High-efficiency concrete water-reducing agent and preparation method thereof

Abstract

The present application relates to the technical field of concrete water reducing agent, in particular to a kind of high-efficiency concrete water reducing agent and preparation method thereof, it includes the following weight parts raw materials: 6-10 parts slow-release filler, 6-8 parts water-reducing additive and 0.8-1 parts preservative;By loading naphthalene sulfonate formaldehyde condensate, so that water reducing agent has certain slow-release performance, thereby solve the problem that the slump loss of existing naphthalene water reducing agent is larger, also by combining with water-reducing additive, so that high-efficiency concrete water reducing agent still has good performance under high temperature environment, and reduce the influence of naphthalene sulfonate formaldehyde condensate on the early strength development of concrete.

Description

Technical Field

[0001] This invention relates to the field of concrete water-reducing agent technology, specifically to a high-efficiency concrete water-reducing agent and its preparation method. Background Technology

[0002] With social development, traditional concrete has been gradually replaced by high-performance concrete, and concrete water-reducing agents play an extremely important role in this process. They can effectively reduce the water-cement ratio in concrete. However, the commonly used naphthalene-based water-reducing agents, namely naphthalene sulfonate formaldehyde condensate, often have the problem of large slump loss under high temperature conditions. In order to improve the slump loss problem, retarders are usually added to concrete. However, the addition of retarders will affect the early strength development of concrete, resulting in its performance failing to meet market demands. Summary of the Invention

[0003] The purpose of this invention is to provide a high-efficiency concrete water-reducing agent and its preparation method. By loading naphthalene sulfonate formaldehyde condensate, the water-reducing agent has a certain slow-release performance, thereby solving the problem of large slump loss in existing naphthalene-based water-reducing agents. At the same time, by combining it with water-reducing additives, the high-efficiency concrete water-reducing agent still has good performance in high-temperature environments and reduces the impact of naphthalene sulfonate formaldehyde condensate on the early strength development of concrete.

[0004] The objective of this invention can be achieved through the following technical solution: a method for preparing a high-efficiency concrete water-reducing agent, comprising the following steps: weighing the following parts by weight of raw materials: 6-10 parts of slow-release filler, 6-8 parts of water-reducing additive and 0.8-1 parts of preservative, mixing the slow-release filler, water-reducing additive and preservative to obtain a high-efficiency concrete water-reducing agent; The corrosion inhibitor is Mingjiang Chemical's concrete corrosion inhibitor; The water-reducing agent is prepared through the following steps: Step A1: Tartaric acid and glycidyl methacrylate are mixed and stirred at a speed of 140-160 rpm and a temperature of 98-100℃. Triphenylphosphine and p-hydroxyanisole are added and the mixture is reacted for 6-8 hours. Then the temperature is lowered to 52-55℃ and pyrophosphate is added. The reaction is continued for 24 hours to obtain intermediate 1. The ratio of tartaric acid, glycidyl methacrylate, triphenylphosphine, p-hydroxyanisole, and pyrophosphate is 0.11-0.12 mol: 0.24-0.25 mol: 0.23-0.25 g: 0.11-0.13 g: 0.46-0.48 mol. During the reaction, under the conditions of triphenylphosphine and p-hydroxyanisole as catalysts, the carboxyl group in tartaric acid first reacts with the epoxy group in glycidyl methacrylate, while introducing a double bond and forming a new hydroxyl group. Then, pyrophosphate is added to react with the hydroxyl group to form a phosphate ester structure, thus obtaining intermediate 1. Step A2: Mix guar gum and tetrahydrofuran, stir at a stirring speed of 160-180 rpm and a temperature of 40-42℃, add potassium hydroxide, react for 12-14 h, then add carbon disulfide, continue the reaction for 2-3 h, then add methyl 2-bromoisobutyrate, continue the reaction for 22-24 h to obtain modified guar gum; The ratio of guar gum, potassium hydroxide, carbon disulfide, and methyl 2-bromoisobutyrate is 4.3-4.5 g : 0.08-0.082 mol : 0.085-0.09 mol : 0.082-0.085 mol; During the reaction, under the action of potassium hydroxide, the hydroxyl groups in guar gum form a potassium salt structure, which then reacts with carbon disulfide and methyl 2-bromoisobutyrate to obtain modified guar gum.

