CN116217830A - Water reducer for calcined kaolin-cement system, and preparation method and application thereof - Google Patents
Water reducer for calcined kaolin-cement system, and preparation method and application thereof Download PDFInfo
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- CN116217830A CN116217830A CN202310212501.5A CN202310212501A CN116217830A CN 116217830 A CN116217830 A CN 116217830A CN 202310212501 A CN202310212501 A CN 202310212501A CN 116217830 A CN116217830 A CN 116217830A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
- C08F283/06—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals
- C08F283/065—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals on to unsaturated polyethers, polyoxymethylenes or polyacetals
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/24—Macromolecular compounds
- C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- C04B24/2688—Copolymers containing at least three different monomers
- C04B24/2694—Copolymers containing at least three different monomers containing polyether side chains
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/38—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/30—Water reducers, plasticisers, air-entrainers, flow improvers
- C04B2103/302—Water reducers
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- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
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Abstract
The invention discloses a water reducer for a calcined kaolin-cement system, and a preparation method and application thereof. Adding hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) and an oxidant into water, and uniformly stirring until the mixture is dissolved to obtain a mixed solution; step 2, adding carboxylic acid monomers and cationic monomers into water, and stirring until the carboxylic acid monomers and the cationic monomers are dissolved to obtain a mixed solution A; adding a reducing agent into water, and stirring until the reducing agent is dissolved to obtain a mixed solution B; adding a chain transfer agent into water, and stirring until the chain transfer agent is dissolved to obtain a mixed solution C; and 3, simultaneously dripping the mixed solution A, the mixed solution B and the mixed solution C obtained in the step 2 into the mixed solution obtained in the step 1, uniformly stirring, and adjusting the pH value to obtain the water reducer for the calcined kaolin-cement system. The preparation method of the invention uses water as a dispersion medium, has simple preparation process and low cost, and is easy to realize industrial production.
Description
Technical Field
The invention belongs to the technical field of building cement water reducing agents, and particularly relates to a water reducing agent for a calcined kaolin-cement system, a preparation method and application thereof.
Background
In the industrial production of cement, large amounts of carbon dioxide are released, accounting for 8% of the global human carbon dioxide emission process, nearly 65% of which is due to the decomposition of calcium carbonate during portland cement production, with a small fraction coming from the energy consumption of the clinker firing and ball milling process. Thus, there is a need to find supplementary cementitious materials to replace part of the cement. In practice, the most widely used SCMs include limestone, fly ash, slag, and the like, but the global availability of fly ash and slag is limited. Calcined kaolin is now receiving increasing attention as a substitute for supplementary cementitious materials due to its global richness. The temperature range required for calcination of the raw clay is 600-900 ℃ and is far lower than 1450 ℃. The carbon dioxide released in the production of calcined kaolin is much less and does not contain substantial limestone decomposition. Thus, the use of calcined kaolin in place of a portion of the cement is feasible. However, the process of replacing part of cement with calcined kaolin has the problems that the high specific surface area of the single calcined kaolin is larger than that of cement, so that the processing is difficult, the water demand is increased, and the fluidity of the slurry is deteriorated. In order to solve the problem of flow retention of the calcined kaolin and cement mixed system, a water reducer can be introduced into the system.
After the first-generation common water reducer represented by calcium lignin and the second-generation high-efficiency water reducer represented by naphthalene, the polycarboxylic acid water reducer has been rapidly developed in recent years, and the polycarboxylic acid water reducer can prevent concrete slump loss without causing obvious retardation, high plasticizing effect at low mixing amount, good fluidity retention and the like. The cement paste added with the polycarboxylate water reducer has excellent construction workability, good strength development and durability, and meets the requirements of modern concrete engineering. In the development of the polycarboxylate water reducer, macromers such as allyl polyethylene glycol (APEG), methyl allyl polyoxyethylene ether (HPEG), isopentenyl alcohol polyoxyethylene ether (TPEG) and the like appear in main synthetic raw materials, but in recent years, hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) macromers have higher activity compared with the prior macromers, so that the macromers do not need to be polymerized at a higher temperature in the preparation process of the water reducer, can be polymerized in a shorter time, can shorten the industrial production time and reduce the production preparation temperature. However, the addition of a single anionic polycarboxylate water reducer does not allow the dispersion of calcined kaolin.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a preparation method of a water reducer for a calcined kaolin-cement system, and the water reducer obtained by the method can improve the fluidity and the flow retention of the calcined kaolin-cement composite system and can also improve the cement strength.
