Concrete super-plasticizing retarder and preparation method thereof

Abstract

The application relates to the technical field of concrete admixtures, and particularly discloses a concrete super-plasticizing retarding agent and a preparation method thereof. The concrete super-plasticizing retarding agent comprises 100-200 parts of unsaturated polyether monomers, 50-150 parts of unsaturated monomers, 20-80 parts of acrylic acid, 1-5 parts of ammonium persulfate, 1-5 parts of ascorbic acid, 5-15 parts of a chain transfer agent, 5-15 parts of a non-ionic polyurethane thickening agent, 1-2 parts of a preservative and 600-800 parts of deionized water. The application can improve the retarding effect and stability when the retarding agent is used together with different types of water reducing agents.

Description

Technical Field

[0001] This invention relates to the technical field of concrete admixtures, and in particular to a super-retarding concrete retarder and its preparation method. Background Technology

[0002] In scenarios such as long-distance transportation of ready-mixed concrete, construction in high-temperature environments, and high-rise pumping, the slump of freshly mixed concrete can rapidly decrease due to factors such as water evaporation and cement hydration. In large-volume concrete pouring, construction during hot seasons, long-distance transportation, or complex structures requiring continuous pouring over extended periods, it is crucial to effectively slow down the heat release process of cement hydration, control the internal and external temperature differences, and prevent the formation of temperature stress cracks. Therefore, retarders are needed to ensure that the concrete maintains good fluidity and pumpability for a longer period (usually more than 90 minutes), providing ample operational window for construction and preventing the formation of construction cold joints.

[0003] In related technologies, a super-resistant concrete retarder is disclosed, characterized by comprising the following components in parts by weight: 300-600 parts of main retarder, 20-300 parts of auxiliary retarder, 7-15 parts of stabilizer, and 350-500 parts of water; wherein the main retarder is an organophosphonate; the auxiliary retarder is selected from one or more of sodium gluconate, tartaric acid, sodium citrate, sodium pyrophosphate, sucrose, and maltodextrin; and the stabilizer is selected from one or more of bio-glue, hydroxymethyl cellulose ether, and polyacrylamide.

[0004] However, during use, the aforementioned retarders may interact with the water-reducing agents in concrete, resulting in negative effects such as flocculation or phase separation. When different types of water-reducing agents are used together with retarders, the retardation effect of concrete may change drastically, making it difficult to control the initial setting time, final setting time, and mechanical properties of concrete. Summary of the Invention

[0005] In order to improve the retarding effect and stability when retarder is used in combination with different types of water-reducing agents, this application provides a super-plastic retarder for concrete and its preparation method.

[0006] Firstly, this application provides a concrete super-plasticity retarder, which adopts the following technical solution: A concrete super-resistant plastic retarder comprises the following raw materials in parts by weight: 100-200 parts of unsaturated polyether monomer, 50-150 parts of unsaturated monomer, 20-80 parts of acrylic acid, 1-5 parts of ammonium persulfate, 1-5 parts of ascorbic acid, 5-15 parts of chain transfer agent, 5-15 parts of nonionic polyurethane thickener, 1-2 parts of preservative, and 600-800 parts of deionized water.

[0007] In one specific implementation, the unsaturated polyether monomer comprises isopentenyl alcohol polyoxyethylene ether and polyethylene glycol polypropylene glycol allyl ether in a weight ratio of (3.5-4.5):1.

[0008] In one specific embodiment, the unsaturated monomer comprises 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate phosphate, and N-vinylpyrrolidone in a weight ratio of (5.5-6.5):(2.8-3.2):1.

[0009] In one specific feasible implementation, mercaptopropionic acid is also included.

[0010] In one specific implementation, sodium gluconate or sodium citrate may also be included.

[0011] Secondly, this application provides a method for preparing a super-resistant concrete retarder, which adopts the following technical solution: A method for preparing a super-resistant concrete retarder includes the following steps: S1. Divide the deionized water into four parts. Heat the first part of the deionized water to 60-65℃, add unsaturated polyether monomer and unsaturated monomer, mix evenly to obtain a pre-emulsion. Mix acrylic acid and chain transfer agent with the second part of the deionized water to obtain solution A. Mix ammonium persulfate with the third part of the deionized water to obtain solution B. Mix ascorbic acid with the fourth part of the deionized water to obtain solution C. S2. Keep at 60-65℃, add liquids A, B and C dropwise to the pre-emulsion. After the addition is complete, keep warm for 1-2 hours, let it cool naturally to room temperature, add non-ionic polyurethane thickener and preservative, stir until uniform, filter, and obtain concrete super plastic retarder.

