A concrete water-retaining and slurry-enhancing agent and its preparation method
By combining allyl oxy polyacrylate water-reducing agent with cellulose mercaptoacetate, the problem of insufficient performance of polyacrylic acid concrete additives was solved, and the fluidity and mechanical properties of concrete were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIEYANG JIANBAO BUILDING MATERIALS CO LTD
- Filing Date
- 2026-03-09
- Publication Date
- 2026-06-30
AI Technical Summary
Existing polyacrylic acid-based concrete additives have low performance and are difficult to effectively improve the fluidity and mechanical properties of concrete mortar.
By using a compound of allyloxy polyacrylate water-reducing agent, thioglycolic acid cellulose and triethylamine, the aggregation of cement silicate particles is inhibited by the formation of electrostatic repulsion and steric hindrance, and a hydrophilic polymer hydration film is formed by chemical cross-linking on the surface of inorganic particles such as cement silicate, thereby improving the fluidity and mechanical strength of concrete.
It improves the fluidity and flowability of concrete paste, reduces bleeding and water seepage, and enhances the cohesiveness, water retention, compressive and flexural strength of concrete.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of concrete technology, specifically to a concrete water-retaining and slurry-enhancing agent and its preparation method. Background Technology
[0002] Concrete is mainly composed of water, aggregates such as sand and gravel, and cementitious materials such as cement. It is widely used in civil construction, transportation engineering, water conservancy projects, and special engineering projects. In order to reduce the water consumption of concrete and improve the fluidity and mechanical properties of concrete mortar, functional additives such as water-reducing agents, thickeners, and mortar enhancers need to be added.
[0003] Commonly used water-reducing agents include polyacrylic acid-based and lignin sulfonate-based agents. Among them, polyacrylic acid-based water-reducing agents are simple to prepare, have diverse monomers, and rich functions. However, ordinary polyacrylic acid-based water-reducing agents are difficult to effectively improve the fluidity and other properties of concrete mortar, which is not conducive to improving the mechanical properties of concrete. Hydroxypropyl methylcellulose is a high-performance thickener that is inexpensive, readily available, and environmentally friendly, and has wide applications in concrete and other materials. This invention aims to use polyacrylic acid-based water-reducing agents, hydroxypropyl methylcellulose, and other raw materials to formulate a high-performance water-retaining and mortar-enhancing agent to improve the fluidity, mechanical strength, and other properties of concrete mortar. Summary of the Invention
[0004] In view of the shortcomings of the prior art, the present invention solves the problem of low performance of existing polyacrylic concrete additives.
[0005] The technical solution of the present invention is: a method for preparing a concrete water-retaining and slurry-enhancing agent, wherein the concrete water-retaining and slurry-enhancing agent comprises allyl oxy polyacrylate water-reducing agent, mercaptoacetate cellulose, and triethylamine in a ratio of 100g:(5-20)g:(0.14-0.6)g.
[0006] Preferably, the preparation method of allyl polyacrylate water-reducing agent is as follows: add polyacrylate water-reducing agent and sodium hydroxide to water, activate it by stirring in a nitrogen atmosphere, then add allyl glycidyl ether to react, pour the solution into ethanol, filter, wash the filter cake with ethanol, and dry to obtain allyl polyacrylate water-reducing agent.
[0007] Preferably, the activation temperature is 65-80℃ and the activation time is 40-60 min.
[0008] Preferably, the reaction temperature is 65-80℃ and the reaction time is 4-8h.
[0009] Preferably, the ratio of polyacrylate water-reducing agent, sodium hydroxide, and allyl glycidyl ether is 100g:(0.7-3.5)g:(2-10)g.
[0010] Preferably, the preparation method of the polyacrylate water-reducing agent is as follows: acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, and hydroxyethyl acrylate are added to water, heated to the reaction temperature, stirred, and then an aqueous solution of ammonium persulfate is added dropwise under a nitrogen atmosphere. The polymerization reaction is carried out by stirring, and an aqueous solution of sodium hydroxide is added dropwise to adjust the pH to 6-8. The mixture is then cooled and discharged to obtain the polyacrylate water-reducing agent.
