Preparation method of anti-crack waterproof agent suitable for long-distance water delivery tunnel lining in cold region

Abstract

The invention relates to a preparation method of an anti-crack waterproof agent suitable for a long-distance water delivery tunnel lining in a cold region, and belongs to the technical field of concrete additives. The preparation method comprises the following steps: grafting a hydrophobic organic silicon chain segment to the surface of nano aluminum oxide, and reacting sulfydryl modified chrysotile fibers and sulfydryl modified polypropylene fibers through sulfydryl and epoxy groups grafted on the surface of the nano aluminum oxide to obtain an aluminum oxide fiber compound; the nano aluminum oxide, the chrysotile fiber and the polypropylene fiber can be bonded together through a hydrophobic long chain, so that the binding force among the three is improved. When the anti-crack waterproof agent containing the alumina fiber compound is used in concrete, the alumina fiber compound can be endowed with certain elasticity by long-chain silicone oil chain segments among nano-alumina, chrysotile fibers and polypropylene fibers and a tannic acid polymer on the surface of the polypropylene fibers, so that the crack resistance and the anti-freezing grade of the concrete are improved.

Description

Technical Field

[0001] The invention relates to a method for preparing an anti-cracking waterproofing agent suitable for lining of a long-distance water delivery tunnel in cold regions, and belongs to the technical field of concrete additives. Background Art

[0002] Concrete is currently the most widely used building material in the field of civil engineering. With the construction of super-long structures, underground structures, and large-volume concrete structures in recent years, the amount of concrete used has further increased. Imperfect waterproofing and drainage systems and the presence of concrete cracks may cause groundwater to come into contact with engineering concrete, causing leakage problems and seriously interfering with the normal operation of the project. In order to improve the strength of concrete, a large amount of admixtures are usually added to the concrete, resulting in a significant reduction in the water-cement ratio of the concrete, which in turn makes the free water in the concrete less and less, causing the concrete to be prone to plastic shrinkage and cracks on the surface.

[0003] In order to improve the waterproof and anti-seepage performance of concrete, it is currently common to add fibers, waterproofing agents and expansion agents to concrete. Fibers can overlap and entangle each other in concrete to form a fiber mesh, increase the adsorption force between concrete aggregates, significantly improve the crack resistance of concrete, and reduce plastic shrinkage cracks. Waterproof additives can significantly optimize the waterproofness and resistance to penetration of concrete. Expansion agents can improve the self-expansion characteristics of concrete and reduce microcracks caused by shrinkage. For example, Chinese patent document CN109053023A discloses an expansion fiber anti-cracking waterproofing agent, which is composed of the following raw materials in mass percentage: anti-cracking expansion agent 10% to 30%, microbead powder 20% to 40%, coal gangue 30% to 45%, modified basalt fiber 0.5% to 5%, cellulose grafted chitosan 0.4% to 2%, early strength agent 1% to 2%, water reducer 0.5% to 1.0%, defoamer 0.1% to 0.2%. The expansion fiber anti-cracking waterproofing agent can play a role in compensating shrinkage in concrete, effectively avoiding microcracks caused by different reasons at different ages of concrete, preventing and inhibiting the generation and development of cracks, and improving the flexural strength, impermeability and frost resistance of concrete. However, as the use environment of concrete becomes more and more demanding, for example, in cold-region drainage tunnel projects with low temperatures all year round, the expansion fiber anti-cracking waterproofing agent will not be able to meet the use requirements.

[0004] Therefore, it is urgent to develop an anti-cracking waterproofing agent to further improve the anti-cracking, waterproofing, anti-seepage and anti-freezing properties of concrete to meet the use requirements of long-distance water supply tunnel linings in cold regions. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing an anti-cracking waterproofing agent suitable for lining of long-distance water conveyance tunnels in cold regions, so as to solve the problem of deviation in the anti-cracking, waterproofing, anti-seepage and anti-freezing properties of current concrete.

