An additive for suppressing mud powder in machine-made sand and a preparation method thereof

Abstract

The present invention discloses an admixture for inhibiting mud powder in machine-made sand and a preparation method thereof, and belongs to the technical field of building materials. The admixture of the present invention is prepared by mud-blocking component A, sacrificial component B and retarding component C. The mud-blocking component A plays a role in neutralizing the negative charge on the surface of mud powder particles, which can separate water from clay, reduce the water adsorbed by the clay layered structure, increase the free water in the cement paste, and reduce the water demand of concrete and the adsorption of mud powder to the admixture. The molecular structure of the sacrificial component B has the characteristics of short side chain, high acid-ether ratio, high charge density and small molecule, and can be adsorbed and interspersed in the mud powder layered structure faster than conventional polycarboxylate water reducer, reducing the adsorption of mud powder to water reducer. The retarding component C can form a complex with calcium ions in the solution, inhibit the precipitation of calcium hydroxide, delay cement hydration, improve the plasticity of concrete, and at the same time improve the distribution of cement particles and reduce the shrinkage of concrete caused by mud powder.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to an additive for suppressing mud powder in machine-made sand and a preparation method thereof. Background Art

[0002] With the development and continuous expansion of the construction industry, concrete, as one of the main building materials, has become the largest and most widely used building material in construction projects. Concrete plays a function and role that cannot be replaced by other materials in terms of structural safety, reliability and durability, so it is crucial to control the quality of concrete. Sand is an important component of concrete, and the quality of sand and gravel directly affects the workability, strength and durability of concrete. As river sand resources are constantly limited, the use of machine-made sand instead of river sand in concrete has become an inevitable trend for the sustainable development of the concrete industry. However, in the production of machine-made sand, many companies often reduce the cleaning process of machine-made sand in order to reduce cost investment, resulting in a high content of mud powder in the machine-made sand, especially stone powder less than 0.075mm, which contains a lot of mud powder.

[0003] The mud powder in the machine-made sand will increase the water demand of concrete, reduce strength, poor plasticity, large shrinkage, easy cracking and other adverse effects, seriously affecting the working performance and construction quality of concrete. At present, the measures to reduce the impact of mud powder in machine-made sand on concrete mainly include increasing the amount of water reducer to improve the initial fluidity and plasticity of concrete. However, increasing the amount of water reducer will increase the sensitivity of water reducer, making the mixing station extremely difficult to control. The produced concrete has the risk of bleeding and segregation, which also increases the production cost of concrete and seriously affects the pouring and use of concrete.

[0004] Therefore, it is of great significance to prepare an admixture that can suppress the mud powder in machine-made sand and has no adverse effect on the workability and quality of concrete. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes an admixture for inhibiting mud powder in machine-made sand and a preparation method thereof. The admixture of the present invention can effectively reduce the adsorption of mud powder on water reducer, improve the plasticity and fluidity of concrete, and does not affect the strength and shrinkage of concrete.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention:

[0008] An additive for suppressing mud powder in machine-made sand is prepared from the following raw materials in parts by weight:

[0009] 400~500 parts of mud-blocking component A, 300~400 parts of sacrificial component B and 100~300 parts of retarding component C;

[0010] The mud-blocking component A is prepared from the following raw materials in parts by weight: 600-1000 parts of anhydrous ethanol, 500-900 parts of N,N-diethylethylamine, 200-400 parts of N,N-dimethylformamide, 100-300 parts of 1,2,3-tribromobutane and 50-150 parts of epichlorohydrin;

[0011] The sacrificial component B is prepared from the following raw materials by weight: 92-100 parts of isopentanol polyoxyethylene ether (TPEG), 45-50 parts of water, 3 parts of initiator, liquid A and liquid B, wherein the liquid A is composed of 130 parts of acrylic acid and 30 parts of water by weight, and the liquid B is composed of 1 part of ascorbic acid, 2 parts of thioglycolic acid and 40 parts of water;

[0012] The retarding component C is prepared by mixing sodium gluconate and borax in a mass ratio of 1:1.

[0013] In the present invention, the mud-blocking component A can be ionized in water to form a positively charged hydrophilic group that is easily attached to the negatively charged mud powder particles, playing a neutralizing role similar to that of cations in inorganic salts on the negative charge on the surface of the mud powder particles. At the same time, since the hydrophobic end of the mud-blocking component A molecule is a carbon chain, the hydrophobic base forms a hydrophobic protective film in the water, which effectively separates the water from the clay, reduces the water adsorbed by the clay layered structure, and increases the free water in the cement paste, thereby reducing the water demand of the concrete and the adsorption of mud powder on the admixture. The molecular structure of the sacrificial component B has the characteristics of short side chains, high acid-ether ratio, high charge density, and small molecules. It can be adsorbed and interspersed in the mud powder layered structure faster than conventional polycarboxylate water reducers, reducing the adsorption of mud powder on water reducers. The retarding component C can form a complex with calcium ions in the solution, inhibit the precipitation of calcium hydroxide, delay cement hydration, improve the plasticity of concrete, and at the same time improve the distribution of cement particles and reduce the shrinkage of concrete caused by mud powder.

