High-impermeability concrete material and preparation method thereof

Abstract

The invention discloses a high-impermeability concrete material and a preparation method thereof, and belongs to the technical field of concrete materials, and the high-impermeability concrete material specifically comprises the following components in parts by weight: 80-100 parts of stones, 40-60 parts of quartz sand, 25-35 parts of cement, 8-12 parts of an impermeability reinforcing material, 3-5 parts of sodium carboxymethyl cellulose, 1.5-1.8 parts of an additive and 25-30 parts of water. The Portland pozzolana cement concrete is reinforced through mutual cooperation of sodium carboxymethyl cellulose and an anti-permeability reinforcing material, so that the compressive strength and the water permeability resistance of the cement concrete are effectively improved, the corrosion resistance of chloride ions and sulfate is improved, and the service life of the cement concrete in a high-ion environment is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete materials, and particularly relates to a high impermeable concrete material and a preparation method thereof. Background Art

[0002] In the field of construction engineering, as the most commonly used structural material, the impermeability of concrete directly affects the durability, safety and service life of the structure. With the development of modern engineering towards super high-rise, long-span and complex environments (such as marine engineering, underground engineering), concrete materials face more stringent service conditions.

[0003] In the prior art, a patent for invention with the publication number of CN114133187A discloses a crack-resistant and impermeable concrete, which includes 200 - 300 parts of cement, 60 - 100 parts of mineral powder, 30 - 50 parts of fly ash, 150 - 170 parts of water, 880 - 960 parts of sand, 900 - 980 parts of stone, 7 - 12 parts of water reducer, and 0.9 - 1.5 parts of crack-resistant and impermeable enhancer. It uses plasma gas and graphene to modify polypropylene fibers, and the prepared concrete has strong crack-resistant and impermeable properties and has good application prospects.

[0004] The above patent content mainly uses graphene to modify polypropylene fibers, making graphene adhere to the polypropylene fibers to improve the interfacial force in concrete, and then uses chitosan quaternary ammonium salt to treat the graphene-modified polypropylene fibers to improve their water solubility and dispersibility, and improve the crack-resistant and impermeable properties of concrete mixed with polypropylene fibers;

[0005] However, during the hardening process of traditional concrete, capillary pores are formed due to water evaporation, becoming a fast channel for ion intrusion. Chloride ions will penetrate the concrete protective layer to reach the surface of the steel bars, destroy the passivation film on the surface of the steel bars, form local activation areas, and trigger electrochemical corrosion. Sulfate reacts with calcium hydroxide in the cement stone to form gypsum, which further reacts with calcium silicate hydrate to form ettringite, resulting in volume expansion of the concrete material and generating a microcrack network inside the concrete. Currently, under harsh service conditions such as marine environments, deicing salt roads, and chemically corrosive industrial sites, concrete materials are long-term exposed to the erosion of chloride ions and sulfate ions, leading to volume expansion, cracking and degradation of mechanical properties of the concrete, and seriously shortening the engineering life. Summary of the Invention

[0006] The purpose of the present invention is to provide a high impermeable concrete material and a preparation method thereof, which are used to solve the technical problems that the anti-ion penetration performance of cement concrete materials in the prior art needs to be further improved, and the service life of cement concrete materials needs to be further improved.

[0007] The object of the present invention can be achieved by the following technical solutions: A highly impermeable concrete material, comprising the following components by weight: 80-100 parts of stones, 40-60 parts of quartz sand, 25-35 parts of cement, 8-12 parts of impermeability enhancer, 3-5 parts of sodium carboxymethyl cellulose, 1.5-1.8 parts of admixture, and 25-30 parts of water;

[0008] The admixture is composed of a water reducing agent and an air entraining agent in a weight ratio of 3:2.

[0009] Furthermore, the impermeability enhancer is obtained by the following steps:

[0010] A1. Mix hydrophilic modified PVP and N,N-dimethylformamide, raise the temperature of the reaction system to 70-80 °C, stir until the system becomes clear, add isocyanatopropyltriethoxysilane to the reaction system, keep the temperature for reaction for 40-60 min, add inorganic enhancer to the reaction system, keep the temperature and stir for 30-50 min, and gradually lower the temperature of the reaction system to room temperature to obtain a mixed solution;

[0011] A2. Under the condition of high-speed stirring, slowly add the mixed solution to the ethanol dispersion, stir and disperse at room temperature for 60-80 min, and perform post-treatment to obtain the impermeability enhancer.

[0012] The synthesis reaction formula of the impermeability enhancer is:

[0013]

[0014] The synthesis reaction mechanism of the impermeability enhancer is:

[0015] During the reaction process, after promoting the dissolution of water-modified PVP by an organic solvent, the amide bond on the hydrophilic modified PVP molecule reacts with the isocyanate group on the isocyanatopropyltriethoxysilane molecule to form a triethoxysilane modification on the hydrophilic modified PVP molecule. Then it is mixed with the inorganic enhancer to promote the fusion of hydrophilic modified PVP and the inorganic enhancer. Then when it is added to the ethanol dispersion, the hydrophilic modified PVP rapidly precipitates on the inorganic enhancer to form an organic coating. At the same time, under the action of an alkaline aqueous solution as a catalyst, the triethoxysilane modified on the hydrophilic modified PVP molecule is hydrolyzed to form silanol and bond with the active functional groups on the surface of the inorganic enhancer, and the impermeability enhancer is prepared.

