High-strength concrete and process for its production

Abstract

The present application relates to the technical field of concrete, in particular to a high-strength concrete and a preparation process thereof. The present application takes 1,7-dibromoheptane, cyanophenol, cetyl alcohol and 1-ethyl-2-methylimidazole as main raw materials to obtain a nucleating agent. Then the nucleating agent is added to a cellulose solution, and spun extruded and physically mixed with high-strength fibers to obtain high-strength fibers. Then the high-strength fibers are immersed in a mixed solution obtained by adding modified nano titanium dioxide, and dried to obtain composite fibers. Then methyl allyl polyoxyethylene ether, pyromellitic acid, methoxy polyethylene glycol, methyl methacrylic acid and the like are taken as main raw materials to obtain a polycarboxylic acid water reducing agent. Finally, cement, slag powder, silane coupling agent YDH171, coarse aggregate, polycarboxylic acid water reducing agent, composite fibers and water are mixed to obtain a mixture, and then the mixture is molded and cured to obtain a finished product. The finished product obtained by the present application has good ultraviolet aging resistance and mechanical strength, and therefore has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete, and particularly relates to high-strength concrete and a preparation process thereof. BACKGROUND

[0002] Concrete is one of the most commonly used building materials in modern construction engineering, and it has many important modern values. For example, concrete has high strength and durability, can bear the weight and external force of most building structures, can be used for a long time under harsh weather conditions, and can resist natural disasters such as fire and earthquake. Concrete can be constructed in different shapes and sizes to meet various building needs. Through mold and reinforcement design during construction, various building forms can be created. In addition, concrete is a sustainable building material, and its main components are natural resources such as cement, sand and gravel. The production and use of concrete are relatively low-carbon, and can effectively reduce environmental pollution. Therefore, it is very important to prepare high-strength concrete for construction engineering. The improvement of strength not only can improve the safety of building structures, but also can save materials and costs, prolong the service life, improve the construction efficiency, and meet the requirements of sustainable development. Therefore, the improvement of concrete strength is an important direction in the development of modern construction engineering.

[0003] In order to overcome the defects of the prior art, the present application provides high-strength concrete and a preparation process thereof. SUMMARY

[0004] The present application aims to provide high-strength concrete and a preparation process thereof to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present application provides the following technical solutions:

[0006] A preparation process of high-strength concrete comprises the following steps:

[0007] Step one: 1,7-dibromoheptane, cyanophenol, cetyl alcohol are added to 3 / 4 mass fraction of acetonitrile, then potassium carbonate aqueous solution is added, and the reaction is carried out at 70-90℃ for 8-10h, then vacuum filtration, washing and drying are carried out to obtain an intermediate product; then the intermediate product and 1-ethyl-2-methyl imidazole are refluxed in 1 / 4 mass fraction of acetonitrile, and the reflux reaction is carried out at 70-90℃ for 6-8h, then vacuum filtration and drying are carried out after the reaction to prepare a nucleating agent; the nucleating agent is added to a cellulose solution, and after stirring and dissolving, degassing is carried out at 70-80℃ to obtain a spinning solution; the spinning solution is extruded through a spinning nozzle to prepare a modified fiber; the modified fiber, polypropylene fiber and steel fiber are physically mixed to obtain a high-strength fiber; the modified nano titanium dioxide is added to deionized water and stirred to obtain a mixed solution; then the high-strength fiber is immersed in the mixed solution, stirred at 25-30℃ for 20-25h, and then dried to obtain a composite fiber;

[0008] Step two: the water reducing agent macromolecule, methacrylic acid and ammonium persulfate are mixed to obtain solution 1; sodium methacrylate and 2-acrylamido-2-methylpropyl sodium sulfonate are dissolved in distilled water to obtain solution 2; solution 1 is slowly added to solution 2 at 80-90℃, and the dropping is carried out for 3-4h, and the reaction is carried out for 4-6h, then sodium hydroxide solution is added to adjust the pH to 7-8 after the reaction to prepare a polycarboxylic acid water reducing agent;

[0009] Step three: cement, slag powder, silane coupling agent YDH171, coarse aggregate, polycarboxylic acid water reducing agent, composite fiber and water are mixed to obtain a mixture, and the mixture is molded and cured to prepare a finished product.

[0010] More preferably, in step one, the content of each component of the spinning solution is: 25-30 parts by mass of 1,7-dibromoheptane, 10-15 parts of cyanophenol, 12-15 parts of cetyl alcohol, 40-60 parts of acetonitrile, 10-15 parts of potassium carbonate aqueous solution, 11-15 parts of 1-ethyl-2-methyl imidazole, and 60-70 parts of cellulose solution; the mass ratio of modified fiber, polypropylene fiber and steel fiber in high-strength fiber is 1-1.5:3:3; the mass ratio of modified nano titanium dioxide and deionized water in the mixed solution is 0.2-0.4:100.

[0011] More preferably, in step one, the preparation of the cellulose solution: cellulose and N,N-dimethylacetamide are mixed, stirred and activated at 120-140℃ for 2-4h, then cooled to 100-110℃, and lithium chloride is added and stirred for 10-20min to obtain a cellulose solution.

