A viscosity-reducing C80 grade concrete and its preparation method

Abstract

The present invention provides a viscosity-reducing C80-grade concrete and a preparation method thereof, comprising the following raw materials: 350-400 parts by weight of cement, 100-150 parts by weight of admixture, 600-700 parts by weight of fine aggregate, 850-1000 parts by weight of coarse aggregate, 5-8 parts by weight of polycarboxylate water-reducing agent solution, 2-4 parts by weight of nonylphenol polyoxyethylene ether, 2-4 parts by weight of tea saponin, 25-30 parts by weight of toughening agent and water, and the mass ratio of the sum of the masses of cement and admixture to the mass of water is 1:0.2-0.28; the solid content of the polycarboxylate water-reducing agent solution is 35-45 wt%; the polycarboxylate water-reducing agent is copolymerized from an alkenyl polyether macromonomer, an alkenyl dimether macromonomer of formula I, an unsaturated acid derivative, and a phenyl acrylate derivative in a mass ratio of 70-80:20-30:7-10:5-10; the polycarboxylate water-reducing agent of the present invention forms a relatively thick water film layer between the cementitious particles, reducing the viscosity of the concrete.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete, and particularly relates to a viscosity-reducing C80 grade concrete and a preparation method thereof. Background Art

[0002] With the rapid development of the construction industry, building structures are gradually developing towards super high-rise, lightweight and large-span directions, posing higher requirements for the mechanical properties and construction performance of concrete, and also greatly promoting the development of concrete pumping technology. High-strength concrete structures have higher bearing capacities. When the design loads are the same, smaller cross-sectional areas can be used, better adapting to various requirements of architectural designs. At the same time, the self-weight of concrete structures can be reduced. Therefore, it has attracted much attention. For example, a high-strength and high-toughness concrete and a preparation method thereof disclosed in Patent CN113264728B. The preparation raw materials of the high-strength and high-toughness concrete include, by weight, 150 - 170 parts of water, 200 - 250 parts of cement, 200 - 250 parts of coarse aggregate, 350 - 400 parts of fine aggregate, 40 - 70 parts of ultra-fine powder, 50 - 70 parts of structural modifier, 10 - 20 parts of cellulose, and 10 - 25 parts of chemical auxiliary agent. A high-strength impermeable concrete and a production method thereof disclosed in Patent CN113880521B are mainly made from the following raw materials in parts by weight: 650 - 780 parts of aggregate, 500 - 600 parts of sand, 280 - 400 parts of cement, 80 - 120 parts of fly ash, 100 - 200 parts of water, 25 - 40 parts of water reducer, 75 - 90 parts of admixture, and 80 - 150 parts of impermeability agent; the impermeability agent is composed of the sum of the masses of polyethylene oxide and sorbitan fatty acid ester and nickel salt in a mass ratio of (2.5 - 4):(4 - 7), and the admixture is at least two of tuff powder, limestone powder, and quartz powder.

[0003] The above are high-strength concretes with relatively high strength. To make the concrete reach high strength, a large amount of cementitious materials and a low water-binder ratio are adopted, resulting in a relatively high viscosity and a decrease in fluidity of the fresh concrete, reducing the pumping performance of the concrete, seriously affecting the construction efficiency, and restricting its application and promotion. Therefore, it is necessary to develop a high-strength concrete with low viscosity. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a viscosity-reducing C80 grade concrete and a preparation method thereof. The polymerization monomer of the polycarboxylate water reducer used includes an alkenyl diglycidyl ether macromonomer with strong hydrophilicity. It is first prepared by reacting 1,3-diglycidyl ether glycerol with an acryloyl chloride derivative to obtain unsaturated diglycidyl ether, and then reacting the unsaturated diglycidyl ether with O-(2-aminoethyl) polyethylene glycol. The monomer acrylate phenyl ester derivative has a hydrophobic phenyl group. Adjusting the relative ratio of the two monomers is beneficial to forming a thicker water film layer between the cement and admixture cementitious particles, reducing the viscosity of the concrete.