[0005] Step A3: Mix acrylic acid, isopentenyl alcohol polyoxyethylene ether, modified guar gum, azobisisobutyronitrile and dimethyl sulfoxide, and react for 22-24 hours under nitrogen protection, stirring speed of 150-180 rpm and temperature of 70-72℃ to obtain water-reducing additive. The ratio of acrylic acid, isopentenyl alcohol polyoxyethylene ether, modified guar gum, and azobisisobutyronitrile is 0.012-0.015 mol: 2.3-2.5 g: 4.5-4.8 g: 0.12-0.15 g; The isopentenyl alcohol polyoxyethylene ether is Kemic TPEG-2400; During the reaction, under the action of the initiator azobisisobutyronitrile, modified guar gum is used as a macromolecular chain transfer agent. Through the reversible addition-fragmentation chain transfer polymerization method, modified guar gum is polymerized with acrylic acid and isopentenyl alcohol polyoxyethylene ether to form a water-reducing agent with modified guar gum as the main body and containing a multi-branched block side chain structure. The slow-release filler is prepared by the following steps: Step B1: Cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium carbonate, and deionized water are mixed. Under the conditions of stirring speed of 120-140 rpm and room temperature, sodium hydroxide solution is added to maintain the pH value of the system at 10. The temperature is raised to 145-150℃ and crystallized for 12-14 h. After filtration, washing, and drying, precursor 1 is obtained. Precursor 1 is mixed with formamide and stirred for 8-10 h under nitrogen protection, stirring speed of 400-450 rpm, and room temperature. After centrifugation, the upper layer is taken to obtain the hydrotalcite exfoliation system. The sodium hydroxide solution has a mass fraction of 15%, and the ratio of cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and sodium carbonate is 0.02-0.022 mol: 0.01-0.11 mol: 0.02-0.022 mol: 0.01-0.011 mol: 12-13 g; the ratio of precursor 1 to formamide is 2.4-2.5 g: 40-45 mL. During the reaction, a precursor 1 with a water fossil-like structure was prepared by co-precipitation method using cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate as cobalt, iron, magnesium and aluminum sources respectively. Then, the precursor 1 was exfoliated by formamide exfoliation method to obtain the hydrotalcite exfoliation system. Step B2: Hollow mesoporous silica, naphthalene sulfonate formaldehyde condensate and deionized water are mixed and stirred for 12 h at a stirring rate of 120-140 rpm and a temperature of 95-100℃ to obtain precursor 2. Precursor 2 is added to the hydrotalcite exfoliation system and reacted for 30-40 min under nitrogen protection, stirring rate of 90-120 rpm and a temperature of room temperature. After filtration, washing and drying, the slow-release filler is obtained. The ratio of hollow mesoporous silica, naphthalene sulfonate formaldehyde condensate, and deionized water is 1.5-1.6 g: 2.2-2.3 g: 80-85 mL; the ratio of precursor 2 and hydrotalcite exfoliation system is 0.1-0.12 g: 15-20 mL. The hollow mesoporous silica is JK-04-009; The naphthalene sulfonate formaldehyde condensate is Wanshan brand FDN-A; During the reaction, the naphthalene sulfonate formaldehyde condensate is first loaded in hollow mesoporous silica to obtain precursor 2. Since the hydrotalcite nanocrystal obtained after the exfoliation of precursor 1 is positively charged, it can interact electrostatically with the negatively charged precursor 2 after loading the naphthalene sulfonate formaldehyde condensate. Thus, the hydrotalcite nanocrystal is wrapped on the precursor 2 through layer-by-layer self-assembly technology to obtain the slow-release filler. The beneficial effects of this invention are as follows: This invention discloses a high-efficiency concrete water-reducing agent and its preparation method. By loading naphthalene sulfonate formaldehyde condensate, the water-reducing agent acquires a certain slow-release property, thereby solving the problem of large slump loss in existing naphthalene-based water-reducing agents. Furthermore, by combining it with water-reducing additives, the high-efficiency concrete water-reducing agent maintains good performance under high-temperature conditions and reduces the impact of naphthalene sulfonate formaldehyde condensate on the early strength development of concrete. After loading the naphthalene sulfonate formaldehyde condensate onto hollow mesoporous silica, hydrotalcite nanocrystals are encapsulated through electrostatic interaction. During the concrete setting process, due to the characteristics of the concrete itself, the pH value of the environment changes, causing the encapsulated hydrotalcite nanocrystals to detach, releasing the naphthalene sulfonate nanocrystals inside. The formaldehyde condensate of naphthalene sulfonate is released slowly, and the encapsulation of hydrotalcite nanocrystals when not in use ensures its stability during storage. Furthermore, the hydrotalcite nanocrystals themselves contain cobalt, iron, magnesium, and aluminum, which promote the hydration process. Since the water-reducing agent is based on guar gum and undergoes reversible addition-fragmentation chain transfer polymerization to form a structure with multi-branched block side chains, and contains a large number of phosphate groups, these groups can effectively cooperate with the detached hydrotalcite nanocrystals under alkaline conditions, thus ensuring the early strength development of concrete and reducing the impact of naphthalene sulfonate formaldehyde condensate on the early strength development of concrete. Simultaneously, its multi-branched block side chain structure ensures that the water-reducing agent maintains good performance even at high temperatures. Detailed Implementation

