Concrete containing polycarboxylate water reducer and preparation process thereof

Abstract

The invention relates to the technical field of concrete, and in particular to concrete containing a polycarboxylate water-reducing agent and a preparation process thereof. In order to improve the performance of concrete, the invention prepares a polycarboxylate water-reducing agent with a carboxyl protection function. The invention introduces a large number of amide groups into the water-reducing agent, so that in the process of preparing concrete, the polycarboxylate water-reducing agent can be gradually hydrolyzed to generate carboxyl groups in an alkaline environment, and then the cement particles in the concrete are subjected to secondary adsorption, thereby prolonging the working time of the water-reducing agent on the cement particles. In addition, the invention further increases the length of the side chains in the water-reducing agent, provides steric hindrance, further prevents the aggregation between cement particles, improves the water-reducing property, thereby avoiding the solidification between cement particles, maintains the fluidity for a long time, and prolongs the construction time of the concrete.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, in particular to concrete containing a polycarboxylate water reducer and a preparation process thereof. Background Art

[0002] Water reducers are an indispensable component in modern concrete engineering. By adding water reducers to concrete aggregates, the fluidity and slump of concrete can be effectively improved. Moreover, due to the regulation of the water-cement ratio of concrete by water reducers, the later strength of concrete can be effectively improved, thereby improving the quality of concrete. However, there are various types of water reducers at present, and most of them will face the problem of excessive slump loss and rapid decrease in later fluidity during use as the cement hydration process deepens. This can easily cause troubles to construction sites and lead to a decline in concrete quality. Therefore, it is necessary to overcome this defect. Summary of the invention

[0003] The object of the present invention is to provide a concrete containing a polycarboxylate water-reducing agent and a preparation process thereof, so as to solve the problems raised in the above background technology.

[0004] In order to solve the above technical problems, the present invention provides the following technical solution: a concrete containing a polycarboxylate water reducer, having the following technical characteristics: calculated by weight, the concrete containing the polycarboxylate water reducer consists of 240-270 parts of cement, 1000-1100 parts of coarse aggregate, 750-800 parts of fine aggregate, 1.5-2.5 parts of polycarboxylate water reducer, 90-120 parts of fly ash, and 155-170 parts of mixing water.

[0005] Further, the cement is silicate cement;

[0006] The coarse aggregate is gravel with a particle size of 5-20 mm and a continuous grade; the fine aggregate is river sand with a particle size of 0.5-3 mm and a continuous grade.

[0007] Furthermore, the fly ash is any one of primary fly ash and secondary fly ash.

[0008] A method for preparing concrete containing a polycarboxylate water-reducing agent comprises the following steps:

[0009] S1. Preparation of polycarboxylate water reducer;

[0010] S11. Disperse fumaric acid in pure DMF, heat to 30-40°C, stir and mix for 15-20 min, and then cool the mixed solution to room temperature to obtain a fumaric acid solution;

[0011] Disperse 4,4'-diaminodiphenyl ether in DMF, stir and mix for 30-45 minutes, protect under nitrogen atmosphere, cool to 5-8°C, and then dropwise add fumaric acid solution thereto for 50-150 minutes. After the dropwise addition is completed, heat to 85-90°C, continue to stir and react for 1-2.5 hours, and then evaporate excess solvent in vacuo to obtain an enamide compound;

[0012] S12. Disperse the enamide compound in pure DMF, heat it to 35-50°C, stir and disperse it for 15-30 minutes, then add a DMF solution containing 4-aminobutyric acid thereto, and add it dropwise for 2-4 hours. Protect the nitrogen atmosphere during the addition. After the addition is completed, heat it to 65-75°C, stir and react for 90-150 minutes, and then remove the excess solvent by rotary evaporation. Collect the reaction product, wash the surface with deionized water, and disperse the washed product in ethyl acetate. Heat it to 60-75°C, stir and disperse it for 1.5-2 hours, then recrystallize and collect the solid product at the bottom of the mixed solution, and vacuum evaporate it to constant weight to obtain a small molecule carboxyl protected compound;