[0006] The invention provides a method for preparing an anti-cracking waterproofing agent suitable for lining of a long-distance water conveyance tunnel in a cold region, comprising the following steps: mixing calcium sulfate, calcium oxide, iron oxide and an alumina fiber composite to obtain an anti-cracking waterproofing agent suitable for lining of a long-distance water conveyance tunnel in a cold region; the mass ratio of the calcium sulfate, calcium oxide, iron oxide and alumina fiber composite is 30-40:5-8:3-4:10-15; the preparation method of the alumina fiber composite is as follows: (1) The double-bond-terminated epoxy silicone oil and triethoxysilane are reacted to obtain an epoxy silicone oil-modified silane coupling agent; the structure of the double-bond-terminated epoxy silicone oil is as follows: ; The structure of epoxy silicone oil modified silane coupling agent is as follows: ; (2) reacting the epoxy silicone oil modified silane coupling agent with nano-alumina to obtain epoxy silicone oil modified nano-alumina; the average particle size of the nano-alumina is 40-70 nm; (3) reacting 3-mercaptopropyltriethoxysilane with chrysotile fiber to obtain mercapto-modified inorganic fiber; (4) reacting tannic acid with polypropylene fiber to obtain phenol compound modified polypropylene fiber; then reacting the phenol compound modified polypropylene fiber with 3-mercaptopropyltriethoxysilane to obtain mercapto modified polypropylene fiber; (5) The epoxy silicone oil modified nano alumina, the mercapto modified inorganic fiber and the mercapto modified polypropylene fiber are reacted to obtain an alumina fiber composite; the mass ratio of the mercapto modified inorganic fiber and the mercapto modified polypropylene fiber is 3-5:2-3, and the ratio of the sum of the molar amounts of the mercapto groups in the mercapto modified inorganic fiber and the mercapto modified polypropylene fiber to the molar amount of the epoxy groups in the epoxy silicone oil modified nano alumina is 1.2-1.4:1.

[0007] Preferably, the double-bond-terminated epoxy-terminated silicone oil is prepared by mixing epoxy-terminated silicone oil and acrylic acid under the catalysis of tetrabutylammonium bromide at 90-100° C. for 5-7 hours; the molar ratio of epoxy group to acrylic acid in the epoxy-terminated silicone oil is 2:1.

[0008] Preferably, the number average molecular weight of the epoxy-terminated silicone oil is 1500-3000.

[0009] Preferably, when the double-bond-terminated epoxy-terminated silicone oil and triethoxysilane are reacted, chloroplatinic acid is used as a catalyst, p-hydroxyanisole is used as an inhibitor, the reaction temperature is 85-95° C., and the time is 6-8 hours; the molar ratio of the double bond and triethoxysilane in the double-bond-terminated epoxy-terminated silicone oil is 1:1.02-1.05, the mass of p-hydroxyanisole is 0.2-0.5% of the mass of the double-bond-terminated epoxy-terminated silicone oil, and the mass of chloroplatinic acid is 0.007-0.01% of the mass of the double-bond-terminated epoxy-terminated silicone oil.

[0010] Preferably, the method for reacting the epoxy silicone oil modified silane coupling agent and nano alumina is as follows: mix the epoxy silicone oil modified silane coupling agent, ethanol and water in a mass ratio of 10:30~40:5~8, then adjust the pH to 4~5 with hydrochloric acid, add an ethanol dispersion of nano alumina with a mass fraction of 15~20%, heat to 70~80°C, mix for 7~10h, and obtain epoxy silicone oil modified nano alumina; the mass ratio of the epoxy silicone oil modified silane coupling agent and the nano alumina is 10:2~3.

[0011] Preferably, the method for reacting 3-mercaptopropyltriethoxysilane and chrysotile fiber is as follows: 3-mercaptopropyltriethoxysilane, ethanol and water in a mass ratio of 7:30~40:5~8 are mixed, and then the pH is adjusted to 4~5 with hydrochloric acid, and then an ethanol dispersion of chrysotile fiber with a mass fraction of 0.4~0.7% is added, heated to 70~80°C, and mixed for reaction for 5~8h to obtain mercapto-modified inorganic fiber; the mass ratio of 3-mercaptopropyltriethoxysilane and chrysotile fiber is 2~3:1, and the average length of the chrysotile fiber is 7~10μm and the average diameter is 30~50nm.