[0016] Further, in step A1, the dosage ratio of the hydrophilic modified PVP, N,N-dimethylformamide, isocyanatopropyltriethoxysilane and inorganic reinforcing material is 7 g: 40 mL: 2 g: 10 g; in step A2, the dosage ratio of the mixed solution to the ethanol dispersion is 1 g: 5 mL, and the ethanol dispersion is composed of absolute ethanol, 10 wt% sodium hydroxide aqueous solution and polyethylene glycol 800 in a ratio of 40 mL: 9 mL: 1 g. The post-treatment includes: after the reaction is completed, suction filtration is carried out, the filter cake is washed 3 times with absolute ethanol and then dried by suction, the filter cake is transferred to a drying oven at a temperature of 50-60 °C and dried to a constant weight to obtain the anti-seepage reinforcing material.

[0017] Further, the inorganic reinforcing material is composed of calcium magnesium carbonate, sodium sulfate, sodium silicate and supported biomass powder in a weight ratio of 3: 2: 2: 4.

[0018] Further, the preparation method of the hydrophilic modified PVP is as follows: polyvinylpyrrolidone and deionized water are mixed, the temperature of the reaction system is raised to 70-80 °C, stirred until the system is clear, acrylamide and 2-acrylamido-2-methylpropanesulfonic acid sodium salt are added to the reaction system, stirred for 10-20 min, an initiator is added dropwise to the reaction system, and the reaction is carried out under insulation for 4-6 h, followed by post-treatment to obtain the hydrophilic modified PVP.

[0019] The synthesis reaction formula of the hydrophilic modified PVP is:

[0020]

[0021] The synthesis reaction mechanism of the hydrophilic modified PVP is:

[0022] During the reaction process, under the action of heating and a free radical initiator, the polyvinylpyrrolidone molecular chain is attacked by sulfate radicals to form macromolecular radicals on the polyvinylpyrrolidone molecular chain. The olefin double bonds on the acrylamide and 2-acrylamido-2-methylpropanesulfonic acid sodium salt molecules are attacked by sulfate radicals to form active radicals on the molecules, which undergo a free radical condensation reaction with the radicals on the polyvinylpyrrolidone molecular chain to prepare the hydrophilic modified PVP with an amide bond and a sulfonate-modified PVP molecular chain.

[0023] Further, the dosage ratio of the polyvinylpyrrolidone, deionized water, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid sodium salt and initiator is 2 g: 15 mL: 1 g: 5 g: 5 mL, and the initiator is composed of potassium persulfate and deionized water in a ratio of 1 g: 10 mL. The post-treatment includes: after the reaction is completed, the temperature of the reaction system is kept at 70-80 °C, and low-boiling substances are removed by reduced pressure evaporation to obtain the hydrophilic modified PVP.

[0024] Further, the supported biomass powder is processed by the following steps:

[0025] B1. Crush the corncob and sieve it through a 10-mesh sieve to obtain corncob powder;

[0026] B2. Mix the corncob powder with the activation solution, raise the temperature of the reaction system to the reflux temperature of the system, keep it warm for 16 - 18 h, and perform post-treatment to obtain activated corncob powder;

[0027] B3. Mix sodium hexametaphosphate, disodium ethylenediaminetetraacetate and purified water, raise the temperature of the reaction system to 50 - 60 °C, keep stirring until the system becomes clear, add the activated corncob powder to the reaction system, stir and disperse for 30 - 50 min, and perform post-treatment to obtain the supported biomass powder.

[0028] The synthesis reaction mechanism of the supported biomass powder is as follows:

[0029] During the reaction process, sodium hydroxide provides a strong alkaline environment, which destroys the ester bonds and ether bonds of lignin and hemicellulose in the corncob, promotes the depolymerization of macromolecules, exposes the cellulose microcrystalline structure. In the alkaline environment, hydrogen peroxide decomposes into HOO - and HO2 - , and urea acts as a hydrogen bond breaker, promoting the swelling of cellulose, synergistically enhancing the delignification effect with H2O2, increasing the porosity and the density of surface oxygen-containing functional groups of the activated corncob powder, providing anchor sites for subsequent loading;

[0030] By dissolving sodium hexametaphosphate and disodium ethylenediaminetetraacetate and then mixing them with the activated corncob powder, after stirring and dispersing, it promotes the combination of free sodium hexametaphosphate and disodium ethylenediaminetetraacetate with the corncob powder. After vacuum concentration, the induced hydrophobic effect of ethanol promotes the precipitation and fixation of the loaded substances, loading sodium hexametaphosphate and disodium ethylenediaminetetraacetate on the corncob powder to prepare the supported biomass powder.