[0013] S13. The methyl allyl polyoxyethylene ether was mixed with deionized water, stirred evenly, and the mixed solution was heated to 60-65 ° C, stirred and mixed for 5-15 minutes, and ascorbic acid and mercaptopropionic acid were added thereto. Under a nitrogen atmosphere, the temperature was raised to 65-70 ° C, and acrylic acid and a small molecule carboxyl protected compound were added dropwise. The addition time was 1.5-3h. After the addition was completed, stirring was continued and the reaction was kept warm for 2.5-3h, and the solid content was adjusted to 38-41% by vacuum evaporation. The mixture was cooled to room temperature to obtain a polycarboxylate water reducer;

[0014] S2. Mix cement, coarse aggregate, fine aggregate, reinforcing fiber and fly ash, stir for 2-4 minutes, add polycarboxylate water reducer and mixing water, continue stirring for 3-5 minutes, obtain concrete aggregate, tamp and cast it into shape, and obtain concrete containing polycarboxylate water reducer.

[0015] Furthermore, in terms of weight, in step S11, the mass ratio of the fumaric acid to 4,4'-diaminodiphenyl ether is 1:(0.8-0.87).

[0016] Furthermore, in terms of parts by weight, in step S12, the mass ratio of the enamide compound to 4-aminobutyric acid is 1:(0.44-0.48).

[0017] Furthermore, in terms of weight, in step S13, the mass ratio of the methyl allyl polyoxyethylene ether, ascorbic acid, and mercaptopropionic acid is 100:(0.03-0.04):(0.07-0.09).

[0018] Wherein, the weight average molecular weight M of the methyl allyl polyoxyethylene ether is W It is 2000-2500.

[0019] Furthermore, in terms of weight, in step S13, the mass ratio of the methyl allyl polyoxyethylene ether, acrylic acid, and small molecule carboxyl protection compound is 100:(0.4-0.46):(1.2-2.4).

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0021] 1. In order to improve the performance of concrete, the present invention prepares a polycarboxylate water-reducing agent with a carboxyl protection function, so that in the process of preparing concrete, the polycarboxylate water-reducing agent can be gradually hydrolyzed in an alkaline environment to generate carboxyl groups, and then the cement particles in the concrete are secondary adsorbed, thereby extending the working time of the water-reducing agent on the cement particles, thereby avoiding solidification between cement particles, maintaining fluidity for a long time, and improving the construction time of concrete;

[0022] 2. In the process of preparing the polycarboxylic acid water-reducing agent of the present invention, fumaric acid is first used as a reaction raw material. Fumaric acid contains two carboxylic acid groups. By reacting with the amino group in 4,4'-diaminodiphenyl ether, two amide groups can be generated. In an alkaline environment, these amide groups will be hydrolyzed again to generate anionic groups such as carboxyl groups, thereby secondary adsorption of cement particles; and the present invention further uses 4-aminobutyric acid to react with enamide compounds, thereby increasing the number of amide groups in the small molecule carboxyl protection compound and improving its collapse retention performance. At the same time, the small molecule carboxyl protection compound prepared in the present application has an increased carbon chain length through the amide group reaction. After reacting with substances such as methyl allyl polyoxyethylene ether, it can also effectively enhance the steric hindrance of the water-reducing agent molecule, further prevent the aggregation between cement particles, and improve the water-reducing property. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The fumaric acid used in this application was provided by Guangzhou Haoyu International Trade Co., Ltd.; the 4,4'-diaminodiphenyl ether used was provided by Shanghai Haohong Biomedical Technology Co., Ltd.; the 4-aminobutyric acid used was provided by Ningxiang County Jiayuan Biotechnology Co., Ltd.; the methyl allyl polyoxyethylene ether used was HPEG-2400, provided by Hubei Longxin Chemical Industry Co., Ltd.; the fly ash used was secondary fly ash, provided by Lingshou County Yubang Mining Co., Ltd.; the concrete used was Jiangnan Onoda P.II52.5 silicate cement;

[0025] Embodiment 1. A method for preparing concrete containing a polycarboxylate water-reducing agent, comprising the following steps:

[0026] S1. Preparation of polycarboxylate water reducer;

[0027] S11. Disperse 1 part of fumaric acid in pure DMF by weight, heat to 30°C, stir and mix for 15 min, and then cool the mixed solution to room temperature to obtain a fumaric acid solution;