[0006] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on 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.

[0007] Example 1 A method for preparing a high-efficiency concrete water-reducing agent, comprising the following steps: weighing the following parts by weight of raw materials: 6 parts of slow-release filler, 8 parts of water-reducing agent and 0.8 parts of preservative, mixing the slow-release filler, water-reducing agent and preservative to obtain a high-efficiency concrete water-reducing agent; The corrosion inhibitor is Mingjiang Chemical's concrete corrosion inhibitor; The water-reducing agent is prepared through the following steps: Step A1: Tartaric acid and glycidyl methacrylate were mixed and stirred at 140 rpm and 98°C. Triphenylphosphine and p-hydroxyanisole were added and the mixture was reacted for 6 h. The mixture was then cooled to 52°C and pyrophosphate was added. The reaction was continued for 24 h to obtain intermediate 1. The ratio of tartaric acid, glycidyl methacrylate, triphenylphosphine, p-hydroxyanisole, and pyrophosphate was 0.11 mol: 0.24 mol: 0.23 g: 0.11 g: 0.46 mol. Step A2: Mix guar gum and tetrahydrofuran, stir at 160 rpm and 40°C, add potassium hydroxide and react for 12 h, then add carbon disulfide and continue reacting for 2 h, then add methyl 2-bromoisobutyrate and continue reacting for 22 h to obtain modified guar gum. The ratio of guar gum, potassium hydroxide, carbon disulfide, and methyl 2-bromoisobutyrate was 4.3 g: 0.08 mol: 0.085 mol: 0.082 mol. Step A3: Mix acrylic acid, isopentenyl alcohol polyoxyethylene ether, modified guar gum, azobisisobutyronitrile and dimethyl sulfoxide, and react for 22 h under nitrogen protection, stirring speed of 150 rpm and temperature of 70℃ to obtain water-reducing additive. The ratio of acrylic acid, isopentenyl alcohol polyoxyethylene ether, modified guar gum, and azobisisobutyronitrile is 0.012 mol: 2.3 g: 4.5 g: 0.12 g; The isopentenyl alcohol polyoxyethylene ether is Kemic TPEG-2400; The slow-release filler is prepared by the following steps: Step B1: Cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium carbonate, and deionized water were mixed. The mixture was stirred at 140 rpm at room temperature, and sodium hydroxide solution was added to maintain the pH of the system at 10. The temperature was raised to 150°C and crystallized for 14 h. The mixture was then filtered, washed, and dried to obtain precursor 1. Precursor 1 was mixed with formamide and stirred at 450 rpm at room temperature under nitrogen protection for 10 h. The mixture was then centrifuged, and the upper layer was collected to obtain the hydrotalcite exfoliation system. The sodium hydroxide solution has a mass fraction of 15%, and the ratio of cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and sodium carbonate is 0.022 mol: 0.11 mol: 0.022 mol: 0.011 mol: 13 g; the ratio of precursor 1 to formamide is 2.5 g: 45 mL. Step B2: Hollow mesoporous silica, naphthalene sulfonate formaldehyde condensate and deionized water are mixed and stirred for 12 h at a stirring rate of 140 rpm and a temperature of 100 °C to obtain precursor 2. Precursor 2 is added to the hydrotalcite exfoliation system and reacted for 40 min under nitrogen protection, stirring rate of 120 rpm and a temperature of room temperature. After filtration, washing and drying, the slow-release filler is obtained. The ratio of hollow mesoporous silica, naphthalene sulfonate formaldehyde condensate, and deionized water was 1.6 g: 2.3 g: 85 mL; the ratio of precursor 2 and hydrotalcite exfoliation system was 0.12 g: 20 mL. The hollow mesoporous silica is JK-04-009; The naphthalene sulfonate formaldehyde condensate is Wanshan brand FDN-A.