[0012] More preferably, the content of each component of the cellulose solution is: 3-5 parts by mass of cellulose, 65-80 parts of N,N-dimethylacetamide, and 7-10 parts of lithium chloride.

[0013] More preferably, in step one, the preparation method of the modified nano-titanium dioxide is as follows: the silane coupling agent KH550 is added dropwise into deionized water, and ultrasonic oscillation is performed for 30-50 min to obtain solution 3; then the nano-titanium dioxide is added into ethyl acetate, and ultrasonic oscillation is performed for 30-50 min to obtain solution 4; solution 3 and solution 4 are mixed, and reflux reaction is performed at 80-90 DEG C for 6-8 h, and then centrifugation, washing, drying and grinding are performed to obtain the modified nano-titanium dioxide.

[0014] More preferably, the content of each component of the modified nano-titanium dioxide is as follows: 10-15 parts of the silane coupling agent KH550, 100-120 parts of deionized water, 2-3 parts of nano-titanium dioxide and 100-120 parts of ethyl acetate.

[0015] More preferably, in step two, the preparation method of the water-reducing agent macromolecule is as follows: under the nitrogen environment, the methyl allyl polyoxyethylene ether and the pyromellitic acid are mixed, 1 / 2 of the catalyst p-toluenesulfonic acid is added, esterification reaction is performed at 100-130 DEG C for 6-8 h, then 1 / 2 of the catalyst p-toluenesulfonic acid and the methoxyl polyethylene glycol are added, and esterification reaction is performed at 100-130 DEG C for 6-8 h to obtain the water-reducing agent macromolecule.

[0016] More preferably, the content of each component of the water-reducing agent macromolecule is as follows: 10-20 parts of the methyl allyl polyoxyethylene ether, 35-40 parts of the pyromellitic acid, 2.0-3.6 parts of the catalyst p-toluenesulfonic acid and 40-60 parts of the methoxyl polyethylene glycol.

[0017] More preferably, in step two, the mass ratio of the water-reducing agent macromolecule, the methyl methacrylate, the sodium methyl methacrylate and the sodium 2-acrylamido-2-methylpropanesulfonate is 70:5-7:3:5; the dosage of the ammonium persulfate is 6.5-7.5% of the mass of the water-reducing agent macromolecule.

[0018] More preferably, in step three, the content of each component of the mixture is as follows: 250-300 parts of cement, 150-180 parts of slag powder, 1-3 parts of the silane coupling agent YDH171, 1000-1200 parts of coarse aggregate, 2-5 parts of the polycarboxylic acid water-reducing agent, 30-50 parts of the composite fiber and 130-150 parts of water.

[0019] The beneficial effects of the present application are as follows:

[0020] The nucleating agent is prepared by adding 1,7-dibromoheptane, cyanophenol, cetyl alcohol, acetonitrile, potassium carbonate aqueous solution and 1-ethyl-2-methyl imidazole.The modified fiber is prepared by adding the nucleating agent to the cellulose solution and jetting extrusion.The high-strength fiber is prepared by physically mixing the modified fiber, polypropylene fiber and steel fiber.The composite fiber is prepared by dipping the high-strength fiber in the mixed solution added with modified nano-titanium dioxide and drying.The water-reducing agent macromolecule is prepared by esterification reaction of adding methyl allyl polyoxyethylene ether, pyromellitic acid, p-toluene sulfonic acid and methoxy polyethylene glycol.The polycarboxylic acid water-reducing agent is prepared by using the water-reducing agent macromolecule, methacrylic acid, ammonium persulfate, sodium methacrylate and 2-acrylamido-2-methylpropyl sulfonate as raw materials.The finished product is prepared by mixing cement, slag powder, silane coupling agent YDH171, coarse aggregate, polycarboxylic acid water-reducing agent, composite fiber and water, and then molding and curing the mixture.

[0021] The application has the characteristics that in step one, the bromine group of 1,7-dibromoheptane and the hydroxyl group of cyanophenol with biphenyl structure are reacted to obtain an intermediate product by adding cyanophenol with biphenyl structure in the nucleating agent, so that the biphenyl group with anti-ultraviolet aging ability is introduced into the nucleating agent, thereby improving the anti-ultraviolet and anti-aging ability of the fiber.The surface tension of the fiber is reduced by adding long-chain aliphatic hydrocarbon cetyl alcohol in the nucleating agent, thereby improving the water resistance and moisture resistance of the composite fiber.Further adding 1-ethyl-2-methyl imidazole can utilize the hydrogen bond interaction between the imidazole group and the hydroxyl group of the fiber, thereby inducing fiber crystallization, changing the molecular structure into an extended state, triggering lattice rearrangement, and effectively improving the mechanical strength of the fiber.In addition, the high-strength fiber is obtained by physically mixing the modified fiber, polypropylene fiber and steel fiber, which can effectively guarantee the mechanical strength of the composite fiber.The composite fiber obtained by dipping the high-strength fiber in the mixed solution added with modified nano-titanium dioxide can further improve the anti-ultraviolet aging performance.

