A mud resisting agent for maintaining slump based on artificial sand mud powder encapsulation in-situ sealing and application thereof

Abstract

The application belongs to the technical field of concrete admixtures, and provides a slump-keeping anti-mud agent based on artificial sand mud powder encapsulation in-situ sealing and application thereof.The slump-keeping anti-mud agent comprises component A and component B;the component A comprises a water-soluble multifunctional amine compound;the component B comprises an oil-soluble multifunctional acyl chloride or sulfonyl chloride compound;the molar ratio of amine groups in the component A to acyl chloride groups or sulfonyl chloride groups in the component B is 1:0.7-1.2.The water-soluble component in the anti-mud agent is adsorbed on the surface of mud powder, and the small molecules of the oil-soluble component rapidly diffuse to the water-oil interface on the surface of mud powder, an irreversible interfacial polymerization reaction occurs, a dense impermeable polymer shell is formed, the mud powder is isolated from the external paste, the mud powder cannot adsorb water and admixtures any more, and thus the problem that the slump loss of mud-containing aggregate concrete is too fast is solved, and the unit water consumption and the cementitious material consumption of concrete are greatly reduced on the premise that the mechanical properties and the durability are not reduced.

Description

Technical Field

[0001] This invention relates to the field of concrete admixture technology, and in particular to a slump-preserving and mud-resistant agent based on in-situ solidification of artificial sand and mud powder by encapsulation, and its application. Background Technology

[0002] With the continuous advancement of national water network projects, high-quality natural sand resources are becoming increasingly scarce, leading to the widespread application of manufactured sand in my country. However, during the production process, manufactured sand inevitably mixes with soil, primarily originating from weak interlayers and weathered metamorphic layers in the original rock, or from soil mixed into the production site. This soil often contains various types of clay minerals, such as kaolinite, montmorillonite, illite, and vermiculite. Clay mineral soils have a huge specific surface area and strong adsorption properties, irreversibly and massively adsorbing polycarboxylate superplasticizer (PCE) molecules. This results in a sharp drop in the effective content of admixtures, a severe loss of concrete slump in a short period, and decreased fluidity, seriously affecting construction operability, concrete homogeneity, and the final project quality.

[0003] To address the issue of mud powder adsorption, existing technologies primarily employ pretreatment, chemical compensation, or competitive adsorption methods. Pretreatment involves washing or sorting sand and gravel to reduce mud powder content; however, this method is energy-intensive, costly, and wasteful of water resources, and cannot completely remove fine mud powder, making large-scale application in actual production difficult. Chemical compensation reduces the impact of mud powder adsorption by increasing the dosage of polycarbonate (PCE) or by compounding slow-release or anti-mud PCE. However, this method passively increases the amount of admixture to compensate for losses, without fundamentally solving the problem. It significantly increases costs, and excessive PCE may cause new problems such as concrete segregation and bleeding, resulting in unstable effectiveness. Competitive adsorption involves adding sacrificial agents such as phosphate esters and cationic polymers that preferentially adsorb onto the mud powder surface. This method reduces PCE adsorption to some extent, but the sacrificial agents themselves do not reduce water content, and their binding with mud powder is mostly physical adsorption or ion exchange, posing a risk of desorption, resulting in insufficient long-term stability and limited effectiveness.

[0004] Therefore, there is an urgent need to provide a slump-preserving anti-mud agent that can proactively and thoroughly solve the problem of mud powder adsorption on concrete admixtures, especially polycarboxylate superplasticizers, while turning mud powder into a valuable resource and improving the mechanical properties of concrete. Summary of the Invention

[0005] In view of this, the present invention provides a slump-preserving anti-mud agent based on in-situ solidification of artificial sand and mud powder by encapsulation and its application, in order to solve the problem of excessively rapid slump loss of concrete caused by the large amount of polycarboxylate superplasticizer (PCE) adsorbed by mud powder.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a collapse-preventing anti-mud agent based on in-situ solidification of artificial sand and mud powder encapsulation, comprising component A and component B; component A comprises a water-soluble polyfunctional amine compound; and component B comprises an oil-soluble polyfunctional acyl chloride compound or a polyfunctional sulfonyl chloride compound.