[0031] Furthermore, the dosage ratio of the corncob powder to the activation solution is 1 g:20 mL. The activation solution is composed of 6 - 8 wt% sodium hydroxide aqueous solution, 20 wt% hydrogen peroxide solution, urea and sodium dodecyl sulfate in a ratio of 50 mL:10 mL:2 g:0.3 g. The post-treatment includes: after the reaction is completed, lower the temperature of the reaction system to room temperature, perform suction filtration, wash the filter cake with purified water until it is neutral and then drain it, transfer the filter cake to an oven at 70 - 80 °C, and vacuum dry it to constant weight to obtain the activated corncob powder; in step B3, the dosage ratio of sodium hexametaphosphate, disodium ethylenediaminetetraacetate, purified water and the activated corncob powder is 1.2 g:1.8 g:25 mL:8 g. The post-treatment includes: after the reaction is completed, raise the temperature of the reaction system to 60 - 70 °C and reduce the pressure to collect at least a small amount of solution, add absolute ethanol to the reaction system, keep stirring for 20 - 30 min, and reduce the pressure to remove the low-boiling substances to obtain the supported biomass powder.

[0032] The present invention also provides a method for preparing a highly impermeable concrete material, comprising the following steps:

[0033] S1. Mix gravel, quartz sand, cement, impermeability enhancer, sodium carboxymethyl cellulose, and admixture evenly, add water to the mixed system, and stir for 15 - 20 min to obtain concrete mortar;

[0034] S2. Pour the concrete mortar into a mold and cure for 15 days to obtain the concrete material.

[0035] Further, the particle size of the gravel is 5 - 25 mm, the particle size of the quartz sand is 0.2 - 3 mm, and the cement is pozzolanic Portland cement.

[0036] The present invention has the following beneficial effects:

[0037] 1. For the highly impermeable concrete material of the present invention, through the mutual cooperation of sodium carboxymethyl cellulose and the impermeability enhancer, the thickening and water retention characteristics of sodium carboxymethyl cellulose ensure the full progress of the hydration reaction, reduce the pores caused by bleeding, improve the early strength, and the rigid filling of the impermeability enhancer and the water retention effect of sodium carboxymethyl cellulose jointly optimize the pore structure, construct an anti-seepage and strengthening system in the pozzolanic Portland cement concrete, enhance the anti-ion permeability and compressive performance of the concrete material, and effectively extend the service life of the cement concrete in a high-ion environment.

[0038] 2. The high impermeable concrete material of the present invention uses corn cob powder as raw material. After activation, it is loaded with sodium hexametaphosphate and disodium ethylenediaminetetraacetate to prepare a supported biomass powder. The porous structure and cellulose network of the activated corn cob can extend the migration path of ions and hinder ion diffusion. Moreover, the activated corn cob cellulose forms a porous skeleton structure, and its microfibers can be used as a reinforcing phase after being dispersed in the concrete. By bridging cracks, it can inhibit crack propagation, improve the toughness and crack resistance of the concrete. Additionally, the sodium hexametaphosphate loaded on the activated corn powder can act as a dispersant, improve the dispersibility of cement particles, reduce agglomeration, promote the uniform progress of the hydration reaction, increase the density, and thus improve its compressive strength. The phosphate groups on the sodium hexametaphosphate molecules combine with chloride ions through electrostatic adsorption to form a stable complex, reducing the concentration of free chlorine. The carboxylic acid groups on the disodium ethylenediaminetetraacetate molecules have competitive repulsion for chloride ions, further reducing the amount of migratable chloride ions. Through the dual mechanisms of physical barrier and chemical adsorption, the chloride ion diffusion is significantly reduced. The micron-scale fibers of the activated corn cob and the supported phosphate / disodium ethylenediaminetetraacetate nanoparticles hierarchically fill the capillary pores of the concrete, reduce the pore connectivity, and improve its water penetration resistance. The chelating effect of disodium ethylenediaminetetraacetate will combine with calcium ions, reduce the reaction of sulfate with the calcium hydroxide produced by cement hydration to form gypsum and ettringite, and inhibit the expansive damage. The passivation effect of sodium hexametaphosphate forms a phosphate protective layer on the surface of cement particles, slowing down the erosion rate of sulfate ions. And the active SiO2 and Al2O3 in the pozzolanic Portland cement react with sulfate to form stable calcium silicate and calcium aluminate. The supported biomass powder enhances the efficiency of this process by optimizing the pore structure and improves its sulfate resistance performance.