[0022] In step two, the water-reducing agent macromolecule with multi-branch structure is prepared by esterification reaction of adding methyl allyl polyoxyethylene ether, pyromellitic acid and methoxyl polyethylene glycol. Then, the polycarboxylate superplasticizer with multi-branch structure is prepared by using the water-reducing agent macromolecule, methacrylic acid, ammonium persulfate, sodium methallyl sulfonate and 2-acrylamido-2-methylpropyl sulfonic acid sodium as raw materials. On the one hand, the polycarboxylate superplasticizer has multi-branch structure, so when it is added to concrete as an additive, it has good dispersibility. On the other hand, the carboxyl groups are introduced by adding methacrylic acid, and the sulfonic acid groups are introduced by adding sodium methallyl sulfonate and 2-acrylamido-2-methylpropyl sulfonic acid sodium. The carboxyl groups and sulfonic acid groups can enhance the interaction between the polycarboxylate molecules and the cement particles, and improve the dispersibility. In concrete, this helps to disperse the cement particles, reduces the accumulation and agglomeration of particles, thereby improving the fluidity and water-reducing effect. It can also improve the interaction force between the polycarboxylate molecules and the cement stone, increase the bonding force between the cement particles, and thus improve the mechanical properties of the concrete, including compressive strength, flexural strength and durability, etc. DETAILED DESCRIPTION

[0023] The technical solutions in the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0024] Raw material sources:

[0025] Cellulose, provided by Shandong Hailong Co., Ltd., DP = 500; polypropylene fiber, provided by Shandong Yiheng Engineering Material Co., Ltd., diameter 20 μm; steel fiber, provided by Shandong Futai Fiber Co., Ltd., diameter 0.5 mm; methyl allyl polyoxyethylene ether, provided by Hubei Xingheng Technology Co., Ltd., molecular weight 2200; methoxyl polyethylene glycol, provided by Haian Petroleum Chemical Factory of Jiangsu Province, model MPEG400, molecular weight 400; silane coupling agent YDH171, provided by Jiangsu Puleisi Biological Technology Co., Ltd., model YDH171; silane coupling agent KH550, provided by Shandong Huachen New Material Co., Ltd., model KH550; cement, provided by Wuxi Jinying Building Material Co., Ltd., model JY-6; coarse aggregate, provided by Zhengzhou Ruicheng Refractory Material Co., Ltd., model 0-3; slag powder, provided by Tangshan Chengye Building Material Co., Ltd., model S95; nano titanium dioxide, provided by Shijiazhuang Wengbo Mineral Products Co., Ltd., particle size 325 mesh.

[0026] Example 1: Step one: 27g of 1,7-dibromoheptane, 10g of cyanobiphenyl, 12g of cetyl alcohol are added to 30g of acetonitrile, then 10g of potassium carbonate aqueous solution is added, and the reaction is carried out at 90℃ for 10h, then vacuum filtration, washing and drying are carried out to obtain an intermediate product; the prepared intermediate product and 11g of 1-ethyl-2-methyl imidazole are refluxed in 10g of acetonitrile, and the reaction is carried out at 90℃ for 8h, then vacuum filtration and drying are carried out after the reaction to obtain a nucleating agent; 3g of cellulose and 65g of N,N-dimethylacetamide are mixed, and the mixture is stirred and activated at 140℃ for 4h, then the temperature is lowered to 110℃, 7g of lithium chloride is added and stirred for 20min to obtain a cellulose solution; the prepared nucleating agent is added to 60g of the cellulose solution, and after stirring and dissolving, the solution is degassed at 80℃ to obtain a spinning solution; the spinning solution is extruded through a spinning nozzle to prepare a modified fiber; 5g of the modified fiber, 15g of polypropylene fiber and 15g of steel fiber are physically mixed to obtain a high-strength fiber;

[0027] Step two: 10g of silane coupling agent KH550 is added dropwise to 100g of deionized water, and ultrasonic oscillation is carried out for 50min to obtain solution 3; then 2g of nano titanium dioxide is added to 100g of ethyl acetate, and ultrasonic oscillation is carried out for 50min to obtain solution 4; solutions 3 and 4 are mixed, and the reaction is carried out at 90℃ for 8h, then centrifugation, washing, drying and grinding are carried out to prepare modified nano titanium dioxide; 0.2g of the modified nano titanium dioxide is added to 100g of deionized water, and the mixture is stirred to obtain a mixed solution; then the high-strength fiber is immersed in the mixed solution, and the mixture is stirred at 30℃ for 25h, then dried to obtain a composite fiber;

[0028] Step three: 10g of methyl allyl polyoxyethylene ether and 35g of pyromellitic acid are mixed, then 1g of catalyst p-toluenesulfonic acid is added, and esterification reaction is carried out at 130℃ for 8h, then 40g of methoxy polyethylene glycol and 1g of catalyst p-toluenesulfonic acid are added, and esterification reaction is carried out at 130℃ for 8h to prepare a superplasticizer macromolecule;

[0029] Step four: 70g of the superplasticizer macromolecule, 5g of methacrylic acid and 4.6g of ammonium persulfate are mixed to obtain solution 1; 3g of sodium methallyl sulfonate and 5g of 2-acrylamido-2-methylpropyl sulfonic acid sodium are dissolved in distilled water to obtain solution 2; solution 1 is slowly added to solution 2 at 90℃, and the reaction is carried out for 4h, then the temperature is kept for 6h after the reaction, then sodium hydroxide solution is added to adjust the pH to 8 to prepare a polycarboxylic acid superplasticizer;

[0030] Step five: 250g of cement, 150g of slag powder, 1g of silane coupling agent YDH171, 1000g of coarse aggregate, 2g of polycarboxylic acid superplasticizer, 30g of composite fiber and 130g of water are mixed to obtain a mixture, and the mixture is molded and cured to prepare a finished product.

