CN115536779A - Carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent and preparation method thereof - Google Patents
Carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent and preparation method thereof Download PDFInfo
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- CN115536779A CN115536779A CN202211032280.5A CN202211032280A CN115536779A CN 115536779 A CN115536779 A CN 115536779A CN 202211032280 A CN202211032280 A CN 202211032280A CN 115536779 A CN115536779 A CN 115536779A
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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
- C08F251/00—Macromolecular compounds obtained by polymerising monomers on to polysaccharides or derivatives thereof
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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
- C04B24/38—Polysaccharides or derivatives thereof
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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
- C04B24/38—Polysaccharides or derivatives thereof
- C04B24/383—Cellulose or derivatives thereof
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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
- C08F251/00—Macromolecular compounds obtained by polymerising monomers on to polysaccharides or derivatives thereof
- C08F251/02—Macromolecular compounds obtained by polymerising monomers on to polysaccharides or derivatives thereof on to cellulose or derivatives thereof
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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
- C04B2103/46—Water-loss or fluid-loss reducers, hygroscopic or hydrophilic agents, water retention agents
- C04B2103/465—Water-sorbing agents, hygroscopic or hydrophilic agents
Abstract
The invention discloses a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent, which comprises the following raw materials in parts by weight: 5-25 parts of unsaturated carboxylic acid monomer, 30-50 parts of unsaturated amide monomer, 20-40 parts of functional monomer, 2-5 parts of cross-linking agent and 3-7 parts of initiator. The invention also discloses a preparation method of the carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent. The water-retaining agent prepared by the invention can effectively reduce the bleeding rate of the concrete mixture, improve the water-retaining property of the concrete mixture and simultaneously improve the workability of the concrete mixture.
Description
Technical Field
The invention relates to the technical field of building materials, in particular to a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent and a preparation method thereof.
Background
The polycarboxylate superplasticizer becomes a high-performance concrete admixture after a lignin superplasticizer and a naphthalene series superplasticizer due to the properties of low mixing amount, high water reduction, strong dispersion, low slump loss and the like, and is widely applied to capital construction and various large-scale concrete construction projects. However, with the development of economy, high speed and high quality in China, the quantity of various building projects is increased rapidly, so that raw material resources such as high-quality sandstone and the like are exhausted day by day, and with the policy of prohibiting river sand mining which is implemented in recent years, a large amount of machine-made sandstone with high mud content, poor particle grading and poor quality becomes a main aggregate component of concrete, the compatibility of a polycarboxylic acid water reducing agent and materials is weakened, the phenomena of poor wrapping property, low cohesiveness, quick slump loss, high bleeding segregation rate and the like of fresh concrete occur, and the workability and the working performance of the concrete are reduced. Meanwhile, the variety and quality of mineral admixtures in the cement bring the problems of adaptability and sensitivity of the polycarboxylic acid water reducing agent.
In order to solve the problems, some chemical substances capable of increasing the viscosity of the mixture, such as polyvinyl alcohol, thermometer glue, cellulose ether, polyacrylamide, starch ether and the like, are often compounded with a polycarboxylic acid water reducing agent in the production process of concrete, so that the viscosity of the concrete mixture is improved, and the purposes of reducing segregation, bottom grabbing and bleeding amplification are achieved. However, although these chemicals have a certain effect of improving the viscosity of concrete, they have a large molecular weight, low solubility, and a slow dissolution rate, and are very prone to agglomeration, flocculation, and delamination during the compounding process of the additive, which affects the working performance and long-term storage stability of the product. In addition, the chemical substances can improve the viscosity of the concrete and simultaneously reduce the flowing property of the concrete, thereby being not beneficial to long-distance transportation and pumping construction.
Disclosure of Invention
The invention aims to provide a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent and a preparation method thereof, which are used for solving the technical problems of poor wrapping property, low cohesiveness, quick slump loss and high bleeding segregation rate of concrete caused by weak compatibility of a polycarboxylic acid water reducing agent and materials in the prior art.
In order to achieve the above purpose, an embodiment of the present invention provides a carboxyl-hydroxyl condensation crosslinking type concrete water retention agent, which comprises the following raw materials in parts by weight:
5 to 25 parts of unsaturated carboxylic acid monomer, 30 to 50 parts of unsaturated amide monomer,
20-40 parts of functional monomer, 2-5 parts of cross-linking agent and 3-7 parts of initiator.