[0012] In one specific feasible implementation, in step S1, acrylic acid, chain transfer agent, mercaptopropionic acid and a second part of deionized water are mixed to obtain liquid A; in step S2, after naturally cooling to room temperature, a nonionic polyurethane thickener and preservative are added and stirred until uniform, then sodium gluconate or sodium citrate is added and stirred until uniform, filtered, to obtain concrete super-resistant plastic retarder.

[0013] In one specific feasible implementation, in step S2, the mixture is allowed to cool naturally to room temperature, and the pH is adjusted to 6.0-7.0 using a 30% NaOH aqueous solution.

[0014] In summary, this application has the following beneficial effects: 1. This application improves the retarding effect and stability when retarder is used in combination with different types of water-reducing agents by using a specific ratio of unsaturated polyether monomers, unsaturated monomers, acrylic acid, ammonium persulfate and ascorbic acid.

[0015] 2. In this application, mercaptopropionic acid and sodium gluconate or sodium citrate are preferred, which can further improve the retarding effect and stability when the retarder is used together with different types of water-reducing agents. Detailed Implementation

[0016] Unless otherwise specified, all raw materials used in this application are commercially available. Isoprene alcohol polyoxyethylene ether is Kemic brand TPEG-2400. 2-Acrylamide-2-methylpropanesulfonic acid, AR grade, CAS No. 15214-89-8. Acrylic acid, Zhejiang Satellite brand, 99.5% purity, CAS No. 79-10-7. Ammonium persulfate, 98.5% purity. Nonionic polyurethane thickener (Qingdao Enze PU-16). Benzisothiazolinone (Kason New Materials BIT20). Ascorbic acid is Qinweiya brand industrial grade L-ascorbic acid, CAS No. 50-81-7. Sodium hypophosphite, CAS No. 7681-53-0. Polyethylene glycol polypropylene glycol allyl ether, CAS No. 9041-33-2, 98% purity. 2-Hydroxyethyl methacrylate phosphate, brand HEMAP / PM-2, CAS No. 52628-03-2. N-Vinylpyrrolidone, Brand: Shengyong, CAS No. 88-12-0. Mercaptopropionic acid, Brand: Xinling Chemical, CAS No. 107-96-0. Sodium citrate, AR grade, Brand: Pengcai Chemical. Sodium gluconate, Brand: Angtuo, CAS No. 527-07-1.

[0017] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0018] Example Example 1

[0019] This embodiment provides a super-resistant plastic retarder for concrete, comprising the following raw materials: 150 kg of isopentenyl alcohol polyoxyethylene ether, 100 kg of 2-acrylamide-2-methylpropanesulfonic acid, 50 kg of acrylic acid, 3 kg of ammonium persulfate, 3 kg of ascorbic acid, 10 kg of sodium hypophosphite, 10 kg of nonionic polyurethane thickener, 1.5 kg of benzisothiazolinone, and 700 kg of deionized water.

[0020] This embodiment also provides a method for preparing a super-resistant concrete retarder, comprising the following steps: S1. Divide the deionized water into four equal parts. Heat the first part of the deionized water to 63°C in a water bath, add isopentenyl polyoxyethylene ether and 2-acrylamide-2-methylpropanesulfonic acid, and stir for 30 minutes until homogeneous to obtain a pre-emulsion. Mix acrylic acid and sodium hypophosphite with the second part of the deionized water and stir until completely dissolved to obtain solution A. Mix ammonium persulfate with the third part of the deionized water to obtain solution B. Mix ascorbic acid with the fourth part of the deionized water to obtain solution C.

[0021] S2. Under a water bath heating temperature of 63℃, add liquids A, B and C together dropwise into the pre-emulsion through three dropping funnels. After the addition is complete, keep it at the temperature for 1.5 hours and let it cool naturally to room temperature. Then, add non-ionic polyurethane thickener and preservative, stir until uniform, filter, and obtain concrete super plastic retarder.