[0031] Example 2: Step one: 27g of 1,7-dibromoheptane, 10g of cyanobiphenyl, 12g of cetyl alcohol were added to 30g of acetonitrile, then 10g of potassium carbonate aqueous solution was added, and the reaction was carried out at 85°C for 9.5h, then vacuum filtration, washing and drying were carried out to obtain an intermediate product; the prepared intermediate product and 11g of 1-ethyl-2-methyl imidazole were refluxed in 10g of acetonitrile, and the reaction was carried out at 85°C for 7.5h, then vacuum filtration and drying were carried out after the reaction to obtain a nucleating agent; 3g of cellulose and 65g of N,N-dimethylacetamide were mixed, stirred and activated at 135°C for 3.5h, then the temperature was lowered to 107°C, 7g of lithium chloride was added and stirred for 17min to obtain a cellulose solution; the prepared nucleating agent was added to 60g of the cellulose solution, stirred and dissolved, and then degassed at 77°C to obtain a spinning solution; the spinning solution was extruded through a spinner to prepare a modified fiber; 5g of the modified fiber, 15g of polypropylene fiber and 15g of steel fiber were physically mixed to obtain a high-strength fiber;

[0032] Step two: 10g of silane coupling agent KH550 was added dropwise to 100g of deionized water, and ultrasonic oscillation was carried out for 45min to obtain solution 3; 2g of nano titanium dioxide was added to 100g of ethyl acetate, and ultrasonic oscillation was carried out for 45min to obtain solution 4; solution 3 and solution 4 were mixed, and the reaction was carried out at 87°C for 7.5h, then centrifugation, washing, drying and grinding were carried out to prepare modified nano titanium dioxide; 0.2g of the modified nano titanium dioxide was added to 100g of deionized water, and stirred to obtain a mixed solution; the high-strength fiber was immersed in the mixed solution, stirred at 29°C for 24h, and then dried to obtain a composite fiber;

[0033] Step three: 10g of methyl allyl polyoxyethylene ether and 35g of pyromellitic acid were mixed, 1g of catalyst p-toluenesulfonic acid was added, esterification reaction was carried out at 125°C for 7.5h, then 40g of methoxy polyethylene glycol and 1g of catalyst p-toluenesulfonic acid were added, and esterification reaction was carried out at 125°C for 7.5h to prepare a superplasticizer macromolecule;

[0034] Step four: 70g of superplasticizer macromolecule, 5g of methacrylic acid and 4.6g of ammonium persulfate were mixed to obtain solution 1; 3g of sodium methacrylate and 5g of 2-acrylamido-2-methylpropyl sulfonic acid sodium were dissolved in distilled water to obtain solution 2; solution 1 was slowly added to solution 2 at 87°C, and the dropping was carried out for 3.7h, and the reaction was carried out for 5.5h, then sodium hydroxide solution was added to adjust the pH to 7.7 to prepare a polycarboxylic acid superplasticizer;

[0035] Step five: 250 g cement, 150 g slag powder, 1 g silane coupling agent YDH171, 1000 g coarse aggregate, 2 g polycarboxylic acid water reducer, 30 g composite fiber and 130 g water are mixed to obtain a mixture, and the mixture is molded and cured to obtain a finished product.

[0036] Example 3: Step one: 27 g of 1,7-dibromoheptane, 10 g of cyanobiphenol, 12 g of cetyl alcohol, 10 g of potassium carbonate aqueous solution were added to 30 g of acetonitrile, and reacted at 80℃ for 9 h, then vacuum filtration, washing and drying were performed to obtain an intermediate product; the prepared intermediate product and 11 g of 1-ethyl-2-methyl imidazole were refluxed in 10 g of acetonitrile, and reacted at 80℃ for 7 h, then vacuum filtration and drying were performed after the reaction to obtain a nucleating agent; 3 g of cellulose and 65 g of N,N-dimethylacetamide were mixed, stirred and activated at 130℃ for 3 h, then cooled to 105℃, 7 g of lithium chloride was added and stirred for 15 min to obtain a cellulose solution; the prepared nucleating agent was added to 60 g of the cellulose solution, stirred and dissolved, and then degassed at 75℃ to obtain a spinning solution; the spinning solution was extruded through a spinning nozzle to prepare a modified fiber; 5 g of the modified fiber, 15 g of polypropylene fiber and 15 g of steel fiber were physically mixed to obtain high-strength fiber;