[0011] Preferably, the polymerization reaction temperature is 65-75℃ and the reaction time is 1.5-3h.
[0012] Preferably, the ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, hydroxyethyl acrylate, and ammonium persulfate is (35-42) g: (16-25) g: (16-28) g: (14-22) g: (0.7-0.9) g.
[0013] Preferably, the preparation method of cellulose thioglycolate is as follows: acetic anhydride, concentrated sulfuric acid, thioglycolic acid, and hydroxypropyl methylcellulose are added to glacial acetic acid to carry out an esterification reaction. The solution is poured into water, filtered, and the filter cake is washed with water and dried to obtain cellulose thioglycolate.
[0014] Preferably, the ratio of thioglycolic acid to hydroxypropyl methylcellulose is (120-200) g: 100 g.
[0015] Preferably, the esterification reaction temperature is 35-45℃ and the reaction time is 60-72h.
[0016] (III) Beneficial Technical Effects: This invention polymerizes 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, and hydroxyethyl acrylate to obtain a polyacrylate water-reducing agent. Sodium hydroxide is used to activate the hydroxyl groups of the water-reducing agent, which then undergo a ring-opening reaction with the epoxy groups of allyl glycidyl ether. Simultaneously, the epoxy ring-opening generates hydroxyl groups, yielding an allyloxy polyacrylate water-reducing agent. This agent is then compounded with cellulose mercaptoacetate and triethylamine to obtain a concrete water-retaining and slurry-enhancing agent. The allyloxy polyacrylate water-reducing agent contains a large number of anchoring groups such as carboxylates, sulfonates, and hydroxyl groups, which can adsorb onto the surface of inorganic particles such as cement silicate, forming electrostatic repulsion and steric hindrance. This inhibits the aggregation of cement silicate particles and suppresses the adsorption and expansion forces of inorganic particles through steric hindrance shielding. It reduces large particles of fly ash cementitious materials, increases the number of small particles, and makes the cement-based mineral fine powder more uniformly dispersed. While reducing water content, it improves the fluidity, consistency, and stability of concrete slurry, which is beneficial for improving the mechanical strength of concrete.
[0017] The cellulose in the water-retaining and slurry-enhancing agent of this invention can act as a thickener and viscosity improver, regulate the consistency of the slurry mixture, improve bleeding, water seepage, and bottoming phenomena, and enhance the cohesiveness and water retention of concrete. When the desired plastic viscosity is achieved, the concrete exhibits better fluidity and workability. Furthermore, during concrete curing, under the catalysis of triethylamine, a large number of alkenyl groups on the side chains of the allyloxy polyacrylate water-reducing agent undergo an addition reaction with the thiol groups of cellulose, chemically cross-linking on the surface of inorganic particles such as cement silicate to form a hydrophilic polymer hydration film. This hydration film can reduce the sliding resistance between inorganic particles, improve slurry fluidity, enhance the wettability of cement particles, accelerate the uniformity of the hydration reaction, and further improve the compressive and flexural strength of the concrete. Detailed Implementation
[0018] To make the objectives, technical solutions, and technical effects of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. In conjunction with the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] Example 1: A concrete water-retaining and slurry-enhancing agent, composed of 100g allyloxy polyacrylate water-reducing agent, 5g cellulose mercaptoacetate, and 0.14g triethylamine.
[0020] (1) Add 42g acrylamide, 16g 2-acrylamido-2-methylpropanesulfonic acid, 28g acrylic acid and 14g hydroxyethyl acrylate to 700mL of water, heat to 70℃, stir, and then add 12mL of aqueous solution containing 0.8g ammonium persulfate dropwise under nitrogen atmosphere. Stir for 2h, and then add 20% sodium hydroxide aqueous solution to adjust the pH to 7.5. Cool and discharge to obtain polyacrylate water-reducing agent.