[0014] Preferably, the preparation method of the mud-blocking component A is as follows: after mixing 400-600 parts of anhydrous ethanol, 200-400 parts of N,N-diethylethylamine and 200-400 parts of N,N-dimethylformamide by weight, heating to 50-70°C, stirring evenly, and then dripping 100-300 parts of 1,2,3-tribromobutane, keeping warm after the dripping is completed, and removing the solvent by reduced pressure distillation after the reaction is completed, extracting with acetone, and drying to obtain a light yellow solid a;

[0015] Mix 300-500 parts of N,N-diethylethylamine and 200-400 parts of anhydrous ethanol, heat to 40-60°C, stir evenly, then start to drop 50-150 parts of epichlorohydrin, keep warm after the dropwise addition is complete, continue stirring after the reaction is complete, add the light yellow solid a, stir for 30 minutes, and stir evenly to obtain the mud-blocking component A.

[0016] In the preparation process of mud-blocking component A, N,N-diethylethylamine, N,N-dimethylformamide and 1,2,3-tribromobutane undergo substitution reaction to generate quaternary ammonium salt. N,N-diethylethylamine and epichlorohydrin undergo substitution reaction to generate quaternary ammonium salt. The generated quaternary ammonium salt ionizes in water to form positively charged hydrophilic groups that are easily attached to negatively charged mud powder particles, playing a role similar to the neutralization of negative charges on the surface of mud powder particles by cations in inorganic salts. At the same time, since the hydrophobic end of the generated molecule is a carbon chain, the hydrophobic base forms a hydrophobic protective film in the water, which effectively separates water from clay, reduces the water adsorbed by the clay layered structure, and increases the free water in the cement paste, thereby reducing the water demand of concrete and the adsorption of mud powder on admixtures.

[0017] Preferably, in the method for preparing the sludge-blocking component A, after heating to 50-70° C., stirring is performed uniformly at a speed of 150-250 r / min; and / or

[0018] The addition time of 1,2,3-tribromobutane is 1.8-2.5h; and / or

[0019] After the addition of 1,2,3-tribromobutane is completed, the temperature is kept at room temperature for 5-7 hours; and / or

[0020] After heating to 40-60°C, stir evenly at a speed of 150-250r / min; and / or

[0021] The dripping time of epichlorohydrin is 1.8-2.5h; and / or

[0022] After the addition of epichlorohydrin is completed, the insulation time is 5-7 hours.

[0023] More preferably, the preparation method of the mud-blocking component A is as follows: according to the weight parts, 500 parts of anhydrous ethanol, 300 parts of N,N-diethylethylamine and 300 parts of N,N-dimethylformamide are mixed in a three-necked flask equipped with a stirring and heating device, the temperature is raised to 60°C, and after stirring evenly, 200 parts of 1,2,3-tribromobutane are added dropwise for 2 hours. After the addition is completed, the temperature is kept for 6 hours. After the reaction is completed, the solvent is removed by reduced pressure distillation, extracted with acetone, and dried to obtain a light yellow solid a;

[0024] Add 400 parts of N,N-diethylethylamine and 300 parts of anhydrous ethanol to a three-necked flask equipped with a stirring and heating device, heat to 50°C, stir at a speed of 200 r / min, and after stirring evenly, start to drop 100 parts of epichlorohydrin for 2 hours. After the addition is completed, keep warm for 6 hours. After the reaction is completed, continue stirring, add the light yellow solid a, stir for 30 minutes, and stir evenly to obtain the mud-blocking component A.

[0025] Preferably, the preparation method of the sacrificial component B is as follows: according to the weight parts, 92-100 parts of isopentanol polyoxyethylene ether and 45-50 parts of water are mixed, the temperature is raised to 40-50°C, and 3 parts of initiator are added after stirring evenly, and then liquid a and liquid b are added dropwise (liquid a and liquid b are added dropwise at the same time), and the reaction is continued for 2 hours after the dropwise addition is completed. After the reaction is completed, the temperature is lowered to room temperature, the pH of the solution is adjusted to 7, and the concentration is adjusted to 38-42wt% to obtain the sacrificial component B;

[0026] The initiator is composed of 2 parts of hydrogen peroxide and 1 part of ferrous sulfate in terms of weight, and the concentration of ferrous sulfate is 1wt.%;

[0027] In terms of weight, the liquid a is composed of 130 parts of acrylic acid and 30 parts of water, and the liquid b is composed of 1 part of ascorbic acid, 2 parts of thioglycolic acid and 40 parts of water.