[0037] Step two: 10 g of silane coupling agent KH550 was added dropwise to 100 g of deionized water, and ultrasonic oscillation was performed for 40 min to obtain solution 3; 2 g of nano titanium dioxide was added to 100 g of ethyl acetate, and ultrasonic oscillation was performed for 40 min to obtain solution 4; solution 3 and solution 4 were mixed, and reflux reaction was performed at 85℃ for 7 h, then centrifugation, washing, drying and grinding were performed to obtain modified nano titanium dioxide; 0.2 g of the modified nano titanium dioxide was added to 100 g of deionized water, and stirred to obtain a mixture; the high-strength fiber was immersed in the mixture, and stirred at 28℃ for 23 h, then dried to obtain a composite fiber;

[0038] Step three: 10 g of methyl allyl polyoxyethylene ether and 35 g of pyromellitic acid were mixed, 1 g of catalyst p-toluenesulfonic acid was added, esterification reaction was performed at 120℃ for 7 h, then 40 g of methoxy polyethylene glycol and 1 g of catalyst p-toluenesulfonic acid were added, esterification reaction was performed at 120℃ for 7 h to obtain a water reducer macromolecule;

[0039] Step four: 70 g of water reducer macromolecule, 5 g of methacrylic acid and 4.6 g of ammonium persulfate were mixed to obtain solution 1; 3 g of sodium methallyl sulfonate and 5 g of 2-acrylamido-2-methylpropyl sulfonic acid sodium were dissolved in distilled water to obtain solution 2; solution 1 was slowly added to solution 2 at 85℃, and the dropping was performed for 3.5 h, and the reaction was performed for 5 h, then sodium hydroxide solution was added to adjust the pH to 7.5 to obtain a polycarboxylic acid water reducer;

[0040] Step five: 250g cement, 150g slag powder, 1g silane coupling agent YDH171, 1000g coarse aggregate, 2g polycarboxylic acid water reducer, 30g composite fiber and 130g water are mixed to obtain a mixture, and the mixture is molded and cured to prepare a finished product.

[0041] Example 4: Step one: 27g 1,7-dibromoheptane, 10g cyanobiphenol, 12g hexadecanol, 10g potassium carbonate aqueous solution were added to 30g acetonitrile, and the mixture was reacted at 75℃ for 8.5h, then vacuum filtration, washing and drying were carried out to obtain an intermediate product; the prepared intermediate product and 11g 1-ethyl-2-methylimidazole were refluxed in 10g acetonitrile, and the mixture was refluxed at 75℃ for 6.5h, then vacuum filtration and drying were carried out after the reaction to prepare a nucleating agent; 3g cellulose and 65g N,N-dimethylacetamide were mixed, stirred and activated at 125℃ for 2.5h, then the temperature was lowered to 103℃, 7g lithium chloride was added and stirred for 13min to obtain a cellulose solution; the prepared nucleating agent was added to 60g cellulose solution, stirred and dissolved, and then degassed at 73℃ to obtain a spinning solution; the spinning solution was extruded through a spinneret to prepare a modified fiber; 5g modified fiber, 15g polypropylene fiber and 15g steel fiber were physically mixed to obtain high-strength fiber;

[0042] Step two: 10g silane coupling agent KH550 was added dropwise to 100g deionized water, and ultrasonic oscillation was carried out for 35min to obtain solution 3; 2g nano titanium dioxide was added to 100g ethyl acetate, and ultrasonic oscillation was carried out for 35min to obtain solution 4; solution 3 and solution 4 were mixed, and reflux reaction was carried out at 83℃ for 6.5h, then centrifugation, washing, drying and grinding were carried out to prepare modified nano titanium dioxide; 0.2g modified nano titanium dioxide was added to 100g deionized water, and stirred to obtain a mixture; the high-strength fiber was immersed in the mixture, stirred at 27℃ for 21h, and then dried to obtain a composite fiber;

[0043] Step three: 10g methylallyl polyoxyethylene ether and 35g pyromellitic acid were mixed, 1g catalyst p-toluenesulfonic acid was added, esterification reaction was carried out at 110℃ for 6.5h, then 40g methoxy polyethylene glycol and 1g catalyst p-toluenesulfonic acid were added, and esterification reaction was carried out at 110℃ for 6.5h to prepare a water reducer macromolecule;

[0044] Step four: 70g of superplasticizer macromolecule, 5g of methacrylic acid and 4.6g of ammonium persulfate were mixed to obtain solution 1; 3g of sodium methacrylsulfonate and 5g of 2-acrylamido-2-methylpropyl sulfonate sodium were dissolved in distilled water to obtain solution 2; solution 1 was slowly added to solution 2 at 83℃, and the reaction was carried out for 3.3h and 4.5h of incubation, after the reaction was completed, sodium hydroxide solution was added to adjust the PH to 7, and the polycarboxylic acid superplasticizer was prepared;

[0045] Step five: 250g of cement, 150g of slag powder, 1g of silane coupling agent YDH171, 1000g of coarse aggregate, 2g of polycarboxylic acid superplasticizer, 30g of composite fiber and 130g of water were mixed to obtain a mixture, and the mixture was molded and cured to obtain a finished product.

