A solid waste-based low-carbon cement concrete high slump-retention water-reducing agent and its application

Abstract

The invention discloses a high-slump-retaining water-reducing agent for solid waste-based low-carbon cement concrete and its application. The high-slump-retaining water-reducing agent is obtained by adding 20-35 parts of high-performance superplasticizer, 25-50 parts of super-slump-retaining agent, 10-15 parts of hydrophobic agent, 2-6 parts of slurry-lifting agent, 0-1 parts of softener, and 110-140 parts of water to a stirred reactor in sequence and stirring evenly. The present invention takes improving the workability and workability of solid waste-based low-carbon cement concrete as a starting point, analyzes the core key points of the disease generation, such as small concrete particle size, large specific surface area, porous, strong water absorption, high adsorption, etc., and designs a high-slump-retaining water-reducing agent that can improve the above-mentioned problems of solid waste-based low-carbon cement concrete. The high-slump-retaining water-reducing agent has easy-to-obtain raw materials, reasonable formula, and easy processing, and can realize the resource utilization of solid waste-based low-carbon cement in concrete.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete admixtures, and in particular to a high slump-retention water-reducing agent for solid waste-based low-carbon cement concrete. The present invention also relates to application of the high slump-retention water-reducing agent in solid waste-based low-carbon cement concrete. Background Art

[0002] In the process of rapid development of industry and infrastructure construction, a large amount of solid waste has been generated, such as fly ash from coal-fired power plants, desulfurized gypsum, and slag, steel slag, tailings slag, and stone dust from steel plants. These solid wastes have been extensively studied and applied in cement and concrete products. At the same time, solid waste-based cementitious materials that have been mixed, ground, and stimulated have also emerged as solid waste-based low-carbon cement, which has a great impact on the working performance of freshly mixed concrete. First of all, solid waste-based low-carbon cement has a small particle size and a large specific surface area (generally ≥600m 2 / kg), with the characteristics of being porous, highly absorbent and highly adsorbent, it causes problems such as large slump loss, poor workability, poor compatibility with water reducers, and low strength in concrete applications. Although polycarboxylic acid water reducers exhibit excellent performance of high water reduction rate and small slump loss in ordinary concrete, ordinary polycarboxylic acid water reducers cannot effectively fill and seal the excessive open pores of solid waste-based low-carbon cement, and form a hydrophobic film on the surface of the powder particles, thereby reducing the absorption of water by solid waste-based low-carbon cement. Therefore, the adsorption of the effective ingredients of the water reducer makes it difficult for ordinary polycarboxylic acid water reducers to exert excellent performance in solid waste-based low-carbon cement and solid waste-based low-carbon cement concrete. Therefore, the functional requirements of solid waste-based low-carbon cement and solid waste-based low-carbon cement concrete on water reducers are further improved, resulting in an increase in the amount of water reducer used and an increase in the requirements for controlling the loss of concrete slump. Secondly, under the same concrete mix ratio, the water-cement ratio required for solid waste-based low-carbon cement and solid waste-based low-carbon cement concrete to achieve the same working strength increases, resulting in easy segregation and water seepage after concrete pouring, settlement and cracking of concrete after hardening, and reduced strength, making it easy for harmful media such as water, carbon dioxide and chloride ions to penetrate and infiltrate, resulting in large shrinkage of concrete, and poor resistance to carbonation, impermeability, frost resistance, and resistance to saline water and seawater corrosion, resulting in the overall durability of concrete being damaged. In addition, the greater the amount of solid waste-based low-carbon cement in concrete or mortar, the more serious the above-mentioned diseases.

[0003] Chinese invention patent CN 106045372 B discloses a special polycarboxylate water-reducing agent for concrete and its preparation method for adding basalt powder to concrete. The method has a simple operation process, and the prepared special polycarboxylate water-reducing agent effectively solves the problem that basalt powder is not suitable as a concrete admixture due to its strong water absorption and low activity. However, it does not provide a solution to the problems of large collapse loss, poor workability, poor compatibility with water-reducing agent, and low strength of solid waste-based low-carbon cement in concrete applications, which greatly limits the promotion and application of solid waste-based low-carbon cement. Summary of the invention

[0004] The purpose of the present invention is to provide a high slump-retaining water-reducing agent for solid waste-based low-carbon cement concrete, so as to solve the problem that the existing polycarboxylic acid water-reducing agent is not harmoniously compatible with solid waste-based low-carbon cement concrete, realize the high performance of solid waste-based low-carbon cement concrete, and effectively promote the high-value utilization of industrial solid waste resources.

