Additive for improving compactness of concrete

Abstract

The invention discloses an additive for improving the compactness of concrete. Comprising the following components in parts by weight: 30-50 parts of a water reducing agent, 10-20 parts of an anti-permeability agent, 1-2 parts of an air entraining agent, 3-5 parts of a defoaming agent, 3-6 parts of a thickening agent and 3-5 parts of a dispersing agent. When the admixture is used for concrete, the compactness of the concrete is greatly improved, so that the compressive strength, the impermeability and the impact toughness of the concrete are improved. The combined use of polyethylene glycol-polyamino acid polymer and unsaturated amino polyoxyethylene ether in the admixture component improves the compressive strength of concrete, the combined use of sulfonated graphene and calcium formate improves the anti-permeability grade of concrete, and the combined use of alpha-olefin sodium sulfonate and allyl fatty alcohol polyoxyethylene ether improves the anti-permeability grade of concrete. The impact resistance of the concrete is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete, and particularly relates to an admixture for improving the compactness of concrete. Background Art

[0002] The compactness of concrete refers to the tightness between the internal aggregate and cement paste in concrete, that is, the degree of filling of solid materials in concrete. It is usually expressed by porosity or relative density. The lower the porosity, the higher the compactness, and the better the mechanical strength, impermeability, crack resistance and durability of concrete.

[0003] The factors affecting the compactness of concrete mainly include: (1) The variety and fineness of cement, and the particle size, gradation and shape of aggregate have a direct impact on the compactness of concrete. For example, insufficient cement dosage or unreasonable aggregate gradation will lead to a decrease in the compactness of concrete. (2) The water-cement ratio is a key parameter for controlling the compactness of concrete. An excessively high water-cement ratio will increase the fluidity of concrete, but at the same time reduce the compactness; while an excessively low water-cement ratio may make it difficult to construct concrete. (3) Admixtures such as water reducers and retarders can improve the workability of concrete and reduce the water consumption, thereby improving the compactness.

[0004] Controlling the water-cement ratio and changing the cement variety often incur higher costs. Adding a small amount of admixtures can well change the compactness of concrete, and then improve the mechanical properties and impermeability of concrete. However, at present, there is little research on admixtures aimed at changing the compactness of concrete, and the effect is not obvious, and technical improvement is urgently needed. Summary of the Invention

[0005] The purpose of the present invention is to provide an admixture for improving the compactness of concrete.

[0006] An admixture for improving the compactness of concrete, comprising the following components in parts by weight: 30-50 parts of water reducer, 10-20 parts of impermeability agent, 1-2 parts of air-entraining agent, 3-5 parts of defoaming agent, 3-6 parts of thickening agent, 3-5 parts of dispersing agent.

[0007] The water reducer is a mixture of polyethylene glycol-polyamino acid polymer and unsaturated amino polyoxyethylene ether mixed in a mass ratio of (1-3):1.

[0008] The preparation method of the polyethylene glycol-polyamino acid polymer is as follows: By weight, take 15-25 parts of amino polyethylene glycol monomethyl ether and 20-40 parts of glutamic acid-5-benzyl ester-N-carboxy anhydride and dissolve them in 300-500 parts of N, N-dimethylformamide. Heat up to 25-35 °C, keep the temperature for reaction for 36-72 h. After the reaction is completed, cool to room temperature, precipitate with ether, and dry to obtain a polyethylene glycol-polyamino acid block polymer. Dissolve the obtained product in excessive trifluoroacetic acid and hydrobromic acid, react at room temperature for 4-6 h. After the reaction is completed, spin off trifluoroacetic acid, then precipitate with ether and dry to obtain the polyethylene glycol-polyamino acid polymer.

[0009] The preparation method of the unsaturated amino polyoxyethylene ether is as follows: By weight, take 80-120 parts of isopentenol polyoxyethylene ether with a molecular weight of 1800-2600 and heat it to melt. Dehydrate it under vacuum at 100-140 °C for 1-3 h, and cool to 50-70 °C to obtain a molten unsaturated polyoxyethylene ether. Add 10-13 parts of isophorone diisocyanate and 4-6 parts of dibutyltin dilaurate, heat up to 70-80 °C, react for 1-3 h, and cool to room temperature; drop the obtained reaction product into 8-10 parts of isophorone diamine. After the dropping is completed, continue to react for 0.5-1.5 h to obtain the unsaturated amino polyoxyethylene ether.