[0028] The isopentanol polyoxyethylene ether and acrylic acid undergo a redox free radical polymerization reaction to generate a sacrificial component B. The molecular weight and conversion rate of the sacrificial component B are controlled by controlling the molar ratio of acrylic acid to the isopentanol polyoxyethylene ether, the reaction temperature, the stirring speed, the chain transfer agent and the amount of redox.

[0029] Preferably, in the preparation method of sacrificial component B, after the temperature is raised to 40-50° C., the rotation speed is set to 200-240 r / min; and / or

[0030] The addition time of liquid a and liquid b is 2h.

[0031] More preferably, the preparation method of the sacrificial component B is as follows: according to the weight parts, 96 parts of isopentanol polyoxyethylene ether and 48 parts of water are mixed, the temperature is raised to 45°C, and 3 parts of initiator are added after stirring evenly, and then liquid a and liquid b are added dropwise for 2 hours. After the addition is completed, the reaction is continued for 2 hours. After the reaction is completed, the temperature is lowered to room temperature, the pH of the solution is adjusted to 7, and the concentration is adjusted to 40wt% to obtain the sacrificial component B;

[0032] The initiator is composed of 2 parts of hydrogen peroxide and 1 part of ferrous sulfate in terms of weight;

[0033] In terms of weight, the liquid a is composed of 130 parts of acrylic acid and 30 parts of water, and the liquid b is composed of 1 part of ascorbic acid, 2 parts of thioglycolic acid and 40 parts of water.

[0034] The weight average molecular weight (Mw) of the sacrificial component B of the present invention is 8000-11000 g / mol, and the conversion rate is above 90%.

[0035] The mud powder less than 0.075 mm in the machine-made sand mostly exists in a layered aluminosilicate structure. The layered structure causes the comb-shaped polycarboxylate water-reducing agent to be unable to escape after entering, and cannot effectively disperse the cement particles, thereby leading to problems such as high concrete water-reducing agent dosage, high water demand, and poor plasticity. After adding the admixture of the present invention to inhibit mud powder in the machine-made sand, the molecular structure of the sacrificial component B has the characteristics of short side chain, high acid-ether ratio, high charge density, and small molecule, which can be adsorbed and interspersed in the mud powder layered structure faster than conventional polycarboxylate water-reducing agents, reducing the adsorption of mud powder on water-reducing agents, and can significantly reduce the problem of high water-reducing agent dosage. The mud-blocking component A in the admixture can be ionized in water to form a positively charged hydrophilic group that is easily attached to the negatively charged mud powder particles, playing a neutralizing role similar to the cations in inorganic salts on the negative charge on the surface of the mud powder particles. At the same time, because the hydrophobic end of the mud-blocking component A molecule is a carbon chain, the hydrophobic base forms a hydrophobic protective film in the water, which effectively separates the water from the clay, reduces the water adsorbed by the clay layered structure, and increases the free water in the cement paste, thereby further reducing the water demand of the concrete and the dosage of the admixture. The retarding component C can form a complex with the calcium ions in the solution, form a barrier layer on the surface of the cement particles, inhibit the precipitation of calcium hydroxide, delay the hydration of cement, thereby improving the plasticity of the concrete, and at the same time can improve the distribution of cement particles and reduce the shrinkage of the concrete caused by mud powder. Under the joint action of the three components, the high water demand of concrete caused by mud powder in the machine-made sand, the decrease in strength, the poor plasticity, the large shrinkage rate, the high dosage of water reducer and other undesirable problems can be effectively solved.

[0036] The second technical solution of the present invention:

[0037] The present invention also provides a method for preparing the additive for inhibiting mud powder in machine-made sand, comprising uniformly mixing mud-blocking component A, sacrificial component B and retarding component C in parts by weight to obtain the additive for inhibiting mud powder in machine-made sand.