[0021] (2) Add 100g of polyacrylate water-reducing agent and 0.7g of sodium hydroxide to 300mL of water, heat to 70℃ in a nitrogen atmosphere, stir and activate for 40min, then add 2g of allyl glycidyl ether, stir and react for 5h, pour the solution into ethanol, filter, wash the filter cake with ethanol, and dry to obtain allyl polyacrylate water-reducing agent.
[0022] (3) Add 100 mL of acetic anhydride, 0.3 mL of 98% concentrated sulfuric acid, 32 g of mercaptoacetic acid and 20 g of hydroxypropyl methylcellulose to 60 mL of glacial acetic acid, heat to 40 °C, stir and react for 72 h, pour the solution into water, filter, wash the filter cake with water and dry to obtain mercaptoacetic acid cellulose.
[0023] Example 2: A concrete water-retaining and slurry-enhancing agent, composed of 100g allyloxy polyacrylate water-reducing agent, 13g thioglycolic acid cellulose, and 0.4g triethylamine.
[0024] (1) Add 40g acrylamide, 25g 2-acrylamido-2-methylpropanesulfonic acid, 20g acrylic acid, and 22g hydroxyethyl acrylate to 750mL of water, heat to 75℃, stir, and then add 12mL of aqueous solution containing 0.7g ammonium persulfate dropwise under a nitrogen atmosphere. Stir for 1.5h, and then add 30% sodium hydroxide aqueous solution to adjust the pH to 7.5. Cool and discharge to obtain polyacrylate water-reducing agent.
[0025] (2) Add 100g of polyacrylate water-reducing agent and 3.5g of sodium hydroxide to 400mL of water, heat to 65℃ in a nitrogen atmosphere, stir and activate for 60min, then add 10g of allyl glycidyl ether, stir and react for 8h, pour the solution into ethanol, filter, wash the filter cake with ethanol, and dry to obtain allyl polyacrylate water-reducing agent.
[0026] (3) Add 110 mL of acetic anhydride, 0.24 mL of 98% concentrated sulfuric acid, 40 g of mercaptoacetic acid and 20 g of hydroxypropyl methylcellulose to 70 mL of glacial acetic acid, heat to 45 °C, stir and react for 60 h, pour the solution into water, filter, wash the filter cake with water, and dry to obtain mercaptoacetic acid cellulose.
[0027] Example 3: A concrete water-retaining and slurry-enhancing agent, composed of 100g allyloxy polyacrylate water-reducing agent, 20g thioglycolic acid cellulose, and 0.6g triethylamine.
[0028] (1) Add 35g acrylamide, 20g 2-acrylamido-2-methylpropanesulfonic acid, 16g acrylic acid and 19g hydroxyethyl acrylate to 750mL of water, heat to 65℃, stir, and then add 15mL of aqueous solution containing 0.9g ammonium persulfate dropwise under nitrogen atmosphere. Stir for 3h, and then add 20% sodium hydroxide aqueous solution to adjust the pH to 7. Cool and discharge to obtain polyacrylate water-reducing agent.
[0029] (2) Add 100g of polyacrylate water-reducing agent and 2.2g of sodium hydroxide to 400mL of water, heat to 80℃ in a nitrogen atmosphere, stir and activate for 40min, then add 6g of allyl glycidyl ether, stir and react for 4h, pour the solution into ethanol, filter, wash the filter cake with ethanol, and dry to obtain allyl polyacrylate water-reducing agent.
[0030] (3) Add 100 mL of acetic anhydride, 0.28 mL of 98% concentrated sulfuric acid, 24 g of mercaptoacetic acid and 20 g of hydroxypropyl methylcellulose to 60 mL of glacial acetic acid, heat to 35 °C, stir and react for 72 h, pour the solution into water, filter, wash the filter cake with water and dry to obtain mercaptoacetic acid cellulose.