In a preferred embodiment of the present invention, the unsaturated carboxylic acid monomer is at least one of acrylic acid, methacrylic acid, sodium acrylate, maleic acid, maleic anhydride, fumaric acid, and itaconic acid.
In a preferred embodiment of the present invention, the unsaturated amide monomer is at least one of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and N-isopropylacrylamide.
In a preferred embodiment of the present invention, the functional monomer is at least one selected from the group consisting of maltodextrin, cyclodextrin, yellow dextrin, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose, cellulose ether, carboxyethyl cellulose ether, cellulose hydroxyalkyl ether, hydroxypropyl methyl cellulose ether, hydroxyethyl methyl cellulose ether, potato starch ether, corn starch ether, tapioca starch ether, wheat starch ether, guar gum ether, and hydroxypropyl starch ether.
In a preferred embodiment of the present invention, the cross-linking agent is at least one selected from the group consisting of N, N-methylenebisacrylamide, sodium trimetaphosphate, phosphorus oxychloride, adipic acid, isocyanate, sodium p-styrenesulfonate, N-methylolacrylamide, and polyethylene glycol.
In a preferred embodiment of the present invention, the initiator is at least one of ammonium persulfate, potassium persulfate, azobisisobutylamidine hydrochloride, sodium bisulfite, vitamin C, and sodium thiosulfate.
Based on the carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent disclosed by the invention, the invention also discloses a preparation method of the carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent, which comprises the following steps:
step (1): mixing an initiator and water to prepare a solution A, and mixing an unsaturated carboxylic acid monomer and water to prepare a solution B; putting the unsaturated amide monomers, the functional monomers and water into a flask, and uniformly mixing to prepare a bottom material solution C;
step (2): and adding a cross-linking agent into the bottom material solution C in the flask, then simultaneously dropwise adding the solution A and the solution B into the flask, stirring while dropwise adding, continuously stirring after dropwise adding is finished, adding water for diluting after stirring is finished, and adjusting the pH value by using a sodium hydroxide solution to obtain the carboxyl-hydroxyl condensation cross-linking type concrete water-retaining agent.
In one preferable scheme of the invention, the dripping time of the solution A and the dripping time of the solution B in the step (2) are both 0.5h-2.5h, the continuous stirring time is 1.5h-3h, and the pH value is adjusted to 5-6.
In conclusion, the beneficial effects of the invention are as follows:
1. the functional monomer is cellulose or starch and derivatives thereof, is a green raw material, has the characteristics of wide source, low price, environmental friendliness and the like, is used as a raw material to form a composite cross-linked three-dimensional space structure after being subjected to micro cross-linking with an unsaturated carboxylic acid monomer, and has strong water absorption capacity, so that on one hand, the cohesiveness of a concrete mixture is improved, and the slump loss, delamination and bleeding of slurry are effectively reduced; on the other hand, the water-retaining agent molecule with a cross-linked structure has certain space benefit, and the aggregation tendency of cement particles is weakened, so that the stability of a concrete mixture system is improved.
2. The functional monomer in the invention is cellulose or starch and derivatives thereof, is a polymer with a flexible long chain with less branches and a spiral monomer structure, and contains-COOH and-CONH on the main chain or the branch chain 2 And hydrophilic groups such as-OH and the like have surface activity, so that the surface tension of water can be greatly reduced, and the mutual movement resistance of the concrete mixture in the flowing process can be effectively reduced.
3. In the invention, the unsaturated amide monomer is introduced into the cross-linked three-dimensional space structure in a copolymerization mode with the unsaturated carboxylic acid monomer, so that the cross-linking density of the cross-linking structure is improved, and the structural strength of the carboxyl-hydroxyl condensation cross-linking type concrete water-retaining agent is further ensured.
Detailed Description
The invention discloses a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent, which comprises the following raw materials in parts by weight:
5-25 parts of unsaturated carboxylic acid monomer, 30-50 parts of unsaturated amide monomer, 20-40 parts of functional monomer, 2-5 parts of cross-linking agent and 3-7 parts of initiator.