[0038] Compared with the prior art, the present invention has the following advantages and technical effects:

[0039] In the present invention, the mud-blocking component A can be ionized in water to form a positively charged hydrophilic group that is easily attached to the negatively charged mud powder particles, playing a neutralizing role similar to that of cations in inorganic salts on the negative charge on the surface of the mud powder particles. At the same time, since the hydrophobic end of the mud-blocking component A molecule is a carbon chain, the hydrophobic base forms a hydrophobic protective film in the water, which effectively separates the water from the clay, reduces the water adsorbed by the clay layered structure, and increases the free water in the cement paste, thereby reducing the water demand of the concrete and the adsorption of mud powder on the admixture. The molecular structure of the sacrificial component B has the characteristics of short side chains, high acid-ether ratio, high charge density, and small molecules. It can be adsorbed and interspersed in the mud powder layered structure faster than conventional polycarboxylate water reducers, reducing the adsorption of mud powder on water reducers. The retarding component C can form a complex with calcium ions in the solution, inhibit the precipitation of calcium hydroxide, delay cement hydration, improve the plasticity of concrete, and at the same time improve the distribution of cement particles and reduce the shrinkage of concrete caused by mud powder. DETAILED DESCRIPTION

[0040] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0041] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0042] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0043] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0044] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0045] The technical solution of the present invention is further illustrated by the following embodiments.

[0046] Unless otherwise specified, the room temperature in the present invention is 25±2°C.

[0047] All raw materials used in the examples of the present invention are commercially available.

[0048] In the following examples and comparative examples of the present invention, the TPEG used is TPEG with a molecular weight of 400, denoted as TPEG400.

[0049] Unless otherwise specified, the “parts” used in the embodiments of the present invention are “parts by weight”.

[0050] The technical solution of the present invention is further illustrated by the following embodiments.

[0051] Example 1

[0052] This embodiment provides an admixture for inhibiting mud powder in machine-made sand, which is prepared from the following raw materials in parts by weight: 400 parts of mud-blocking component A, 300 parts of sacrificial component B, and 300 parts of retarding component C;

[0053] Preparation of mud-blocking component A: 400 parts of anhydrous ethanol, 400 parts of N,N-diethylethylamine and 350 parts of N,N-dimethylformamide were added to a three-necked flask equipped with a reflux condenser. After mixing, the temperature was raised to 70°C and the stirring speed was 150 r / min. After stirring evenly, 300 parts of 1,2,3-tribromobutane were added dropwise for 2.5 hours. After the addition was completed, the temperature was kept for 7 hours. After the reaction was completed, the solvent was removed by vacuum distillation, and the mixture was extracted and dried with acetone to obtain Light yellow solid a; add 500 parts of N,N-diethylethylamine and 200 parts of anhydrous ethanol to a three-necked flask equipped with a stirring and heating device, raise the temperature to 60°C, and stir at a speed of 250 r / min. After stirring evenly, begin to drop 150 parts of epichlorohydrin for 2.5 hours. After the addition is complete, keep warm for 7 hours. After the reaction is completed, continue stirring, add the light yellow solid a obtained above, stir for 30 minutes, and stir evenly to obtain a yellow liquid anti-sludge component A.

[0054] Preparation of sacrificial component B: In a reactor equipped with a stirrer, a dropping device and a heating device, 92 parts of TPEG400 and 50 parts of deionized water were added, heated to 50°C, the speed was set to 200r / min, an initiator (2 parts of hydrogen peroxide and 1 part of ferrous sulfate (1wt.%)) was added, and liquid a and liquid b (liquid a was composed of 130 parts of acrylic acid and 30 parts of deionized water; liquid b was composed of 1 part of ascorbic acid, 2 parts of thioglycolic acid and 40 parts of deionized water) were added dropwise for 2h. After the addition was completed, the reaction was continued for 2h. After the reaction was completed, the temperature of the system was lowered to room temperature, and the solution was neutralized with NaOH solution and deionized water to pH 7, and the concentration was adjusted to 40wt.% to obtain sacrificial component B. The weight average molecular weight (Mw) of sacrificial component B was measured by gel permeation chromatography to be 10538g / mol, and the conversion rate was 94%.

[0055] Preparation of retarding component C: The retarding component C is prepared by mixing sodium gluconate and borax in a mass ratio of 1:1.

[0056] The preparation method of the admixture for suppressing mud powder in machine-made sand is as follows: the mud-blocking component A, the sacrificial component B and the retarding component C are uniformly mixed according to weight proportions to obtain the admixture for suppressing mud powder in machine-made sand.