[0046] Example 5: Step one: 27g of 1,7-dibromoheptane, 10g of cyanobiphenol, 12g of cetyl alcohol were added to 30g of acetonitrile, then 10g of potassium carbonate aqueous solution was added, and the reaction was carried out at 70℃ for 8h, then vacuum filtration, washing and drying were carried out to obtain an intermediate product; the prepared intermediate product and 11g of 1-ethyl-2-methyl imidazole were refluxed in 10g of acetonitrile, and the reaction was carried out at 70℃ for 6h, then vacuum filtration and drying were carried out after the reaction was completed to obtain a nucleating agent; 3g of cellulose and 65g of N,N-dimethylacetamide were mixed, stirred and activated at 120℃ for 2h, then cooled to 100℃, 7g of lithium chloride was added and stirred for 10min to obtain a cellulose solution; the prepared nucleating agent was added to 60g of the cellulose solution, stirred and dissolved, and then degassed at 70℃ to obtain a spinning solution; the spinning solution was extruded by spinning to obtain modified fibers; 5g of modified fibers, 15g of polypropylene fibers and 15g of steel fibers were physically mixed to obtain high-strength fibers;

[0047] Step two: 10g of silane coupling agent KH550 was added to 100g of deionized water and ultrasonically oscillated for 30min to obtain solution 3; 2g of nano titanium dioxide was added to 100g of ethyl acetate and ultrasonically oscillated for 30min to obtain solution 4; solution 3 and solution 4 were mixed and refluxed at 80℃ for 6h, then centrifuged, washed, dried and ground to obtain modified nano titanium dioxide; 0.2g of modified nano titanium dioxide was added to 100g of deionized water and stirred to obtain a mixture; the high-strength fibers were immersed in the mixture and stirred at 26℃ for 20h, then dried to obtain composite fibers;

[0048] Step three: 10g of methyl allyl polyoxyethylene ether and 35g of pyromellitic acid were mixed under a nitrogen environment, then 1g of catalyst p-toluenesulfonic acid was added, and esterification reaction was carried out at 100℃ for 6h, then 40g of methoxy polyethylene glycol and 1g of catalyst p-toluenesulfonic acid were added, and esterification reaction was carried out at 100℃ for 6h to obtain a superplasticizer macromolecule;

[0049] Step four: 70 g of water-reducing agent macromolecule, 5 g of methacrylic acid and 4.6 g of ammonium persulfate were mixed to obtain solution 1; 3 g of sodium methacryl sulfonate and 5 g of 2-acrylamido-2-methylpropyl sulfonate sodium were fully dissolved in distilled water to obtain solution 2; solution 1 was slowly added to solution 2 at 80℃, and the dropping time was 3 h, and the reaction was kept for 4 h; after the reaction was completed, sodium hydroxide solution was added to adjust the pH to 7, and a polycarboxylic acid water-reducing agent was prepared;

[0050] Step five: 250 g of cement, 150 g of slag powder, 1 g of silane coupling agent YDH171, 1000 g of coarse aggregate, 2 g of polycarboxylic acid water-reducing agent, 30 g of composite fiber and 130 g of water were mixed to obtain a mixture, and the mixture was molded and cured to obtain a finished product.

[0051] Comparative example 1: the preparation steps of the composite fiber were removed, and the rest was the same as example 1, and the specific steps were as follows: step one: 10 g of methyl allyl polyoxyethylene ether and 35 g of pyromellitic acid were mixed under a nitrogen environment, 1 g of catalyst p-toluenesulfonic acid was added, esterification reaction was carried out at 130℃ for 8 h, 40 g of methoxy polyethylene glycol and 1 g of catalyst p-toluenesulfonic acid were added after the reaction was completed, and esterification reaction was carried out at 130℃ for 8 h to prepare a water-reducing agent macromolecule;

[0052] Step two: Step three: 70 g of water-reducing agent macromolecule, 5 g of methacrylic acid and 4.6 g of ammonium persulfate were mixed to obtain solution 1; 3 g of sodium methacryl sulfonate and 5 g of 2-acrylamido-2-methylpropyl sulfonate sodium were fully dissolved in distilled water to obtain solution 2; solution 1 was slowly added to solution 2 at 90℃, and the dropping time was 4 h, and the reaction was kept for 6 h; after the reaction was completed, sodium hydroxide solution was added to adjust the pH to 8, and a polycarboxylic acid water-reducing agent was prepared;

[0053] Step three: 250 g of cement, 150 g of slag powder, 1 g of silane coupling agent YDH171, 1000 g of coarse aggregate, 2 g of polycarboxylic acid water-reducing agent and 130 g of water were mixed to obtain a mixture, and the mixture was molded and cured to obtain a finished product.