[0005] To achieve the above object, the following technical solutions are adopted:

[0006] A viscosity-reducing C80-grade concrete, comprising the following raw materials: 350-400 parts by weight of cement, 100-150 parts by weight of admixture, 600-700 parts by weight of fine aggregate, 850-1000 parts by weight of coarse aggregate, 5-8 parts by weight of polycarboxylate water-reducing agent solution, 2-4 parts by weight of nonylphenol polyoxyethylene ether, 2-4 parts by weight of tea saponin, 25-30 parts by weight of toughening agent and water, the mass ratio of the total mass of cement and admixture to the mass of water is 1:0.2-0.28; the solid content of the polycarboxylate water-reducing agent solution is 35-45 wt%; the polycarboxylate water-reducing agent is copolymerized from an alkenyl polyether macromonomer, an alkenyl dimer polyether macromonomer, an unsaturated acid derivative, and a phenyl acrylate derivative in a mass ratio of 70-80:20-30:7-10:5-10;

[0007] The structural formula of the alkenyl dimer polyether macromonomer is as shown in the following formula (I):

[0008] (I);

[0009] Among them, m and n are independently integers between 40 and 80, and R is -CH3 or -H.

[0010] There are many hydroxyl groups on the monosaccharide of tea saponin that can form hydrogen bonds with water molecules, so it has strong hydrophilicity. The aglycone in the aglycone group has lipophilicity and is a hydrophobic group, so tea saponin belongs to a non-ionic surfactant. Applying tea saponin to concrete has the effects of generating uniform and tiny bubbles, improving the toughness and durability of concrete; in addition, because the bubbles also have a lubricating effect, tea saponin can also reduce the viscosity of the concrete slurry.

[0011] The polymerization monomer alkenyl dimer polyether macromonomer of the polycarboxylate water-reducing agent has strong hydrophilicity, which helps to form a thicker water film layer between the cement and admixture mixed cementitious particles, reducing the viscosity of the concrete. However, the polyether chain generated by the hydrolysis of the alkenyl dimer polyether macromonomer has a defoaming effect, resulting in poor toughness of the concrete. Using an appropriate amount of foam stabilizer nonylphenol polyoxyethylene ether can improve the toughness of the slurry without affecting other properties of the concrete slurry.

[0012] The alkenyl dimer polyether macromonomer is prepared by a method including the following steps:

[0013] 1) Under an inert atmosphere, add 1,3-diglycidyl ether glycerol, (meth)acryloyl chloride, an acid-binding agent, an inhibitor, and an organic solvent to a reaction kettle, control the temperature for reaction, and after the reaction is completed, filter and distill under reduced pressure to obtain an unsaturated diglycidyl ether;

[0014] 2) Under an inert atmosphere, an unsaturated diglycidyl ester, O-(2-aminoethyl) polyethylene glycol, an inhibitor, and an organic solvent are mixed evenly, heated up and kept at a constant temperature for reaction. After the reaction is completed, it is concentrated and separated by gel column chromatography to obtain an alkenyl dimethyl ether macromonomer.

[0015] The organic solvent described in step 1) is selected from one or a combination of two of chloroform and petroleum ether. The mass of the organic solvent is 3-5 times the sum of the masses of 1,3-diglycidyl ether glycerol and (meth)acryloyl chloride. The acid-binding agent is selected from one or a combination of two or more of triethylamine, N,N-diisopropylethylamine, 2-methylpyridine, and pyridine. The temperature control is to control at 1-10 °C, and the reaction time is 3-5 h. The inhibitor is selected from one or a combination of two or more of p-tert-butylphenol, p-methoxyphenol, and hydroquinone. The molar ratio of (meth)acryloyl chloride, 1,3-diglycidyl ether glycerol, and the acid-binding agent is 1:1.1-1.15:1-1.1. The inhibitor is 0.1-0.3 wt% of the acryloyl chloride derivative.