[0057] Example 2

[0058] This embodiment provides an admixture for inhibiting mud powder in machine-made sand, which is prepared from the following raw materials in parts by weight: 500 parts of mud-blocking component A, 400 parts of sacrificial component B, and 100 parts of retarding component C;

[0059] Preparation of mud-blocking component A: 600 parts of anhydrous ethanol, 200 parts of N,N-diethylethylamine and 200 parts of N,N-dimethylformamide were added to a three-necked flask equipped with a reflux condenser. After mixing, the temperature was raised to 50°C and the stirring speed was 250 r / min. After stirring evenly, 100 parts of 1,2,3-tribromobutane were added dropwise for 1.8 hours. After the addition was completed, the mixture was kept warm for 5 hours. After the reaction was completed, the solvent was removed by vacuum distillation and the mixture was extracted and dried with acetone to obtain Light yellow solid a; add 300 parts of N,N-diethylethylamine and 400 parts of anhydrous ethanol to a three-necked flask equipped with a stirring and heating device, raise the temperature to 40°C, and stir at a speed of 150 r / min. After stirring evenly, begin to drop 50 parts of epichlorohydrin for 1.8 hours. After the addition is complete, keep warm for 5 hours. After the reaction is completed, continue stirring, add the light yellow solid a obtained above, stir for 30 minutes, and stir evenly to obtain a yellow liquid anti-sludge component A.

[0060] Preparation of sacrificial component B: In a reactor equipped with a stirrer, a dropping device and a heating device, 100 parts of TPEG400 and 45 parts of deionized water were added, heated to 40°C, the speed was set to 240r / min, an initiator (2 parts of hydrogen peroxide and 1 part of ferrous sulfate (1wt.%)) was added, and liquid a and liquid b (liquid a was composed of 130 parts of acrylic acid and 30 parts of deionized water; liquid b was composed of 1 part of ascorbic acid, 2 parts of thioglycolic acid and 40 parts of deionized water) were added dropwise for 2h. After the addition was completed, the reaction was continued for 2h. After the reaction was completed, the temperature of the system was lowered to room temperature, and the solution was neutralized with NaOH solution and deionized water to pH 7, and the concentration was adjusted to 40wt.% to obtain sacrificial component B. The Mw of sacrificial component B was measured by gel permeation chromatography to be 8464g / mol, and the conversion rate was 93%.

[0061] Retarding component C: It is a mixture of sodium gluconate and borax in a mass ratio of 1:1.

[0062] The preparation method of the admixture for suppressing mud powder in machine-made sand is as follows: the mud-blocking component A, the sacrificial component B and the retarding component C are uniformly mixed according to weight proportions to obtain the admixture for suppressing mud powder in machine-made sand.

[0063] Example 3

[0064] This embodiment provides an admixture for inhibiting mud powder in machine-made sand, which is prepared from the following raw materials in parts by weight: 450 parts of mud-blocking component A, 350 parts of sacrificial component B, and 200 parts of retarding component C;

[0065] Preparation of mud-blocking component A: Add 500 parts of anhydrous ethanol, 300 parts of N,N-diethylethylamine and 300 parts of N,N-dimethylformamide to a three-necked flask equipped with a reflux condenser. After mixing, the temperature is raised to 60°C and the stirring speed is 200 r / min. After stirring evenly, 200 parts of 1,2,3-tribromobutane are added dropwise for 2 hours. After the addition is completed, the mixture is kept warm for 6 hours. After the reaction is completed, the solvent is removed by distillation under reduced pressure and the mixture is extracted and dried with acetone to obtain a light yellow solid a. In a three-necked flask equipped with a stirring and heating device, add 400 parts of N,N-diethylethylamine and 300 parts of anhydrous ethanol, raise the temperature to 50°C, and stir at a speed of 200 r / min. After stirring evenly, begin to drop 100 parts of epichlorohydrin for 2 hours. After the addition is complete, keep warm for 6 hours. After the reaction is completed, continue stirring, add the light yellow solid a obtained above, stir for 30 minutes, and after stirring evenly, obtain a yellow liquid anti-mud component A.

[0066] Preparation of sacrificial component B: In a reactor equipped with a stirrer, a dropping device and a heating device, 96 parts of TPEG400 and 48 parts of deionized water were added, heated to 45°C, the speed was set to 220r / min, an initiator (2 parts of hydrogen peroxide and 1 part of ferrous sulfate (1wt.%)) was added, and liquid a and liquid b (liquid a was composed of 130 parts of acrylic acid and 30 parts of deionized water; liquid b was composed of 1 part of ascorbic acid, 2 parts of thioglycolic acid and 40 parts of deionized water) were added dropwise for 2h. After the addition was completed, the reaction was continued for 2h. After the reaction was completed, the temperature of the system was lowered to room temperature, and the solution was neutralized with NaOH solution and deionized water to a pH of 7, and the concentration was adjusted to 40wt.% to obtain sacrificial component B. The Mw of sacrificial component B was measured by gel permeation chromatography to be 9025g / mol, and the conversion rate was 96%.