[0039] 3. The high impermeable concrete material of the present invention consists of an inorganic reinforcing material composed of calcium magnesium carbonate, sodium sulfate, sodium silicate and a supported biomass powder, and then hydrophilic modified PVP is modified on its outer surface. The grafted acrylamide and sulfonic acid groups on the PVP enhance the hydrogen bond binding between the impermeability reinforcing material and cement particles, improve the interfacial compatibility between the inorganic reinforcing material and the cement matrix, and make it easier to be uniformly dispersed in the cement concrete. Calcium magnesium carbonate gradually decomposes in the alkaline environment of the cement to generate micro-nano particles of calcium carbonate and magnesium hydroxide to fill the concrete pores, increasing the density. The gelling properties of magnesium hydroxide and sodium silicate participate in the cement hydration reaction, promote the secondary hydration of the pozzolanic cement, increase the content of the gelling phase, optimize the microstructure, and enhance the matrix strength. Moreover, the silicic acid gel generated by sodium silicate blocks the capillary pores, reducing the pore connectivity. The sulfonic acid groups modified on the hydrophilic modified PVP molecules hinder the migration of chloride ions through electrostatic repulsion. At the same time, the hydrophilic network constructed by the hydrophilic modified PVP and the activated corn cob powder binds water through hydrogen bonds, reducing the content of free water, and forms a physical barrier through the interweaving of the cellulose of the corn cob powder and the hydrophilic PVP, extending the penetration path, and improving the water and ion penetration resistance effect of the concrete material. Detailed implementation manners

[0040] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] In this application, calcium magnesium carbonate is selected from Shijiazhuang Yitian Mineral Products Co., Ltd., with a density of 2.86 g / cm 3 , and the mesh number is 325;

[0042] In this application, polyvinylpyrrolidone is selected from Leshengyuan Biotechnology (Nanjing) Co., Ltd., with an active ingredient content of 99%, and the property is dry powder;

[0043] In this application, the CAS number of sodium carboxymethyl cellulose is 9004-32-4;

[0044] In this application, the naphthalene sulfonate water reducer is sodium poly(naphthalene formaldehyde sulfonate), and the CAS number is 9084-06-4;

[0045] In this application, the sodium rosinate air-entraining agent is selected from Wanhua New Materials, with the property of powdery solid and the CAS number of 14351-66-7.

[0046] Example 1

[0047] This example provides a preparation method of an anti-seepage and strengthening material for high anti-seepage concrete materials, including the following steps:

[0048] A1. Preparation of supported biomass powder

[0049] The corncob is crushed and sieved through a 10-mesh sieve to obtain corncob powder;

[0050] A 6 wt% sodium hydroxide aqueous solution, a 20 wt% hydrogen peroxide solution, urea and sodium dodecyl sulfate are mixed evenly in a ratio of 50 mL:10 mL:2 g:0.3 g to obtain an activation solution for standby;

[0051] Weigh: 100 g of corncob powder and 2000 mL of activation solution are added to a 5 L reaction flask and stirred. The temperature of the reaction flask is raised to the system reflux, kept warm and stirred for 16 h. The temperature of the reaction flask is lowered to room temperature, filtered by suction. The filter cake is washed with purified water until neutral and then dried by suction. The filter cake is transferred to a drying oven at 70 °C and vacuum dried to constant weight to obtain activated corncob powder;

[0052] Weigh: 12 g of sodium hexametaphosphate, 18 g of disodium ethylenediaminetetraacetate and 250 mL of purified water are added to a 1 L reaction flask and stirred. The temperature of the reaction flask is raised to 50 °C, and it is kept warm and stirred until the system becomes clear. 80 g of activated corncob powder is added to the reaction flask, and it is stirred and dispersed for 30 min. The temperature of the reaction flask is raised to 60 °C, and the negative pressure is pumped to 0.1 MPa. The pressure is reduced until a small amount of solution is collected. 500 mL of absolute ethanol is added to the reaction flask, and it is kept warm and stirred for 20 min. The reaction flask is pumped to a negative pressure of 0.1 MPa, and the low-boiling substances are removed by reduced pressure to obtain the supported biomass powder.

[0053] A2. Preparation of inorganic reinforcing material

[0054] Mix magnesium calcium carbonate, sodium sulfate, sodium silicate and supported biomass powder evenly according to the weight ratio of 3:2:2:4 to obtain the inorganic reinforcing material.

[0055] A3. Preparation of hydrophilic modified PVP

[0056] Mix potassium persulfate and deionized water at 1 g:10 mL and stir until the system becomes clear to obtain the initiator;

[0057] Weigh: 20 g of polyvinylpyrrolidone and 150 mL of deionized water are added to a 1 L reaction flask and stirred. The temperature of the reaction flask is raised to 70 °C, and it is stirred until the system becomes clear. 10 g of acrylamide and 50 g of 2-acrylamido-2-methylpropanesulfonic acid sodium salt are added to the reaction flask, and it is stirred for 10 min. 50 mL of the initiator is added dropwise to the reaction flask, and it is kept warm and reacted for 4 h. The temperature of the reaction flask is kept at 70 °C, and the reaction flask is pumped to a negative pressure of 0.1 MPa. The low-boiling substances are removed by reduced pressure to obtain the hydrophilic modified PVP.