[0007] Preferably, the molar ratio of the amino group in component A to the acyl chloride group or sulfonyl chloride group in component B is 1:0.7~1.2.

[0008] Preferably, component A includes one or more of polyethyleneimine, tetraethylenepentamine, diethylenetriamine, and triethylenetetramine.

[0009] Preferably, component B includes one or more of sebacate, pyromellitic methyl methacrylate, terephthaloyl chloride, isophthaloyl chloride, and 1,3,5-benzenetrisulfonyl chloride.

[0010] The present invention also provides an application of the above-mentioned anti-slump agent based on in-situ solidification of artificial sand and mud powder encapsulation, the method of application comprising the following steps: First, mix component A, mud-containing aggregate, and water to allow component A to be adsorbed onto the surface of the mud powder in the mud-containing aggregate. Then, add component B, which undergoes an interfacial polymerization reaction with component A on the surface of the mud powder to form a polymer shell. Finally, add the remaining concrete mix.

[0011] Preferably, the mud powder in the mud-containing aggregate includes one or more of kaolinite, montmorillonite, illite and vermiculite; the mass percentage of the mud powder in the mud-containing aggregate is 0.1~11%; and the mass ratio of component A to the mud powder and water in the mud-containing aggregate is 0.5~2:100:50~200.

[0012] Preferably, the time for the interfacial polymerization reaction is 10~30 s.

[0013] Preferably, the thickness of the polymer shell is 20~100 nm.

[0014] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows: 1. In practical application, the two-component system (component A, a water-soluble polyfunctional amine compound, and component B, an oil-soluble polyfunctional acyl chloride or sulfonyl chloride compound) of the present invention, as a slump-preserving and anti-mud agent, allows component A to be rapidly adsorbed by mud powder, while the small molecules of component B rapidly diffuse to the water-oil interface on the surface of the mud powder and undergo an irreversible interfacial polymerization reaction with component A. This rapidly generates a dense polymer shell (microcapsule shell) on the surface of the mud powder particles, thereby achieving physical isolation of the mud powder and completely eliminating the adsorption of polycarboxylate superplasticizer by the mud powder, thus solving the problem of excessively rapid slump loss in concrete. 2. The slump-preserving anti-mud agent of this invention transforms harmful mud powder into high-strength fine aggregate, turning waste into treasure. It not only maintains the slump of concrete but also improves its mechanical properties. Simultaneously, the microcapsules formed by encapsulating the mud powder with the slump-preserving anti-mud agent of this invention act as microspheres, providing a "bearing" effect and enhancing the lubricity and stability of the concrete mix. Furthermore, the effect of the slump-preserving anti-mud agent of this invention does not depend on the chemical properties of the mud powder but only on its physical surface, making it highly versatile. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 The diagram shows the initial slump and 1-hour slump of the concrete mix for the reference group of this invention. Figure 2 The diagram shows the initial slump and 1-hour slump of the concrete mix in Example 3 of this invention. Detailed Implementation

[0017] This invention provides a collapse-preventing anti-mud agent based on in-situ solidification of artificial sand and mud powder encapsulation, comprising component A and component B; component A comprises a water-soluble polyfunctional amine compound; and component B comprises an oil-soluble polyfunctional acyl chloride compound or a polyfunctional sulfonyl chloride compound.

[0018] In this invention, the molar ratio of the amino group in component A to the acyl chloride group or sulfonyl chloride group in component B is 1:0.7~1.2, preferably 1:0.8~1.1, and more preferably 1:0.9~1.0.

[0019] In this invention, component A preferably includes one or more of polyethyleneimine, tetraethylenepentamine, diethylenetriamine, and triethylenetetramine.

[0020] In this invention, component B preferably includes one or more of sebacate, pyromellitic methyl methacrylate, terephthaloyl chloride, isophthaloyl chloride, and 1,3,5-benzenetrisulfonyl chloride.

[0021] This invention also provides an application of the above-mentioned anti-slump agent based on in-situ solidification of artificial sand and mud powder encapsulation, the application method comprising the following steps: First, mix component A, mud-containing aggregate, and water to allow component A to be adsorbed onto the surface of the mud powder in the mud-containing aggregate. Then, add component B, which undergoes an interfacial polymerization reaction with component A on the surface of the mud powder to form a polymer shell. Finally, add the remaining concrete mix.