The invention also aims to provide the water reducer for the calcined kaolin-cement system, which is obtained by the preparation method.
Another object of the present invention is to provide the use of a water reducing agent for calcined kaolin-cement systems in calcined kaolin-cement composite systems.
The aim of the invention is achieved by the following technical scheme.
The preparation method of the water reducer for the calcined kaolin-cement system comprises the following steps:
step 1, adding hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) and an oxidant into water, and uniformly stirring until the hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) and the oxidant are dissolved to obtain a mixed solution, wherein the hydroxybutyl vinyl polyoxyethylene ether, the oxidant and the water are in the following ratio (27-29) in parts by mass: (0.8-1.2) 35-45;
in the step 1, the stirring is carried out in a water bath at the temperature of 10-20 ℃.
In the step 1, the oxidant is hydrogen peroxide or potassium persulfate.
Step 2, adding 1-2 parts of carboxylic acid monomers and 1-2 parts of cationic monomers into 8-12 parts of water according to parts by weight, and stirring until the monomers are dissolved to obtain a mixed solution A; adding 0.2-0.3 part of reducing agent into 4-6 parts of water, and stirring until the reducing agent is dissolved to obtain a mixed solution B; adding 0.02-0.04 part of chain transfer agent into 4-6 parts of water, and stirring until the chain transfer agent is dissolved to obtain a mixed solution C;
in the step 2, the carboxylic acid monomer is acrylic acid, maleic anhydride or itaconic acid.
In the step 2, the cationic monomer is dimethyl diallyl ammonium chloride or methacryloyloxyethyl trimethyl ammonium chloride.
In the step 2, the reducing agent is ascorbic acid, sodium sulfite or sodium thiosulfate.
In the step 2, the chain transfer agent is 3-mercaptopropionic acid or sodium hypophosphite.
And 3, simultaneously dripping the mixed solution A, the mixed solution B and the mixed solution C obtained in the step 2 into the mixed solution obtained in the step 1, uniformly stirring, and regulating the pH to 6-7 to obtain the water reducer for the calcined kaolin-cement system.
In the step 3, the stirring is carried out in a water bath at the temperature of 10-20 ℃.
In the step 3, the stirring time is 20-40 min.
In the step 3, the pH is adjusted to 6 to 7 with a sodium hydroxide solution.
The water reducer for the calcined kaolin-cement system is prepared by the preparation method.
The application of the water reducer for the calcined kaolin-cement system in the calcined kaolin-cement composite system comprises the following steps:
the calcined kaolin-cement system is stirred uniformly by using a water reducing agent and water, and is added into a calcined kaolin-cement composite system, wherein the mass of the water reducing agent for the calcined kaolin-cement system accounts for 0.3-0.6% of the total mass of the calcined kaolin-cement composite system, the ratio of the mass of water to the mass of the calcined kaolin-cement composite system is 0.45, and the calcined kaolin-cement composite system comprises 10-30 parts of calcined kaolin and 70-90 parts of cement according to parts by weight.
The invention has the advantages and beneficial effects that:
1. the preparation method of the invention uses water as a dispersion medium, has simple preparation process and low cost, and is easy to realize industrial production.
2. From the aspect of molecular structure design, VPEG has higher activity, so the synthesis of the invention can be prepared in a short period at low temperature without higher temperature, and the production condition is simplified.
3. The water reducer for the calcined kaolin-cement system, which is obtained by the invention, has the advantages that the adsorption capacity of the water reducer on the surface of the calcined kaolin is increased by introducing cations, so that the water reducer has the maximum adsorption capacity on the whole calcined kaolin-cement composite system, the steric hindrance performance of a long side chain can be fully exerted, the water requirement and rheological property of the calcined kaolin-cement composite system can be effectively reduced, the dispersing effect on cement particles is better, the adaptability to cement is better, and the water reducer is suitable for being used in engineering.
4. The invention improves the fluidity retention of the calcined kaolin-cement slurry by increasing the fluidity of the calcined kaolin-cement slurry.