[0028] Disperse 0.8 parts of 4,4'-diaminodiphenyl ether in DMF, stir and mix for 30 minutes, protect under nitrogen atmosphere, cool to 5°C, and then dropwise add fumaric acid solution thereto for 50 minutes. After the dropwise addition is completed, heat to 85°C, continue to stir and react for 1 hour, and then evaporate the excess solvent in vacuo to obtain an ene amide compound;

[0029] S12. Disperse 1 part of the enamide compound in pure DMF by weight, heat to 35°C, stir and disperse for 15 minutes, add 0.44 parts of 4-aminobutyric acid dissolved in DMF solution, add for 2 hours, protect with nitrogen atmosphere during the addition, heat to 65°C after the addition, stir and react for 90 minutes, remove excess solvent by rotary evaporation, collect the reaction product, wash the surface with deionized water, and disperse the washed product in ethyl acetate, heat to 60°C, stir and disperse for 1.5 hours, collect the solid product at the bottom of the mixed solution by recrystallization, and evaporate in vacuo to constant weight to obtain a small molecule carboxyl protected compound;

[0030] S13. By weight, 100 parts of methyl allyl polyoxyethylene ether were mixed with deionized water, stirred evenly, and the mixed solution was heated to 60 ° C. After stirring for 5 minutes, 0.03 parts of ascorbic acid and 0.07 parts of mercaptopropionic acid were added thereto. Under a nitrogen atmosphere, the temperature was raised to 65 ° C., and a mixture of 0.4 parts of acrylic acid and 1.2 parts of a small molecule carboxyl protection compound was added dropwise. The addition time was 1.5 hours. After the addition was completed, stirring was continued and the reaction was kept warm for 2.5 hours, and the solid content was adjusted to 39% by vacuum evaporation, and cooled to room temperature to obtain a polycarboxylate water reducer;

[0031] S2. 260 parts of cement, 1050 parts of coarse aggregate, 780 parts of fine aggregate and 110 parts of fly ash were mixed and stirred for 2 minutes, and then 1.5 parts of polycarboxylate water reducer and 160 parts of mixing water were added. After further stirring for 3 minutes, concrete aggregate was obtained, which was rammed and cast to obtain concrete containing polycarboxylate water reducer.

[0032] Embodiment 2. A method for preparing concrete containing a polycarboxylate water-reducing agent, comprising the following steps:

[0033] Compared with Example 1, this example increases the amount of 4,4'-diaminodiphenyl ether added in step S11;

[0034] S1. Preparation of polycarboxylate water reducer;

[0035] S11. Disperse 1 part of fumaric acid in pure DMF by weight, heat to 30°C, stir and mix for 15 min, and then cool the mixed solution to room temperature to obtain a fumaric acid solution;

[0036] Disperse 0.87 parts of 4,4'-diaminodiphenyl ether in DMF, stir and mix for 30 minutes, protect under nitrogen atmosphere, cool to 5°C, and then dropwise add fumaric acid solution thereto for 50 minutes. After the dropwise addition is completed, heat to 85°C, continue to stir and react for 1 hour, and then evaporate the excess solvent in vacuo to obtain an ene amide compound;

[0037] S12. Disperse 1 part of the enamide compound in pure DMF by weight, heat to 35°C, stir and disperse for 15 minutes, add 0.44 parts of 4-aminobutyric acid dissolved in DMF solution, add for 2 hours, protect with nitrogen atmosphere during the addition, heat to 65°C after the addition, stir and react for 90 minutes, remove excess solvent by rotary evaporation, collect the reaction product, wash the surface with deionized water, and disperse the washed product in ethyl acetate, heat to 60°C, stir and disperse for 1.5 hours, collect the solid product at the bottom of the mixed solution by recrystallization, and evaporate in vacuo to constant weight to obtain a small molecule carboxyl protected compound;

[0038] S13. By weight, 100 parts of methyl allyl polyoxyethylene ether were mixed with deionized water, stirred evenly, and the mixed solution was heated to 60 ° C. After stirring for 5 minutes, 0.03 parts of ascorbic acid and 0.07 parts of mercaptopropionic acid were added thereto. Under a nitrogen atmosphere, the temperature was raised to 65 ° C., and a mixture of 0.4 parts of acrylic acid and 1.2 parts of a small molecule carboxyl protection compound was added dropwise. The addition time was 1.5 hours. After the addition was completed, stirring was continued and the reaction was kept warm for 2.5 hours, and the solid content was adjusted to 39% by vacuum evaporation, and cooled to room temperature to obtain a polycarboxylate water reducer;

[0039] S2. 260 parts of cement, 1050 parts of coarse aggregate, 780 parts of fine aggregate and 110 parts of fly ash were mixed and stirred for 2 minutes, and then 1.5 parts of polycarboxylate water reducer and 160 parts of mixing water were added. After further stirring for 3 minutes, concrete aggregate was obtained, which was rammed and cast to obtain concrete containing polycarboxylate water reducer.