[0022] Example 2

[0023] The only difference between this embodiment and Embodiment 1 is that the concrete super-resistant retarder includes the following raw materials: 100 kg of isopentenyl alcohol polyoxyethylene ether, 150 kg of 2-acrylamide-2-methylpropanesulfonic acid, 80 kg of acrylic acid, 5 kg of ammonium persulfate, 5 kg of ascorbic acid, 15 kg of sodium hypophosphite, 15 kg of nonionic polyurethane thickener, 2 kg of benzisothiazolinone, and 800 kg of deionized water.

[0024] Example 3

[0025] The only difference between this embodiment and Embodiment 1 is that the concrete super-resistant retarder includes the following raw materials: 200 kg of isopentenyl alcohol polyoxyethylene ether, 50 kg of 2-acrylamide-2-methylpropanesulfonic acid, 20 kg of acrylic acid, 1 kg of ammonium persulfate, 1 kg of ascorbic acid, 5 kg of sodium hypophosphite, 5 kg of nonionic polyurethane thickener, 1 kg of benzisothiazolinone, and 600 kg of deionized water.

[0026] Example 4

[0027] The only difference between this embodiment and Embodiment 1 is that isopentenyl alcohol polyoxyethylene ether is replaced with a mixture of isopentenyl alcohol polyoxyethylene ether and polyethylene glycol polypropylene glycol allyl ether in an equal weight ratio of 3:1.

[0028] Example 5

[0029] The only difference between this embodiment and Embodiment 1 is that isopentenyl alcohol polyoxyethylene ether is replaced with a mixture of isopentenyl alcohol polyoxyethylene ether and polyethylene glycol polypropylene glycol allyl ether in equal weight ratios of 3.5:1.

[0030] Example 6

[0031] The only difference between this embodiment and Embodiment 1 is that isopentenyl alcohol polyoxyethylene ether is replaced with a mixture of isopentenyl alcohol polyoxyethylene ether and polyethylene glycol polypropylene glycol allyl ether in an equal weight ratio of 4:1.

[0032] Example 7

[0033] The only difference between this embodiment and Embodiment 1 is that isopentenyl alcohol polyoxyethylene ether is replaced with a mixture of isopentenyl alcohol polyoxyethylene ether and polyethylene glycol polypropylene glycol allyl ether in equal weight ratios of 4.5:1.

[0034] Example 8

[0035] The only difference between this embodiment and Embodiment 1 is that isopentenyl alcohol polyoxyethylene ether is replaced with a mixture of isopentenyl alcohol polyoxyethylene ether and polyethylene glycol polypropylene glycol allyl ether in an equal weight ratio of 5:1.

[0036] Example 9

[0037] The only difference between this embodiment and Example 1 is that 2-acrylamide-2-methylpropanesulfonic acid is replaced with a mixture of equal weight ratios of 5:3.4:1 of 2-acrylamide-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate phosphate, and N-vinylpyrrolidone.

[0038] Example 10

[0039] The only difference between this embodiment and Example 1 is that 2-acrylamide-2-methylpropanesulfonic acid is replaced with a mixture of equal weight ratios of 5.5:3.2:1 of 2-acrylamide-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate phosphate, and N-vinylpyrrolidone.

[0040] Example 11

[0041] The only difference between this embodiment and Example 1 is that 2-acrylamide-2-methylpropanesulfonic acid is replaced with a mixture of equal weight ratios of 2-acrylamide-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate phosphate, and N-vinylpyrrolidone in a weight ratio of 6:3:1.

[0042] Example 12

[0043] The only difference between this embodiment and Example 1 is that 2-acrylamide-2-methylpropanesulfonic acid is replaced with a mixture of equal weight ratios of 6.5:2.8:1 of 2-acrylamide-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate phosphate, and N-vinylpyrrolidone.

[0044] Example 13

[0045] The only difference between this embodiment and Example 1 is that 2-acrylamide-2-methylpropanesulfonic acid is replaced with a mixture of equal weight ratios of 7:2.6:1 of 2-acrylamide-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate phosphate, and N-vinylpyrrolidone.

[0046] Example 14

[0047] The only difference between this embodiment and Embodiment 1 is that the preparation method of the concrete super-plastic retarder in this embodiment is as follows: S1. Divide the deionized water into four equal parts. Heat the first part of the deionized water to 60°C in a water bath, add isopentenyl polyoxyethylene ether and 2-acrylamide-2-methylpropanesulfonic acid, and stir for 30 minutes until homogeneous to obtain a pre-emulsion. Mix acrylic acid and sodium hypophosphite with the second part of the deionized water and stir until completely dissolved to obtain solution A. Mix ammonium persulfate with the third part of the deionized water to obtain solution B. Mix ascorbic acid with the fourth part of the deionized water to obtain solution C.