[0054] Comparative Example 2: The polycarboxylic acid water reducing agent prepared in the application was replaced with a polycarboxylic acid water reducing agent provided by Jinan Hongtai Chemical Co., Ltd., model 0007, and the rest was the same as Example 1. The specific steps are as follows: Step one: 27 g of 1,7-dibromoheptane, 10 g of cyanophenol, 12 g of cetyl alcohol were added to 30 g of acetonitrile, then 10 g of potassium carbonate aqueous solution was added, and the reaction was carried out at 90°C for 10 h. Then vacuum filtration, washing and drying were carried out to obtain an intermediate product. The prepared intermediate product and 11 g of 1-ethyl-2-methylimidazole were refluxed in 10 g of acetonitrile, and the reaction was carried out at 90°C for 8 h. After the reaction was completed, vacuum filtration and drying were carried out to prepare a nucleating agent. 3 g of cellulose and 65 g of N,N-dimethylacetamide were mixed, stirred and activated at 140°C for 4 h, then cooled to 110°C, and 7 g of lithium chloride was added and stirred for 20 min to obtain a cellulose solution. The prepared nucleating agent was added to 60 g of the cellulose solution, stirred and dissolved, and then degassed at 80°C to obtain a spinning solution. The spinning solution was extruded through a spinning nozzle to prepare a modified fiber. 5 g of the modified fiber, 15 g of polypropylene fiber and 15 g of steel fiber were physically mixed to obtain a high-strength fiber.

[0055] Step two: 10 g of silane coupling agent KH550 was added dropwise to 100 g of deionized water, and ultrasonic oscillation was carried out for 50 min to obtain solution 3. Then 2 g of nano titanium dioxide was added to 100 g of ethyl acetate, and ultrasonic oscillation was carried out for 50 min to obtain solution 4. Solution 3 and solution 4 were mixed, and the reaction was carried out at 90°C for 8 h. Then centrifugation, washing, drying and grinding were carried out to prepare modified nano titanium dioxide. 0.2 g of modified nano titanium dioxide was added to 100 g of deionized water, and stirred to obtain a mixture. The high-strength fiber was immersed in the mixture, stirred at 30°C for 25 h, and then dried to obtain a composite fiber.

[0056] Step three: 250 g of cement, 150 g of slag powder, 1 g of silane coupling agent YDH171, 1000 g of coarse aggregate, 2 g of polycarboxylic acid water reducing agent with model 0007, 30 g of composite fiber and 130 g of water were mixed to obtain a mixture. The mixture was molded and cured to prepare a finished product.

[0057] Test experiment:

[0058] Splitting tensile strength test: According to GB / T 50081-2019 "Standard for testing methods of physical and mechanical properties of concrete", the mixture prepared in the application was molded and cured to obtain a 150 mm x 150 mm x 150 mm cube specimen. The specimen was tested by adding load using a pressure testing machine, the loading speed was 0.05 MPa / s, the failure load was recorded, and then the data was substituted into the formula to calculate the splitting tensile strength.

[0059] Compressive strength test: according to GB / T 50081-2019 "Standard for test methods of physical and mechanical properties of concrete", the mixture prepared by the application is molded and cured to obtain a 150mmx150mmx150mm cube specimen. The pressure testing machine is used to test the load of the specimen, the loading speed is 0.5MPa / s, the failure load is recorded, and then the data is substituted into the formula to calculate the compressive strength. The results are as follows:

[0060] Flexural strength / MPa Compressive strength / MPa Example 1 6.35 49.8 Example 2 6.34 49.7 Example 3 6.33 49.7 Example 4 6.32 49.6 Example 5 6.31 49.6 Comparative Example 1 5.39 42.3 Comparative Example 2 5.84 45.8

[0061] Conclusion: the dosage of examples 1-5 remains unchanged, only the reaction parameters are modified. According to the experimental data, the performance of the concrete does not change significantly. Comparative example 1: remove the preparation steps of the composite fiber, and the rest is the same as example 1. According to the experimental data, compared with example 1, the splitting tensile strength is reduced to 5.39MPa, and the compressive strength is reduced to 42.3MPa. The analysis reason is: removing the preparation steps of the composite fiber, on the one hand, it will lose three kinds of high-strength fibers, which will lead to the decrease of the strength of the concrete; on the other hand, the preparation of the fiber nucleating agent and the modification of the nano-titanium dioxide will also be removed, so the anti-aging performance of the concrete will be reduced, and therefore the strength of the concrete will decrease.

[0062] Comparative example 2: replace the polycarboxylic acid water reducer prepared by the application with a commercially available polycarboxylic acid water reducer of type 0007, and the rest is the same as example 1. According to the experimental data, compared with example 1, the splitting tensile strength is reduced to 5.84MPa, and the compressive strength is reduced to 45.8MPa. The analysis reason is: the polycarboxylic acid water reducer prepared by the application has a multi-branch structure and sulfonic acid groups and carboxyl groups, so the prepared water reducing agent has good dispersibility and water reducing effect, which can effectively improve the mechanical properties of the concrete. Therefore, replacing the polycarboxylic acid water reducer prepared by the application with a commercially available polycarboxylic acid water reducer will reduce the splitting tensile strength and the compressive strength.

[0063] It should be noted that in this paper, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process method article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process method article or equipment.