[0008] Example 2 A method for preparing a high-efficiency concrete water-reducing agent, comprising the following steps: weighing the following parts by weight of raw materials: 10 parts of slow-release filler, 6 parts of water-reducing agent and 1 part of preservative, mixing the slow-release filler, water-reducing agent and preservative to obtain a high-efficiency concrete water-reducing agent; The corrosion inhibitor is Mingjiang Chemical's concrete corrosion inhibitor; The water-reducing agent is prepared through the following steps: Step A1: Tartaric acid and glycidyl methacrylate were mixed and stirred at 160 rpm and 100 °C. Triphenylphosphine and p-hydroxyanisole were added and the mixture was reacted for 8 h. The mixture was then cooled to 55 °C and pyrophosphate was added. The reaction was continued for 24 h to obtain intermediate 1. The ratio of tartaric acid, glycidyl methacrylate, triphenylphosphine, p-hydroxyanisole, and pyrophosphate was 0.12 mol: 0.25 mol: 0.25 g: 0.13 g: 0.48 mol. Step A2: Mix guar gum and tetrahydrofuran, stir at 180 rpm and 42°C, add potassium hydroxide and react for 14 h, then add carbon disulfide and continue reacting for 3 h, then add methyl 2-bromoisobutyrate and continue reacting for 24 h to obtain modified guar gum. The ratio of guar gum, potassium hydroxide, carbon disulfide, and methyl 2-bromoisobutyrate was 4.5 g: 0.082 mol: 0.09 mol: 0.085 mol. Step A3: Mix acrylic acid, isopentenyl alcohol polyoxyethylene ether, modified guar gum, azobisisobutyronitrile and dimethyl sulfoxide, and react for 24 h under nitrogen protection, stirring speed of 180 rpm and temperature of 72℃ to obtain water-reducing additive. The ratio of acrylic acid, isopentenyl alcohol polyoxyethylene ether, modified guar gum, and azobisisobutyronitrile is 0.015 mol: 2.5 g: 4.8 g: 0.15 g; The isopentenyl alcohol polyoxyethylene ether is Kemic TPEG-2400; The slow-release filler is prepared by the following steps: Step B1: Cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium carbonate, and deionized water were mixed. The mixture was stirred at 120 rpm at room temperature, and sodium hydroxide solution was added to maintain the pH of the system at 10. The temperature was raised to 145℃ and crystallized for 12 h. The mixture was filtered, washed, and dried to obtain precursor 1. Precursor 1 was mixed with formamide and stirred at 400 rpm at room temperature under nitrogen protection for 8 h. The mixture was centrifuged, and the upper layer was collected to obtain the hydrotalcite exfoliation system. The sodium hydroxide solution has a mass fraction of 15%, and the ratio of cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and sodium carbonate is 0.02 mol: 0.01 mol: 0.02 mol: 0.01 mol: 12 g; the ratio of precursor 1 to formamide is 2.4 g: 40 mL. Step B2: Hollow mesoporous silica, naphthalene sulfonate formaldehyde condensate and deionized water are mixed and stirred for 12 h at a stirring rate of 120 rpm and a temperature of 95 ℃ to obtain precursor 2. Precursor 2 is added to the hydrotalcite exfoliation system and reacted for 30 min under nitrogen protection, stirring rate of 90 rpm and a temperature of room temperature. After filtration, washing and drying, the slow-release filler is obtained. The ratio of hollow mesoporous silica, naphthalene sulfonate formaldehyde condensate, and deionized water was 1.5 g: 2.2 g: 80 mL; the ratio of precursor 2 and hydrotalcite exfoliation system was 0.1 g: 150 mL. The hollow mesoporous silica is JK-04-009; The naphthalene sulfonate formaldehyde condensate is Wanshan brand FDN-A.