[0031] Comparative Example 1: A concrete water-retaining and slurry-enhancing agent, composed of 100g polyacrylate water-reducing agent (prepared according to the method of Example 1), 5g hydroxypropyl methylcellulose, and 0.14g triethylamine.
[0032] Comparative Example 2: A concrete water-retaining and slurry-enhancing agent, composed of 100g polyacrylate water-reducing agent (prepared according to the method of Example 1), 5g cellulose mercaptoacetate (prepared according to the method of Example 1), and 0.14g triethylamine.
[0033] Comparative Example 3: A concrete water-retaining and slurry-enhancing agent, composed of 100g allyl polyacrylate water-reducing agent (prepared according to the method of Example 1), 5g hydroxypropyl methylcellulose, and 0.14g triethylamine.
[0034] Comparative Example 4: A concrete water-retaining and slurry-enhancing agent, composed of 100g allyloxy polyacrylate water-reducing agent, 5g cellulose mercaptoacetate (prepared according to the method of Example 1), and 0.14g triethylamine.
[0035] (1) Add 100g of polyacrylate water-reducing agent (prepared according to the method of Example 1) and 0.7g of sodium hydroxide to 300mL of water. Heat to 70℃ in a nitrogen atmosphere and stir to activate for 40min. Then add 2g of bromopropylene and stir to react for 5h. Pour the solution into ethanol, filter, wash the filter cake with ethanol, and dry to obtain allyl polyacrylate water-reducing agent.
[0036] Taking Example 1 as an example, 22.3 kg of medium sand (average particle size 0.5 mm) and 34.2 g of crushed stone aggregate (particle size between 5-20 mm) were added to 5.2 L of water. After mixing, 11.6 kg of PO 42.5 cement, 4.6 kg of fly ash, 1.3 L of water, 100 g of allyl oxyacrylate water-reducing agent, 5 g of cellulose mercaptoacetate, and 0.14 g of triethylamine water-retaining and slurry-enhancing agent were added. The mixture was stirred evenly, compacted, and poured into a mold. The sample was molded and cured according to the method specified in GB / T 50081-2019 for 7-28 days, and the mechanical properties were tested. The fluidity of the neat paste was tested according to GB_T 8077-2023 standard.
[0037] Table 1. Performance of Concrete
[0038]
[0039] In Examples 1-3, allyloxy polyacrylate water-reducing agent, cellulose mercaptoacetate, and triethylamine were added to the concrete as water-retaining and slurry-enhancing agents. Allyloxy polyacrylate water-reducing agent contains a large number of anchoring groups such as carboxylates, sulfonates, and hydroxyl groups, which can adsorb onto the surface of inorganic particles such as cement silicate and form electrostatic repulsion and steric hindrance, inhibiting the aggregation of cement silicate particles. While reducing water, it improves the fluidity, flowability, and stability of the concrete slurry, which is beneficial to improving the mechanical strength of the concrete. The added cellulose can act as a thickener and viscosity improver, adjust the consistency of the slurry mixture, improve bleeding, and enhance the cohesiveness, water retention, and workability of the concrete. Compared with Comparative Example 1, during the curing process of concrete in each embodiment, under the catalysis of triethylamine, a large number of alkenyl groups on the side chain of the allyloxy polyacrylate water-reducing agent undergo an addition reaction with the thiol groups of cellulose, forming a hydrophilic polymer hydration film on the surface of inorganic particles such as cement silicate through chemical cross-linking. The hydration film can reduce the sliding resistance between inorganic particles, improve the fluidity of the paste, improve the wettability of cement particles, accelerate the uniformity of the hydration reaction, and further improve the compressive and flexural strength of concrete.
[0040] The polyacrylate water-reducing agent in Comparative Example 2 does not contain alkenyl groups and cannot undergo cross-linking reaction with the thiol groups of cellulose. It does not form a hydrophilic polymer hydration film on the surface of inorganic particles such as cement silicate through chemical cross-linking. As a result, the compressive strength and flexural strength of the concrete are lower than those in Example 1.