[0048] S2. Under a water bath heating temperature of 60℃, add liquids A, B and C together dropwise into the pre-emulsion through three dropping funnels. After the addition is complete, keep it at the temperature for 2 hours and let it cool naturally to room temperature. Then, add non-ionic polyurethane thickener and preservative, stir until uniform, filter, and obtain concrete super plastic retarder.

[0049] Example 15

[0050] The only difference between this embodiment and Embodiment 1 is that the preparation method of the concrete super-plastic retarder in this embodiment is as follows: S1. Divide the deionized water into four equal parts. Heat the first part of the deionized water to 65°C in a water bath, add isopentenyl alcohol polyoxyethylene ether and 2-acrylamide-2-methylpropanesulfonic acid, and stir for 30 minutes until homogeneous to obtain a pre-emulsion. Mix acrylic acid and sodium hypophosphite with the second part of the deionized water and stir until completely dissolved to obtain solution A. Mix ammonium persulfate with the third part of the deionized water to obtain solution B. Mix ascorbic acid with the fourth part of the deionized water to obtain solution C.

[0051] S2. Under a water bath heating temperature of 65℃, add liquids A, B and C together dropwise into the pre-emulsion through three dropping funnels. After the addition is complete, keep it at the temperature for 1 hour and let it cool naturally to room temperature. Then, add non-ionic polyurethane thickener and preservative, stir until uniform, filter, and obtain concrete super plastic retarder.

[0052] Example 16

[0053] The only difference between this embodiment and Embodiment 1 is that in step S2 of the method for preparing the super-plastic retarder for concrete, after naturally cooling to room temperature, the pH is adjusted to 6.0-7.0 with a 30% NaOH aqueous solution. Then, a non-ionic polyurethane thickener and a preservative are added, stirred until uniform, filtered, and the super-plastic retarder for concrete is obtained.

[0054] Example 17

[0055] The only difference between this embodiment and Embodiment 1 is that the concrete super-resistant retarder includes the following raw materials: 150 kg of isopentenyl alcohol polyoxyethylene ether, 100 kg of 2-acrylamide-2-methylpropanesulfonic acid, 50 kg of acrylic acid, 3 kg of ammonium persulfate, 3 kg of ascorbic acid, 10 kg of sodium hypophosphite, 35 kg of 30% NaOH aqueous solution, 10 kg of nonionic polyurethane thickener, 1.5 kg of benzisothiazolinone, 3.5 kg of mercaptopropionic acid, and 700 kg of deionized water.

[0056] The method for preparing the super-plastic retarder for concrete according to this application includes the following steps: S1. Divide the deionized water into four equal portions. Heat the first portion of deionized water to 63°C in a water bath, add isopentenyl polyoxyethylene ether and 2-acrylamide-2-methylpropanesulfonic acid, and stir for 30 minutes until homogeneous to obtain a pre-emulsion. Mix acrylic acid, sodium hypophosphite, and mercaptopropionic acid with the second portion of deionized water and stir until completely dissolved to obtain solution A. Mix ammonium persulfate with the third portion of deionized water to obtain solution B. Mix ascorbic acid with the fourth portion of deionized water to obtain solution C.

[0057] S2. While maintaining a water bath heating temperature of 63℃, add liquids A, B, and C dropwise to the pre-emulsion using three dropping funnels. After the addition is complete, keep the mixture at this temperature for 1.5 hours, allow it to cool naturally to room temperature, adjust the pH to 6.0-7.0 with a 30% NaOH aqueous solution, then add a non-ionic polyurethane thickener and preservative, stir until homogeneous, filter, and obtain the super-resistant concrete retarder.

[0058] Example 18

[0059] The only difference between this embodiment and Embodiment 1 is that the concrete super-resistant retarder includes the following raw materials: 150 kg of isopentenyl alcohol polyoxyethylene ether, 100 kg of 2-acrylamide-2-methylpropanesulfonic acid, 50 kg of acrylic acid, 3 kg of ammonium persulfate, 3 kg of ascorbic acid, 10 kg of sodium hypophosphite, 35 kg of 30% NaOH aqueous solution, 10 kg of nonionic polyurethane thickener, 1.5 kg of benzisothiazolinone, 20 kg of sodium gluconate, and 700 kg of deionized water.