5. The invention can improve the strength of the composite cement stone.
6. The water reducer for the calcined kaolin-cement system has the advantages of simple preparation process, low cost, easiness in storage and the like. The water reducer successfully polymerizes high-activity six-carbon polyether macromonomer, carboxylic acid monomer and cationic monomer to prepare the product. The water reducer has the advantage of low-temperature polymerization, does not need to have excessive temperature in the preparation process, and provides convenience for industrial production. Meanwhile, the addition of the water reducer enables the fluidity and the flow retention of the calcined kaolin-cement composite system to be excellent. The addition of the water reducing agent solves the problem of slurry fluidity reduction caused by the addition of calcined kaolin, expands the application range of the calcined kaolin in cement, and ensures that the cured cement stone has the effect of strength improvement. In general, the water reducer has excellent water reducing performance, is a high-efficiency low-temperature polymerized water reducer, and is suitable for a calcined kaolin-cement composite system.
Drawings
FIG. 1 is an infrared spectrum of a water reducing agent for a calcined kaolin-cement composite system prepared in example 1.
FIG. 2 is an illustration of the effect of the water reducer for calcined kaolin-cement composite systems prepared in example 1 on the flow retention of cement paste.
FIG. 3 shows the adsorption of the water reducer for calcined kaolin-cement system prepared in example 1 in each system.
Detailed Description
The technical scheme of the invention is further described below with reference to specific embodiments.
Example 1
The preparation method of the water reducer for the calcined kaolin-cement system comprises the following steps:
step 1, adding hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) and an oxidant into water, and uniformly stirring in a water bath at 10 ℃ to obtain a mixed solution, wherein the ratio of the hydroxybutyl vinyl polyoxyethylene ether to the oxidant to the water is 27.81 in parts by weight: 1:40, the oxidant is hydrogen peroxide;
step 2, adding 1.48 parts of carboxylic acid monomers and 1.11 parts of cationic monomers into 10 parts of water according to parts by weight, and stirring until the monomers are dissolved to obtain a mixed solution A; adding 0.25 part of reducing agent into 5 parts of water, and stirring until the reducing agent is dissolved to obtain a mixed solution B; adding 0.03 part of chain transfer agent into 5 parts of water, and stirring until the chain transfer agent is dissolved to obtain a mixed solution C, wherein the carboxylic acid monomer is acrylic acid, the cationic monomer is dimethyl diallyl ammonium chloride, the reducing agent is ascorbic acid, and the chain transfer agent is 3-mercaptopropionic acid.
And 3, simultaneously dropwise adding the mixed solution A, the mixed solution B and the mixed solution C obtained in the step 2 into the mixed solution obtained in the step 1, stirring for 30min in a water bath at 10 ℃ until the mixed solution is uniform, and regulating the pH to 6-7 by using a sodium hydroxide solution (a mixed solution of sodium hydroxide and water) to obtain the water reducer for the calcined kaolin-cement system.
Example 2
The preparation method of the water reducer for the calcined kaolin-cement system comprises the following steps:
step 1, adding hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) and an oxidant into water, and uniformly stirring in a water bath at 15 ℃ to obtain a mixed solution, wherein the ratio of the hydroxybutyl vinyl polyoxyethylene ether to the oxidant to the water is 27 in parts by weight: 1.2:35, wherein the oxidant is potassium persulfate;
step 2, adding 1 part of carboxylic acid monomer and 1 part of cationic monomer into 12 parts of water according to parts by weight, and stirring until the monomers are dissolved to obtain a mixed solution A; adding 0.2 part of reducing agent into 4 parts of water, and stirring until the reducing agent is dissolved to obtain a mixed solution B; adding 0.02 part of chain transfer agent into 6 parts of water, and stirring until the chain transfer agent is dissolved to obtain a mixed solution C, wherein the carboxylic acid monomer is maleic anhydride, the cationic monomer is methacryloyloxyethyl trimethyl ammonium chloride, the reducing agent is sodium sulfite, and the chain transfer agent is sodium hypophosphite.
And 3, simultaneously dropwise adding the mixed solution A, the mixed solution B and the mixed solution C obtained in the step 2 into the mixed solution obtained in the step 1, stirring for 20min in a water bath at 15 ℃ until the mixed solution is uniform, and regulating the pH to 6-7 by using a sodium hydroxide solution (a mixed solution of sodium hydroxide and water) to obtain the water reducer for the calcined kaolin-cement system.