[0009] Example 3 A method for preparing a high-efficiency concrete water-reducing agent, comprising the following steps: weighing the following parts by weight of raw materials: 10 parts of slow-release filler, 8 parts of water-reducing agent and 1 part of preservative, mixing the slow-release filler, water-reducing agent and preservative to obtain a high-efficiency concrete water-reducing agent; The corrosion inhibitor is Mingjiang Chemical's concrete corrosion inhibitor; The water-reducing agent is prepared through the following steps: Step A1: Tartaric acid and glycidyl methacrylate were mixed and stirred at 160 rpm and 100 °C. Triphenylphosphine and p-hydroxyanisole were added and the mixture was reacted for 8 h. The mixture was then cooled to 55 °C and pyrophosphate was added. The reaction was continued for 24 h to obtain intermediate 1. The ratio of tartaric acid, glycidyl methacrylate, triphenylphosphine, p-hydroxyanisole, and pyrophosphate was 0.12 mol: 0.25 mol: 0.25 g: 0.13 g: 0.48 mol. Step A2: Mix guar gum and tetrahydrofuran, stir at 180 rpm and 42°C, add potassium hydroxide and react for 14 h, then add carbon disulfide and continue reacting for 3 h, then add methyl 2-bromoisobutyrate and continue reacting for 24 h to obtain modified guar gum. The ratio of guar gum, potassium hydroxide, carbon disulfide, and methyl 2-bromoisobutyrate was 4.5 g: 0.082 mol: 0.09 mol: 0.085 mol. Step A3: Mix acrylic acid, isopentenyl alcohol polyoxyethylene ether, modified guar gum, azobisisobutyronitrile and dimethyl sulfoxide, and react for 24 h under nitrogen protection, stirring speed of 180 rpm and temperature of 70-72℃ to obtain water-reducing additive. The ratio of acrylic acid, isopentenyl alcohol polyoxyethylene ether, modified guar gum, and azobisisobutyronitrile is 0.015 mol: 2.5 g: 4.8 g: 0.15 g; The isopentenyl alcohol polyoxyethylene ether is Kemic TPEG-2400; The slow-release filler is prepared by the following steps: Step B1: Cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium carbonate, and deionized water were mixed. The mixture was stirred at 140 rpm at room temperature, and sodium hydroxide solution was added to maintain the pH of the system at 10. The temperature was raised to 150°C and crystallized for 14 h. The mixture was then filtered, washed, and dried to obtain precursor 1. Precursor 1 was mixed with formamide and stirred at 450 rpm at room temperature under nitrogen protection for 10 h. The mixture was then centrifuged, and the upper layer was collected to obtain the hydrotalcite exfoliation system. The sodium hydroxide solution has a mass fraction of 15%, and the ratio of cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and sodium carbonate is 0.022 mol: 0.11 mol: 0.022 mol: 0.011 mol: 13 g; the ratio of precursor 1 to formamide is 2.5 g: 45 mL. Step B2: Hollow mesoporous silica, naphthalene sulfonate formaldehyde condensate and deionized water are mixed and stirred for 12 h at a stirring rate of 140 rpm and a temperature of 100 °C to obtain precursor 2. Precursor 2 is added to the hydrotalcite exfoliation system and reacted for 40 min under nitrogen protection, stirring rate of 120 rpm and a temperature of room temperature. After filtration, washing and drying, the slow-release filler is obtained. The ratio of hollow mesoporous silica, naphthalene sulfonate formaldehyde condensate, and deionized water was 1.6 g: 2.3 g: 85 mL; the ratio of precursor 2 and hydrotalcite exfoliation system was 0.12 g: 20 mL. The hollow mesoporous silica is JK-04-009; The naphthalene sulfonate formaldehyde condensate is Wanshan brand FDN-A.