[0058] A4. Preparation of anti-seepage reinforcing material

[0059] Weigh: 70 g of hydrophilic modified PVP and 400 mL of N,N-dimethylformamide are added to a 1 L reaction flask and stirred. The temperature of the reaction flask is raised to 70 °C, and it is stirred until the system becomes clear. 20 g of isocyanatopropyltriethoxysilane is added to the reaction flask, and it is kept warm and reacted for 40 min. 100 g of the inorganic reinforcing material is added to the reaction flask, and it is kept warm and stirred for 30 min. The temperature of the reaction system is gradually reduced to room temperature to obtain the mixed solution;

[0060] Mix absolute ethanol, 10 wt% sodium hydroxide aqueous solution and polyethylene glycol 800 evenly according to 40 mL:9 mL:1 g to obtain the ethanol dispersion;

[0061] Add 3 L of ethanol dispersion to a 5 L reaction flask, set the stirring speed to 1000 r / min, slowly add 600 g of the mixed solution to the reaction flask, stir and disperse for 60 min at room temperature, perform suction filtration, wash the filter cake 3 times with absolute ethanol and then drain it, transfer the filter cake to a drying oven at 50 °C, and dry it to a constant weight to obtain the anti-seepage enhancing material.

[0062] Example 2

[0063] This example provides a preparation method of an anti-seepage enhancing material for high anti-seepage concrete materials, including the following steps:

[0064] A1. Prepare the supported biomass powder

[0065] Crush the corncobs and sieve them through a 10-mesh sieve to obtain corncob powder;

[0066] Mix 7 wt% sodium hydroxide aqueous solution, 20 wt% hydrogen peroxide solution, urea and sodium dodecyl sulfate in a ratio of 50 mL: 10 mL: 2 g: 0.3 g evenly to obtain the activation solution for standby;

[0067] Weigh: Add 100 g of corncob powder and 2000 mL of the activation solution to a 5 L reaction flask and stir. Raise the temperature of the reaction flask to the system reflux temperature, keep stirring for 17 h, lower the temperature of the reaction flask to room temperature, perform suction filtration, wash the filter cake with purified water until neutral and then drain it, transfer the filter cake to a drying oven at 75 °C, and vacuum dry it to a constant weight to obtain the activated corncob powder;

[0068] Weigh: Add 12 g of sodium hexametaphosphate, 18 g of disodium ethylenediaminetetraacetate and 250 mL of purified water to a 1 L reaction flask and stir. Raise the temperature of the reaction flask to 55 °C, keep stirring until the system is clear, add 80 g of the activated corncob powder to the reaction flask, stir and disperse for 40 min, raise the temperature of the reaction flask to 65 °C, draw a negative pressure until the negative pressure is 0.1 MPa, reduce the pressure until a small amount of solution is taken out, add 500 mL of absolute ethanol to the reaction flask, keep stirring for 25 min, draw a negative pressure in the reaction flask until the negative pressure is 0.1 MPa, reduce the pressure to remove the low-boiling substances to obtain the supported biomass powder.

[0069] A2. Prepare the inorganic reinforcing material

[0070] Mix calcium magnesium carbonate, sodium sulfate, sodium silicate and the supported biomass powder evenly according to the weight ratio of 3: 2: 2: 4 to obtain the inorganic reinforcing material.

[0071] A3. Prepare the hydrophilic modified PVP

[0072] Mix potassium persulfate and deionized water in a ratio of 1 g: 10 mL and stir until the system is clear to obtain the initiator;

[0073] Weigh: 20 g of polyvinylpyrrolidone and 150 mL of deionized water are added to a 1 L reaction flask and stirred. The temperature of the reaction flask is raised to 75 °C, and stirring is continued until the system becomes clear. Then, 10 g of acrylamide and 50 g of 2-acrylamido-2-methylpropanesulfonic acid sodium salt are added to the reaction flask, and stirring is carried out for 15 min. Next, 50 mL of initiator is added dropwise to the reaction flask, and the reaction is carried out under insulation for 5 h while maintaining the temperature of the reaction flask at 75 °C. The pressure in the reaction flask is reduced to a negative pressure of 0.1 MPa, and low-boiling substances are removed by vacuum distillation to obtain hydrophilically modified PVP.

[0074] A4. Preparation of anti-seepage and strengthening material

[0075] Weigh: 70 g of hydrophilically modified PVP and 400 mL of N,N-dimethylformamide are added to a 1 L reaction flask and stirred. The temperature of the reaction flask is raised to 75 °C, and stirring is continued until the system becomes clear. Then, 20 g of isocyanatopropyltriethoxysilane is added to the reaction flask, and the reaction is carried out under insulation for 50 min. Next, 100 g of inorganic strengthening material is added to the reaction flask, and stirring is carried out under insulation for 40 min. The temperature of the reaction system is gradually reduced to room temperature to obtain a mixed solution.

[0076] Mix anhydrous ethanol, 10 wt% sodium hydroxide aqueous solution, and polyethylene glycol 800 in a ratio of 40 mL: 9 mL: 1 g to obtain an ethanol dispersion.

[0077] Add 3 L of ethanol dispersion to a 5 L reaction flask, set the stirring speed to 1000 r / min, and slowly add 600 g of the mixed solution to the reaction flask. Stir and disperse at room temperature for 70 min, then filter. The filter cake is washed 3 times with anhydrous ethanol and then dried by suction. The filter cake is transferred to a drying oven at 55 °C and dried to a constant weight to obtain the anti-seepage and strengthening material.

[0078] Example 3

[0079] This example provides a preparation method of an anti-seepage and strengthening material for high anti-seepage concrete materials, including the following steps:

[0080] A1. Preparation of supported biomass powder

[0081] Crush corn cobs and pass them through a 10-mesh sieve to obtain corn cob powder.