[0040] Embodiment 3. A method for preparing concrete containing a polycarboxylate water-reducing agent, comprising the following steps:

[0041] Compared with Example 1, this example increases the amount of 4-aminobutyric acid added in step S12;

[0042] S1. Preparation of polycarboxylate water reducer;

[0043] S11. Disperse 1 part of fumaric acid in pure DMF by weight, heat to 30°C, stir and mix for 15 min, and then cool the mixed solution to room temperature to obtain a fumaric acid solution;

[0044] Disperse 0.8 parts of 4,4'-diaminodiphenyl ether in DMF, stir and mix for 30 minutes, protect under nitrogen atmosphere, cool to 5°C, and then dropwise add fumaric acid solution thereto for 50 minutes. After the dropwise addition is completed, heat to 85°C, continue to stir and react for 1 hour, and then evaporate the excess solvent in vacuo to obtain an ene amide compound;

[0045] S12. Disperse 1 part of the enamide compound in pure DMF by weight, heat to 35°C, stir and disperse for 15 minutes, add 0.48 parts of 4-aminobutyric acid in DMF solution, add for 2 hours, protect with nitrogen atmosphere during the addition, heat to 65°C after the addition, stir and react for 90 minutes, remove excess solvent by rotary evaporation, collect the reaction product, wash the surface with deionized water, and disperse the washed product in ethyl acetate, heat to 60°C, stir and disperse for 1.5 hours, collect the solid product at the bottom of the mixed solution by recrystallization, and evaporate in vacuo to constant weight to obtain a small molecule carboxyl protected compound;

[0046] S13. By weight, 100 parts of methyl allyl polyoxyethylene ether were mixed with deionized water, stirred evenly, and the mixed solution was heated to 60 ° C. After stirring for 5 minutes, 0.03 parts of ascorbic acid and 0.07 parts of mercaptopropionic acid were added thereto. Under a nitrogen atmosphere, the temperature was raised to 65 ° C., and a mixture of 0.4 parts of acrylic acid and 1.2 parts of a small molecule carboxyl protection compound was added dropwise. The addition time was 1.5 hours. After the addition was completed, stirring was continued and the reaction was kept warm for 2.5 hours, and the solid content was adjusted to 39% by vacuum evaporation, and cooled to room temperature to obtain a polycarboxylate water reducer;

[0047] S2. 260 parts of cement, 1050 parts of coarse aggregate, 780 parts of fine aggregate and 110 parts of fly ash were mixed and stirred for 2 minutes, and then 1.5 parts of polycarboxylate water reducer and 160 parts of mixing water were added. After further stirring for 3 minutes, concrete aggregate was obtained, which was rammed and cast to obtain concrete containing polycarboxylate water reducer.

[0048] Embodiment 4. A method for preparing concrete containing a polycarboxylate water-reducing agent, comprising the following steps:

[0049] Compared with Example 1, this example increases the amount of the small molecule carboxyl protection compound in step S13;

[0050] S1. Preparation of polycarboxylate water reducer;

[0051] S11. Disperse 1 part of fumaric acid in pure DMF by weight, heat to 30°C, stir and mix for 15 min, and then cool the mixed solution to room temperature to obtain a fumaric acid solution;

[0052] Disperse 0.8 parts of 4,4'-diaminodiphenyl ether in DMF, stir and mix for 30 minutes, protect under nitrogen atmosphere, cool to 5°C, and then dropwise add fumaric acid solution thereto for 50 minutes. After the dropwise addition is completed, heat to 85°C, continue to stir and react for 1 hour, and then evaporate the excess solvent in vacuo to obtain an ene amide compound;