[0010] The anti-seepage agent is a mixture of sulfonated graphene and calcium formate mixed according to a mass ratio of 1:(2-6).

[0011] The air-entraining agent is a mixture of sodium α-olefin sulfonate and allyl alcohol polyoxyethylene ether mixed according to a mass ratio of 1:(1-3).

[0012] The defoaming agent is one or more of dimethyl silicone oil, hydroxyfluorosilicone oil, polyoxypropylene oxyethylene glycerol ether, and BYC-0852 defoaming agent.

[0013] The thickening agent is one or more of carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and polyvinylpyrrolidone.

[0014] The dispersant is one or more of fatty alcohol polyoxyethylene ether, monoglyceride stearate, vinyl bisstearamide, sodium hexametaphosphate, and sodium pyrophosphate.

[0015] Advantages of the present invention: The admixture of the present invention is used in concrete, which greatly improves the compactness of the concrete, thereby enhancing the compressive strength, impermeability, and impact toughness of the concrete. It can also significantly improve the microstructure of the cement paste and enhance the interfacial strength between aggregates, and has great application value in environments such as construction projects, water conservancy projects, marine projects, and underground projects. The combined use of polyethylene glycol-polyamino acid polymer and unsaturated amino polyoxyethylene ether in the admixture components improves the compressive strength of the concrete, the combined use of sulfonated graphene and calcium formate improves the impermeability grade of the concrete, and the combined use of α-olefin sulfonate and allyl alcohol polyoxyethylene ether improves the impact resistance of the concrete. Detailed implementation mode

[0016] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0017] Example 1

[0018] An admixture for improving the compactness of concrete, comprising the following components in parts by weight: 40 parts of water reducer, 15 parts of impermeability agent, 1.5 parts of air-entraining agent, 4 parts of dimethyl silicone oil, 5 parts of carboxymethyl cellulose, and 4 parts of monoglyceride stearate; the water reducer is a mixture of polyethylene glycol-polyamino acid polymer and unsaturated amino polyoxyethylene ether mixed in a mass ratio of 2:1; the impermeability agent is a mixture of sulfonated graphene and calcium formate mixed in a mass ratio of 1:4; the air-entraining agent is a mixture of α-olefin sulfonate and allyl alcohol polyoxyethylene ether mixed in a mass ratio of 1:2.

[0019] The preparation method of the polyethylene glycol-polyamino acid polymer is as follows: According to the parts by weight, take 20 parts of amino polyethylene glycol monomethyl ether and 32 parts of glutamate-5-benzyl ester-N-carboxycyclic anhydride and dissolve them in 420 parts of N, N-dimethylformamide, heat up to 30°C, keep the temperature for reaction for 48 hours, cool to room temperature after the reaction, precipitate with ether, dry to obtain a polyethylene glycol-polyamino acid block polymer, dissolve the obtained product in an excess of trifluoroacetic acid and hydrobromic acid, react at room temperature for 5 hours, remove trifluoroacetic acid by rotary evaporation after the reaction, and then precipitate with ether and dry to obtain the polyethylene glycol-polyamino acid polymer.

[0020] The preparation method of the unsaturated amino polyoxyethylene ether is as follows: By weight, take 100 parts of isopentenol polyoxyethylene ether with a molecular weight of 2200, heat and melt it, dehydrate it under vacuum at 120 °C for 2 h, cool it to 60 °C to obtain molten unsaturated polyoxyethylene ether, add 12 parts of isophorone diisocyanate and 5 parts of dibutyltin dilaurate, raise the temperature to 75 °C, react for 2 h, and then cool it to room temperature; drop the obtained reaction product into 9 parts of isophorone diamine, and after the dropping is completed, continue to react for 1 h to obtain the unsaturated amino polyoxyethylene ether.