[0082] Mix 8 wt% sodium hydroxide aqueous solution, 20 wt% hydrogen peroxide solution, urea, and sodium dodecyl sulfate in a ratio of 50 mL: 10 mL: 2 g: 0.3 g to obtain an activation solution for standby.

[0083] Weigh: Add 100 g of corncob powder and 2000 mL of activation solution into a 5 L reaction flask and stir. Raise the temperature of the reaction flask to the reflux temperature of the system, keep stirring for 18 h, then lower the temperature of the reaction flask to room temperature, filter by suction. Wash the filter cake with purified water until neutral and then drain it by suction. Transfer the filter cake to a drying oven at 80 °C and dry it under vacuum until constant weight to obtain activated corncob powder;

[0084] Weigh: Add 12 g of sodium hexametaphosphate, 18 g of disodium ethylenediaminetetraacetate and 250 mL of purified water into a 1 L reaction flask and stir. Raise the temperature of the reaction flask to 60 °C and keep stirring until the system becomes clear. Add 80 g of activated corncob powder into the reaction flask, stir and disperse for 50 min. Raise the temperature of the reaction flask to 70 °C, draw a negative pressure until the negative pressure is 0.1 MPa, reduce the pressure until a small amount of solution is collected. Add 500 mL of absolute ethanol into the reaction flask, keep stirring for 30 min. Draw a negative pressure in the reaction flask until the negative pressure is 0.1 MPa, reduce the pressure to remove the low-boiling substances to obtain the supported biomass powder.

[0085] A2. Preparation of inorganic reinforcing material

[0086] Mix magnesium calcium carbonate, sodium sulfate, sodium silicate and supported biomass powder evenly according to the weight ratio of 3:2:2:4 to obtain the inorganic reinforcing material.

[0087] A3. Preparation of hydrophilic modified PVP

[0088] Mix potassium persulfate and deionized water at a ratio of 1 g:10 mL and stir until the system becomes clear to obtain the initiator;

[0089] Weigh: Add 20 g of polyvinylpyrrolidone and 150 mL of deionized water into a 1 L reaction flask and stir. Raise the temperature of the reaction flask to 80 °C and stir until the system becomes clear. Add 10 g of acrylamide and 50 g of 2-acrylamido-2-methylpropanesulfonic acid sodium salt into the reaction flask, stir for 20 min. Add 50 mL of the dropped initiator into the reaction flask, keep the reaction at 80 °C for 6 h. Keep the temperature of the reaction flask at 80 °C, draw a negative pressure in the reaction flask until the negative pressure is 0.1 MPa, reduce the pressure to remove the low-boiling substances to obtain the hydrophilic modified PVP.

[0090] A4. Preparation of anti-seepage reinforcing material

[0091] Weigh: Add 70 g of hydrophilic modified PVP and 400 mL of N,N-dimethylformamide into a 1 L reaction flask and stir. Raise the temperature of the reaction flask to 80 °C and stir until the system becomes clear. Add 20 g of isocyanatopropyltriethoxysilane into the reaction flask, keep the reaction for 60 min. Add 100 g of inorganic reinforcing material into the reaction flask, keep stirring for 50 min. Gradually lower the temperature of the reaction system to room temperature to obtain the mixed solution;

[0092] Mix absolute ethanol, 10wt% sodium hydroxide aqueous solution and polyethylene glycol 800 evenly at a ratio of 40 mL: 9 mL: 1 g to obtain an ethanol dispersion;

[0093] Add 3 L of the ethanol dispersion to a 5 L reaction flask, set the stirring speed to 1000 r / min, slowly add 600 g of the mixed solution to the reaction flask, stir and disperse for 80 min at room temperature, perform suction filtration, wash the filter cake 3 times with absolute ethanol and then drain it, transfer the filter cake to a drying oven at 60 °C and dry to constant weight to obtain an anti-seepage strengthening material.

[0094] Example 4

[0095] This example provides a method for preparing a high anti-seepage concrete material, which includes the following steps:

[0096] S1. Prepare concrete mortar

[0097] Mix naphthalene sulfonate water reducer and rosin sodium air-entraining agent evenly at a weight ratio of 3:2 to obtain an admixture;

[0098] Weigh by weight: 80 parts of stones with a particle size of 5 - 25 mm, 40 parts of quartz sand with a particle size of 0.2 - 3 mm, 25 parts of portland pozzolan cement, 8 parts of the anti-seepage strengthening material prepared in Example 1, 3 parts of sodium carboxymethylcellulose, and 1.5 parts of the admixture, add them to a concrete mixer, mix for 5 min, add 25 parts of drinking water to the concrete mixer, and stir for 15 min to obtain concrete mortar.

[0099] S2. Prepare concrete material

[0100] Pour the concrete mortar into a mold coated with a release agent, vibrate and tamp it, place the specimen in a curing box at a temperature of 25 °C and a humidity of 90%, cure for 15 days, and demold to obtain a concrete material.