[0016] In step 2), the number average molecular weight of O-(2-aminoethyl) polyethylene glycol is 2000-3400. The unsaturated glycidyl ester is selected from one or a combination of two of glycidyl acrylate and glycidyl methacrylate. The temperature rise is to rise to 60-80 °C, and the reaction time is 3-6 h. The organic solvent is selected from one or a combination of two or more of DMF, acetone, acetonitrile, DMSO, and tetrahydrofuran. The mobile phase for the gel column chromatography separation is tetrahydrofuran. The molar ratio of the unsaturated diglycidyl ester to O-(2-aminoethyl) polyethylene glycol is 1:2.1-2.2. The inhibitor is 0.1-0.3 wt% of the unsaturated diglycidyl ester. The inhibitor is selected from one or a combination of two or more of p-tert-butylphenol, p-methoxyphenol, and hydroquinone.

[0017] The number average molecular weight of the alkenyl polyether macromonomer is 2000-2400, and it is selected from one or a combination of two of methylallyl polyoxyethylene ether and allyl polyoxyethylene ether.

[0018] The unsaturated acid derivative is selected from one or a combination of two or more of acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid.

[0019] The phenyl acrylate derivative is selected from one or a combination of two or more of phenyl acrylate, phenyl methacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, and 2-phenylethyl methacrylate.

[0020] The polycarboxylate water reducer is prepared by a method including the following steps:

[0021] Under an inert atmosphere, the vinyl polyether macromonomer and the vinyl dimether macromonomer are added to a reaction kettle, heated to a uniform temperature, and then the unsaturated acid derivative, the phenyl acrylate derivative, the initiator, and the chain transfer agent are added and mixed evenly. Then, it is heated again and kept at a constant temperature for reaction. After the reaction is completed, it is cooled to room temperature, the pH is adjusted, and water is added to adjust the solid content to obtain the polycarboxylate water reducer solution.

[0022] The first heating is to 30 - 50 °C. The second heating is to 60 - 80 °C, and the reaction time is 3 - 5 h. The dosage of the initiator is 1 - 3 wt% of the total mass of the vinyl polyether macromonomer, the vinyl dimether macromonomer, the unsaturated acid derivative, and the phenyl acrylate derivative. The initiator is selected from one or a combination of two or more of BPO, cumene hydroperoxide, and tert-butyl hydroperoxide. The chain transfer agent is selected from one or a combination of two of mercaptoethanol and dodecyl mercaptan. The dosage of the chain transfer agent is 0.5 - 0.8 wt% of the total mass of the vinyl polyether macromonomer, the vinyl dimether macromonomer, the unsaturated acid derivative, and the phenyl acrylate derivative. The pH adjustment is to adjust to 7 - 9 with an alkali solution, and the alkali solution is selected from one or a combination of two or more of sodium hydroxide solution, sodium carbonate solution, and sodium bicarbonate solution. Water is added to adjust the solid content to 35 - 45 wt%.

[0023] The nonylphenol polyoxyethylene ether is selected from one or a combination of two or more of NP-10, NP-16, and NP-20.

[0024] The toughening agent is a liquid rubber-coated inorganic filler, which is prepared by a method including the following steps:

[0025] The inorganic filler, the carboxyl-terminated polybutadiene liquid rubber, the organic solvent, and the ball milling medium are added to a ball mill, and ball milling is carried out to obtain a ball-milled slurry, which is then filtered and dried to obtain the toughening agent.