[0005] Another object of the present invention is to provide an application method of the above-mentioned high slump retention water reducing agent in the preparation of solid waste-based low-carbon cement concrete.

[0006] To achieve its purpose, the present invention adopts the following technical solution:

[0007] The invention provides a solid waste-based low-carbon cement concrete high slump-retaining water-reducing agent, which is obtained by sequentially adding 20-35 parts of high-performance superplasticizer, 25-50 parts of super slump-retaining agent, 10-15 parts of hydrophobic agent, 2-6 parts of slurry-raising agent, 0-1 part of softener and 110-140 parts of water into a stirred reactor and stirring the mixture evenly.

[0008] As a further preferred embodiment of the technical solution of the present invention, the high-performance superplasticizer is Sika 530P high-performance superplasticizer.

[0009] Furthermore, the super collapse-preserving agent is prepared by dissolving 15 parts of sodium gluconate, 10 parts of boric acid, 15 parts of phosphinobutane tricarboxylic acid and 20 parts of zinc sulfate in 40 parts of deionized water.

[0010] Furthermore, the hydrophobic agent is obtained by uniformly mixing 55-85% by mass of amino silane, 5-15% by mass of epoxy silane, 5-15% by mass of sodium metasilicate and 5-10% by mass of oligomeric silsesquioxane.

[0011] Furthermore, the pulping agent is one or a mixture of attapulgite, sodium coconut sulfate or sodium α-olefin sulfonate.

[0012] Further, the softener is one or a mixture of quaternary ammonium pyridinium salt, quaternary ammonium ester salt or polyethylene glycol 2000. Preferably, the softener is a mixture of quaternary ammonium pyridinium salt, quaternary ammonium ester salt and polyethylene glycol 2000 in a mass ratio of 1:1:2.

[0013] Furthermore, the stirring time in the preparation of the high slump-retaining water-reducing agent is 15-30 minutes.

[0014] The high slump-retaining water-reducing agent of the present invention is added into concrete when in use, and the cementitious material is solid waste-based low-carbon cement, with an addition amount of 0.8-0.9wt%.

[0015] By adopting the above technical solution, the beneficial effects achieved by the present invention are as follows:

[0016] 1. The present invention takes improving the workability and workability of solid waste-based low-carbon cement concrete as its starting point. By analyzing the key points of the disease generation, such as small concrete particle size, large specific surface area, porosity, strong water absorption, and high adsorption, a high-slump-retaining water-reducing agent that can improve the above-mentioned problems of solid waste-based low-carbon cement concrete is designed. The water-reducing agent makes full use of the characteristics of solid waste-based low-carbon cement, so that the hydrophobic agent preferentially enters the interlayer of solid waste powder particles after being dissolved in water, and at the same time, it is adsorbed and wrapped in loose openings, thereby reducing the water absorption and adsorption of solid waste-based low-carbon cement. Its raw materials are easily available, the formula is reasonable, and it is easy to process, which can realize the resource utilization of solid waste-based low-carbon cement in concrete.

[0017] 2. The hydrophobic agent in the present invention is an organic silicon compound, which can form a layer of insoluble waterproof polymer compound with a thickness of several molecules on the surface of solid waste-based low-carbon cement powder particles under the action of carbon dioxide and water, thereby forming a mesh organic silicon resin film, which can close some of the open pores of the powder particles and improve the void structure of the powder particles. At the same time, the hydrophobic agent has a strong hydrophobic function, which can further improve the void tortuosity of the solid waste-based low-carbon cement powder particles and further improve the pore structure of the concrete, thereby achieving the purpose of reducing water absorption and adsorption, improving the pore structure of mortar, concrete, etc., and then improving the density of the cast body.

