After the pre-wetted gangue aggregate is graded, 2.82 kg of the sodium polyacrylate solution prepared in Preparation Example 5, 0.78 kg of the admixture prepared in Preparation Example 1, and 11.4 kg of tap water are added and mixed to obtain a gangue coating material;

[0067] Step 2: Add 20kg of cement, 10kg of fly ash, 8kg of water and 2kg of admixture into the gangue wrapping material in sequence and stir and mix them for at least 120s to obtain a uniform mixture, namely the gangue coarse aggregate pumping concrete.

[0068] Example 3

[0069] A method for preparing coal gangue coarse aggregate pumping concrete comprises the following steps:

[0070] Step 1: Preparation of coal gangue wrapping material:

[0071] (1) Take 21kg of gangue coarse aggregate and 24kg of gangue fine aggregate and sprinkle or spray them 12 hours in advance to pre-wet them. During the pre-wetting process, gently turn the gangue aggregate over to ensure the uniformity of the aggregate pre-wetting.

[0072] (2) After the pre-wetted gangue aggregate is graded, 1.62 kg of the sodium polyacrylate solution prepared in Preparation Example 6, 0.54 kg of the admixture prepared in Preparation Example 1, and 12.84 kg of tap water are added and mixed to obtain a gangue coating material;

[0073] Step 2: Add 20kg of cement, 10kg of fly ash, 8kg of water and 2kg of admixture into the gangue wrapping material in sequence and stir and mix them for at least 120s to obtain a uniform mixture, namely the gangue coarse aggregate pumping concrete.

[0074] Examples 4-5

[0075] A gangue coarse aggregate pumping concrete is different from Example 2 in that the mass percentages of the raw materials are as shown in Table 1, and 100 kg of the gangue coarse aggregate pumping concrete is prepared.

[0076] Examples 1-3 Example 4 Example 5 Gangue wrapping material 60％ 68％ 75％ cement 20％ 16％ 8％ admixtures 10％ 8％ 5％ admixtures 2％ 3％ 4％ water 8％ 5％ 8％

[0077] Example 6

[0078] A coal gangue coarse aggregate pumping concrete is different from Example 2 in that the admixture used in this example is prepared in Preparation Example 2.

[0079] Example 7

[0080] A coal gangue coarse aggregate pumping concrete is different from Example 2 in that the admixture used in this example is prepared in Preparation Example 3.

[0081] Example 8

[0082] A coal gangue coarse aggregate pumping concrete is different from Example 2 in that the admixture used in this example is prepared in Preparation Example 4.

[0083] Example 9

[0084] A method for preparing coal gangue coarse aggregate pumping concrete comprises the following steps:

[0085] Step 1: Preparation of a gangue coating material: After the gangue aggregate is graded, 2.82 kg of the sodium polyacrylate solution prepared in Preparation Example 5, 0.78 kg of the admixture prepared in Preparation Example 1, and 11.4 kg of tap water are added and mixed to obtain a gangue coating material;

[0086] Step 2: Add 20kg of cement, 10kg of fly ash, 8kg of water and 2kg of admixture into the gangue wrapping material in sequence and stir and mix them for at least 120s to obtain a uniform mixture, namely the gangue coarse aggregate pumping concrete.

[0087] Comparative Example

[0088] Comparative Example 1

[0089] A gangue coarse aggregate pumping concrete is prepared by: taking 27 kg of gangue coarse aggregate and 18 kg of gangue fine aggregate, sprinkling or spraying them 12 hours in advance to pre-wet them, and gently turning the gangue aggregates continuously during the pre-wetting process to ensure the uniformity of the aggregate pre-wetting; after the pre-wetted gangue aggregates are graded, adding 22.82 kg of cement, 10 kg of fly ash, 19.4 kg of water and 2.78 kg of admixture, and stirring and mixing them; stirring for at least 120 seconds to obtain a uniform mixture, namely, the gangue coarse aggregate pumping concrete.

[0090] Performance testing

[0091] Detection method / test method

[0092] According to GB50080-2016 "Standard for Test Methods of Performance of Ordinary Concrete Mixtures", the apparent density and field expansion of concrete are tested (the greater the expansion, the better the fluidity of the concrete);

[0093] The compressive strength of concrete is tested according to GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete".