[0010] Comparative Example 1: Compared with Example 3, the slow-release filler in the preparation process of the high-efficiency concrete water-reducing agent in Example 3 was replaced with Wanshan brand FDN-A naphthalene sulfonate formaldehyde condensate and JK-04-009 hollow mesoporous silica. The weight ratio of naphthalene sulfonate formaldehyde condensate to hollow mesoporous silica was 1.6g:2.3g. All other steps were the same.

[0011] Comparative Example 2: Compared with Example 3, the water-reducing agent in the preparation process of the high-efficiency concrete water-reducing agent in Example 3 was replaced with Bofei BF-01 polycarboxylate water-reducing agent, while the other steps were the same.

[0012] The high-efficiency concrete water-reducing agents prepared in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2 were used. Referring to GB / T17671-1999, 1350g of standard sand, 80g of fly ash, and 450g of cement were mixed, stirred, and water and 0.8% of the high-efficiency concrete water-reducing agent by mass were added. The water content was adjusted to achieve a cement mortar flowability of 180±5mm. The mixture was then poured into a 40×40×160mm mold and demolded after 24 hours. Curing was performed at 20℃, and the compressive strength was tested at 1d, 7d, and 28d. The curing temperature was then increased to 40℃, and the compressive strength at 28d was measured. The performance retention rate was calculated, referring to GB / T GB 8077-2012, after removing the high-efficiency concrete water-reducing agent, recorded the amount of water used to adjust the water volume to achieve a cement mortar flowability of 180±5mm, thereby calculating its water reduction rate. A mixture of 250g water, 1350g standard sand, 80g fly ash, 450g cement, and 15g high-efficiency concrete water-reducing agent was prepared. Referring to GB 8077-1997, the flowability of the cement paste was measured, and the flow rate after 30 minutes was calculated to determine its retention rate, thus evaluating the slow-release slump reduction effect. The test results are shown in Table 1 below.

[0013] As shown in the table, the test results indicate that when comparing Examples 1, 2, and 3 with Comparative Examples 1 and 2, Comparative Example 1 replaced the slow-release filler in the preparation process of the high-efficiency concrete water-reducing agent in Example 3 with naphthalene sulfonate formaldehyde condensate and hollow mesoporous silica. Due to the lack of slow-release structure and hydrotalcite-like crystals, its performance decreased. In Comparative Example 2, the water-reducing additive in the preparation process of the high-efficiency concrete water-reducing agent in Example 3 was replaced with polycarboxylate water-reducing agent. Due to the lack of multi-branched block side chain structure and phosphate ester groups, its performance decreased.