[0060] The method for preparing the super-plastic retarder for concrete according to this application includes the following steps: S1. Divide the deionized water into four equal portions. Heat the first portion of deionized water to 63°C in a water bath, add isopentenyl polyoxyethylene ether and 2-acrylamide-2-methylpropanesulfonic acid, and stir for 30 minutes until homogeneous to obtain a pre-emulsion. Mix acrylic acid and sodium hypophosphite with the second portion of deionized water and stir until completely dissolved to obtain solution A. Mix ammonium persulfate with the third portion of deionized water to obtain solution B. Mix ascorbic acid with the fourth portion of deionized water to obtain solution C.

[0061] S2. While maintaining a water bath heating temperature of 63℃, add liquids A, B, and C dropwise to the pre-emulsion using three dropping funnels. After the addition is complete, keep the mixture at this temperature for 1.5 hours, allow it to cool naturally to room temperature, adjust the pH to 6.0-7.0 with a 30% NaOH aqueous solution, then add a non-ionic polyurethane thickener and preservative, stir until homogeneous, add sodium gluconate, stir until homogeneous, filter, and obtain the super-resistant concrete retarder.

[0062] Example 19

[0063] The only difference between this embodiment and Embodiment 1 is that the concrete super-resistant retarder includes the following raw materials: 150 kg of isopentenyl alcohol polyoxyethylene ether, 100 kg of 2-acrylamide-2-methylpropanesulfonic acid, 50 kg of acrylic acid, 3 kg of ammonium persulfate, 3 kg of ascorbic acid, 10 kg of sodium hypophosphite, 35 kg of 30% NaOH aqueous solution, 10 kg of nonionic polyurethane thickener, 1.5 kg of benzisothiazolinone, 10 kg of sodium citrate, and 700 kg of deionized water.

[0064] The method for preparing the super-plastic retarder for concrete according to this application includes the following steps: S1. Divide the deionized water into four equal portions. Heat the first portion of deionized water to 63°C in a water bath, add isopentenyl polyoxyethylene ether and 2-acrylamide-2-methylpropanesulfonic acid, and stir for 30 minutes until homogeneous to obtain a pre-emulsion. Mix acrylic acid and sodium hypophosphite with the second portion of deionized water and stir until completely dissolved to obtain solution A. Mix ammonium persulfate with the third portion of deionized water to obtain solution B. Mix ascorbic acid with the fourth portion of deionized water to obtain solution C.

[0065] S2. While maintaining a water bath heating temperature of 63℃, add liquids A, B, and C dropwise to the pre-emulsion using three dropping funnels. After the addition is complete, keep the mixture at this temperature for 1.5 hours, allow it to cool naturally to room temperature, adjust the pH to 6.0-7.0 with a 30% NaOH aqueous solution, then add a non-ionic polyurethane thickener and preservative, stir until homogeneous, add sodium citrate, stir until homogeneous, filter, and obtain the super-resistant concrete retarder.

[0066] Example 20

[0067] The only difference between this embodiment and Embodiment 1 is that the concrete super-resistant retarder includes the following raw materials: 150 kg of isopentenyl alcohol polyoxyethylene ether, 100 kg of 2-acrylamide-2-methylpropanesulfonic acid, 50 kg of acrylic acid, 3 kg of ammonium persulfate, 3 kg of ascorbic acid, 10 kg of sodium hypophosphite, 35 kg of 30% NaOH aqueous solution, 10 kg of nonionic polyurethane thickener, 1.5 kg of benzisothiazolinone, 3.5 kg of mercaptopropionic acid, 20 kg of sodium gluconate, and 700 kg of deionized water.

[0068] The method for preparing the super-plastic retarder for concrete according to this application includes the following steps: S1. Divide the deionized water into four equal portions. Heat the first portion of deionized water to 63°C in a water bath, add isopentenyl polyoxyethylene ether and 2-acrylamide-2-methylpropanesulfonic acid, and stir for 30 minutes until homogeneous to obtain a pre-emulsion. Mix acrylic acid, sodium hypophosphite, and mercaptopropionic acid with the second portion of deionized water and stir until completely dissolved to obtain solution A. Mix ammonium persulfate with the third portion of deionized water to obtain solution B. Mix ascorbic acid with the fourth portion of deionized water to obtain solution C.