Wherein, the unsaturated carboxylic acid monomer is at least one of acrylic acid, methacrylic acid, sodium acrylate, maleic acid, maleic anhydride, fumaric acid and itaconic acid; the unsaturated amide monomer is at least one of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid and N-isopropylacrylamide; the functional monomer is at least one of maltodextrin, cyclodextrin, yellow dextrin, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose, cellulose ether, carboxyethyl cellulose ether, cellulose hydroxyalkyl ether, hydroxypropyl methyl cellulose ether, hydroxyethyl methyl cellulose ether, potato starch ether, corn starch ether, cassava starch ether, wheat starch ether, guar gum ether and hydroxypropyl starch ether; the cross-linking agent is at least one of N, N-methylene bisacrylamide, sodium trimetaphosphate, phosphorus oxychloride, adipic acid, isocyanate, sodium p-styrene sulfonate, N-hydroxymethyl acrylamide and polyethylene glycol; the initiator is at least one of ammonium persulfate, potassium persulfate, azodiisobutyl amidine hydrochloride, sodium bisulfite, vitamin C and sodium thiosulfate.
The invention also discloses a preparation method of the carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent, which comprises the following steps:
step (1): mixing an initiator and water to prepare a solution A, and mixing an unsaturated carboxylic acid monomer and water to prepare a solution B; putting the unsaturated amide monomers, the functional monomers and water into a flask, and uniformly mixing to prepare a uniform bottom material solution C;
step (2): adding a cross-linking agent into the bottom material solution C in the flask, then simultaneously dropwise adding the solution A and the solution B into the flask, slowly stirring while dropwise adding, wherein the dropwise adding time of the solution A and the dropwise adding time of the solution B are both 0.5h-2.5h, continuously stirring for 1.5h-3h after dropwise adding is finished, adding water for diluting after stirring is finished, and adjusting the pH value to 5-6 by using a sodium hydroxide solution to obtain the carboxyl-hydroxyl condensation cross-linking type concrete water-retaining agent.
Example 1
The carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following raw materials in parts by weight:
10 parts of unsaturated carboxylic acid monomer acrylic acid, 35 parts of unsaturated amide monomer 2-acrylamide-2-methylpropanesulfonic acid, 30 parts of functional monomer maltodextrin, 2 parts of cross-linking agent N, N-methylene bisacrylamide and 3 parts of initiator ammonium persulfate.
A preparation method of a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following steps:
step (1): mixing 3 parts of ammonium persulfate and 60 parts of water to prepare a solution A, and mixing 10 parts of acrylic acid and 50 parts of water to prepare a solution B; then 35 parts of 2-acrylamide-2-methylpropanesulfonic acid and 30 parts of maltodextrin are put into a round-bottom flask provided with a thermometer and a stirrer, 190 parts of water is added and stirred uniformly, and uniform bottom material solution C is prepared;
step (2): adding 2 parts of N, N-methylene bisacrylamide into the bottom material solution C in the flask, then simultaneously dropwise adding the solution A and the solution B into the flask, slowly stirring while dropwise adding, wherein the dropwise adding time of the solution A and the dropwise adding time of the solution B are both 0.5h, continuously stirring for 2.5h after dropwise adding is finished, adding 370 parts of water for diluting after stirring is finished, and adjusting the pH to 5-6 by using a sodium hydroxide solution to obtain the carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent.
Example 2
The carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following raw materials in parts by weight:
15 parts of unsaturated carboxylic acid monomer, 30 parts of unsaturated amide monomer acrylamide, 35 parts of functional monomer corn starch ether, 3 parts of cross-linking agent and 5 parts of initiator.
Wherein, the unsaturated carboxylic acid monomer is a mixture of 10 parts of maleic acid and 5 parts of itaconic acid; the cross-linking agent is a mixture of 2 parts of N, N-methylene bisacrylamide and 1 part of N-hydroxymethyl acrylamide; the initiator is a mixture of 3 parts ammonium persulfate and 2 parts sodium bisulfite.