[0053] S12. Disperse 1 part of the enamide compound in pure DMF by weight, heat to 35°C, stir and disperse for 15 minutes, add 0.44 parts of 4-aminobutyric acid dissolved in DMF solution, add for 2 hours, protect with nitrogen atmosphere during the addition, heat to 65°C after the addition, stir and react for 90 minutes, remove excess solvent by rotary evaporation, collect the reaction product, wash the surface with deionized water, and disperse the washed product in ethyl acetate, heat to 60°C, stir and disperse for 1.5 hours, collect the solid product at the bottom of the mixed solution by recrystallization, and evaporate in vacuo to constant weight to obtain a small molecule carboxyl protected compound;

[0054] S13. By weight, 100 parts of methyl allyl polyoxyethylene ether were mixed with deionized water, stirred evenly, and the mixed solution was heated to 60 ° C. After stirring for 5 minutes, 0.03 parts of ascorbic acid and 0.07 parts of mercaptopropionic acid were added thereto. Under a nitrogen atmosphere, the temperature was raised to 65 ° C. A mixture of 0.4 parts of acrylic acid and 2.4 parts of a small molecule carboxyl protection compound was added dropwise. The addition time was 1.5 hours. After the addition was completed, stirring was continued and the reaction was kept warm for 2.5 hours, and the solid content was adjusted to 39% by vacuum evaporation. The mixture was cooled to room temperature to obtain a polycarboxylate water reducer;

[0055] S2. 260 parts of cement, 1050 parts of coarse aggregate, 780 parts of fine aggregate and 110 parts of fly ash were mixed and stirred for 2 minutes, and then 1.5 parts of polycarboxylate water reducer and 160 parts of mixing water were added. After further stirring for 3 minutes, concrete aggregate was obtained, which was rammed and cast to obtain concrete containing polycarboxylate water reducer.

[0056] Embodiment 5. A method for preparing concrete containing a polycarboxylate water-reducing agent, comprising the following steps:

[0057] Compared with Example 1, this embodiment increases the amount of polycarboxylate water-reducing agent added in step S2;

[0058] S1. Preparation of polycarboxylate water reducer;

[0059] S11. Disperse 1 part of fumaric acid in pure DMF by weight, heat to 30°C, stir and mix for 15 min, and then cool the mixed solution to room temperature to obtain a fumaric acid solution;

[0060] Disperse 0.8 parts of 4,4'-diaminodiphenyl ether in DMF, stir and mix for 30 minutes, protect under nitrogen atmosphere, cool to 5°C, and then dropwise add fumaric acid solution thereto for 50 minutes. After the dropwise addition is completed, heat to 85°C, continue to stir and react for 1 hour, and then evaporate the excess solvent in vacuo to obtain an ene amide compound;

[0061] S12. Disperse 1 part of the enamide compound in pure DMF by weight, heat to 35°C, stir and disperse for 15 minutes, add 0.44 parts of 4-aminobutyric acid dissolved in DMF solution, add for 2 hours, protect with nitrogen atmosphere during the addition, heat to 65°C after the addition, stir and react for 90 minutes, remove excess solvent by rotary evaporation, collect the reaction product, wash the surface with deionized water, and disperse the washed product in ethyl acetate, heat to 60°C, stir and disperse for 1.5 hours, collect the solid product at the bottom of the mixed solution by recrystallization, and evaporate in vacuo to constant weight to obtain a small molecule carboxyl protected compound;

[0062] S13. By weight, 100 parts of methyl allyl polyoxyethylene ether were mixed with deionized water, stirred evenly, and the mixed solution was heated to 60 ° C. After stirring for 5 minutes, 0.03 parts of ascorbic acid and 0.07 parts of mercaptopropionic acid were added thereto. Under a nitrogen atmosphere, the temperature was raised to 65 ° C., and a mixture of 0.4 parts of acrylic acid and 1.2 parts of a small molecule carboxyl protection compound was added dropwise. The addition time was 1.5 hours. After the addition was completed, stirring was continued and the reaction was kept warm for 2.5 hours, and the solid content was adjusted to 39% by vacuum evaporation, and cooled to room temperature to obtain a polycarboxylate water reducer;

[0063] S2. 260 parts of cement, 1050 parts of coarse aggregate, 780 parts of fine aggregate and 110 parts of fly ash were mixed and stirred for 2 minutes, and then 2.5 parts of polycarboxylate water reducer and 160 parts of mixing water were added. After further stirring for 3 minutes, concrete aggregate was obtained, which was rammed and cast to obtain concrete containing polycarboxylate water reducer.