[0069] S2. While maintaining a water bath heating temperature of 63℃, add liquids A, B, and C dropwise to the pre-emulsion using three dropping funnels. After the addition is complete, keep the mixture at this temperature for 1.5 hours, allow it to cool naturally to room temperature, adjust the pH to 6.0-7.0 with a 30% NaOH aqueous solution, then add a non-ionic polyurethane thickener and preservative, stir until homogeneous, add sodium gluconate, stir until homogeneous, filter, and obtain the super-resistant concrete retarder.

[0070] Comparative Example Comparative Example 1 The only difference between this comparative example and Example 1 is that, in the raw materials and preparation method of the concrete super-resistant retarder, an equal amount of isopentenyl alcohol polyoxyethylene ether is used to replace 2-acrylamide-2-methylpropanesulfonic acid.

[0071] Comparative Example 2 The only difference between this comparative example and Example 1 is that, in the raw materials and preparation method of the concrete super-resistant retarder, an equal amount of isopentenyl alcohol polyoxyethylene ether is used to replace acrylic acid.

[0072] Comparative Example 3 The only difference between this comparative example and Example 1 is that, in the raw materials and preparation method of the concrete super-resistant retarder, an equal amount of ammonium persulfate is used to replace ascorbic acid.

[0073] Comparative Example 4 The only difference between this comparative example and Example 1 is that, in the raw materials and preparation method of the concrete super-resistant retarder, an equal amount of ammonium persulfate is used to replace sodium hypophosphite.

[0074] Performance testing The following performance tests were conducted on Examples 1-20 and Comparative Examples 1-4: Experimental materials: P.O42.5 cement; sand (medium sand, fineness modulus 2.3-2.8) and aggregate (5-25mm continuously graded crushed stone) conforming to GB / T14684 and GB / T14685. BASF RHEOPLUS411 early-strength water-reducing agent, Wanshan FDN-A naphthalene-based water-reducing agent, and Tongsheng Building Materials TB-103 high-slump-retention water-reducing agent. Super-resistant retarders for concrete prepared in each example and comparative example.

[0075] Reference mix ratio: Cement: 360kg / m 3 Sand: 750kg / m 3 Stone: 1050kg / m 3 Water: 180kg / m 3 Water-reducing agent dosage: 0.3% (as a percentage of cement mass).

[0076] Dosage of super-resistant plastic retarder for concrete: 0.3% (as a percentage of cement mass).

[0077] A blank control group was set with 0% super-resistant plastic retarder for concrete.

[0078] According to the "Standard for Test Methods of Performance of Ordinary Concrete Mixtures" (GB / T50080-2016), "Standard for Test Methods of Homogeneity of Concrete Admixtures" (GB / T8077-2012), "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T50081-2019), and "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T8076-2008), the test materials were mixed according to the above-mentioned reference mix proportions. After stirring, the initial setting time (h, min, observed every 5 min), the final setting time (h, min, observed every 5 min), and the 28-day compressive strength (MPa) of the concrete were recorded.

[0079] The test results are shown in Tables 1 and 2.

[0080] Table 1

[0081] Table 2

[0082] Combining Example 1, Comparative Examples 1-4, and the blank control group, and referring to Table 1, it can be seen that compared to the blank control group, the initial setting time and final setting time of concrete prepared using the retarders of Example 1 and Comparative Examples 1-4 are both longer. However, when the retarders of Comparative Examples 1-4 are used in combination with different water-reducing agents, the initial setting time, final setting time, and 28-day compressive strength of concrete using different water-reducing agents vary significantly. In contrast, when the retarder of Example 1 is used in combination with different water-reducing agents, the initial setting time, final setting time, and 28-day compressive strength of concrete using different water-reducing agents show smaller differences. This indicates that using the raw material ratio and preparation method of Example 1 can improve the retarding effect and stability when the retarder is used in combination with different types of water-reducing agents.