[0101] Example 5

[0102] This example provides a method for preparing a high anti-seepage concrete material, which includes the following steps:

[0103] S1. Prepare concrete mortar

[0104] Mix naphthalene sulfonate water reducer and rosin sodium air-entraining agent evenly at a weight ratio of 3:2 to obtain an admixture;

[0105] Weigh by parts by weight: 90 parts of stones with a particle size of 5 - 25 mm, 50 parts of quartz sand with a particle size of 0.2 - 3 mm, 30 parts of pozzolanic Portland cement, 10 parts of the anti-seepage and strengthening material prepared in Example 2, 4 parts of sodium carboxymethylcellulose, and 1.7 parts of an admixture. Add them to a concrete mixer and mix for 6.5 min. Then add 28 parts of drinking water to the concrete mixer and stir for 18 min to obtain concrete mortar.

[0106] S2. Prepare concrete materials

[0107] Pour the concrete mortar into a mold coated with a release agent, vibrate and tamp it. Place the specimen in a curing box at a temperature of 27°C and a humidity of 94% for 15 days, then demold to obtain concrete materials.

[0108] Example 6

[0109] This example provides a preparation method of a high anti-seepage concrete material, which includes the following steps:

[0110] S1. Prepare concrete mortar

[0111] Mix the naphthalene sulfonate water reducer and the rosin sodium air-entraining agent evenly according to a weight ratio of 3:2 to obtain an admixture;

[0112] Weigh by parts by weight: 100 parts of stones with a particle size of 5 - 25 mm, 60 parts of quartz sand with a particle size of 0.2 - 3 mm, 35 parts of pozzolanic Portland cement, 12 parts of the anti-seepage and strengthening material prepared in Example 3, 5 parts of sodium carboxymethylcellulose, and 1.8 parts of an admixture. Add them to a concrete mixer and mix for 8 min. Then add 30 parts of drinking water to the concrete mixer and stir for 20 min to obtain concrete mortar.

[0113] S2. Prepare concrete materials

[0114] Pour the concrete mortar into a mold coated with a release agent, vibrate and tamp it. Place the specimen in a curing box at a temperature of 30°C and a humidity of 98% for 15 days, then demold to obtain concrete materials.

[0115] Comparative Example 1

[0116] The difference between this comparative example and Example 6 is that sodium carboxymethylcellulose was not added in step S1.

[0117] Comparative Example 2

[0118] The difference between this comparative example and Example 6 is that the anti-seepage and strengthening material prepared in Example 3 used in step S1 was replaced with an equal amount of the inorganic strengthening material prepared in step A2.

[0119] Comparative Example 3

[0120] The difference between this comparative example and Example 6 is that when preparing the anti-seepage enhancer prepared in Example 3 in step S1, step A1 is cancelled, and the supported biomass powder in step A2 is replaced by a mixture composed of sodium hexametaphosphate and disodium ethylenediaminetetraacetate in a weight ratio of 2:3.

[0121] Comparative Example 4

[0122] The difference between this comparative example and Example 6 is that when preparing the anti-seepage enhancer prepared in Example 3 in step S1, sodium 2-acrylamido-2-methylpropanesulfonate is not added in step A3.

[0123] Performance test:

[0124] Referring to the standard GB / T 50082-2024 "Standard for Test Methods of Long-Term Performance and Durability of Concrete", the chloride ion penetration resistance, sulfate erosion resistance and water penetration resistance of the concrete material specimens prepared in Examples 4-6 and Comparative Examples 1-4 were measured. Among them, the chloride ion penetration resistance was measured by the electric flux method in the standard, and the electric flux after 28 days of specimen curing was measured; the water penetration resistance was measured by the step-by-step pressure method in the standard, and the specimen was tested under a pressure of 1.2 MPa for 8 hours of constant pressure test, and the surface water seepage of the specimen was observed; the sulfate erosion resistance was measured by the sulfate erosion resistance test in the standard, and the corrosion resistance coefficient of the compressive strength of the specimen was tested;

[0125] Referring to the standard DB33 / T 2341-2021 "Test Code for Compressive Strength of Dry-Hardened Cement Concrete Precast Blocks", the compressive strength of the concrete material specimens prepared in Examples 4-6 and Comparative Examples 1-4 was measured. The specific test results are shown in Table 1 below.

[0126] Table 1 - Performance test data table of specimens

[0127]

[0128] Data analysis:

[0129] By comparing and analyzing the data in Table 1 above, the compressive strength of the cement concrete specimen prepared by the present invention reaches 28.8 MPa, the electric flux reaches 2566 C, the corrosion resistance coefficient of the compressive strength reaches 98%, and under the condition of a pressure of 1.2 MPa and a constant pressure test of 8 hours, no water seepage occurs on the surface of the specimen. All the performance test data are better than those of the comparative examples. Therefore, the present invention enhances the pozzolanic Portland cement concrete by the mutual cooperation of sodium carboxymethylcellulose and the anti-seepage enhancer, which not only effectively improves the compressive strength and water penetration resistance of the cement concrete, but also improves its resistance to chloride ion and sulfate erosion, and prolongs the service life of the cement concrete in a high-ion environment.