[0022] In this invention, by controlling the order of adding component A and component B, component A is first mixed with the mud-containing aggregate, allowing component A to be pre-adsorbed onto the surface of the mud powder. Then, a carrier containing component B is added, or component B is added directly, accompanied by efficient stirring, to promote rapid contact and reaction between component B and component A on the surface of the mud powder. Finally, it is mixed with other concrete raw materials. This invention, by utilizing the characteristic reaction of amine-acyl chloride with higher reactivity, precise material proportioning, and the characteristic that the reaction occurs at the local interface of the mud powder, "competitively wins" over the ordinary hydrolysis reaction of component B with water and alkali in both time and space. The trace, unavoidable hydrolysis side reactions do not affect the main reaction pathway and the final effect.

[0023] In this invention, the mud powder in the mud-containing aggregate preferably includes one or more of kaolinite, montmorillonite, illite, and vermiculite; the mass percentage of the mud powder in the mud-containing aggregate is 0.1-11%, preferably 0.2-10.53%, more preferably 0.5-10%, and even more preferably 1-5%; the mass ratio of component A to the mud powder and water in the mud-containing aggregate is 0.5-2:100:50-200, preferably 0.6-1.8:100:60-150, more preferably 0.8-1.5:100:70-110, and even more preferably 1.0-1.2:100:80-100; the particle size of the mud powder is preferably ≤75 μm, more preferably 5-70 μm, and even more preferably 20-50 μm.

[0024] In this invention, the time for the interfacial polymerization reaction is 10-30 s, preferably 12-28 s, more preferably 15-25 s, and even more preferably 18-20 s.

[0025] In this invention, the thickness of the polymer shell is 20~100 nm, preferably 30~80 nm, more preferably 40~70 nm, and even more preferably 50~60 nm.

[0026] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0027] Example 1

[0028] This embodiment provides a collapse-preserving anti-sludge agent based on in-situ solidification of artificial sand and mud powder encapsulation, comprising component A and component B: Component A is polyethyleneimine; Component B is sebacate chloride; the molar ratio of amine groups in component A to acyl chloride groups in component B is 1:0.7.

[0029] Application of anti-mud agent: Component A is added to the mud-containing aggregate (containing 5% mud powder by mass) at a mass ratio of 0.5:100:200 to mud powder and water in the mud-containing aggregate during the mixing process. After mixing for 30 seconds, component B is added to the aggregate at a molar ratio of acyl chloride groups to amine groups in component A of 1:0.7. Component B quickly diffuses to the surface of the mud powder. After continuing to stir for 10 seconds, it undergoes an interfacial polymerization reaction with component A at room temperature, forming a polyamide shell with a thickness of 80 nm on the surface of the mud powder. Finally, it is added to the remaining concrete mix.

[0030] In this embodiment, the raw material for the concrete mix is: 150 kg / m³ of deionized water. 3 Ordinary Portland cement 268 kg / m 3 89 kg / m³ of fly ash 3 736 kg / m³ of artificial sand 3 1116 kg / m³ of crushed stone 3 Polycarboxylate superplasticizer 3.57 kg / m 3 Anti-mud agent 0.36 kg / m 3 .

[0031] Example 2

[0032] This embodiment provides a collapse-preserving anti-sludge agent based on in-situ solidification of artificial sand and mud powder encapsulation, comprising component A and component B: Component A is tetraethylenepentamine; component B is pyromellitic acid chloride; the molar ratio of the amine group in component A to the acyl chloride group in component B is 1:1.2.

[0033] Application of anti-mud agent: Component A is added to the mud-containing aggregate (containing 3% mud powder by mass) at a mass ratio of 1:100:200 with mud powder and water in the mud-containing aggregate during the mixing process. After mixing for 30 s, component B is added to the aggregate at a molar ratio of acyl chloride groups to amine groups in component A of 1:1.2. Component B quickly diffuses to the surface of the mud powder. After continuing to stir for 20 s, it undergoes an interfacial polymerization reaction with component A at room temperature, forming a polyamide shell with a thickness of 60 nm on the surface of the mud powder. Finally, it is added to the remaining concrete mix.