[0067] Preparation of retarding component C: The retarding component is prepared by mixing sodium gluconate and borax in a mass ratio of 1:1.

[0068] The preparation method of the admixture for suppressing mud powder in machine-made sand is as follows: the mud-blocking component A, the sacrificial component B and the retarding component C are uniformly mixed according to weight proportions to obtain the admixture for suppressing mud powder in machine-made sand.

[0069] Example 4

[0070] This embodiment provides an admixture for inhibiting mud powder in machine-made sand, which is prepared from the following raw materials in parts by weight: 450 parts of mud-blocking component A, 300 parts of sacrificial component B, and 250 parts of retarding component C;

[0071] Preparation of mud-blocking component A: Add 500 parts of anhydrous ethanol, 300 parts of N,N-diethylethylamine and 300 parts of N,N-dimethylformamide to a three-necked flask equipped with a reflux condenser. After mixing, the temperature is raised to 60°C and the stirring speed is 200 r / min. After stirring evenly, 200 parts of 1,2,3-tribromobutane are added dropwise for 2 hours. After the addition is completed, the mixture is kept warm for 6 hours. After the reaction is completed, the solvent is removed by distillation under reduced pressure and the mixture is extracted and dried with acetone to obtain a light yellow solid a. In a three-necked flask equipped with a stirring and heating device, add 400 parts of N,N-diethylethylamine and 300 parts of anhydrous ethanol, raise the temperature to 50°C, and stir at a speed of 200 r / min. After stirring evenly, begin to drop 100 parts of epichlorohydrin for 2 hours. After the addition is complete, keep warm for 6 hours. After the reaction is completed, continue stirring, add the light yellow solid a obtained above, stir for 30 minutes, and after stirring evenly, obtain a yellow liquid anti-mud component A.

[0072] Preparation of sacrificial component B: In a reactor equipped with a stirrer, a dropping device and a heating device, 96 parts of TPEG400 and 48 parts of deionized water were added, heated to 45°C, the speed was set to 220r / min, an initiator (2 parts of hydrogen peroxide and 1 part of ferrous sulfate (1wt.%)) was added, and liquid a and liquid b (liquid a was composed of 130 parts of acrylic acid and 30 parts of deionized water; liquid b was composed of 1 part of ascorbic acid, 2 parts of thioglycolic acid and 40 parts of deionized water) were added dropwise for 2h. After the addition was completed, the reaction was continued for 2h. After the reaction was completed, the temperature of the system was lowered to room temperature, and the solution was neutralized with NaOH solution and deionized water to a pH of 7, and the concentration was adjusted to 40wt.% to obtain sacrificial component B. The Mw of sacrificial component B was measured by gel permeation chromatography to be 9025g / mol, and the conversion rate was 96%.

[0073] Retarding component C: It is a mixture of sodium gluconate and borax in a mass ratio of 1:1.

[0074] The preparation method of the admixture for suppressing mud powder in machine-made sand is as follows: the mud-blocking component A, the sacrificial component B and the retarding component C are uniformly mixed according to weight proportions to obtain the admixture for suppressing mud powder in machine-made sand.

[0075] Comparative Example 1

[0076] Compared with Example 3, in Comparative Example 1, the anti-mud component A is replaced with an equal amount of JTx037 anti-mud agent (purchased from Hubei Jiutian Biotechnology Co., Ltd.), and the rest is the same as Example 3.

[0077] Comparative Example 2

[0078] Compared with Example 3, in Comparative Example 2, the sacrificial component B is replaced with a ZJKJ polycarboxylate water-reducing agent (purchased from Jinan Juxin Chemical Co., Ltd.) of equal solid content, and the rest is the same as Example 3.

[0079] Comparative Example 3

[0080] Compared with Example 3, in Comparative Example 3, the retarding component C is replaced with an equal amount of citric acid (purchased from Henan Fengwei Biotechnology Co., Ltd.), and the rest is the same as Example 3.

[0081] Comparative Example 4

[0082] Compared with Example 3, the difference of Comparative Example 4 is that the admixture for suppressing mud powder in machine-made sand is prepared from the following raw materials in parts by weight: 300 parts of mud-blocking component A, 500 parts of sacrificial component B, and 200 parts of retarding component C, and the rest is the same as Example 3.

[0083] Concrete performance test:

[0084] The performance of the admixtures obtained in each embodiment and comparative example was tested by concrete test. The cement was Esheng P·O 42.5 cement, the fineness modulus of mud-containing machine-made sand was 2.8, the stone powder content was 7wt.%, and the methylene blue MB value was 5.0. The stone powder of mud-containing machine-made sand less than 0.075mm was analyzed by mineral analysis, and it was found that its main component was layered aluminosilicate structure, indicating that the less than 0.075mm in the machine-made sand was mainly mud powder, not stone powder. The concrete mix ratio is shown in Table 1.