[0026] The ball milling medium is zirconia beads with a particle size of 0.1 mm - 0.5 mm. The rotation speed of the ball milling is 200 - 800 r / min. The ball milling time is 3 - 5 h. The mass ratio of the total mass of the inorganic filler and the liquid rubber to the mass of the ball milling medium is 1:20 - 25. The mass ratio of the inorganic filler, the liquid rubber, and the organic solvent is 5:0.4 - 0.5:10 - 15. The organic solvent is selected from one or a combination of two or more of toluene, benzene, dichloromethane, methyl ethyl ketone, and ethyl acetate. The temperature of the ball milling is 25 - 50 °C. The drying is carried out at 60 - 80 °C and a vacuum degree of 0.01 - 0.1 MPa for 1 - 3 h.

[0027] The number average molecular weight of the liquid rubber is 3000 - 5000, and it is selected from one or a combination of two or more of carboxyl-terminated polybutadiene liquid rubber, hydroxyl-terminated polybutadiene liquid rubber, and polybutadiene liquid rubber.

[0028] The average particle size of the inorganic filler is 50-100 nm, and it is selected from one or a combination of two or more of silica, calcium carbonate, talcum powder, and magnesium carbonate.

[0029] The cement is Portland cement with a strength grade of 42.5 to 52.5.

[0030] The fine aggregate is quartz sand with a fineness modulus of 3.0-2.3.

[0031] The coarse aggregate is continuously graded crushed stone with a particle size of 5-20 mm.

[0032] The admixture is selected from one or a combination of two of fly ash and slag powder.

[0033] The admixture is a mixture of fly ash and slag powder with a mass ratio of 1:2-5.

[0034] The fly ash is selected from one or a combination of two of Class I fly ash and Class II fly ash.

[0035] The slag powder is selected from one or a combination of two of S105 slag powder, S95 slag powder, and S75 slag powder.

[0036] The present invention also provides a method for preparing the above-mentioned viscosity-reducing C80 grade concrete, which includes the following steps:

[0037] Mix cement, admixture, polycarboxylate superplasticizer solution, nonylphenol polyoxyethylene ether, tea saponin, toughening agent, and water evenly to obtain a slurry, and add coarse aggregate and fine aggregate to the slurry and mix evenly to obtain viscosity-reducing C80 grade concrete.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] The polycarboxylate superplasticizer of the present invention is copolymerized by bulk polymerization of an alkenyl polyether macromonomer, an alkenyl dimethyl ether macromonomer, an unsaturated acid derivative, and an acrylic acid phenyl ester derivative. The alkenyl dimethyl ether macromonomer is an alkenyl dimethyl ether macromonomer with strong hydrophilicity. It is first prepared by reacting 1,3-diglycidyl ether glycerol and acryloyl chloride derivative to obtain unsaturated diglycidyl ether, and then reacting unsaturated diglycidyl ether with O-(2-aminoethyl) polyethylene glycol. The monomer acrylic acid phenyl ester derivative has a hydrophobic phenyl group. Adjusting the relative proportion of the two monomers is beneficial to forming a thicker water film layer between cement and admixture cementitious particles, reducing the viscosity of concrete. Specific embodiments

[0040] The present invention will be further described below in conjunction with specific embodiments, but it is not limited to the content in the specification. Unless otherwise specified, "parts" in the embodiments of the present invention are all parts by weight. The reagents used are all commercially available reagents in the art.

[0041] O-(2-aminoethyl) polyethylene glycol with a number average molecular weight of 2000, product number H917140, was purchased from Macklin.

[0042] O-(2-aminoethyl) polyethylene glycol with a number average molecular weight of 3400, product number H917141, was purchased from Macklin.

[0043] Allyl polyoxyethylene ether with a number average molecular weight of APEG2400 was purchased from Wuhan Xinxin Jiali Biotechnology Co., Ltd.

[0044] Continuously graded crushed stone with a particle size of 5-20 mm was purchased from Huzhou Xinkaiyuan Crushed Stone Co., Ltd.

[0045] Quartz sand with a fineness modulus of 2.6 was purchased from Fengyang Jihui Quartz Sand Co., Ltd.