[0014] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0015] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-efficiency concrete water-reducing agent, characterized in that: The process includes the following steps: Weigh the following raw materials by weight: 6-10 parts of slow-release filler, 6-8 parts of water-reducing agent and 0.8-1 parts of corrosion inhibitor; mix the slow-release filler, water-reducing agent and corrosion inhibitor to obtain a high-efficiency concrete water-reducing agent. The water-reducing agent is prepared through the following steps: Step A1: Tartaric acid and glycidyl methacrylate are mixed and stirred at a speed of 140-160 rpm and a temperature of 98-100℃. Triphenylphosphine and p-hydroxyanisole are added and the mixture is reacted for 6-8 hours. Then the temperature is lowered to 52-55℃ and pyrophosphate is added. The reaction is continued for 24 hours to obtain intermediate 1. Step A2: Mix guar gum and tetrahydrofuran, stir at a stirring speed of 160-180 rpm and a temperature of 40-42℃, add potassium hydroxide, react for 12-14 h, then add carbon disulfide, continue the reaction for 2-3 h, then add methyl 2-bromoisobutyrate, continue the reaction for 22-24 h to obtain modified guar gum; Step A3: Mix acrylic acid, isopentenyl alcohol polyoxyethylene ether, modified guar gum, azobisisobutyronitrile and dimethyl sulfoxide, and react for 22-24 hours under nitrogen protection, stirring speed of 150-180 rpm and temperature of 70-72℃ to obtain water-reducing additive. The slow-release filler is prepared by the following steps: Step B1: Cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium carbonate, and deionized water are mixed. Under the conditions of stirring speed of 120-140 rpm and room temperature, sodium hydroxide solution is added to maintain the pH value of the system at 10. The temperature is raised to 145-150℃ and crystallized for 12-14 h. After filtration, washing, and drying, precursor 1 is obtained. Precursor 1 is mixed with formamide and stirred for 8-10 h under nitrogen protection, stirring speed of 400-450 rpm, and room temperature. After centrifugation, the upper layer is taken to obtain the hydrotalcite exfoliation system. Step B2: Hollow mesoporous silica, naphthalene sulfonate formaldehyde condensate and deionized water are mixed and stirred for 12 h at a stirring rate of 120-140 rpm and a temperature of 95-100℃ to obtain precursor 2. Precursor 2 is added to the hydrotalcite exfoliation system and reacted for 30-40 min under nitrogen protection, stirring rate of 90-120 rpm and a temperature of room temperature. After filtration, washing and drying, the slow-release filler is obtained.

2. The preparation method of a high-efficiency concrete water-reducing agent according to claim 1, characterized in that: In step A1, the ratio of tartaric acid, glycidyl methacrylate, triphenylphosphine, p-hydroxyanisole, and pyrophosphate is 0.11-0.12 mol: 0.24-0.25 mol: 0.23-0.25 g: 0.11-0.13 g: 0.46-0.48 mol.

3. The preparation method of a high-efficiency concrete water-reducing agent according to claim 1, characterized in that: In step A2: the ratio of guar gum, potassium hydroxide, carbon disulfide and methyl 2-bromoisobutyrate is 4.3-4.5g: 0.08-0.082mol: 0.085-0.09mol: 0.082-0.085mol.

4. The preparation method of a high-efficiency concrete water-reducing agent according to claim 1, characterized in that: In step A3, the ratio of acrylic acid, isopentenyl alcohol polyoxyethylene ether, modified guar gum and azobisisobutyronitrile is 0.012-0.015 mol: 2.3-2.5 g: 4.5-4.8 g: 0.12-0.15 g.

5. The preparation method of a high-efficiency concrete water-reducing agent according to claim 1, characterized in that: In step B1: the mass fraction of sodium hydroxide solution is 15%, and the ratio of cobalt nitrate hexahydrate, ferric nitrate nonahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and sodium carbonate is 0.02-0.022 mol: 0.01-0.11 mol: 0.02-0.022 mol: 0.01-0.011 mol: 12-13 g; the ratio of precursor 1 to formamide is 2.4-2.5 g: 40-45 mL.

6. The preparation method of a high-efficiency concrete water-reducing agent according to claim 5, characterized in that: In step B2: the ratio of hollow mesoporous silica, naphthalene sulfonate formaldehyde condensate and deionized water is 1.5-1.6g: 2.2-2.3g: 80-85mL; the ratio of precursor 2 and hydrotalcite exfoliation system is 0.1-0.12g: 15-20mL.

7. A high-efficiency concrete water-reducing agent, characterized in that: It is prepared according to any one of the preparation methods described in claims 1-6.

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