[0012] Preferably, the method for reacting tannic acid and polypropylene fiber is as follows: tris(hydroxymethyl)aminomethane, sodium chloride, tannic acid and water in a mass ratio of 0.5:2.5:0.5:150-180 are mixed to obtain a mixed solution, and then the pH of the mixed solution is adjusted to 8-9 to obtain a modified solution; the polypropylene fiber is immersed in the modified solution and subjected to an oscillating reaction at a rotation speed of 200-250 r / min for 24-30 hours to obtain a phenolic compound modified polypropylene fiber.

[0013] Preferably, the polypropylene fibers have an average diameter of 30-50 μm and an average length of 15-20 mm.

[0014] Preferably, the method for reacting phenolic compound modified polypropylene fiber and 3-mercaptopropyltriethoxysilane is as follows: 3-mercaptopropyltriethoxysilane, ethanol and water in a mass ratio of 8:30~40:5~8 are mixed, and then the pH is adjusted to 4~5 with hydrochloric acid, and then an ethanol dispersion of phenolic compound modified polypropylene fiber with a mass fraction of 5~8% is added, heated to 70~80°C, and mixed for reaction for 5~8h to obtain mercapto modified polypropylene fiber; the mass ratio of 3-mercaptopropyltriethoxysilane and phenolic compound modified polypropylene fiber is 3~5:1.

[0015] Preferably, when epoxy silicone oil modified nano alumina, mercapto modified inorganic fiber and mercapto modified polypropylene fiber are reacted, tetrabutylammonium fluoride is used as a catalyst, the reaction temperature is 50-60°C, the time is 6-8h, and the mass of tetrabutylammonium fluoride is 0.05-0.08% of the mass of epoxy silicone oil modified nano alumina.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention grafts hydrophobic organosilicon segments onto the surface of nano-alumina, and reacts mercapto-modified chrysotile fibers and mercapto-modified polypropylene fibers via mercapto groups and epoxy groups grafted onto the surface of nano-alumina to obtain an alumina fiber composite. The nano-alumina, chrysotile fibers, and polypropylene fibers can be bonded together via hydrophobic long chains to improve the bonding strength among the three. When the anti-cracking waterproofing agent including the alumina fiber composite is then used in concrete, the silicone oil molecular chains connected between the nano-alumina, chrysotile fibers and polypropylene fibers contain a large number of hydrophilic hydroxyl groups, and the lipophilic silicone segments and the hydrophilic hydroxyl groups cooperate with each other to form a good surface active system, thereby improving the dispersibility of the alumina fiber composite in the aqueous concrete slurry. The chrysotile fibers and polypropylene fibers radiate outward with the nano-alumina as the central core point to form a branched network structure, thereby improving the dispersion uniformity of the chrysotile fibers and the polypropylene fibers, avoiding the disordered cross-entanglement of linear fibers, increasing the contact area with the concrete, and thereby improving the support for the main structure of the concrete, and reducing the cracking of the concrete when subjected to external force.

[0017] (2) Since nano-alumina, chrysotile fibers and polypropylene fibers are bonded together by chemical bonds, the three can form a stable anchoring structure, improving the tensile strength, flexural strength, waterproof performance and maximum water seepage pressure of concrete; the hydrophobic long chains between the three can further improve the waterproof performance and maximum water seepage pressure of concrete. In addition, the tannic acid polymer deposited on the surface of polypropylene fibers can improve the wettability and dispersibility of oleophilic polypropylene fibers in concrete slurry, and can improve the surface roughness of polypropylene fibers, improve the interlocking strength and affinity between polypropylene fibers and concrete, and thus improve the strength, waterproofness and impermeability of concrete. Finally, the long-chain silicone oil segments between nano-alumina, chrysotile fibers and polypropylene fibers and the tannic acid polymer on the surface of polypropylene fibers can give the alumina fiber composite a certain elasticity, improving the crack resistance and frost resistance of concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the H-NMR spectrum of the double-bond-terminated epoxy-terminated silicone oil prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0019] The following examples are intended to further illustrate the present invention rather than to limit the scope of protection of the present invention.