Example 3
The preparation method of the water reducer for the calcined kaolin-cement system comprises the following steps:
step 1, adding hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) and an oxidant into water, and uniformly stirring in a water bath at 20 ℃ to obtain a mixed solution, wherein the ratio of the hydroxybutyl vinyl polyoxyethylene ether to the oxidant to the water is 29:0.8:45, wherein the oxidant is hydrogen peroxide;
2, adding 2 parts of carboxylic acid monomers and 6 parts of cationic monomers into 8 parts of water according to parts by weight, and stirring until the monomers are dissolved to obtain a mixed solution A; adding 0.3 part of reducing agent into 4 parts of water, and stirring until the reducing agent is dissolved to obtain a mixed solution B; adding 0.04 part of chain transfer agent into 4 parts of water, and stirring until the chain transfer agent is dissolved to obtain a mixed solution C, wherein the carboxylic acid monomer is itaconic acid, the cationic monomer is methacryloyloxyethyl trimethyl ammonium chloride, the reducing agent is sodium sulfite, and the chain transfer agent is sodium hypophosphite.
And 3, simultaneously dropwise adding the mixed solution A, the mixed solution B and the mixed solution C obtained in the step 2 into the mixed solution obtained in the step 1, stirring for 40min in a water bath at 20 ℃ until the mixed solution is uniform, and regulating the pH to 6-7 by using a sodium hydroxide solution (a mixed solution of sodium hydroxide and water) to obtain the water reducer for the calcined kaolin-cement system.
Example 4
The preparation method of the water reducer for the calcined kaolin-cement system comprises the following steps:
step 1, adding hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) and an oxidant into water, and uniformly stirring in a water bath at 10 ℃ to obtain a mixed solution, wherein the ratio of the hydroxybutyl vinyl polyoxyethylene ether to the oxidant to the water is 28:1:40, wherein the oxidant is potassium persulfate;
step 2, adding 1.5 parts of carboxylic acid monomers and 1.5 parts of cationic monomers into 9 parts of water according to parts by weight, and stirring until the monomers are dissolved to obtain a mixed solution A; adding 0.27 part of reducing agent into 5 parts of water, and stirring until the reducing agent is dissolved to obtain a mixed solution B; adding 0.03 part of chain transfer agent into 5 parts of water, and stirring until the chain transfer agent is dissolved to obtain a mixed solution C, wherein the carboxylic acid monomer is itaconic acid, the cationic monomer is dimethyl diallyl ammonium chloride, the reducing agent is sodium thiosulfate, and the chain transfer agent is sodium hypophosphite.
And 3, simultaneously dropwise adding the mixed solution A, the mixed solution B and the mixed solution C obtained in the step 2 into the mixed solution obtained in the step 1, stirring for 20min in a water bath at 10 ℃ until the mixed solution is uniform, and regulating the pH to 6-7 by using a sodium hydroxide solution (a mixed solution of sodium hydroxide and water) to obtain the water reducer for the calcined kaolin-cement system.
Example 5
The application of the water reducer for the calcined kaolin-cement system prepared in the embodiment comprises the following steps:
in a slurry cup, uniformly stirring water and the calcined kaolin-cement system water reducer at 62 revolutions per minute, adding the calcined kaolin-cement composite system for 2 minutes, stopping for 15 seconds, and stirring at a high speed of 125 revolutions per minute for 2 minutes to finish slurry stirring to obtain 4 calcined kaolin-cement slurry systems, wherein the mass of the calcined kaolin-cement system water reducer accounts for 0.4% of the total mass of the calcined kaolin-cement composite system, the ratio of the mass of water to the mass of the calcined kaolin-cement composite system is 0.45, and the calcined kaolin-cement composite system is 20 parts of calcined kaolin and 80 parts of cement in parts by mass, wherein the calcined kaolin-cement system water reducer is the water reducer prepared in any one of examples 1-4.
Comparative example
The preparation method of the anionic water reducer for the calcined kaolin-cement system comprises the following steps:
step 1, adding hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) and an oxidant into water, and uniformly stirring in a water bath at 10 ℃ to obtain a mixed solution, wherein the ratio of the hydroxybutyl vinyl polyoxyethylene ether to the oxidant to the water is 27.98:1:40, the oxidant is hydrogen peroxide;
step 2, adding 2.02 parts of carboxylic acid monomers into 10 parts of water according to parts by weight, and stirring until the carboxylic acid monomers are dissolved to obtain a mixed solution A; adding 0.25 part of reducing agent into 5 parts of water, and stirring until the reducing agent is dissolved to obtain a mixed solution B; adding 0.03 part of chain transfer agent into 5 parts of water, and stirring until the chain transfer agent is dissolved to obtain a mixed solution C, wherein the carboxylic acid monomer is acrylic acid, the cationic monomer is dimethyl diallyl ammonium chloride, the reducing agent is ascorbic acid, and the chain transfer agent is 3-mercaptopropionic acid.