[0018] 3. The sodium coconut sulfate and sodium α-olefin sulfonate in the slurry raising agent of the present invention are cationic surfactants. First, they can be selectively and preferentially adsorbed on the surface of solid waste-based low-carbon cement particles, which can effectively inhibit the water absorption of solid waste-based low-carbon cement and the adsorption of polycarboxylic acid water reducer. Second, a large number of tiny closed bubbles can be formed in the concrete mixture. These microbubbles are like balls, which reduce the adverse effect of some non-spherical solid waste powder particles causing increased friction resistance between adhesive particles, resulting in poor fluidity of concrete slurry, increase the fluidity of concrete mixture, and make up for the shortcomings of strong water absorption and easy water seepage of solid waste-based low-carbon cement. At the same time, the attapulgite in the slurry raising agent has good water retention and anti-water seepage properties, which can suspend and stabilize concrete slurry to prevent it from sinking, improve the wrapping performance of concrete slurry on aggregates, and improve the workability of fresh concrete.

[0019] 4. The present invention introduces a softener, which can reduce the interactions such as adhesion and friction between slurry particles and improve the fluidity and stability of the slurry. DETAILED DESCRIPTION

[0020] The composition, use method and effect of the high slump-retaining water-reducing agent of the present invention are described in detail below in conjunction with specific embodiments.

[0021] In the following embodiments of the present invention, the high-performance superplasticizer is 530P high-performance superplasticizer purchased from Swiss Sika Company China Branch; the super collapse-preserving agent is prepared by dissolving 15 parts of sodium gluconate, 10 parts of boric acid, 15 parts of phosphinobutane tricarboxylic acid, and 20 parts of zinc sulfate in 40 parts of deionized water in parts by weight. The softener is a mixture of pyridinium quaternary ammonium salt, ester quaternary ammonium salt and polyethylene glycol 2000 in a mass ratio of 1:1:2.

[0022] Example 1

[0023] The solid waste-based low-carbon cement concrete high slump-retaining water-reducing agent provided in this embodiment is obtained by adding 20 parts by weight of high-performance superplasticizer, 50 parts of super slump-retaining agent, 10 parts of hydrophobic agent, 3 parts of slurry raising agent, 0.5 part of softener, and 120 parts of water into a stirred reactor in sequence, stirring for 25 minutes, and fully mixing.

[0024] The hydrophobic agent is obtained by uniformly mixing 60% by mass of amino silane, 15% by mass of epoxy silane, 15% by mass of sodium metasilicate and 10% by mass of oligomeric silsesquioxane.

[0025] The slurry lifting agent is a mixture of attapulgite and sodium coconut sulfate in a mass ratio of 1:1.

[0026] Example 2

[0027] The solid waste-based low-carbon cement concrete high slump-retaining water-reducing agent provided in this embodiment is obtained by adding 27 parts by weight of high-performance superplasticizer, 45 parts of super slump-retaining agent, 10 parts of hydrophobic agent, 3 parts of slurry raising agent, 0.3 part of softener, and 130 parts of water into a stirred reactor in sequence, stirring for 20 minutes, and fully mixing.

[0028] The hydrophobic agent is obtained by uniformly mixing 65% by mass of amino silane, 15% by mass of epoxy silane, 10% by mass of sodium metasilicate and 10% by mass of oligomeric silsesquioxane.

[0029] The slurry lifting agent is a mixture of attapulgite and sodium α-olefin sulfonate in a mass ratio of 2:3.

[0030] Example 3

[0031] The solid waste-based low-carbon cement concrete high slump-retaining water-reducing agent provided in this embodiment is obtained by adding 22 parts by weight of high-performance superplasticizer, 35 parts of super slump-retaining agent, 15 parts of hydrophobic agent, 5 parts of slurry raising agent, 0.4 part of softener, and 120 parts of water into a stirred reactor in sequence, stirring for 30 minutes, and fully mixing.

[0032] The hydrophobic agent is obtained by uniformly mixing 75% by mass of amino silane, 5% by mass of epoxy silane, 15% by mass of sodium metasilicate and 5% by mass of oligomeric silsesquioxane.

[0033] The slurry lifting agent is a mixture of attapulgite and sodium α-olefin sulfonate in a mass ratio of 1:1.