A preparation method of a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following steps:
step (1): mixing 3 parts of ammonium persulfate, 2 parts of sodium bisulfite and 60 parts of water to prepare a solution A, and mixing 10 parts of maleic acid, 5 parts of itaconic acid and 60 parts of water to prepare a solution B; placing 30 parts of acrylamide and 35 parts of corn starch ether into a round-bottom flask provided with a thermometer and a stirrer, adding 195 parts of water, and uniformly stirring to prepare a uniform bottom material solution C;
step (2): adding 2 parts of N, N-methylene bisacrylamide and 1 part of N-hydroxymethyl acrylamide into the bottom material solution C in the flask, then simultaneously dropwise adding the solution A and the solution B into the flask, slowly stirring while dropwise adding, wherein the dropwise adding time of the solution A and the dropwise adding time of the solution B are both 1h, continuously stirring for 2h after the dropwise adding is finished, adding 397 parts of water for diluting after the stirring is finished, and adjusting the pH value to 5-6 by using a sodium hydroxide solution to obtain the carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent.
Example 3
A carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following raw materials in parts by weight:
25 parts of unsaturated carboxylic acid monomer, 45 parts of unsaturated amide monomer, 35 parts of functional monomer, 5 parts of cross-linking agent and 6 parts of initiator;
wherein the unsaturated carboxylic acid monomer is a mixture of 17 parts of fumaric acid and 8 parts of itaconic acid; the unsaturated amide monomer is a mixture of 20 parts of 2-acrylamide-2-methylpropanesulfonic acid and 25 parts of N-isopropylacrylamide; the functional monomer is a mixture of 20 parts of hydroxypropyl methyl cellulose and 15 parts of cyclodextrin; the cross-linking agent is 3 parts of N, N-methylene-bisacrylamide and 2 parts of sodium p-styrene sulfonate; the initiator is a mixture of 4 parts potassium persulfate and 2 parts vitamin C.
A preparation method of a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following steps:
step (1): mixing 4 parts of potassium persulfate, 2 parts of vitamin C and 60 parts of water to prepare a solution A, and mixing 17 parts of fumaric acid, 8 parts of itaconic acid and 60 parts of water to prepare a solution B; then 20 parts of 2-acrylamide-2-methylpropanesulfonic acid, 25 parts of N-isopropylacrylamide, 20 parts of hydroxypropyl methylcellulose and 15 parts of cyclodextrin are placed into a round-bottom flask provided with a thermometer and a stirrer, 294 parts of water is added, and the mixture is stirred uniformly to prepare a uniform bottom material solution C;
step (2): adding 3 parts of N, N-methylene bisacrylamide and 2 parts of sodium p-styrenesulfonate into the bottom material solution C in the flask, then simultaneously dropwise adding the solution A and the solution B into the flask, slowly stirring while dropwise adding, wherein the dropwise adding time of the solution A and the dropwise adding time of the solution B are both 1.5h, continuously stirring for 1.5h after the dropwise adding is finished, adding 520 parts of water for diluting after the stirring is finished, and adjusting the pH to 5-6 by using a sodium hydroxide solution to obtain the carboxyl-hydroxyl condensation crosslinking type water-retaining agent concrete.
Example 4
A carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following raw materials in parts by weight:
20 parts of unsaturated carboxylic acid monomer, 40 parts of unsaturated amide monomer N-isopropyl acrylamide, 38 parts of functional monomer, 4 parts of cross-linking agent sodium trimetaphosphate and 5 parts of initiator;
wherein the unsaturated carboxylic acid monomer is a mixture of 5 parts of methacrylic acid, 10 parts of itaconic acid and 5 parts of maleic anhydride; the functional monomer is a mixture of 30 parts of wheat starch ether and 8 parts of yellow dextrin; the initiator was a mixture of 3.5 parts ammonium persulfate and 1.5 parts sodium thiosulfate.
A preparation method of a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following steps:
step (1): mixing 3.5 parts of ammonium persulfate, 1.5 parts of sodium thiosulfate and 60 parts of water to prepare a solution A, and mixing 5 parts of methacrylic acid, 10 parts of itaconic acid, 5 parts of maleic anhydride and 55 parts of water to prepare a solution B; then putting 40 parts of N-isopropylacrylamide, 30 parts of wheat starch ether and 8 parts of yellow dextrin into a round-bottom flask provided with a thermometer and a stirrer, adding 272 parts of water, and uniformly stirring to prepare a uniform bottom material solution C;
step (2): adding 4 parts of sodium trimetaphosphate into a bottom material solution C in a flask, then simultaneously dropwise adding the solution A and the solution B into the flask, slowly stirring while dropwise adding, wherein the dropwise adding time of the solution A and the dropwise adding time of the solution B are both 2 hours, continuously stirring for 1 hour after the dropwise adding is finished, adding 486 parts of water for diluting after the stirring is finished, and adjusting the pH value to 5-6 by using a sodium hydroxide solution to obtain the carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent.