[0021] Example 2

[0022] An admixture for improving the compactness of concrete, comprising the following components by weight: 30 parts of water reducer, 10 parts of impermeability agent, 1 part of air-entraining agent, 3 parts of polyoxypropylene oxyethylene glycerol ether, 3 parts of hydroxypropyl methylcellulose, and 3 parts of fatty alcohol polyoxyethylene ether; the water reducer is a mixture of polyethylene glycol-polyamino acid polymer and unsaturated amino polyoxyethylene ether in a mass ratio of 1:1; the impermeability agent is a mixture of sulfonated graphene and calcium formate in a mass ratio of 1:3; the air-entraining agent is a mixture of α-olefin sulfonate and allyl fatty alcohol polyoxyethylene ether in a mass ratio of 1:1.

[0023] The preparation method of the polyethylene glycol-polyamino acid polymer is as follows: By weight, take 15 parts of amino polyethylene glycol monomethyl ether and 20 parts of glutamic acid-5-benzyl ester-N-carboxyl cyclic anhydride, dissolve them in 300 parts of N, N-dimethylformamide, raise the temperature to 25 °C, keep the temperature and react for 36 h, cool to room temperature after the reaction, precipitate with ether, and dry to obtain a polyethylene glycol-polyamino acid block polymer. Dissolve the obtained product in an excess of trifluoroacetic acid and hydrobromic acid, react at room temperature for 4 h, remove trifluoroacetic acid by rotary evaporation after the reaction, and then precipitate with ether and dry to obtain the polyethylene glycol-polyamino acid polymer.

[0024] The preparation method of the unsaturated amino polyoxyethylene ether is as follows: By weight, take 80 parts of isopentenol polyoxyethylene ether with a molecular weight of 1800, heat and melt it, dehydrate it under vacuum at 100 °C for 1 h, cool it to 50 °C to obtain molten unsaturated polyoxyethylene ether, add 10 parts of isophorone diisocyanate and 4 parts of dibutyltin dilaurate, raise the temperature to 70 °C, react for 1 h, and then cool it to room temperature; drop the obtained reaction product into 8 parts of isophorone diamine, and after the dropping is completed, continue to react for 0.5 h to obtain the unsaturated amino polyoxyethylene ether.

[0025] Example 3

[0026] An admixture for improving the compactness of concrete, comprising the following components in parts by weight: 50 parts of water reducer, 20 parts of impermeability agent, 2 parts of air-entraining agent, 5 parts of BYC-0852 defoamer, 6 parts of polyvinylpyrrolidone, and 5 parts of sodium hexametaphosphate. The water reducer is a mixture of polyethylene glycol-polyamino acid polymer and unsaturated amino polyoxyethylene ether mixed in a mass ratio of 3:1; the impermeability agent is a mixture of sulfonated graphene and calcium formate mixed in a mass ratio of 1:5; the air-entraining agent is a mixture of sodium α-olefin sulfonate and allyl alcohol polyoxyethylene ether mixed in a mass ratio of 1:3.

[0027] The preparation method of the polyethylene glycol-polyamino acid polymer is as follows: According to the parts by weight, take 25 parts of amino polyethylene glycol monomethyl ether and 40 parts of glutamate-5-benzyl ester-N-carboxy anhydride and dissolve them in 500 parts of N, N-dimethylformamide. Heat up to 35 °C and keep the reaction for 72 h. After the reaction is completed, cool to room temperature, precipitate with ether, and dry to obtain a polyethylene glycol-polyamino acid block polymer. Dissolve the obtained product in excess trifluoroacetic acid and hydrobromic acid, react at room temperature for 6 h. After the reaction is completed, spin off trifluoroacetic acid, and then precipitate with ether and dry to obtain the polyethylene glycol-polyamino acid polymer.

[0028] The preparation method of the unsaturated amino polyoxyethylene ether is as follows: According to the parts by weight, take 120 parts of isopentenol polyoxyethylene ether with a molecular weight of 2600 and heat it to melt. Dehydrate it under vacuum at 140 °C for 3 h, and cool to 70 °C to obtain a molten unsaturated polyoxyethylene ether. Add 13 parts of isophorone diisocyanate and 6 parts of dibutyltin dilaurate, heat up to 80 °C, and react for 3 h, then cool to room temperature; drop the obtained reaction product into 10 parts of isophorone diamine. After the dropping is completed, continue to react for 1.5 h to obtain the unsaturated amino polyoxyethylene ether.