[0046] Nano-silica DK-SiO2-60 with an average particle size of 60 nm was purchased from Zhongke Jinyan (Beijing) Technology Co., Ltd.

[0047] Type I carboxyl-terminated polybutadiene liquid rubber with a number average molecular mass of 5000 was purchased from Tianyuan Aviation Materials.

[0048] Example 1

[0049] 1) Under a nitrogen atmosphere, 1.1 mol of 1,3-diglycidyl ether glycerol, 1 mol of acryloyl chloride, 1 mol of triethylamine, 0.1 wt% of hydroquinone based on the mass of acryloyl chloride, and chloroform three times the sum of the masses of 1,3-diglycidyl ether glycerol and acryloyl chloride were added to a reaction kettle. The temperature was controlled at 10 °C for reaction for 3 h. After the reaction, solid triethylamine hydrochloride was filtered off and distilled under reduced pressure to obtain unsaturated diglycidyl ether;

[0050] 2) Under a nitrogen atmosphere, 1 mol of unsaturated diglycidyl ester, 2.1 mol of O-(2-aminoethyl) polyethylene glycol with the product number H917141, 0.2 wt% of hydroquinone based on the mass of unsaturated diglycidyl ester, and tetrahydrofuran three times the sum of the masses of unsaturated diglycidyl ester and O-(2-aminoethyl) polyethylene glycol were mixed evenly and heated to 60 °C and kept at a constant temperature for reaction for 6 h. After the reaction, it was concentrated and separated by gel chromatography with tetrahydrofuran as the mobile phase to obtain the alkenyl dimether macromonomer.

[0051] 3) Under an inert atmosphere, add 80 g of APEG2400 and 30 g of vinyl dimeric ether macromonomer to the reaction kettle, heat up to 50 °C and mix evenly, add 10 g of maleic acid, 10 g of phenyl acrylate, 3 wt% of BPO based on the total mass of the four polymerization monomers, and 0.8 wt% of mercaptoethanol based on the total mass of the four polymerization monomers, mix evenly, heat up to 60 °C and keep the temperature constant for reaction. After 5 h of reaction, cool to room temperature, adjust the pH to 7 with 32 wt% sodium hydroxide solution, and add water to adjust the solid content to 45 wt%, thus obtaining the polycarboxylate superplasticizer solution.

[0052] 4) Add 50 g of DK-SiO2-60, 5 g of type I carboxyl-terminated polybutadiene liquid rubber, 150 g of toluene, and zirconia beads with a particle size of 0.2 mm to the ball mill, with a ball-to-material ratio of 20:1, ball mill at 30 °C for 5 h to obtain the ball-milled slurry, filter, and dry at 60 °C and a vacuum degree of 0.08 MPa to obtain the toughening agent.

[0053] 5) Mix 400 parts by mass of Portland cement with a strength grade of 52.5, 150 parts by mass of admixture composed of class I fly ash and S95-grade blast furnace slag powder mixed in a mass ratio of 1:5, 8 parts by mass of polycarboxylate superplasticizer solution, 4 parts by mass of nonylphenol polyoxyethylene ether NP-20, 4 parts by mass of tea saponin, and 30 parts by mass of toughening agent, and mix evenly with water that is 0.28 times the total mass of Portland cement and admixture to obtain a slurry. Add 1000 parts by mass of crushed stone and 700 parts by mass of quartz sand to the slurry and mix evenly to obtain the viscosity-reducing C80-grade concrete.

[0054] Example 2

[0055] The rest is the same as in Example 1, except that in step 3), the dosage of vinyl dimeric ether macromonomer is 20 g.

[0056] Example 3

[0057] The rest is the same as in Example 1, except that in step 3), the dosage of phenyl acrylate is 5 g.

[0058] Example 4

[0059] The rest is the same as in Example 1, except that in step 3), O-(2-aminoethyl) polyethylene glycol with the product number H917140 is used to replace O-(2-aminoethyl) polyethylene glycol with the product number H917141 in an equimolar amount.