[0064] Comparative Example 1. A method for preparing concrete containing a polycarboxylate water-reducing agent, comprising the following steps:

[0065] Compared with Example 1, this comparative example does not perform step S12 processing;

[0066] S1. Preparation of polycarboxylate water reducer;

[0067] S11. Disperse 1 part of fumaric acid in pure DMF by weight, heat to 30°C, stir and mix for 15 min, and then cool the mixed solution to room temperature to obtain a fumaric acid solution;

[0068] Disperse 0.8 parts of 4,4'-diaminodiphenyl ether in DMF, stir and mix for 30 minutes, protect under nitrogen atmosphere, cool to 5°C, and then dropwise add fumaric acid solution thereto for 50 minutes. After the dropwise addition is completed, heat to 85°C, continue to stir and react for 1 hour, and then evaporate the excess solvent in vacuo to obtain an ene amide compound;

[0069] S12. By weight, 100 parts of methyl allyl polyoxyethylene ether were mixed with deionized water, stirred evenly, and the mixed solution was heated to 60 ° C. After stirring for 5 min, 0.03 parts of ascorbic acid and 0.07 parts of mercaptopropionic acid were added thereto. Under a nitrogen atmosphere, the temperature was raised to 65 ° C. A mixture of 0.4 parts of acrylic acid and 1.2 parts of an amide compound was added dropwise, and the addition time was 1.5 h. After the addition was completed, stirring was continued and the reaction was kept warm for 2.5 h, and the solid content was adjusted to 39% by vacuum evaporation, and cooled to room temperature to obtain a polycarboxylate water reducer;

[0070] S2. 260 parts of cement, 1050 parts of coarse aggregate, 780 parts of fine aggregate and 110 parts of fly ash were mixed and stirred for 2 minutes, and then 1.5 parts of polycarboxylate water reducer and 160 parts of mixing water were added. After further stirring for 3 minutes, concrete aggregate was obtained, which was rammed and cast to obtain concrete containing polycarboxylate water reducer.

[0071] Comparative Example 2. A method for preparing concrete containing a polycarboxylate water-reducing agent, comprising the following steps:

[0072] Compared with Example 1, this comparative example did not add a small molecule carboxyl protection compound to prepare the polycarboxylate water reducer;

[0073] S1. Preparation of polycarboxylate water reducer;

[0074] By weight, 100 parts of methyl allyl polyoxyethylene ether were mixed with deionized water, and after stirring evenly, the mixed solution was heated to 60° C., stirred and mixed for 5 minutes, 0.03 parts of ascorbic acid and 0.07 parts of mercaptopropionic acid were added thereto, and the temperature was raised to 65° C. under a nitrogen atmosphere, and 0.8 parts of acrylic acid were added dropwise thereto for 1.5 hours. After the addition was completed, stirring was continued and the reaction was kept warm for 2.5 hours, and vacuum evaporated to adjust the solid content to 39%, and cooled to room temperature to obtain a polycarboxylate water reducer;

[0075] S2. 260 parts of cement, 1050 parts of coarse aggregate, 780 parts of fine aggregate and 110 parts of fly ash were mixed and stirred for 2 minutes, and then 1.5 parts of polycarboxylate water reducer and 160 parts of mixing water were added. After further stirring for 3 minutes, concrete aggregate was obtained, which was rammed and cast to obtain concrete containing polycarboxylate water reducer.

[0076] Testing: After the concrete glue prepared in the above-mentioned Examples 1-5 and Comparative Examples 1-2 is mixed according to the ratio, the concrete slump performance is tested according to GB / T50080, and after curing for 28 days in a standard environment, the compressive strength is tested according to GB 8076-2008. The test results are shown in the following table;

[0077]

[0078]