[0029] Comparative Example 1

[0030] An admixture for improving the compactness of concrete, comprising the following components in parts by weight: 40 parts of polyethylene glycol-polyamino acid polymer, 15 parts of impermeability agent, 1.5 parts of air-entraining agent, 4 parts of dimethyl silicone oil, 5 parts of carboxymethyl cellulose, and 4 parts of monoglyceride stearate; the impermeability agent is a mixture of sulfonated graphene and calcium formate mixed in a mass ratio of 1:4; the air-entraining agent is a mixture of sodium α-olefin sulfonate and allyl alcohol polyoxyethylene ether mixed in a mass ratio of 1:2.

[0031] The preparation method of the polyethylene glycol-polyamino acid polymer is as follows: By weight, take 20 parts of amino polyethylene glycol monomethyl ether and 32 parts of glutamic acid-5-benzyl ester-N-carboxylic acid cyclic anhydride and dissolve them in 420 parts of N,N-dimethylformamide. Heat up to 30 °C and keep the reaction for 48 h. After the reaction is completed, cool to room temperature, precipitate with ether, and dry to obtain the polyethylene glycol-polyamino acid block polymer. Dissolve the obtained product in excess trifluoroacetic acid and hydrobromic acid, react at room temperature for 5 h. After the reaction is completed, spin off trifluoroacetic acid, then precipitate with ether and dry to obtain the polyethylene glycol-polyamino acid polymer.

[0032] Comparative Example 2

[0033] An admixture for improving the compactness of concrete, comprising the following components by weight: 40 parts of unsaturated amino polyoxyethylene ether, 15 parts of impermeability agent, 1.5 parts of air-entraining agent, 4 parts of dimethyl silicone oil, 5 parts of carboxymethyl cellulose, 4 parts of monoglyceryl stearate; the impermeability agent is a mixture of sulfonated graphene and calcium formate in a mass ratio of 1:4; the air-entraining agent is a mixture of α-olefin sulfonate and allyl fatty alcohol polyoxyethylene ether in a mass ratio of 1:2.

[0034] The preparation method of the unsaturated amino polyoxyethylene ether is as follows: By weight, take 100 parts of isopentenol polyoxyethylene ether with a molecular weight of 2200, heat and melt it, vacuum dehydrate at 120 °C for 2 h, cool to 60 °C to obtain molten unsaturated polyoxyethylene ether, add 12 parts of isophorone diisocyanate and 5 parts of dibutyltin dilaurate, heat up to 75 °C and react for 2 h, then cool to room temperature; drop the obtained reaction product into 9 parts of isophorone diamine, and continue to react for 1 h after dropping to obtain the unsaturated amino polyoxyethylene ether.

[0035] Comparative Example 3

[0036] An admixture for improving the compactness of concrete, comprising the following components by weight: 40 parts of water reducing agent, 15 parts of sulfonated graphene, 1.5 parts of air-entraining agent, 4 parts of dimethyl silicone oil, 5 parts of carboxymethyl cellulose, 4 parts of monoglyceryl stearate; the water reducing agent is a mixture of polyethylene glycol-polyamino acid polymer and unsaturated amino polyoxyethylene ether in a mass ratio of 2:1; the air-entraining agent is a mixture of α-olefin sulfonate and allyl fatty alcohol polyoxyethylene ether in a mass ratio of 1:2.

[0037] The preparation method of the polyethylene glycol-polyamino acid polymer is as follows: By weight, take 20 parts of amino-polyethylene glycol monomethyl ether and 32 parts of glutamic acid-5-benzyl ester-N-carboxy anhydride, dissolve them in 420 parts of N,N-dimethylformamide, heat up to 30 °C, keep the temperature for reaction for 48 h, after the reaction is completed, cool to room temperature, precipitate with ether, and dry to obtain a polyethylene glycol-polyamino acid block polymer. Dissolve the obtained product in excessive trifluoroacetic acid and hydrobromic acid, react at room temperature for 5 h, after the reaction is completed, spin off trifluoroacetic acid, then precipitate with ether, and dry to obtain the polyethylene glycol-polyamino acid polymer.