[0034] Example 4

[0035] The solid waste-based low-carbon cement concrete high slump-retaining water-reducing agent provided in this embodiment is obtained by adding 23 parts by weight of high-performance superplasticizer, 40 parts of super slump-retaining agent, 14 parts of hydrophobic agent, 6 parts of slurry raising agent, 0.6 part of softener, and 140 parts of water into a stirred reactor in sequence, stirring for 25 minutes, and fully mixing.

[0036] The hydrophobic agent is obtained by uniformly mixing 85% by mass of amino silane, 5% by mass of epoxy silane, 5% by mass of sodium metasilicate and 5% by mass of oligomeric silsesquioxane.

[0037] The slurry lifting agent is a mixture of attapulgite, sodium α-olefin sulfonate and sodium coconut sulfate in a mass ratio of 2:1:1.

[0038] Example 5

[0039] The solid waste-based low-carbon cement concrete high slump-retaining water-reducing agent provided in this embodiment is obtained by adding 25 parts by weight of high-performance superplasticizer, 35 parts of super slump-retaining agent, 13 parts of hydrophobic agent, 6 parts of slurry raising agent, 1 part of softener, and 110 parts of water into a stirred reactor in sequence, stirring for 30 minutes, and fully mixing.

[0040] The hydrophobic agent is obtained by uniformly mixing 80% by mass of amino silane, 10% by mass of epoxy silane, 5% by mass of sodium metasilicate and 5% by mass of oligomeric silsesquioxane.

[0041] The slurry lifting agent is a mixture of attapulgite and sodium coconut sulfate in a mass ratio of 2:1.

[0042] Example 6

[0043] The solid waste-based low-carbon cement concrete high slump-retaining water-reducing agent provided in this embodiment is obtained by adding 30 parts by weight of high-performance superplasticizer, 30 parts by weight of super slump-retaining agent, 15 parts by weight of hydrophobic agent, 4 parts by weight of slurry raising agent, 0.8 part by weight of softener, and 140 parts by weight of water into a stirred reactor, stirring for 30 minutes, and mixing thoroughly.

[0044] The hydrophobic agent is obtained by uniformly mixing 72% by mass of amino silane, 10% by mass of epoxy silane, 10% by mass of sodium metasilicate and 8% by mass of oligomeric silsesquioxane.

[0045] The slurry lifting agent is a mixture of attapulgite, sodium α-olefin sulfonate and sodium coconut sulfate in a mass ratio of 1:2:1.

[0046] Example 7

[0047] The solid waste-based low-carbon cement concrete high slump-retaining water-reducing agent provided in this embodiment is obtained by sequentially adding 35 parts by weight of a high-performance superplasticizer, 25 parts of a super slump-retaining agent, 13 parts of a hydrophobic agent, 5 parts of a slurry-raising agent, and 130 parts of water into a stirred reactor, stirring for 30 minutes, and fully mixing.

[0048] The hydrophobic agent is obtained by uniformly mixing 63% by mass of amino silane, 15% by mass of epoxy silane, 12% by mass of sodium metasilicate and 10% by mass of oligomeric silsesquioxane.

[0049] The slurry lifting agent is a mixture of sodium α-olefin sulfonate and sodium coconut sulfate in a mass ratio of 1:2.

[0050] The polycarboxylic acid water-reducing agent with a water-reducing rate of 28% produced by Jiangsu Subote New Materials Co., Ltd., which is currently on the market, was used as a comparative water-reducing agent. With the other components being the same as those of the solid waste-based low-carbon cement concrete high slump-retention water-reducing agent obtained in Examples 1-7 of the present invention, C30 ordinary solid waste-based low-carbon cement concrete was prepared and the concrete performance test was carried out. The formulation of the C30 ordinary solid waste-based low-carbon cement concrete is shown in Table 1. In the test, the dosage of the high slump-retention water-reducing agent for solid waste-based low-carbon cement concrete of the present invention is 0.8-0.9wt% of the cementitious material (Table 2). The cementitious material is 42.5 grade solid waste-based low-carbon cement produced by Lanzhou Cast Stone. The solid waste-based low-carbon cement is ground by a vertical mill and a ball mill. It has a standard consistency of 33.5% and a specific surface area of ​​650m 2 / kg of powder. In Table 1, 1.70% is the optimal dosage of the comparative water reducer under the conditions of fixed water-binder ratio and sand ratio, when the slump of the freshly mixed concrete reaches 200mm and the workability (characterized by expansion, large expansion indicates good workability, fluidity and workability) is good in the preparation of C30 ordinary solid waste-based low-carbon cement concrete. Sand is medium sand that meets the requirements of Zone II in GB / T14684, with a fineness modulus of 2.98 and a mud content of 0.95; crushed stone meets the requirements of GB / T14685 and adopts a three-level preparation, of which 5-10mm particle size accounts for 20%, 10-20mm particle size accounts for 50%, and 20-31.5mm particle size accounts for 30%. The corresponding concrete performance test results are shown in Table 2.