Example 5
The carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following raw materials in parts by weight:
20 parts of unsaturated carboxylic acid monomer, 35 parts of unsaturated amide monomer, 30 parts of functional monomer, 3 parts of cross-linking agent and 6 parts of initiator azo diisobutyl amidine hydrochloride;
wherein the unsaturated carboxylic acid monomer is a mixture of 15 parts of methacrylic acid and 5 parts of fumaric acid; the unsaturated amide monomer is a mixture of 25 parts of acrylamide and 10 parts of N-isopropyl acrylamide; the functional monomer is a mixture of 20 parts of hydroxypropyl methyl cellulose ether and 10 parts of guar gum ether; the cross-linking agent is 2 parts of phosphorus oxychloride and 1 part of N-hydroxymethyl acrylamide.
A preparation method of a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following steps:
step (1): mixing 6 parts of azobisisobutylamidine hydrochloride with 60 parts of water to obtain solution A, and mixing 15 parts of methacrylic acid, 5 parts of fumaric acid and 45 parts of water to obtain solution B; then 25 parts of acrylamide, 10 parts of N-isopropylacrylamide, 20 parts of hydroxypropyl methylcellulose ether and 10 parts of guar gum ether are put into a round-bottom flask provided with a thermometer and a stirrer, 229 parts of water is added and stirred uniformly to prepare a uniform bottom material solution C;
step (2): adding 2 parts of phosphorus oxychloride and 1 part of N-hydroxymethyl acrylamide into the bottom material solution C in the flask, then simultaneously dropwise adding the solution A and the solution B into the flask, slowly stirring while dropwise adding, wherein the dropwise adding time of the solution A and the dropwise adding time of the solution B are both 2.5h, continuously stirring for 0.5h after dropwise adding is finished, adding 422 parts of water for diluting after stirring is finished, and adjusting the pH to 5-6 by using a sodium hydroxide solution to obtain the carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent.
Example 6
The carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following raw materials in parts by weight:
20 parts of unsaturated carboxylic acid monomer, 43 parts of unsaturated amide monomer, 30 parts of functional monomer, 5 parts of cross-linking agent and 5 parts of initiator;
wherein the unsaturated carboxylic acid monomer is a mixture of 5 parts of sodium acrylate, 8 parts of itaconic acid and 7 parts of methacrylic acid; the unsaturated amide monomer is a mixture of 15 parts of acrylamide, 10 parts of 2-acrylamide-2-methylpropanesulfonic acid and 18 parts of N-isopropyl acrylamide; the functional monomer is a mixture of 6 parts of yellow dextrin, 15 parts of hydroxypropyl starch ether and 9 parts of maltodextrin; the cross-linking agent is a mixture of 3 parts of adipic acid and 2 parts of polyethylene glycol; the initiator is a mixture of 2 parts of ammonium persulfate, 2 parts of potassium persulfate and 1 part of vitamin C.
A preparation method of a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent comprises the following steps:
step (1): mixing 2 parts of ammonium persulfate, 2 parts of potassium persulfate, 1 part of vitamin C and 60 parts of water to prepare a solution A, and mixing 5 parts of sodium acrylate, 8 parts of itaconic acid, 7 parts of methacrylic acid and 53 parts of water to prepare a solution B; putting 15 parts of acrylamide, 10 parts of 2-acrylamide-2-methylpropanesulfonic acid, 18 parts of N-isopropylacrylamide, 6 parts of yellow dextrin, 15 parts of hydroxypropyl starch ether and 9 parts of maltodextrin into a round-bottom flask provided with a thermometer and a stirrer, adding 250 parts of water, and uniformly stirring to prepare a uniform bottom material solution C;
step (2): adding 3 parts of adipic acid and 2 parts of polyethylene glycol into the bottom material solution C in the flask, then simultaneously dropwise adding the solution A and the solution B into the flask, slowly stirring while dropwise adding, wherein the dropwise adding time of the solution A and the solution B is 1h, continuously stirring for 1h after the dropwise adding is finished, adding 459 parts of water for diluting after the stirring is finished, and adjusting the pH to 5-6 by using a sodium hydroxide solution to obtain the carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent.