[0085] Table 1 Concrete mix ratio (kg / m 3 )

[0086]

[0087] The effect test of admixtures to inhibit the mud powder in the machine-made sand, concrete fluidity, slump, test block forming, production and maintenance refer to GBT50080-2016 "Standard for Test Methods of Ordinary Concrete Mixtures", dry shrinkage test according to GBT50082-2009 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete", and concrete strength according to GBT 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete". In the blank control, no admixtures to inhibit the mud powder in the machine-made sand were added to each ton of compound water reducer, and the mass ratio of a single ton of compound water reducer was: polycarboxylate water reducer (six carbon type P6): slump retainer (six carbon type C8): retarder (sodium gluconate): air entraining agent (triterpenoid saponin): water = 300:100:20:1:579. In each embodiment and comparative example, a mud powder suppressing admixture (840kg×7%×0.6%=0.353kg) containing 0.6% mud-containing machine-made sand and gravel powder by mass is added to each ton of composite water reducer (840kg×7%×0.6%=0.353kg, the content of the mud powder suppressing admixture is converted to the content of 1wt% of the adhesive material per ton of composite water reducer, and the mass ratio of each ton of composite water reducer is: polycarboxylate water reducer (six carbon type P6): collapse retaining agent (six carbon type C8): retarder (sodium gluconate): mud powder suppressing admixture: air entraining agent (triterpenoid saponin): water = 300:100:20:100:1:479), and all test groups maintain the same expansion of concrete out of the machine. Since each ton of composite water reducer in the blank control group does not contain mud powder suppressing admixture, the dosage required to achieve the same expansion is significantly higher than that of the embodiment and comparative example. The test results are shown in Table 2.

[0088] Table 2 Concrete test results

[0089]

[0090] From the analysis of Table 2, it can be seen that the prepared admixture for inhibiting mud powder in machine-made sand is applied to concrete. Compared with the blank group (i.e., the blank control group), when the same expansion is achieved, the dosage required for the embodiment is greatly reduced, from 1.5% of the adhesive dosage to 1.0%, the concrete slump and expansion loss in 1 hour are smaller, the workability of the embodiment is better, the slurry is soft, and the concrete surface of the blank group bleeds. From the perspective of concrete dry shrinkage, the dry shrinkage of the embodiment is significantly reduced. From the perspective of the compressive strength of 3d, 7d, and 28d, the compressive strength of the embodiment is significantly improved relative to the blank group. Compared with the comparative example, when the same expansion is achieved, the dosage required for the embodiment is lower, the concrete slump and expansion loss in 1 hour is smaller, the workability of the embodiment is better, the slurry is soft, and slight bleeding occurs on the concrete surface of the control group. From the perspective of concrete dry shrinkage, the dry shrinkage of the embodiment is lower. From the perspective of the compressive strength of 3d, 7d, and 28d, the compressive strength of the embodiment is higher than that of the control group.

[0091] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An admixture for inhibiting mud powder in machine-made sand, characterized in that: According to parts by weight, it is prepared from the following raw materials: 400~500 parts of mud-blocking component A, 300~400 parts of sacrificial component B and 100~300 parts of retarding component C; The mud-blocking component A is prepared from the following raw materials in parts by weight: 600-1000 parts of anhydrous ethanol, 500-900 parts of N,N-diethylethylamine, 200-400 parts of N,N-dimethylformamide, 100-300 parts of 1,2,3-tribromobutane and 50-150 parts of epichlorohydrin; The sacrificial component B is prepared from the following raw materials by weight: 92-100 parts of isopentanol polyoxyethylene ether, 45-50 parts of water, 3 parts of initiator, liquid A and liquid B, wherein the liquid A is composed of 130 parts of acrylic acid and 30 parts of water by weight, and the liquid B is composed of 1 part of ascorbic acid, 2 parts of thioglycolic acid and 40 parts of water; The retarding component C is prepared by mixing sodium gluconate and borax in a mass ratio of 1:

1.