[0094] Table 2 Performance test results

[0095]

[0096]

[0097] Combining Examples 1-5 and Comparative Example 1 and Table 2, it can be seen that the experimental data of Examples 1-5 are all better than those of Comparative Example 1, indicating that pre-preparing the gangue aggregate into a coating material and then mixing it with other components in concrete is more conducive to mixing the components. The prepared coating material is added to the concrete not only to make the surface of the gangue aggregate smoother, reduce friction and inter-ionic interaction, increase the fluidity of the concrete slurry, but also reduce the pores and defects in the gangue. The gangue aggregate after being coated with the sodium polyacrylate solution and the admixture has good compatibility with other components in the concrete, avoids the reduction of the strength of the interface bonding area, and improves the strength and fluidity of the concrete.

[0098] Comparing Example 2 with Examples 6-8 and Table 2, it can be seen that all experimental data for Example 2 are superior to those for Examples 6-8, indicating that the composition of the admixture affects the ultimate performance of concrete. The choice of polycarboxylate superplasticizer can better coordinate with other components in gangue concrete, maintaining the concrete's initial and later strengths. Polycarboxylate superplasticizers not only help the concrete distribute more evenly in the early stages, improving fluidity, but also improve the concrete's microstructure in the later stages, making the concrete grid structure denser and increasing the concrete's later strength.

[0099] Combining Example 2 with Example 9 and Table 2, it can be seen that the experimental data of Example 2 are all better than those of Example 9, indicating that pre-wetting the gangue aggregate in advance is not only beneficial to improving the fluidity of the concrete, but also can release the moisture contained in it again when the humidity inside the concrete is insufficient in the later stage, playing the role of internal curing, thereby improving the later strength of the concrete.

[0100] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A coal gangue coarse aggregate pumping concrete, characterized in that: The raw materials include the following mass percentages: Gangue coating material 60%-75%, cement 8%-20%, admixture 5%-10%, admixture 2.0%-4.0%, water 4.0%-8%, the sum of the mass percentages of the above raw materials is 100%; the gangue coating material comprises: gangue coarse aggregate 25%-45%, gangue fine aggregate 30%-50%, sodium polyacrylate solution 2.7%-6.7%, admixture 0.6%-1.3%, the balance is water, the sum of the mass percentages of the components of the gangue coating material is 100%; the sodium polyacrylate solution is prepared by mixing sodium acrylate, butyl acrylate, potassium persulfate, triethanolamine and water, wherein the weight ratio of sodium acrylate, butyl acrylate, potassium persulfate, triethanolamine and water is (15-20): 6:1:1:100; The gangue coating material is prepared by the following steps: (1) Pre-wet the coarse and fine aggregates of coal gangue by sprinkling or spraying at least 12 hours in advance, and gently turn the coal gangue aggregates over during the pre-wetting process; (2) After the pre-wetted gangue aggregate is graded, the sodium polyacrylate solution and the admixture are added and mixed to obtain the gangue coating material.

2. The coal gangue coarse aggregate pumping concrete according to claim 1, characterized in that: The loose bulk density of the gangue coarse aggregate is 1100-1500kg / m 3 , 5-25mm continuous grading, crushing value 10.0%; fine aggregate apparent density is 1400-1800kg / m 3 , with a continuous gradation of 0-4.75mm.

3. The coal gangue coarse aggregate pumping concrete according to claim 1, characterized in that: The admixture is a mixture of one or more of fly ash, limestone powder, silica fume, micro beads, mineral powder, metakaolin, rice husk ash and glass powder.

4. The coal gangue coarse aggregate pumping concrete according to claim 1, characterized in that: The admixture consists of 5-14% of water reducing agent, 4-10% of slump retaining agent, 0.5-5% of retarder, 0.5-2% of viscosity modifier, 0-0.03% of air entraining agent, 0-0.03% of defoaming agent and 70-85% of water.

5. The coal gangue coarse aggregate pumping concrete according to claim 4, characterized in that: The water reducer is a polycarboxylate water reducer.

6. The gangue coarse aggregate pumping concrete according to claim 4, characterized in that: The collapse-preserving agent is sodium gluconate.

7. A method for preparing the gangue coarse aggregate pumping concrete according to any one of claims 1 to 6, comprising the following steps: The cement, admixture, water and additive are sequentially added into the gangue wrapping material and stirred and mixed, and the mixture is stirred for at least 120 seconds to obtain a uniform mixture, that is, the gangue coarse aggregate pumping concrete.

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