[0060] Example 5

[0061] The rest is the same as in Example 1, except that in step 5), the dosage of nonylphenol polyoxyethylene ether NP-20 is 2 parts by mass.

[0062] Example 6

[0063] The rest is the same as in Example 1, except that in step 5), the dosage of the polycarboxylate water reducer solution is 5 parts by mass.

[0064] Example 7

[0065] The rest is the same as in Example 1, except that in step 5), the dosage of tea saponin is 2 parts by mass.

[0066] Example 8

[0067] 1) Under a nitrogen atmosphere, 1.15 mol of 1,3-diglycidyl ether glycerol, 1 mol of acryloyl chloride, 1 mol of triethylamine, hydroquinone at 0.1 wt% of the mass of acryloyl chloride, and chloroform three times the sum of the masses of 1,3-diglycidyl ether glycerol and acryloyl chloride were added to a reaction kettle, and the temperature was controlled at 10 °C for reaction for 3 h. After the reaction, solid triethylamine hydrochloride was removed by filtration and distilled under reduced pressure to obtain unsaturated diglycidyl ether;

[0068] 2) Under a nitrogen atmosphere, 1 mol of unsaturated diglycidyl ester, 2.1 mol of O-(2-aminoethyl) polyethylene glycol with the product number H917140, hydroquinone at 0.2 wt% of the mass of unsaturated diglycidyl ester, and tetrahydrofuran three times the sum of the masses of unsaturated diglycidyl ester and O-(2-aminoethyl) polyethylene glycol were mixed evenly and heated to 60 °C and kept at a constant temperature for reaction for 6 h. After the reaction, it was concentrated and separated by gel chromatography with tetrahydrofuran as the mobile phase to obtain the alkenyl dimether macromonomer.

[0069] 3) Under an inert atmosphere, 80 g of APEG2400 and 30 g of alkenyl dimether macromonomer were added to a reaction kettle, heated to 50 °C and mixed evenly, 7 g of maleic acid, 10 g of 2-phenylethyl methacrylate, BPO at 3 wt% of the sum of the masses of the four polymerization monomers, and mercaptoethanol at 0.8 wt% of the sum of the masses of the four polymerization monomers were added and mixed evenly. Then it was heated to 60 °C again and kept at a constant temperature for reaction. After 5 h of reaction, it was cooled to room temperature, and the pH was adjusted to 7 with 32 wt% sodium hydroxide solution, and water was added to adjust the solid content to 45 wt% to obtain the polycarboxylate water reducer solution.

[0070] 4) 50 g of DK-SiO2-60, 5 g of type I carboxyl-terminated polybutadiene liquid rubber, 150 g of toluene, and zirconia beads with a particle size of 0.2 mm were added to a ball mill, and the ball-to-material ratio was 20:1. Ball milling was carried out at 30 °C for 5 h to obtain a ball-milled slurry, which was filtered and dried at 60 °C and a vacuum degree of 0.08 MPa to obtain the toughening agent.

[0071] 5) Mix 350 parts by mass of portland cement with a strength grade of 52.5, 150 parts by mass of a blend composed of Class I fly ash and S95-grade ground granulated blast-furnace slag mixed at a mass ratio of 1:5, 5 parts by mass of a polycarboxylate superplasticizer solution, 2 parts by mass of nonylphenol polyoxyethylene ether NP-20, 4 parts by mass of tea saponin, and 30 parts by mass of a toughening agent. Mix the portland cement and the blend evenly with 0.28 times the sum of their masses of water to obtain a slurry. Then add 850 parts by mass of crushed stone and 600 parts by mass of quartz sand to the slurry and mix evenly to obtain a viscosity-reducing C80-grade concrete.