[0038] The preparation method of the unsaturated amino polyoxyethylene ether is as follows: By weight, take 100 parts of isopentenol polyoxyethylene ether with a molecular weight of 2200, heat it to melt, dehydrate it under vacuum at 120 °C for 2 h, cool to 60 °C to obtain a molten unsaturated polyoxyethylene ether, add 12 parts of isophorone diisocyanate and 5 parts of dibutyltin dilaurate, heat up to 75 °C, react for 2 h, and cool to room temperature; drop the obtained reaction product into 9 parts of isophorone diamine, after the dropping is completed, continue to react for 1 h to obtain the unsaturated amino polyoxyethylene ether.

[0039] Comparative Example 4

[0040] An admixture for improving the compactness of concrete, comprising the following components by weight: 40 parts of water reducer, 15 parts of calcium formate, 1.5 parts of air-entraining agent, 4 parts of dimethyl silicone oil, 5 parts of carboxymethyl cellulose, and 4 parts of monoglyceryl stearate; the water reducer is a mixture of a polyethylene glycol-polyamino acid polymer and an unsaturated amino polyoxyethylene ether in a mass ratio of 2:1; the air-entraining agent is a mixture of α-olefin sulfonate and allyl alcohol polyoxyethylene ether in a mass ratio of 1:2.

[0041] The preparation method of the polyethylene glycol-polyamino acid polymer is as follows: By weight, take 20 parts of amino-polyethylene glycol monomethyl ether and 32 parts of glutamic acid-5-benzyl ester-N-carboxy anhydride, dissolve them in 420 parts of N,N-dimethylformamide, heat up to 30 °C, keep the temperature for reaction for 48 h, after the reaction is completed, cool to room temperature, precipitate with ether, and dry to obtain a polyethylene glycol-polyamino acid block polymer. Dissolve the obtained product in excessive trifluoroacetic acid and hydrobromic acid, react at room temperature for 5 h, after the reaction is completed, spin off trifluoroacetic acid, then precipitate with ether, and dry to obtain the polyethylene glycol-polyamino acid polymer.

[0042] The preparation method of the unsaturated amino polyoxyethylene ether is as follows: By weight, take 100 parts of isopentenol polyoxyethylene ether with a molecular weight of 2200, heat and melt it, dehydrate it under vacuum at 120 °C for 2 h, cool it to 60 °C to obtain molten unsaturated polyoxyethylene ether, add 12 parts of isophorone diisocyanate and 5 parts of dibutyltin dilaurate, raise the temperature to 75 °C, react for 2 h, and then cool it to room temperature; drop the obtained reaction product into 9 parts of isophorone diamine, and after the dropping is completed, continue to react for 1 h to obtain unsaturated amino polyoxyethylene ether.

[0043] Comparative Example 5

[0044] An admixture for improving the compactness of concrete, comprising the following components by weight: 40 parts of water reducer, 15 parts of impermeability agent, 1.5 parts of α-olefin sulfonate, 4 parts of dimethyl silicone oil, 5 parts of carboxymethyl cellulose, 4 parts of monoglyceride stearate; the water reducer is a mixture of polyethylene glycol-polyamino acid polymer and unsaturated amino polyoxyethylene ether mixed in a mass ratio of 2:1; the impermeability agent is a mixture of sulfonated graphene and calcium formate mixed in a mass ratio of 1:4.

[0045] The preparation method of the polyethylene glycol-polyamino acid polymer is as follows: By weight, take 20 parts of amino poly(ethylene glycol) monomethyl ether and 32 parts of glutamate-5-benzyl ester-N-carboxy anhydride, dissolve them in 420 parts of N,N-dimethylformamide, raise the temperature to 30 °C, keep the temperature and react for 48 h, cool to room temperature after the reaction, precipitate with ether, and dry to obtain a polyethylene glycol-polyamino acid block polymer. Dissolve the obtained product in an excess of trifluoroacetic acid and hydrobromic acid, react at room temperature for 5 h, remove trifluoroacetic acid by rotary evaporation after the reaction, and then precipitate with ether and dry to obtain the polyethylene glycol-polyamino acid polymer.