Experimental detection
The water-retaining agents prepared in examples 1-6 above were added to concrete for testing the performance of concrete mixtures, with a comparative example set for comparison, which did not incorporate any sample of water-retaining agent.
The concrete mix formulation is shown in table 1:
table 1: concrete mixing ratio (kg/m) 3 )
| Strength grade | Cement | Fly ash | Sand | Crushing stone | Water (W) |
| C30 | 250 | 80 | 910 | 1000 | 170 |
Wherein the cement is Emei P.O 42.5 cement, the fly ash is second-grade fly ash, the sand is machine-made sand with fineness modulus of 2.6, and the broken stone is continuous graded broken stone with particle size of 5-30 mm; the additive is a polycarboxylate superplasticizer with solid content of 10 percent and a water-retaining agent with the external doping content of 0.6 percent.
The working performance of the concrete mixture is tested according to a detection method in GB/T50080-2016 Standard test method for Performance of common concrete mixtures, and the working performance of the concrete comprises concrete fluidity and bleeding rate.
1. The concrete fluidity detection method specifically comprises the following steps:
(1) Measuring the initial slump value and the expansion value of the concrete mixture during the machine operation;
(2) Filling all concrete mixture samples into a plastic barrel, and sealing and standing the plastic barrel by a barrel cover;
(3) Timing when stirring and water adding are started, after standing for 60min, pouring all concrete mixture samples in the barrel into a stirrer, stirring for 20s, and carrying out a fluidity test to obtain a slump and an expansion value in 60 min;
(4) Timing when stirring and water adding are started, after standing for 120min, pouring all concrete mixture samples in the barrel into a stirrer, stirring for 20s, and carrying out a fluidity test to obtain a slump and an expansion value of 120 min;
2. the concrete bleeding rate detection method specifically comprises the following steps:
(1) Immediately weighing the inner wall of the volumetric cylinder after the inner wall of the volumetric cylinder is wetted by wet cloth, and recording the mass of the volumetric cylinder;
(2) Filling the concrete mixture into a volumetric cylinder, and recording as a sample;
(3) Wiping the opening and the outer surface of the cylinder, weighing and recording the mass of the volumetric cylinder and the sample, covering the cylinder cover and starting timing;
(4) Sucking the surface bleeding of the sample for 1 time every 10min within 60min after the timing is started; after 60min, sucking the surface of the sample for 1 time every 30min until no bleeding occurs.
The bleeding rate was calculated according to the following formula: b = V w /[(W/m 0 )·(m 1 -m 2 )]
Wherein, V w The cumulative total amount (mL) of bleeding of the test sample, m 0 Total mass (g) of the concrete mixture to be mixed for the test, W is total water consumption (mL) of the concrete mixture to be mixed for the test, and m is 1 Is the total mass (g), m, of the volumetric cylinder and the sample 2 The volumetric cylinder mass (g).
The concrete mixture performance test results are shown in table 2:
table 2: working performance of concrete
As can be seen from table 2: the bleeding rate of the examples 1-6 is obviously lower than that of the comparative example, the concrete slump is larger than the slump value of the comparative example, and the expansion difference is small, so that the water-retaining agent prepared in the examples can obviously reduce the bleeding rate of concrete mixture and improve the workability and water retention of concrete.
Therefore, the water-retaining agent prepared by the invention can effectively reduce the bleeding rate of the concrete mixture, improve the water-retaining property of the concrete mixture and improve the workability of the concrete mixture.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (8)
1. The carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent is characterized by comprising the following raw materials in parts by weight:
5 to 25 parts of unsaturated carboxylic acid monomer, 30 to 50 parts of unsaturated amide monomer,
20-40 parts of functional monomer, 2-5 parts of cross-linking agent and 3-7 parts of initiator.