[0072] Comparative Example 1

[0073] The rest is the same as in Example 1, except that in step 5), an equal amount of octylphenol polyoxyethylene ether TX-25 is used to replace nonylphenol polyoxyethylene ether NP-20.

[0074] Comparative Example 2

[0075] The rest is the same as in Example 1, except that in step 1), an equal mass of APEG2400 is used to replace the alkenyl dimether macromonomer.

[0076] Comparative Example 3

[0077] The rest is the same as in Example 1, except that in step 5), an equal mass of dodecylbenzenesulfonate air-entraining agent is used to replace tea saponin.

[0078] Perform the following performance tests on the concretes prepared in the above examples and comparative examples:

[0079] Flexural strength: Cured under standard conditions for 28 days, and tested in accordance with the standard test method for mechanical properties of ordinary concrete GB / T50081-2002.

[0080] Concrete viscosity: Refer to the Technical Specification for Application of High-Strength Concrete JGJ281-2012, and use an inverted slump bucket to test the evacuation time t of the concrete mixture to evaluate the concrete viscosity.

[0081] Table 1 Performance test results

[0082]

[0083] As can be seen from Table 1, the viscosity-reducing C80-grade concrete prepared by the present invention has excellent mechanical strength and toughness.

[0084] It can be seen from the slump flow cone emptying time t of Examples 1-4 and Comparative Example 2 that the polycarboxylate water reducing agent of the present invention has excellent viscosity reduction effect. It can be seen from the slump flow cone emptying time t of Example 1, Example 5 and Comparative Example 1 that the use of the foam stabilizer nonylphenol polyoxyethylene ether NP-20 has little effect on the viscosity of concrete; however, as time progresses, the vinyl dimether macromonomer hydrolyzes in the alkaline paste, generating a polyether chain segment with defoaming effect, and the flexural strength of the concrete after final hardening in Comparative Example 1 without nonylphenol polyoxyethylene ether is relatively low; it can be seen from Example 1, Example 7 and Comparative Example 3 that the use of tea saponin is beneficial to reducing the viscosity of concrete and improving fluidity. If the highly efficient dodecylbenzenesulfonate air-entraining agent is replaced, although a large number of bubbles can be generated to reduce the viscosity, too much air-entraining reduces the flexural strength, presumably resulting in uneven bubble size and distribution inside the concrete and a significant decrease in toughness. Thus, it can be seen that in order to obtain concrete with both high toughness and low viscosity, the prepared polycarboxylate water reducing agent needs to be used in combination with the foam stabilizer nonylphenol polyoxyethylene ether and tea saponin. There is a synergistic effect between them, and they work together to obtain concrete with both high toughness and low viscosity.

Claims

1. A viscosity-reducing C80 grade concrete, characterized in that, It includes the following raw materials: 350 - 400 parts by weight of cement, 100 - 150 parts by weight of admixture, 600 - 700 parts by weight of fine aggregate, 850 - 1000 parts by weight of coarse aggregate, 5 - 8 parts by weight of polycarboxylate superplasticizer solution, 2 - 4 parts by weight of nonylphenol polyoxyethylene ether, 2 - 4 parts by weight of tea saponin, 25 - 30 parts by weight of toughening agent and water. The mass ratio of the total mass of cement and admixture to the mass of water is 1:0.2 - 0.28; the solid content of the polycarboxylate superplasticizer solution is 35 - 45wt%; the polycarboxylate superplasticizer is copolymerized from alkenyl polyether macromonomer, alkenyl dimether macromonomer, unsaturated acid derivative, and phenyl acrylate derivative in a mass ratio of 70 - 80:20 - 30:7 - 10:5 - 10; The structural formula of the alkenyl dimether macromonomer is shown as the following formula (I): (I)； Wherein, m and n are independently integers between 40 - 80, and R is -CH3 or -H.