[0083] This may be because 2-acrylamide-2-methylpropanesulfonic acid is an unsaturated monomer, and its long polyether chain is extremely similar to the macromonomer used in water-reducing agents. This means that the retarder molecule in Example 1 has a natural structural affinity with the water-reducing agent molecule, exhibiting similar spatial conformations and behavioral patterns in cement pore solutions, fundamentally reducing compatibility problems such as mutual repulsion and competitive adsorption caused by excessive differences in molecular structure. The phosphonic acid group (-PO3H2) of the unsaturated monomer has a strong affinity for calcium ions (Ca). 2+ It possesses extremely high affinity, enabling it to firmly adsorb onto the surface of cement particles and hydration products, forming a poorly soluble inhibitory film that effectively halts the cement hydration process. The carboxyl groups of acrylic acid adsorb rapidly, helping polymer molecules to quickly anchor initially and providing a certain degree of electrostatic repulsion. The combination of these two groups may create a "gradient adsorption" and "gradient inhibition" effect, achieving more comprehensive and stable control over the early, middle, and late stages of the hydration process, avoiding the problem of sudden failure of single small-molecule retarders. Ammonium persulfate and ascorbic acid form a redox initiation system, efficiently initiating polymerization reactions even at a relatively low temperature of 60°C, resulting in polymers with a more uniform molecular weight distribution, thus making the retarder's performance more stable.

[0084] As can be seen from Examples 1-20 and Table 1, the initial setting time, final setting time, and 28-day compressive strength of the concrete in Examples 1-20 are all relatively large. Furthermore, the initial setting time, final setting time, and 28-day compressive strength of the concrete using different water-reducing agents show little difference. This indicates that using the raw material ratios and preparation methods within the range of Examples 1-20 can improve the retarding effect and stability when retarders are used in combination with different types of water-reducing agents.

[0085] Comparison of the test data from Examples 1-20 shows that the use of isopentenyl alcohol polyoxyethylene ether and polyethylene glycol polypropylene glycol allyl ether in a weight ratio of (3.5-4.5):1, 2-acrylamide-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate phosphate and N-vinylpyrrolidone, mercaptopropionic acid, and sodium gluconate or sodium citrate in a weight ratio of (5.5-6.5):(2.8-3.2):1 can further improve the retarding effect and stability when the retarder is used in combination with different types of water-reducing agents.

[0086] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A concrete super-resistant retarder, characterized in that, The raw materials include the following parts by weight: 100-200 parts of unsaturated polyether monomer, 50-150 parts of unsaturated monomer, 20-80 parts of acrylic acid, 1-5 parts of ammonium persulfate, 1-5 parts of ascorbic acid, 5-15 parts of chain transfer agent, 5-15 parts of nonionic polyurethane thickener, 1-2 parts of preservative, and 600-800 parts of deionized water. The unsaturated polyether monomer includes isopentenyl alcohol polyoxyethylene ether and polyethylene glycol polypropylene glycol allyl ether in a weight ratio of (3.5-4.5):

1. The unsaturated monomer includes 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate phosphate, and N-vinylpyrrolidone in a weight ratio of (5.5-6.5):(2.8-3.2):

1.

2. The concrete super-resistant retarder according to claim 1, characterized in that, It also includes mercaptopropionic acid.

3. The concrete super-resistant retarder according to claim 2, characterized in that, It also includes sodium gluconate or sodium citrate.

4. A method for preparing a super-resistant concrete retarder as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Divide the deionized water into four parts. Heat the first part of the deionized water to 60-65℃, add unsaturated polyether monomer and unsaturated monomer, mix evenly to obtain a pre-emulsion. Mix acrylic acid and chain transfer agent with the second part of the deionized water to obtain solution A. Mix ammonium persulfate with the third part of the deionized water to obtain solution B. Mix ascorbic acid with the fourth part of the deionized water to obtain solution C. S2. Keep at 60-65℃, add liquids A, B and C dropwise to the pre-emulsion. After the addition is complete, keep warm for 1-2 hours, let it cool naturally to room temperature, add non-ionic polyurethane thickener and preservative, stir until uniform, filter, and obtain concrete super plastic retarder.

5. The preparation method of the super-resistant concrete retarder according to claim 4, characterized in that, In step S1, acrylic acid, chain transfer agent, mercaptopropionic acid and the second part of deionized water are mixed to obtain liquid A; in step S2, after naturally cooling to room temperature, nonionic polyurethane thickener and preservative are added and stirred until uniform, then sodium gluconate or sodium citrate is added and stirred until uniform, filtered, to obtain concrete super plastic retarder.

6. The method for preparing the super-resistant concrete retarder according to claim 4, characterized in that, In step S2, the mixture is allowed to cool naturally to room temperature, and the pH is adjusted to 6.0-7.0 using a 30% NaOH aqueous solution.

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