[0020] Example 1

[0021] The preparation method of the anti-cracking waterproofing agent suitable for the lining of a long-distance water conveyance tunnel in cold regions of this embodiment comprises the following steps: (1) Add terminal epoxy silicone oil, acrylic acid, tetrabutylammonium bromide and acetone into a reaction kettle, heat to 90°C, stir and react for 5 hours, cool to room temperature, remove acetone by vacuum distillation to obtain a concentrated solution, and purify the concentrated solution by column chromatography to obtain a double-bond terminal epoxy silicone oil; wherein the molar ratio of epoxy group to acrylic acid in the terminal epoxy silicone oil is 2:1, the mass of tetrabutylammonium bromide is 0.5% of the mass of the terminal epoxy silicone oil, and the mass of acetone is 40% of the mass of the terminal epoxy silicone oil; the eluent used for column chromatography purification is composed of methanol and dichloromethane in a volume ratio of 0.5:25; the number average molecular weight of the terminal epoxy silicone oil is 1500, and the structure is as follows: ; The NMR hydrogen spectrum of double-bond-terminated epoxy silicone oil is as follows Figure 1 As shown, the structure is as follows: .

[0022] (2) Add double-bond-terminated epoxy-terminated silicone oil, p-hydroxyanisole, chloroplatinic acid and toluene into a reactor, stir evenly, introduce nitrogen into the reactor, heat the temperature of the materials in the reactor and control it at 85°C, add triethoxysilane dropwise into the reactor under a stirring bar, stir the reaction for 6 hours after the addition is completed, and remove toluene by vacuum distillation to obtain an epoxy silicone oil modified silane coupling agent; wherein the molar ratio of double bonds to triethoxysilane in the double-bond-terminated epoxy-terminated silicone oil is 1:1.02, the mass of p-hydroxyanisole is 0.2% of the mass of the double-bond-terminated epoxy-terminated silicone oil, the mass of chloroplatinic acid is 0.007% of the mass of the double-bond-terminated epoxy-terminated silicone oil, and the mass of toluene is 40% of the mass of the double-bond-terminated epoxy-terminated silicone oil; the structure of the epoxy silicone oil modified silane coupling agent is as follows: .

[0023] (3) Add epoxy silicone oil modified silane coupling agent, ethanol and deionized water in a mass ratio of 10:30:5 into a reactor, then add hydrochloric acid into the reactor, adjust the pH of the material in the reactor to 4, then add 15% by mass of nano-alumina ethanol dispersion into the reactor, heat the material in the reactor to 70°C, stir and reflux for 7 hours, filter, wash the filter cake with ethanol, and obtain epoxy silicone oil modified nano-alumina; wherein the mass ratio of epoxy silicone oil modified silane coupling agent to nano-alumina is 10:2, and the average particle size of nano-alumina is 40 nm.

[0024] (4) 3-mercaptopropyltriethoxysilane, ethanol and deionized water in a mass ratio of 7:30:5 were added into a reactor, and then hydrochloric acid was added into the reactor to adjust the pH of the material in the reactor to 4, and then 0.4% by mass fraction of chrysotile fiber ethanol dispersion was added into the reactor, the material in the reactor was heated to 70°C, stirred and refluxed for 5 hours, filtered, and the filter cake was washed with ethanol to obtain mercapto-modified inorganic fibers; wherein the mass ratio of 3-mercaptopropyltriethoxysilane to chrysotile fiber was 2:1, and the average length of the chrysotile fiber was 7 μm and the average diameter was 30 nm.

[0025] (5) Add tris(hydroxymethyl)aminomethane, sodium chloride, tannic acid and water in a mass ratio of 0.5:2.5:0.5:150 into a stirring tank and stir until the solid is fully dissolved to obtain a mixed solution. Use 0.1 mol / L hydrochloric acid to adjust the pH of the mixed solution to 8 to obtain a modified solution. Immerse the polypropylene fiber in the modified solution and place it on a shaking table oscillator for oscillation at a speed of 200 r / min. After oscillating for 24 hours, take out the polypropylene fiber, wash it with deionized water, and dry it to obtain a phenolic compound modified polypropylene fiber. The average diameter of the polypropylene fiber is 30 μm and the average length is 15 mm.

[0026] (6) 3-mercaptopropyltriethoxysilane, ethanol and deionized water in a mass ratio of 8:30:5 were added to a reactor, and hydrochloric acid was added to the reactor to adjust the pH of the material in the reactor to 4. Then, a 5% by mass ethanol dispersion of phenolic compound modified polypropylene fiber was added to the reactor, and the material in the reactor was heated to 70°C, stirred and refluxed for 5 hours, filtered, and the filter cake was washed with ethanol to obtain mercapto modified polypropylene fiber; wherein the mass ratio of 3-mercaptopropyltriethoxysilane to phenolic compound modified polypropylene fiber was 3:1.