[0046] The preparation method of the unsaturated amino polyoxyethylene ether is as follows: By weight, take 100 parts of isopentenol polyoxyethylene ether with a molecular weight of 2200, heat and melt it, dehydrate it under vacuum at 120 °C for 2 h, cool it to 60 °C to obtain molten unsaturated polyoxyethylene ether, add 12 parts of isophorone diisocyanate and 5 parts of dibutyltin dilaurate, raise the temperature to 75 °C, react for 2 h, and then cool it to room temperature; drop the obtained reaction product into 9 parts of isophorone diamine, and after the dropping is completed, continue to react for 1 h to obtain unsaturated amino polyoxyethylene ether.

[0047] Comparative Example 6

[0048] An admixture for improving the compactness of concrete, comprising the following components in parts by weight: 40 parts of water reducer, 15 parts of impermeability agent, 1.5 parts of allyl alcohol polyoxyethylene ether, 4 parts of dimethyl silicone oil, 5 parts of carboxymethyl cellulose, and 4 parts of monoglyceryl stearate; the water reducer is a mixture of polyethylene glycol-polyamino acid polymer and unsaturated amino polyoxyethylene ether mixed in a mass ratio of 2:1; the impermeability agent is a mixture of sulfonated graphene and calcium formate mixed in a mass ratio of 1:4.

[0049] The preparation method of the polyethylene glycol-polyamino acid polymer is as follows: According to the parts by weight, take 20 parts of amino polyethyleneglycol monomethyl ether and 32 parts of glutamic acid-5-benzyl ester-N-carboxy anhydride and dissolve them in 420 parts of N, N-dimethylformamide. Heat up to 30 °C and keep the reaction for 48 h. After the reaction is completed, cool to room temperature, precipitate with ether, and dry to obtain a polyethylene glycol-polyamino acid block polymer. Dissolve the obtained product in an excess of trifluoroacetic acid and hydrobromic acid, react at room temperature for 5 h, remove trifluoroacetic acid by rotary evaporation after the reaction is completed, and then precipitate with ether and dry to obtain the polyethylene glycol-polyamino acid polymer.

[0050] The preparation method of the unsaturated amino polyoxyethylene ether is as follows: According to the parts by weight, take 100 parts of isopentenol polyoxyethylene ether with a molecular weight of 2200, heat and melt it, dehydrate it under vacuum at 120 °C for 2 h, and cool to 60 °C to obtain a molten unsaturated polyoxyethylene ether. Add 12 parts of isophorone diisocyanate and 5 parts of dibutyltin dilaurate, heat up to 75 °C, react for 2 h, and cool to room temperature; drop the obtained reaction product into 9 parts of isophorone diamine. After the dropping is completed, continue the reaction for 1 h to obtain the unsaturated amino polyoxyethylene ether.

[0051] Experimental examples:

[0052] Preparation of concrete specimens: Prepare concrete according to the following concrete slurry ratio: 1000 g of ordinary Portland cement, 2200 g of medium sand, 3000 g of gravel (10 - 15 mm), 5 g of the admixture prepared in Examples 1 - 3 and Comparative Examples 1 - 6, and 600 g of water; the slurry is automatically filled into the mold, treated with a cement oscillator for 10 min, and then placed in a curing room for curing for 28 d and then demolded.

[0053] Refer to GB / T 50081 - 2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete" to measure the compressive strength (MPa) of concrete. The experimental results are statistically analyzed using SPSS24.0 software. The results of measurement data are expressed by (mean ± standard deviation), and the Kolmogorov - Smirnov test method is used for data normality test. For data that conform to normal distribution, the t - test is used to compare the mean differences between two groups. A P < 0.05 indicates that the difference is statistically significant. The measurement results are shown in Table 1:

[0054] Table 1

[0055] Experimental group Compressive strength MPa Example 1 89.3±2.3 Example 2 86.6±1.9 Example 3 88.8±2.1 Comparative example 1 67.4±3.1* Comparative example 2 73.2±2.8*

[0056] Note: * represents P < 0.05 compared with the Example 1 group.