[0034] In this embodiment, the raw material for the concrete mix is: 148 kg / m³ of deionized water. 3 Ordinary Portland cement 264 kg / m 3 88 kg / m³ of fly ash 3739 kg / m³ of artificial sand 3 1122 kg / m³ of crushed stone 3 Polycarboxylate superplasticizer 3.52 kg / m 3 Anti-mud agent 0.35 kg / m 3 .

[0035] Example 3

[0036] This embodiment provides a collapse-preserving anti-sludge agent based on in-situ solidification of artificial sand and mud powder encapsulation, comprising component A and component B: Component A is diethylenetriamine; Component B is pyromellitic acid chloride; the molar ratio of the amine group in component A to the acyl chloride group in component B is 1:1.

[0037] Application of anti-mud agent: Component A is added to the mud-containing aggregate (containing 4% mud powder by mass) at a mass ratio of 2:100:200 with mud powder and water in the mud-containing aggregate during the mixing process. After mixing for 30 seconds, component B is added to the aggregate at a molar ratio of acyl chloride group to amine group in component A of 1:1. Component B quickly diffuses to the surface of mud powder. After continuing to stir for 30 seconds, it undergoes an interfacial polymerization reaction with component A at room temperature, forming a polyamide shell with a thickness of 50 nm on the surface of the mud powder. Finally, it is added to the remaining concrete mix.

[0038] In this embodiment, the raw material for the concrete mix is: 145 kg / m³ of deionized water. 3 Ordinary Portland cement 259 kg / m 3 86 kg / m³ of fly ash 3 745 kg / m³ of artificial sand 3 1130 kg / m³ of crushed stone 3 Polycarboxylate superplasticizer 3.45 kg / m 3 Anti-mud agent 0.35 kg / m 3 .

[0039] Comparative Example 1

[0040] The only difference between Comparative Example 1 and Example 2 is that the mass ratio of component A to the mud powder in the aggregate containing mud powder is 0.3:100, while other application conditions remain unchanged.

[0041] The raw materials for the concrete mix in this comparative example are: 158 kg / m³ of deionized water. 3 Ordinary Portland cement 282 kg / m 3 94 kg / m³ of fly ash 3 720 kg / m³ of artificial sand 3 1092 kg / m³ of crushed stone 3Polycarboxylate superplasticizer 3.76 kg / m 3 Anti-mud agent 0.38 kg / m 3 .

[0042] Comparative Example 2

[0043] The only difference between Comparative Example 2 and Example 2 is that the mass ratio of component A to the mud powder in the aggregate containing mud powder is 7:100, while other application conditions remain unchanged.

[0044] The raw materials for the concrete mix in this comparative example are: 158 kg / m³ of deionized water. 3 Ordinary Portland cement 282 kg / m 3 94 kg / m³ of fly ash 3 720 kg / m³ of artificial sand 3 1092 kg / m³ of crushed stone 3 Polycarboxylate superplasticizer 3.76 kg / m 3 Anti-mud agent 0.38 kg / m 3 .

[0045] Comparative Example 3

[0046] The only difference between Comparative Example 3 and Example 3 is that component B was not added; all other application conditions remain the same.

[0047] The raw materials for the concrete mix in this comparative example are: 159 kg / m³ of deionized water. 3 Ordinary Portland cement 284 kg / m 3 95 kg / m³ of fly ash 3 718 kg / m³ of artificial sand 3 1089 kg / m³ of crushed stone 3 Polycarboxylate superplasticizer 3.79 kg / m 3 Anti-mud agent 0.38 kg / m 3 .

[0048] Comparative Example 4

[0049] The only difference between Comparative Example 4 and Example 3 is that components A and B are added simultaneously to aggregate containing mud powder.

[0050] The raw materials for the concrete mix in this comparative example are: 156 kg / m³ of deionized water. 3 Ordinary Portland cement 279 kg / m 3 93 kg / m³ of fly ash 3 724 kg / m³ of artificial sand 3 1098 kg / m³ of crushed stone 3 Polycarboxylate superplasticizer 3.71 kg / m3 Anti-mud agent 0.37 kg / m 3 .