[0027] (7) Epoxy silicone oil modified nano alumina, mercapto modified inorganic fiber, mercapto modified polypropylene fiber and ethanol are ultrasonically dispersed to obtain a mixed solution, and then tetrabutylammonium fluoride is added to the mixed solution, stirred at room temperature for 25 minutes, and then heated to 50°C and stirred for reaction for 6 hours. The ethanol is removed by vacuum distillation and dried to obtain an alumina fiber composite; wherein the mass ratio of the mercapto modified inorganic fiber and the mercapto modified polypropylene fiber is 3:2, the ratio of the sum of the molar amounts of mercapto groups in the mercapto modified inorganic fiber and the mercapto modified polypropylene fiber to the molar amount of epoxy groups in the epoxy silicone oil modified nano alumina is 1.2:1, the mass of tetrabutylammonium fluoride is 0.05% of the mass of the epoxy silicone oil modified nano alumina, and the mass ratio of the epoxy silicone oil modified nano alumina and ethanol is 1:3.

[0028] (8) Calcium sulfate, calcium oxide, iron oxide and alumina fiber composite are uniformly stirred to obtain an anti-cracking waterproofing agent suitable for lining of long-distance water transfer tunnels in cold regions; wherein the mass ratio of calcium sulfate, calcium oxide, iron oxide and alumina fiber composite is 30:5:3:10.

[0029] Example 2

[0030] The preparation method of the anti-cracking waterproofing agent suitable for the lining of a long-distance water conveyance tunnel in cold regions of this embodiment comprises the following steps: (1) Add terminal epoxy silicone oil, acrylic acid, tetrabutylammonium bromide and acetone into a reaction kettle, heat to 95°C, stir and react for 6 hours, cool to room temperature, remove acetone by vacuum distillation to obtain a concentrated solution, and purify the concentrated solution by column chromatography to obtain a double-bond terminal epoxy silicone oil; wherein the molar ratio of epoxy group to acrylic acid in the terminal epoxy silicone oil is 2:1, the mass of tetrabutylammonium bromide is 0.8% of the mass of the terminal epoxy silicone oil, and the mass of acetone is 45% of the mass of the terminal epoxy silicone oil; the eluent used for column chromatography purification is composed of methanol and dichloromethane in a volume ratio of 0.5:25; the number average molecular weight of the terminal epoxy silicone oil is 2000, and the structure is as follows: ; The structure of double-bond-terminated epoxy silicone oil is as follows: .

[0031] (2) Add double-bond-terminated epoxy-terminated silicone oil, p-hydroxyanisole, chloroplatinic acid and toluene into a reactor, stir evenly, introduce nitrogen into the reactor, heat the temperature of the materials in the reactor and control it at 90°C, add triethoxysilane dropwise into the reactor under stirring, stir and react for 7 hours after the addition is completed, and remove toluene by vacuum distillation to obtain an epoxy silicone oil modified silane coupling agent; wherein the molar ratio of double bonds to triethoxysilane in the double-bond-terminated epoxy-terminated silicone oil is 1:1.03, the mass of p-hydroxyanisole is 0.3% of the mass of the double-bond-terminated epoxy-terminated silicone oil, the mass of chloroplatinic acid is 0.009% of the mass of the double-bond-terminated epoxy-terminated silicone oil, and the mass of toluene is 45% of the mass of the double-bond-terminated epoxy-terminated silicone oil; the structure of the epoxy silicone oil modified silane coupling agent is as follows: .

[0032] (3) Add epoxy silicone oil modified silane coupling agent, ethanol and deionized water in a mass ratio of 10:35:7 into a reactor, then add hydrochloric acid into the reactor, adjust the pH of the material in the reactor to 4.5, then add 17% by mass ethanol dispersion of nano-alumina into the reactor, heat the material in the reactor to 75°C, stir and reflux for 8 hours, filter, wash the filter cake with ethanol, and obtain epoxy silicone oil modified nano-alumina; wherein the mass ratio of epoxy silicone oil modified silane coupling agent to nano-alumina is 10:2.5, and the average particle size of nano-alumina is 55 nm.