[0051]

[0052]

[0053] From the results in Table 1-2, it can be seen that, at the same mix ratio, although the C30 ordinary solid waste-based low-carbon cement concrete with a slump of 200mm and a spread of 465mm can be prepared by using the comparative sample water reducer at a dosage of 1.70%, the slump retention ability of the freshly mixed concrete is poor, resulting in poor working performance, which is not conducive to the promotion and application of solid waste-based low-carbon cement concrete. However, the high slump-retaining water reducer for solid waste-based low-carbon cement concrete added in Examples 1-7 of the present invention not only has a low dosage of the water reducer, but also the slump and spread of the freshly mixed concrete are better than the concrete prepared by the comparative sample on the premise of meeting the requirements. At the same time, the slump loss of the concrete over time is small, the slump retention effect is good, and the fluidity of the concrete can be maintained for a long time, which is conducive to construction. The strength of concrete at different ages is improved, reaching the index range of concrete working performance, especially the concrete prepared by adding the water reducer in Example 7 has better comprehensive performance. It can be seen from this that the present invention has created favorable conditions for the widespread promotion and use of solid waste-based low-carbon cement concrete.

Claims

1. A solid waste-based low-carbon cement concrete high slump-retention water-reducing agent, characterized in that: In parts by weight, the high slump-retaining water-reducing agent is prepared by sequentially adding 20-35 parts of a high-performance superplasticizer, 25-50 parts of a super slump-retaining agent, 10-15 parts of a hydrophobic agent, 2-6 parts of a slurry-lifting agent, 0-1 part of a softener, and 110-140 parts of water into a stirred reactor and stirring the mixture thoroughly; The high-performance superplasticizer is Sika 530P high-performance superplasticizer; The super collapse-preserving agent is prepared by dissolving 15 parts of sodium gluconate, 10 parts of boric acid, 15 parts of phosphinobutane tricarboxylic acid and 20 parts of zinc sulfate in 40 parts of deionized water; The hydrophobic agent is obtained by uniformly mixing 55-85% by mass of amino silane, 5-15% by mass of epoxy silane, 5-15% by mass of sodium metasilicate and 5-10% by mass of oligomeric silsesquioxane; the total mass percentage of the amino silane, epoxy silane, sodium metasilicate and oligomeric silsesquioxane is 100%; The slurry lifting agent is one or a mixture of attapulgite, sodium coconut sulfate or sodium α-olefin sulfonate.

2. A solid waste-based low-carbon cement concrete high slump-retention water-reducing agent as claimed in claim 1, characterized in that: The softener is one of pyridinium quaternary ammonium salt, ester quaternary ammonium salt or polyethylene glycol 2000 or a mixture of the two or more thereof.

3. A solid waste-based low-carbon cement concrete high slump-retention water-reducing agent as claimed in claim 2, characterized in that: The softener is a mixture of pyridinium quaternary ammonium salt, ester quaternary ammonium salt and polyethylene glycol 2000 in a mass ratio of 1:1:

2.

4. A solid waste-based low-carbon cement concrete high slump-retention water-reducing agent as claimed in claim 1, characterized in that: The stirring time in the preparation of the high slump-retaining water-reducing agent is 15-30 minutes.

5. The use of a solid waste-based low-carbon cement concrete high slump-retention water-reducing agent as claimed in any one of claims 1 to 4, characterized in that: The high slump-retention water-reducing agent is added into concrete in an amount of 0.8-0.9wt% of the cementitious material; the cementitious material is solid waste-based low-carbon cement.

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