[0130] The above content is only an example and illustration of the structure of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar ways to replace them. As long as they do not deviate from the structure of the invention or exceed the scope defined by this claims, they shall fall within the protection scope of the present invention.

[0131] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0132] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation manners only. Obviously, many modifications and variations can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principle and practical application of the present invention, so that those skilled in the art of this technology can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A highly impermeable concrete material, characterized in that: The invention comprises the following components in parts by weight: 80-100 parts of gravel, 40-60 parts of quartz sand, 25-35 parts of cement, 8-12 parts of anti-seepage reinforcing material, 3-5 parts of sodium carboxymethyl cellulose, 1.5-1.8 parts of admixture and 25-30 parts of water; The admixture is composed of a water reducing agent and an air entraining agent in a weight ratio of 3:

2.

2. A highly impermeable concrete material according to claim 1, characterized in that: The anti-seepage reinforcing material is obtained by processing the following steps: A1. Mix hydrophilic modified PVP and N,N-dimethylformamide, raise the temperature of the reaction system to 70-80°C, stir until the system is dissolved, add isocyanate propyl triethoxysilane to the reaction system, keep the temperature for 40-60 minutes, add inorganic reinforcing material to the reaction system, keep the temperature for 30-50 minutes, and gradually reduce the temperature of the reaction system to room temperature to obtain a mixed solution; A2. Slowly add the mixed solution into the ethanol dispersion under high-speed stirring, stir and disperse for 60-80 minutes at room temperature, and post-treat to obtain the anti-seepage enhancement material.

3. A highly impermeable concrete material according to claim 2, characterized in that: In step A1, the amount ratio of the hydrophilic modified PVP, N,N-dimethylformamide, isocyanatepropyltriethoxysilane and inorganic reinforcing material is 7g:40mL:2g:10g; in step A2, the amount ratio of the mixed solution and the ethanol dispersion is 1g:5mL, and the ethanol dispersion is composed of anhydrous ethanol, 10wt% sodium hydroxide aqueous solution and polyethylene glycol 800 in a ratio of 40mL:9mL:1g.

4. A highly impermeable concrete material according to claim 2, characterized in that: The inorganic reinforcing material is composed of calcium magnesium carbonate, sodium sulfate, sodium silicate and supported biomass powder in a weight ratio of 3:2:2:

4.

5. The high impermeability concrete material according to claim 2, characterized in that: The preparation method of hydrophilic modified PVP is as follows: polyvinyl pyrrolidone and deionized water are mixed, the temperature of the reaction system is increased to 70-80°C, and the system is stirred until the system is dissolved, acrylamide and 2-acrylamido-2-methylpropanesulfonic acid sodium salt are added to the reaction system, and the mixture is stirred for 10-20 minutes. An initiator is added dropwise to the reaction system, and the reaction is kept warm for 4-6 hours, and the hydrophilic modified PVP is obtained by post-treatment.

6. A highly impermeable concrete material according to claim 5, characterized in that: The dosage ratio of the polyvinyl pyrrolidone, deionized water, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid sodium salt and the initiator is 2g:15mL:1g:5g:5mL, and the initiator is composed of potassium persulfate and deionized water in a ratio of 1g:10mL.

7. A highly impermeable concrete material according to claim 4, characterized in that: The loaded biomass powder is obtained by processing the following steps: B1. Grind the corncob and pass it through a 10-mesh sieve to obtain corncob powder; B2, mixing corncob powder and activation solution, raising the temperature of the reaction system to system reflux, heat preservation treatment for 16-18h, post-treatment, to obtain activated corncob powder; B3. Sodium hexametaphosphate, disodium ethylenediaminetetraacetate and purified water are mixed, the temperature of the reaction system is raised to 50-60°C, and the mixture is stirred and maintained until the system is dissolved. Activated corn cob powder is added to the reaction system, and the mixture is stirred and dispersed for 30-50 minutes. The mixture is post-treated to obtain loaded biomass powder.

8. The high impermeability concrete material according to claim 7, characterized in that: In step B2, the amount ratio of the corn cob powder and the activation solution is 1g:20mL, and the activation solution is composed of 6-8wt% sodium hydroxide aqueous solution, 20wt% hydrogen peroxide solution, urea and sodium dodecyl sulfate in the ratio of 50mL:10mL:2g:0.3g; in step B3, the amount ratio of sodium hexametaphosphate, disodium ethylenediaminetetraacetate, purified water and activated corn cob powder is 1.2g:1.8g:25mL:8g.

9. A method for preparing a highly impermeable concrete material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Evenly mix gravel, quartz sand, cement, anti-seepage reinforcing material, sodium carboxymethyl cellulose and admixture, add water to the mixed system, and stir for 15-20 minutes to obtain concrete mortar; S2. pouring concrete mortar into a mold and curing for 15 days to obtain a concrete material.

10. The method for preparing a highly impermeable concrete material according to claim 9, characterized in that: The particle size of the gravel is 5-25 mm, the particle size of the quartz sand is 0.2-3 mm, and the cement is pozzolanic silicate cement.

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