2. The water-retaining agent for concrete of carboxyl-hydroxyl condensation crosslinking type as claimed in claim 1, wherein: the unsaturated carboxylic acid monomer is at least one of acrylic acid, methacrylic acid, sodium acrylate, maleic acid, maleic anhydride, fumaric acid and itaconic acid.
3. The water retaining agent for concrete of carboxyl-hydroxyl condensation crosslinking type as claimed in claim 1, wherein: the unsaturated amide monomer is at least one of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid and N-isopropylacrylamide.
4. The water retaining agent for concrete of carboxyl-hydroxyl condensation crosslinking type as claimed in claim 1, wherein: the functional monomer is at least one of maltodextrin, cyclodextrin, yellow dextrin, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose, cellulose ether, carboxyethyl cellulose ether, cellulose hydroxyalkyl ether, hydroxypropyl methyl cellulose ether, hydroxyethyl methyl cellulose ether, potato starch ether, corn starch ether, cassava starch ether, wheat starch ether, guar gum ether and hydroxypropyl starch ether.
5. The water-retaining agent for concrete of carboxyl-hydroxyl condensation crosslinking type as claimed in claim 1, wherein: the cross-linking agent is at least one of N, N-methylene bisacrylamide, sodium trimetaphosphate, phosphorus oxychloride, adipic acid, isocyanate, sodium p-styrene sulfonate, N-hydroxymethyl acrylamide and polyethylene glycol.
6. The water retaining agent for concrete of carboxyl-hydroxyl condensation crosslinking type as claimed in claim 1, wherein: the initiator is at least one of ammonium persulfate, potassium persulfate, azo diisobutyl amidine hydrochloride, sodium bisulfite, vitamin C and sodium thiosulfate.
7. A preparation method of a carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent is characterized by comprising the following steps:
step (1): mixing an initiator and water to prepare a solution A, and mixing an unsaturated carboxylic acid monomer and water to prepare a solution B; putting the unsaturated amide monomers, the functional monomers and water into a flask, and uniformly mixing to prepare a bottom material solution C;
step (2): and adding a cross-linking agent into the bottom material solution C in the flask, then simultaneously dropwise adding the solution A and the solution B into the flask, stirring while dropwise adding, continuously stirring after dropwise adding is finished, adding water for diluting after stirring is finished, and adjusting the pH value by using a sodium hydroxide solution to obtain the carboxyl-hydroxyl condensation cross-linking type concrete water-retaining agent.
8. The method for preparing the carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent as claimed in claim 7, wherein: in the step (2), the dripping time of the solution A and the dripping time of the solution B are both 0.5h-2.5h, the stirring is continued for 1.5h-3h, and the pH value is adjusted to 5-6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211032280.5A CN115536779A (en) | 2022-08-26 | 2022-08-26 | Carboxyl-hydroxyl condensation crosslinking type concrete water-retaining agent and preparation method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115947560A (en) * | 2023-03-13 | 2023-04-11 | 石家庄市长安育才建材有限公司 | Additive for improving concrete workability and preparation method thereof |
| CN116239330A (en) * | 2023-03-06 | 2023-06-09 | 湖南中岩建材科技有限公司 | Associative thickening water-retaining agent and preparation method thereof |
| CN117164765A (en) * | 2023-11-01 | 2023-12-05 | 中国核电工程有限公司 | Nuclear engineering concrete temperature-control corrosion-resistant component and preparation method and application thereof |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116239330A (en) * | 2023-03-06 | 2023-06-09 | 湖南中岩建材科技有限公司 | Associative thickening water-retaining agent and preparation method thereof |
| CN115947560A (en) * | 2023-03-13 | 2023-04-11 | 石家庄市长安育才建材有限公司 | Additive for improving concrete workability and preparation method thereof |
| CN115947560B (en) * | 2023-03-13 | 2023-08-04 | 石家庄市长安育才建材有限公司 | Additive for improving workability of concrete and preparation method thereof |
| CN117164765A (en) * | 2023-11-01 | 2023-12-05 | 中国核电工程有限公司 | Nuclear engineering concrete temperature-control corrosion-resistant component and preparation method and application thereof |
| CN117164765B (en) * | 2023-11-01 | 2024-02-23 | 中国核电工程有限公司 | Nuclear engineering concrete temperature-control corrosion-resistant component and preparation method and application thereof |
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