2. The viscosity-reducing C80 grade concrete according to claim 1, characterized in that, The alkenyl dimether macromonomer is prepared by a method including the following steps: 1) Under an inert atmosphere, add 1,3-diglycidyl ether glycerol, (meth)acryloyl chloride, acid-binding agent, inhibitor, and organic solvent to a reaction kettle, control the temperature for reaction. After the reaction is completed, filter and perform vacuum distillation to obtain unsaturated diglycidyl ether; 2) Under an inert atmosphere, mix unsaturated diglycidyl ester, O-(2-aminoethyl) polyethylene glycol, inhibitor, and organic solvent evenly, heat up and keep the temperature constant for reaction. After the reaction is completed, concentrate and perform gel chromatography column chromatography separation to obtain the alkenyl dimether macromonomer.

3. The viscosity-reducing C80 grade concrete according to claim 2, wherein In step 1), the molar ratio of (meth)acryloyl chloride, 1,3-diglycidyl ether glycerol, and acid-binding agent is 1:1.1 - 1.15:1 - 1.

1.

4. The viscosity-reducing C80 grade concrete according to claim 2, wherein In step 1), the temperature control is to control at 1 - 10°C, and the reaction time is 3 - 5h; the inhibitor is 0.1 - 0.3wt% of (meth)acryloyl chloride.

5. The viscosity-reducing C80 grade concrete according to claim 2, wherein In step 2), the molar ratio of unsaturated diglycidyl ester to O-(2-aminoethyl) polyethylene glycol is 1:2.1 - 2.2; the number-average molecular weight of O-(2-aminoethyl) polyethylene glycol is 2000 - 3400; the unsaturated glycidyl ester is selected from one or a combination of two of glycidyl acrylate and glycidyl methacrylate.

6. The viscosity-reducing C80 grade concrete according to claim 2, wherein, In step 2), the temperature rise is to rise to 60 - 80°C, and the reaction time is 3 - 6h.

7. The viscosity-reducing C80 grade concrete according to claim 1, characterized in that, The number-average molecular weight of the alkenyl polyether macromonomer is 2000 - 2400, and it is selected from one or a combination of two of methyl allyl polyoxyethylene ether and allyl polyoxyethylene ether; the unsaturated acid derivative is selected from one or a combination of two or more of acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid; the phenyl acrylate derivative is selected from one or a combination of two or more of phenyl acrylate, phenyl methacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, and 2-phenylethyl methacrylate; the nonylphenol polyoxyethylene ether is selected from one or a combination of two or more of NP-10, NP-16, and NP-20.

8. The viscosity-reducing C80 grade concrete according to claim 1, wherein The polycarboxylate superplasticizer is prepared by a method including the following steps: Under an inert atmosphere, add the vinyl polyether macromonomer and the vinyl dimether macromonomer to a reaction kettle, heat up and mix evenly, add the unsaturated acid derivative, the phenyl acrylate derivative, the initiator, and the chain transfer agent and mix evenly, heat up again and keep the temperature constant for reaction. After the reaction is completed, cool to room temperature, adjust the pH, and add water to adjust the solid content to obtain the polycarboxylate water reducing agent solution.

9. The viscosity-reducing C80 grade concrete according to claim 1, wherein, The toughening agent is an inorganic filler coated with liquid rubber and is prepared by a method including the following steps: Add the inorganic filler, the carboxyl-terminated polybutadiene liquid rubber, the organic solvent, and the ball milling medium to a ball mill, ball mill to obtain a ball mill slurry, filter and dry to obtain the toughening agent.

10. The preparation method of the viscosity-reducing C80 grade concrete according to any one of claims 1-9, characterized in that, Including the following steps: Mix the cement, the admixture, the polycarboxylate water reducing agent solution, the nonylphenol polyoxyethylene ether, the tea saponin, the toughening agent, and water evenly to obtain a slurry, and add the coarse aggregate and the fine aggregate to the slurry and mix evenly to obtain the viscosity-reducing C80 grade concrete.

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