2. The additive for suppressing mud powder in machine-made sand according to claim 1, characterized in that: The preparation method of the mud-blocking component A is as follows: according to weight parts, 400-600 parts of anhydrous ethanol, 200-400 parts of N,N-diethylethylamine and 200-400 parts of N,N-dimethylformamide are mixed, the temperature is raised to 50-70° C., and after being stirred evenly, 100-300 parts of 1,2,3-tribromobutane are added dropwise, and the temperature is kept after the addition is completed. After the reaction is completed, the solvent is removed by reduced pressure distillation, and the mixture is extracted with acetone and dried to obtain a light yellow solid a; Mix 300-500 parts of N,N-diethylethylamine and 200-400 parts of anhydrous ethanol, heat to 40-60°C, stir evenly, then drop 50-150 parts of epichlorohydrin, keep warm after the dropwise addition, continue stirring after the reaction is completed, add the light yellow solid a, stir evenly to obtain the mud-blocking component A.

3. The additive for suppressing mud powder in machine-made sand according to claim 2, characterized in that: After heating to 50-70°C, stir evenly at a speed of 150-250r / min; and / or The addition time of 1,2,3-tribromobutane is 1.8-2.5h; and / or After the addition of 1,2,3-tribromobutane is completed, the temperature is kept at room temperature for 5-7 hours; and / or After heating to 40-60°C, stir evenly at a speed of 150-250r / min; and / or The dripping time of epichlorohydrin is 1.8-2.5h; and / or After the addition of epichlorohydrin is completed, the insulation time is 5-7 hours.

4. The additive for suppressing mud powder in machine-made sand according to claim 3, characterized in that: The preparation method of the mud-blocking component A is as follows: 500 parts of anhydrous ethanol, 300 parts of N,N-diethylethylamine and 300 parts of N,N-dimethylformamide are mixed by weight, the temperature is raised to 60° C., and after being stirred evenly, 200 parts of 1,2,3-tribromobutane are added dropwise for 2 hours. After the addition is completed, the temperature is kept for 6 hours. After the reaction is completed, the solvent is removed by reduced pressure distillation, and the mixture is extracted with acetone and dried to obtain a light yellow solid a; Mix 400 parts of N,N-diethylethylamine and 300 parts of anhydrous ethanol, heat to 50°C, stir at a speed of 200 r / min, and after stirring evenly, add 100 parts of epichlorohydrin dropwise for 2 hours. After the addition is complete, keep warm for 6 hours. After the reaction is completed, continue stirring, add the light yellow solid a, stir for 30 minutes, and after stirring evenly, obtain the mud-blocking component A.

5. The admixture for suppressing mud powder in machine-made sand according to claim 1, characterized in that: The preparation method of the sacrificial component B is as follows: according to the weight parts, 92-100 parts of isopentanol polyoxyethylene ether and 45-50 parts of water are mixed, the temperature is raised to 40-50° C., 3 parts of initiator are added after stirring evenly, and then liquid a and liquid b are added dropwise, and the reaction is continued for 2 hours after the dropwise addition is completed. After the reaction is completed, the temperature is lowered to room temperature, the pH of the solution is adjusted to 7, and the concentration is adjusted to 38-42wt% to obtain the sacrificial component B; The initiator is composed of 2 parts of hydrogen peroxide and 1 part of ferrous sulfate in terms of weight; In terms of weight, the liquid a is composed of 130 parts of acrylic acid and 30 parts of water, and the liquid b is composed of 1 part of ascorbic acid, 2 parts of thioglycolic acid and 40 parts of water.

6. The additive for suppressing mud powder in machine-made sand according to claim 5, characterized in that: After the temperature rises to 40-50°C, the speed is set to 200-240r / min; and / or The addition time of liquid a and liquid b is 2h.

7. The admixture for suppressing mud powder in machine-made sand according to claim 6, characterized in that: The preparation method of the sacrificial component B is as follows: according to the weight parts, 96 parts of isopentanol polyoxyethylene ether and 48 parts of water are mixed, the temperature is raised to 45° C., and after stirring evenly, 3 parts of initiator are added, and then liquid a and liquid b are added dropwise for 2 hours. After the addition is completed, the reaction is continued for 2 hours. After the reaction is completed, the temperature is lowered to room temperature, the pH of the solution is adjusted to 7, and the concentration is adjusted to 40wt% to obtain the sacrificial component B; The initiator is composed of 2 parts of hydrogen peroxide and 1 part of ferrous sulfate in terms of weight; In terms of weight, the liquid a is composed of 130 parts of acrylic acid and 30 parts of water, and the liquid b is composed of 1 part of ascorbic acid, 2 parts of thioglycolic acid and 40 parts of water.

8. A method for preparing an admixture for suppressing mud powder in machine-made sand according to any one of claims 1 to 7, characterized in that: The mud-blocking component A, the sacrificial component B and the retarding component C are uniformly mixed according to weight proportions to obtain the admixture for inhibiting mud powder in machine-made sand.

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