[0057] Referring to the "Concrete Quality Control Standard" GB / T 50164-2011, the impermeability grade of the concrete was measured, and the measurement results are shown in Table 2:

[0058] Table 2

[0059] Experimental group Impermeability grade Example 1 P12 Example 2 P12 Example 3 P12 Comparative example 3 P10 Comparative example 4 P10

[0060] Referring to the experimental method for the impact compression performance of concrete in ACI544.2R-89, the mass of the drop hammer was 4.5 kg, the impact elevation h of the free drop hammer was 475 mm. After the impact ball was lifted to the specified height and released, the impact ball made a free fall motion to impact the concrete specimen. When the first crack appeared in the concrete specimen, the impact energy consumption J required was recorded, and the measurement results are shown in Table 3:

[0061] Table 3

[0062] Experimental group Impact energy dissipation J Example 1 1.42±0.13 Example 2 1.51±0.09 Example 3 1.41±0.15 Comparative example 5 0.98±0.11* Comparative example 6 1.12±0.08*

[0063] Note: * represents P < 0.05 compared with the Example 1 group.

[0064] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. An admixture for improving the compactness of concrete, characterized in that: The invention comprises the following components in parts by weight: 30-50 parts of water reducing agent, 10-20 parts of anti-seepage agent, 1-2 parts of air entraining agent, 3-5 parts of defoaming agent, 3-6 parts of thickener and 3-5 parts of dispersant.

2. The admixture for improving the compactness of concrete according to claim 1, characterized in that: The water reducing agent is a mixture of polyethylene glycol-polyamino acid polymer and unsaturated amino polyoxyethylene ether in a mass ratio of (1-3):

1.

3. The admixture for improving the compactness of concrete according to claim 2, characterized in that: The preparation method of the polyethylene glycol-polyamino acid polymer is as follows: according to weight parts, 15-25 parts of amino polyethylene glycol monomethyl ether and 20-40 parts of glutamic acid-5-benzyl ester-N-carboxyl ring anhydride are dissolved in 300-500 parts of N, N-dimethylformamide, the temperature is raised to 25-35°C, the temperature is kept for reaction for 36-72 hours, the reaction is completed and the temperature is cooled to room temperature, precipitated with ether, and dried to obtain the polyethylene glycol-polyamino acid block polymer, the obtained product is dissolved in excess trifluoroacetic acid and hydrobromic acid, reacted at room temperature for 4-6 hours, the trifluoroacetic acid is removed after the reaction is completed, and the product is precipitated with ether and dried to obtain the polyethylene glycol-polyamino acid polymer.

4. The admixture for improving the compactness of concrete according to claim 2, characterized in that: The preparation method of the unsaturated amino polyoxyethylene ether is as follows: according to weight proportions, 80-120 parts of isopentanol polyoxyethylene ether with a molecular weight of 1800-2600 are taken, heated and melted, vacuum dehydrated at 100-140° C. for 1-3 hours, cooled to 50-70° C. to obtain molten unsaturated polyoxyethylene ether, added with 10-13 parts of isophorone diisocyanate and 4-6 parts of dibutyltin dilaurate, heated to 70-80° C., reacted for 1-3 hours, and cooled to room temperature; the obtained reaction product is added dropwise to 8-10 parts of isophorone diamine, and after the dropwise addition is completed, the reaction is continued for 0.5-1.5 hours to obtain the unsaturated amino polyoxyethylene ether.

5. The admixture for improving the compactness of concrete according to claim 1, characterized in that: The anti-seepage agent is a mixture of sulfonated graphene and calcium formate in a mass ratio of 1:(2-6).

6. The admixture for improving the compactness of concrete according to claim 1, characterized in that: The air entraining agent is a mixture of sodium α-olefin sulfonate and allyl fatty alcohol polyoxyethylene ether in a mass ratio of 1:(1-3).

7. The admixture for improving the compactness of concrete according to claim 1, characterized in that: The defoaming agent is one or more of dimethyl silicone oil, hydroxy fluorosilicone oil, polyoxypropylene oxyethylene glycerol ether, and BYC-0852 defoaming agent.

8. The admixture for improving the compactness of concrete according to claim 1, characterized in that: The thickener is one or more of carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose and polyvinyl pyrrolidone.

9. The admixture for improving the compactness of concrete according to claim 1, characterized in that: The dispersant is one or more of fatty alcohol polyoxyethylene ether, stearic acid monoglyceride, vinyl bisstearamide, sodium hexametaphosphate, and sodium pyrophosphate.