[0064] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalent ones. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A process for preparing high-strength concrete, characterized in that: Includes the following steps: Step 1: Add 1,7-dibromoheptane, cyanobiphenol, and hexadecyl alcohol to 3 / 4 of the mass of acetonitrile, then add potassium carbonate aqueous solution, react at 70-90℃ for 8-10 h, then vacuum filter, wash, and dry to obtain an intermediate product; then reflux the intermediate product and 1-ethyl-2-methylimidazol in 1 / 4 of the mass of acetonitrile, reflux at 70-90℃ for 6-8 h, after the reaction is completed, vacuum filter and dry to prepare a nucleating agent; add the nucleating agent to a cellulose solution, stir to dissolve, and then degas at 70-80℃ to obtain a spinning solution; extrude the spinning solution by spinning to prepare modified fibers; High-strength fibers are obtained by physically mixing modified fibers, polypropylene fibers, and steel fibers. Modified nano-titanium dioxide was added to deionized water and stirred thoroughly to obtain a mixture; then high-strength fibers were impregnated in the mixture and stirred at 25-30℃ for 20-25 hours, and then dried to obtain composite fibers; Step 2: Under nitrogen atmosphere, methyl allyl polyoxyethylene ether and pyromellitic acid are mixed, and 1 / 2 part by mass of p-toluenesulfonic acid catalyst is added. The mixture is then subjected to esterification reaction at 100-130℃ for 6-8 hours. After the reaction is completed, methoxy polyethylene glycol and 1 / 2 part by mass of p-toluenesulfonic acid catalyst are added, and the mixture is subjected to esterification reaction at 100-130℃ for 6-8 hours to prepare the water-reducing agent macromolecule. A water-reducing agent macromolecule, methacrylic acid, and ammonium persulfate were mixed to obtain solution 1; sodium methacrylate sulfonate and sodium 2-acrylamido-2-methylpropyl sulfonate were dissolved in distilled water to obtain solution 2; solution 1 was slowly added dropwise to solution 2 at 80-90℃ for 3-4 hours, and the reaction was maintained at this temperature for 4-6 hours. After the reaction was completed, sodium hydroxide solution was added to adjust the pH to 7-8 to prepare the polycarboxylate water-reducing agent. Step 3: Mix cement, slag powder, silane coupling agent YDH171, coarse aggregate, polycarboxylate superplasticizer, composite fiber and water to obtain a mixture. Then, mold and cure the mixture to obtain the finished product.

2. The preparation process of high-strength concrete according to claim 1, characterized in that: In step one, the content of each component in the spinning solution is as follows (by mass): 25-30 parts 1,7-dibromoheptane, 10-15 parts cyanobiphenyl, 12-15 parts hexadecyl alcohol, 40-60 parts acetonitrile, 10-15 parts potassium carbonate aqueous solution, 11-15 parts 1-ethyl-2-methylimidazolium, and 60-70 parts cellulose solution; the mass ratio of modified fiber, polypropylene fiber, and steel fiber in the high-strength fiber is 1-1.5:3:3; the mass ratio of modified nano-titanium dioxide and deionized water in the mixed solution is 0.2-0.4:

100.

3. The preparation process of high-strength concrete according to claim 1, characterized in that: In step one, the cellulose solution is prepared by mixing cellulose and N,N-dimethylacetamide, stirring and activating at 120-140℃ for 2-4 hours, then cooling to 100-110℃, adding lithium chloride and stirring for 10-20 minutes to obtain the cellulose solution.

4. The preparation process of high-strength concrete according to claim 3, characterized in that: The components of the cellulose solution are as follows (by mass): 3-5 parts cellulose, 65-80 parts N,N-dimethylacetamide, and 7-10 parts lithium chloride.

5. The preparation process of high-strength concrete according to claim 1, characterized in that: In step one, the modified nano-titanium dioxide is prepared by adding silane coupling agent KH550 dropwise to deionized water and ultrasonically vibrating for 30-50 minutes to obtain solution 3. Then, nano-titanium dioxide was added to ethyl acetate and ultrasonically vibrated for 30-50 min to obtain solution 4. Solution 3 and solution 4 were mixed and refluxed at 80-90℃ for 6-8 h. After centrifugation, washing, drying and grinding, modified nano-titanium dioxide was prepared.

6. The preparation process of high-strength concrete according to claim 5, characterized in that: The content of each component of the modified nano-titanium dioxide is as follows (by mass): 10-15 parts silane coupling agent KH550, 100-120 parts deionized water, 2-3 parts nano-titanium dioxide, and 100-120 parts ethyl acetate.

7. The preparation process of high-strength concrete according to claim 1, characterized in that: The content of each component of the water-reducing agent macromolecule is as follows, by mass parts: 10-20 parts methyl allyl polyoxyethylene ether, 35-40 parts pyromellitic acid, 2.0-3.6 parts catalyst p-toluenesulfonic acid, and 40-60 parts methoxy polyethylene glycol.

8. The preparation process of high-strength concrete according to claim 1, characterized in that: In step two, the mass ratio of the water-reducing agent macromolecule, methacrylic acid, sodium methacrylate sulfonate, and sodium 2-acrylamido-2-methylpropyl sulfonate is 70:5-7:3:5; the amount of ammonium persulfate is 6.5-7.5% of the mass of the water-reducing agent macromolecule.

9. The preparation process of high-strength concrete according to claim 1, characterized in that: In step three, the content of each component in the mixture is as follows (by mass): 250-300 parts cement, 150-180 parts slag powder, 1-3 parts silane coupling agent YDH171, 1000-1200 parts coarse aggregate, 2-5 parts polycarboxylate superplasticizer, 30-50 parts composite fiber, and 130-150 parts water.