[0041] The hydroxypropyl methylcellulose in Comparative Example 3 does not contain thiol groups and cannot undergo cross-linking reaction with the alkenyl groups of polyacrylate water-reducing agent. It does not form a hydrophilic polymer hydration film on the surface of inorganic particles such as cement silicate through chemical cross-linking. As a result, the compressive strength and flexural strength of the concrete are lower than those in Example 1.
[0042] Comparative Example 4 utilizes the etherification reaction between bromopropylene and the hydroxyl groups of polyacrylate water-reducing agent to reduce the content of hydroxyl anchoring groups in the water-reducing agent. This weakens the adsorption effect on the surface of inorganic particles such as cement silicate, resulting in poor inhibition of agglomeration. Consequently, the compressive strength and flexural strength of the concrete are lower than those in Example 1.
[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a concrete water-retaining and slurry-enhancing agent, characterized in that, The concrete water-retaining and slurry-enhancing agent includes allyloxy polyacrylate water-reducing agent, cellulose mercaptoacetate, and triethylamine; The preparation method of the allyl polyacrylate water-reducing agent is as follows: add polyacrylate water-reducing agent and sodium hydroxide to water, stir and activate in a nitrogen atmosphere, then add allyl glycidyl ether to react, pour the solution into ethanol, filter, wash the filter cake, and dry to obtain allyl polyacrylate water-reducing agent.
2. The method for preparing the concrete water-retaining and slurry-enhancing agent according to claim 1, characterized in that, The ratio of allyloxy polyacrylate water-reducing agent, mercaptoacetate cellulose, and triethylamine is 100g:(5-20)g:(0.14-0.6)g.
3. The method for preparing the concrete water-retaining and slurry-enhancing agent according to claim 1, characterized in that, The activation temperature is 65-80℃, and the activation time is 40-60 min.
4. The method for preparing the concrete water-retaining and slurry-enhancing agent according to claim 1, characterized in that, The reaction temperature is 65-80℃, and the reaction time is 4-8 hours.
5. The method for preparing the concrete water-retaining and slurry-enhancing agent according to claim 1, characterized in that, The ratio of the polyacrylate water-reducing agent, sodium hydroxide, and allyl glycidyl ether is 100g:(0.7-3.5)g:(2-10)g.
6. The method for preparing the concrete water-retaining and slurry-enhancing agent according to claim 5, characterized in that, The preparation method of the polyacrylate water-reducing agent is as follows: add acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, and hydroxyethyl acrylate to water, heat to 65-75℃, stir, and then add an aqueous solution of ammonium persulfate dropwise under a nitrogen atmosphere. Stir and react for 1.5-3 hours, add an aqueous solution of sodium hydroxide to adjust the pH to 6-8, cool and discharge to obtain the polyacrylate water-reducing agent.
7. The method for preparing the concrete water-retaining and slurry-enhancing agent according to claim 6, characterized in that, The ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, hydroxyethyl acrylate, and ammonium persulfate is (35-42) g: (16-25) g: (16-28) g: (14-22) g: (0.7-0.9) g.
8. The method for preparing the concrete water-retaining and slurry-enhancing agent according to claim 2, characterized in that, The method for preparing the thioglycolic acid cellulose is as follows: acetic anhydride, concentrated sulfuric acid, thioglycolic acid, and hydroxypropyl methylcellulose are added to glacial acetic acid, and the mixture is stirred and reacted at 35-45℃ for 60-72 hours. The solution is then poured into water, filtered, the filter cake is washed, and dried to obtain thioglycolic acid cellulose.
9. The method for preparing the concrete water-retaining and slurry-enhancing agent according to claim 8, characterized in that, The ratio of mercaptoacetic acid to hydroxypropyl methylcellulose is (120-200) g: 100 g.
10. A concrete water-retaining and slurry-enhancing agent obtained by the preparation method according to any one of claims 1-9.