And 3, simultaneously dripping the mixed solution A, the mixed solution B and the mixed solution C obtained in the step 2 into the mixed solution obtained in the step 1, stirring for 30min in a water bath at 10 ℃ until the mixed solution is uniform, and regulating the pH to 6-7 by using a sodium hydroxide solution (a mixed solution of sodium hydroxide and water) to obtain the anionic water reducer for the calcined kaolin-cement system.
The application of the anionic water reducer for the calcined kaolin-cement system prepared in the comparative example comprises the following steps:
in a slurry cup, uniformly stirring water and the calcined kaolin-cement system by using an anionic water reducer at 62 revolutions per minute, adding the calcined kaolin-cement composite system for 2 minutes, stopping for 15 seconds, and stirring at a high speed of 125 revolutions per minute for 2 minutes to finish stirring to obtain a cement slurry system, wherein the mass of the calcined kaolin-cement system by using the anionic water reducer accounts for 0.4% of the total mass of the calcined kaolin-cement composite system, the ratio of the mass of water to the mass of the calcined kaolin-cement composite system is 0.45, and the calcined kaolin-cement composite system is 20 parts of calcined kaolin and 80 parts of cement according to parts by mass.
The performance impact of the water reduction rate, fluidity and compressive strength of the 4 calcined kaolin-cement slurry systems prepared in example 5 and the cement slurry system prepared in comparative example were evaluated, and the results are shown in tables 1, 2 and 3, respectively.
TABLE 1
As can be seen from Table 1, the water reducing agent for calcined kaolin-cement system obtained in the examples has a large water reducing rate in calcined kaolin-cement composite system, so that the amount of water in the mixing water of calcined kaolin-cement composite system can be greatly reduced. The water reducer for the calcined kaolin-cement system enables water wrapped in the flocculation structure of the calcined kaolin-cement composite system to be released, so that the water demand of the composite system is reduced.
TABLE 2
Table 2 shows the effect of the water reducer for calcined kaolin-cement systems on the fluidity of calcined kaolin-cement composite systems. As is clear from Table 2, after the water reducer for the two-calcined kaolin-cement system prepared in the examples was added, the fluidity of the calcined kaolin-cement composite system was increased, and the fluidity was significantly improved as compared with that of the blank sample. The water reducer for the calcined kaolin-cement system damages the flocculation structure of cement particles, and meanwhile, the wrapped mixing water is released in the system, so that cement and kaolin particles can be dispersed, and the whole composite system has better fluidity.
TABLE 3 Table 3
Table 3 shows the effect of the water reducer for calcined kaolin-cement system on the compressive strength of the composite cement obtained after curing the calcined kaolin-cement composite slurry for 3 days. As is clear from Table 3, the compressive strength of the composite cement was increased by adding the water reducer for calcined kaolin-cement system prepared in the examples. The addition of the water reducer for the calcined kaolin-cement system improves the dispersibility of the slurry, reduces the number of pores formed by the evaporation of free water in a flocculation structure, and ensures that the cement stone becomes compact; meanwhile, the water release in the flocculation structure increases the hydration degree, thereby promoting the development of the mechanical strength of the cement stone.
FIG. 1 is an infrared spectrum of a water reducer for calcined kaolin-cement system prepared in example 1. The characteristic absorption peak is: 2880cm -1 Is the stretching vibration peak of methyl; 1730cm -1 Is the absorption peak of-c=o in monomeric acrylic acid; 1340cm -1 The characteristic absorption peak of-CN in the cationic monomer dimethyl diallyl ammonium chloride; 1110cm -1 Is the characteristic absorption peak of ether bond group in VPEG structural unit; the presence of all the groups proves that the calcined kaolin-cement system water reducer is successfully synthesized.
FIG. 2 is an illustration of the effect of the water reducer for calcined kaolin-cement systems prepared in example 1 on the flow retention of calcined kaolin-cement composite slurries. As can be seen from fig. 2, the mass ratio of calcined kaolin to cement is 2:8, the fluidity of the cement is reduced, and the calcined kaolin-cement composite slurry has good fluidity retention within 2 hours after the synthesized calcined kaolin-cement system water reducer is added. The addition of the water reducer for the calcined kaolin-cement system causes the flocculation structure in the composite slurry to be destroyed, and the calcined kaolin and cement particles are dispersed relatively, so that the fluidity of the composite slurry is improved. The steric hindrance effect of the water reducer is not dissipated, and the water reducer has good retention.