[0079] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing concrete containing a polycarboxylate water-reducing agent, characterized in that: The following steps are involved: S1. Preparation of polycarboxylate water reducer; S11. Disperse fumaric acid in pure DMF, heat to 30-40°C, stir and mix for 15-20 min, and then cool the mixed solution to room temperature to obtain a fumaric acid solution; Disperse 4,4'-diaminodiphenyl ether in DMF, stir and mix for 30-45 minutes, protect under nitrogen atmosphere, cool to 5-8°C, and then dropwise add fumaric acid solution thereto for 50-150 minutes. After the dropwise addition is completed, heat to 85-90°C, continue to stir and react for 1-2.5 hours, and then evaporate excess solvent in vacuo to obtain an enamide compound; S12. Disperse the enamide compound in pure DMF, heat it to 35-50°C, stir and disperse it for 15-30 minutes, then add a DMF solution containing 4-aminobutyric acid thereto, and add it dropwise for 2-4 hours. Protect the nitrogen atmosphere during the addition. After the addition is completed, heat it to 65-75°C, stir and react for 90-150 minutes, and then remove the excess solvent by rotary evaporation. Collect the reaction product, wash the surface with deionized water, and disperse the washed product in ethyl acetate. Heat it to 60-75°C, stir and disperse it for 1.5-2 hours, then recrystallize and collect the solid product at the bottom of the mixed solution, and vacuum evaporate it to constant weight to obtain a small molecule carboxyl protected compound; S13. Methyl allyl polyoxyethylene ether was mixed with deionized water, stirred evenly, and the mixed solution was heated to 60-65 ° C, stirred and mixed for 5-15 minutes, and ascorbic acid and mercaptopropionic acid were added thereto. Under a nitrogen atmosphere, the temperature was raised to 65-70 ° C, and a mixture of acrylic acid and a small molecule carboxyl protection compound was added dropwise for 1.5-3 hours. After the addition was completed, stirring was continued and the reaction was kept warm for 2.5-3 hours, and the solid content was adjusted to 38-41% by vacuum evaporation, and cooled to room temperature to obtain a polycarboxylate water reducer; S2. Mix cement, coarse aggregate, fine aggregate and fly ash, stir for 2-4 minutes, add polycarboxylate water reducer and mixing water, continue stirring for 3-5 minutes to obtain concrete aggregate, tamp and cast it to obtain concrete containing polycarboxylate water reducer.

2. The method for preparing concrete containing polycarboxylate water-reducing agent according to claim 1, characterized in that: The concrete containing the polycarboxylate water reducer is composed of 240-270 parts of cement, 1000-1100 parts of coarse aggregate, 750-800 parts of fine aggregate, 1.5-2.5 parts of the polycarboxylate water reducer, 90-120 parts of fly ash and 155-170 parts of mixing water in parts by weight.

3. The method for preparing concrete containing polycarboxylate water-reducing agent according to claim 1, characterized in that: The cement is silicate cement.

4. The method for preparing concrete containing polycarboxylate water-reducing agent according to claim 1, characterized in that: The coarse aggregate is gravel with a particle size of 5-20 mm and a continuous grade; the fine aggregate is river sand with a particle size of 0.5-3 mm and a continuous grade.

5. The method for preparing concrete containing polycarboxylate water-reducing agent according to claim 1, characterized in that: The fly ash is any one of primary fly ash and secondary fly ash.

6. The method for preparing concrete containing polycarboxylate water-reducing agent according to claim 1, characterized in that: In terms of weight, in step S11, the mass ratio of the fumaric acid to 4,4'-diaminodiphenyl ether is 1:(0.8-0.87).

7. The method for preparing concrete containing polycarboxylate water-reducing agent according to claim 1, characterized in that: In terms of parts by weight, in step S12, the mass ratio of the enamide compound to 4-aminobutyric acid is 1:(0.44-0.48).

8. The method for preparing concrete containing polycarboxylate water-reducing agent according to claim 1, characterized in that: In terms of weight, in step S13, the mass ratio of the methyl allyl polyoxyethylene ether, ascorbic acid, and mercaptopropionic acid is 100: (0.03-0.04): (0.07-0.09); Wherein, the weight average molecular weight M of the methyl allyl polyoxyethylene ether is W It is 2000-2500.

9. The method for preparing concrete containing polycarboxylate water-reducing agent according to claim 1, characterized in that: In terms of weight, in step S13, the mass ratio of the methyl allyl polyoxyethylene ether, acrylic acid, and small molecule carboxyl protection compound is 100: (0.4-0.46): (1.2-2.4).

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