[0051] The slump and compressive strength of the concrete mixtures in Examples 1-3 and Comparative Examples 1-4 were tested. The slump, compressive strength, frost resistance, and impermeability were tested according to SL / T 352—2020 "Test Procedures for Hydraulic Concrete". The results are shown in Tables 1 and 2. The initial slump and 1-hour slump of the concrete mixtures in the baseline group and Example 3 are as follows: Figure 1 and Figure 2 As shown.

[0052] Table 1. Concrete mix proportions and test results of asphalt mixture performance.

[0053] Note: The dosage of water-reducing agent is 1.0% of the mass of cementitious material, and the dosage of anti-mud agent is 0.1% of the mass of cementitious material.

[0054] Table 2. Test results of mechanical and durability properties of concrete

[0055] As shown in Table 2, by adding the slump-preserving anti-mud agent based on in-situ solidification of artificial sand and mud powder as described in this invention, the unit water consumption and cementitious material consumption of concrete are significantly reduced while maintaining the initial slump of concrete, mechanical properties and durability properties, and the slump loss over 1 hour is also significantly reduced. As shown in Comparative Examples 2 and 1-2, both excessively high and low amounts of Component A will cause the slump-preserving anti-mud agent of the present invention to fail in encapsulating the mud powder, and will also cause a decrease in the strength of concrete. As shown in Comparative Examples 3 and 4, adding Component A alone cannot form an effective polymer shell (encapsulation layer) on the surface of the mud powder, which will lead to excessively rapid slump loss and reduce the compressive strength of concrete. As shown in Comparative Examples 3 and 4, if Component A and Component B are added to the concrete mix containing mud powder at the same time, they will polymerize prematurely in the concrete mix and cannot be effectively enriched on the surface of the mud powder to form a complete polymer shell. However, by using the application method of the present invention with the slump-preserving anti-mud agent, Component A can be ensured to be adsorbed on the surface of the mud powder first, thereby guiding the interfacial polymerization reaction to occur at the mud powder-solution interface, thus achieving efficient, uniform and stable in-situ encapsulation and solidification of the mud powder.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An application of a collapse-preserving anti-mud agent based on in-situ solidification of artificial sand and mud powder encapsulation, characterized in that, The anti-slump agent based on in-situ solidification of artificial sand and mud powder encapsulation includes component A and component B; Component A includes water-soluble polyfunctional amine compounds; Component B includes oil-soluble polyfunctional acyl chloride compounds or polyfunctional sulfonyl chloride compounds; The molar ratio of the amino group in component A to the acyl chloride group or sulfonyl chloride group in component B is 1:0.7~1.2; The application method of the anti-slump agent based on in-situ solidification of artificial sand and mud powder encapsulation includes the following steps: First, mix component A, mud-containing aggregate, and water to allow component A to be adsorbed onto the surface of the mud powder in the mud-containing aggregate. Then, add component B, which undergoes an interfacial polymerization reaction with component A on the surface of the mud powder to form a polymer shell. Finally, add the remaining concrete mix.

2. The application of the anti-slump agent based on in-situ solidification of artificial sand and mud powder encapsulation according to claim 1, characterized in that, Component A includes one or more of polyethyleneimine, tetraethylenepentamine, diethylenetriamine, and triethylenetetramine.

3. The application of the anti-slump agent based on in-situ solidification of artificial sand and mud powder encapsulation according to claim 2, characterized in that, Component B includes one or more of sebacate, pyromellitic methyl methacrylate, terephthaloyl chloride, isophthaloyl chloride, and 1,3,5-benzenetrisulfonyl chloride.

4. The application of the anti-slump agent based on in-situ solidification of artificial sand and mud powder encapsulation according to claim 3, characterized in that, The mud powder in the mud-containing aggregate includes one or more of kaolinite, montmorillonite, illite and vermiculite; The mass percentage of mud powder in the mud-containing aggregate is 0.1% to 11%. The mass ratio of component A to mud powder and water in the mud-containing aggregate is 0.5~2:100:50~200.

5. The application of the anti-slump agent based on in-situ solidification of artificial sand and mud powder encapsulation according to claim 4, characterized in that, The time for the interfacial polymerization reaction is 10~30 s.

6. The application of the anti-slump agent based on in-situ solidification of artificial sand and mud powder encapsulation according to claim 5, characterized in that, The thickness of the polymer shell is 20~100 nm.

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