FIG. 3 shows the adsorption of the water reducer for calcined kaolin-cement system prepared in example 1 in each system. As can be seen from fig. 3, the water reducer for calcined kaolin-cement system has the maximum adsorption amount in the calcined kaolin-cement composite system, while the adsorption amount in the single cement or the single calcined kaolin system is smaller. The carboxylic acid monomer in the water reducer adsorbs the integral water reducer polymer on the surface of cement particles, and the polymer can be adsorbed in the calcined kaolin laminate in an electrostatic attraction way through the cationic monomer, so that the water reducer for the calcined kaolin-cement system has the maximum adsorption amount in the calcined kaolin-cement composite system.
The foregoing has described exemplary embodiments of the invention, it being understood that any simple variations, modifications, or other equivalent arrangements which would not unduly obscure the invention may be made by those skilled in the art without departing from the spirit of the invention.
Claims (10)
1. The preparation method of the water reducer for the calcined kaolin-cement system is characterized by comprising the following steps of:
step 1, adding hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) and an oxidant into water, and uniformly stirring until the hydroxybutyl Vinyl Polyoxyethylene Ether (VPEG) and the oxidant are dissolved to obtain a mixed solution, wherein the hydroxybutyl vinyl polyoxyethylene ether, the oxidant and the water are in the following ratio (27-29) in parts by mass: (0.8-1.2) 35-45;
step 2, adding 1-2 parts of carboxylic acid monomers and 1-2 parts of cationic monomers into 8-12 parts of water according to parts by weight, and stirring until the monomers are dissolved to obtain a mixed solution A; adding 0.2-0.3 part of reducing agent into 4-6 parts of water, and stirring until the reducing agent is dissolved to obtain a mixed solution B; adding 0.02-0.04 part of chain transfer agent into 4-6 parts of water, and stirring until the chain transfer agent is dissolved to obtain a mixed solution C;
and 3, simultaneously dripping the mixed solution A, the mixed solution B and the mixed solution C obtained in the step 2 into the mixed solution obtained in the step 1, uniformly stirring, and regulating the pH to 6-7 to obtain the water reducer for the calcined kaolin-cement system.
2. The method according to claim 1, wherein in the step 1, the stirring is performed in a water bath at 10 to 20 ℃.
3. The method according to claim 1, wherein in the step 1, the oxidizing agent is hydrogen peroxide or potassium persulfate.
4. The method according to claim 1, wherein in the step 2, the carboxylic acid monomer is acrylic acid, maleic anhydride or itaconic acid.
5. The method according to claim 1, wherein in the step 2, the cationic monomer is dimethyldiallylammonium chloride or methacryloyloxyethyl trimethyl ammonium chloride.
6. The method according to claim 1, wherein in the step 2, the reducing agent is ascorbic acid, sodium sulfite or sodium thiosulfate, and the chain transfer agent is 3-mercaptopropionic acid or sodium hypophosphite.
7. The method according to claim 1, wherein in the step 3, the stirring is performed in a water bath at 10 to 20 ℃, and the stirring time is 20 to 40 minutes.
8. The method according to claim 1, wherein in the step 3, the pH is adjusted to 6 to 7 with a sodium hydroxide solution.
9. A water reducer for calcined kaolin-cement systems obtained by the production method according to any one of claims 1 to 8.
10. Use of the water reducer for calcined kaolin-cement systems according to claim 9, in calcined kaolin-cement composite systems, comprising the following steps:
the calcined kaolin-cement system is stirred uniformly by using a water reducing agent and water, and is added into a calcined kaolin-cement composite system, wherein the mass of the water reducing agent for the calcined kaolin-cement system accounts for 0.3-0.6% of the total mass of the calcined kaolin-cement composite system, the ratio of the mass of water to the mass of the calcined kaolin-cement composite system is 0.45, and the calcined kaolin-cement composite system comprises 10-30 parts of calcined kaolin and 70-90 parts of cement according to parts by weight.
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| CN202310212501.5A CN116217830A (en) | 2023-03-07 | 2023-03-07 | Water reducer for calcined kaolin-cement system, and preparation method and application thereof |
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| CN115926073A (en) * | 2022-12-02 | 2023-04-07 | 西南石油大学 | Nano calcium carbonate modified acrylamide amphoteric copolymer and preparation method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115926073A (en) * | 2022-12-02 | 2023-04-07 | 西南石油大学 | Nano calcium carbonate modified acrylamide amphoteric copolymer and preparation method thereof |
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