[0033] (4) 3-mercaptopropyltriethoxysilane, ethanol and deionized water in a mass ratio of 7:35:7 were added into a reactor, and then hydrochloric acid was added into the reactor to adjust the pH of the material in the reactor to 4.5, and then 0.6% by mass fraction of chrysotile fiber ethanol dispersion was added into the reactor, the material in the reactor was heated to 75°C, stirred and refluxed for 7 hours, filtered, and the filter cake was washed with ethanol to obtain mercapto-modified inorganic fibers; wherein the mass ratio of 3-mercaptopropyltriethoxysilane to chrysotile fiber was 2.5:1, and the average length of the chrysotile fiber was 8 μm and the average diameter was 40 nm.

[0034] (5) Add tris(hydroxymethyl)aminomethane, sodium chloride, tannic acid and water in a mass ratio of 0.5:2.5:0.5:170 into a stirring tank and stir until the solid is fully dissolved to obtain a mixed solution. Use 0.1 mol / L hydrochloric acid to adjust the pH of the mixed solution to 8 to obtain a modified solution. Immerse the polypropylene fiber in the modified solution and place it on a shaking table oscillator for oscillation at a speed of 220 r / min. After oscillation for 27 hours, take out the polypropylene fiber, wash it with deionized water, and dry it to obtain a phenolic compound modified polypropylene fiber. The average diameter of the polypropylene fiber is 40 μm and the average length is 18 mm.

[0035] (6) 3-mercaptopropyltriethoxysilane, ethanol and deionized water in a mass ratio of 8:35:7 were added to a reactor, and hydrochloric acid was added to the reactor to adjust the pH of the material in the reactor to 4.5, and then 7% by mass of an ethanol dispersion of phenolic compound modified polypropylene fiber was added to the reactor, the material in the reactor was heated to 75°C, stirred and refluxed for 6 hours, filtered, and the filter cake was washed with ethanol to obtain mercapto modified polypropylene fiber; wherein the mass ratio of 3-mercaptopropyltriethoxysilane to phenolic compound modified polypropylene fiber was 4:1.

[0036] (7) Epoxy silicone oil modified nano alumina, mercapto modified inorganic fiber, mercapto modified polypropylene fiber and ethanol are ultrasonically dispersed to obtain a mixed solution, and then tetrabutylammonium fluoride is added to the mixed solution, stirred at room temperature for 30 minutes, and then heated to 55°C and stirred for reaction for 7 hours. The ethanol is removed by vacuum distillation and dried to obtain an alumina fiber composite; wherein the mass ratio of the mercapto modified inorganic fiber to the mercapto modified polypropylene fiber is 4:2.5, the ratio of the sum of the molar amounts of mercapto groups in the mercapto modified inorganic fiber and the mercapto modified polypropylene fiber to the molar amount of epoxy groups in the epoxy silicone oil modified nano alumina is 1.3:1, the mass of tetrabutylammonium fluoride is 0.06% of the mass of the epoxy silicone oil modified nano alumina, and the mass ratio of the epoxy silicone oil modified nano alumina to ethanol is 1:4.

[0037] (8) Calcium sulfate, calcium oxide, iron oxide and alumina fiber composite are uniformly stirred to obtain an anti-cracking waterproofing agent suitable for lining of long-distance water transfer tunnels in cold regions; wherein the mass ratio of calcium sulfate, calcium oxide, iron oxide and alumina fiber composite is 35:7:3.5:12.

[0038] Example 3

[0039] The preparation method of the anti-cracking waterproofing agent suitable for the lining of a long-distance water conveyance tunnel in cold regions of this embodiment comprises the following steps: (1) Add terminal epoxy silicone oil, acrylic acid, tetrabutylammonium bromide and acetone into a reaction kettle, heat to 100°C, stir and react for 7 hours, cool to room temperature, remove acetone by reduced pressure distillation to obtain a concentrated solution, and purify the concentrated solution by column chromatography to obtain terminal double bond terminal epoxy silicone oil; wherein the molar ratio of epoxy group to acrylic acid in the terminal epoxy silicone oil is 2:1, the mass of tetrabutylammonium bromide is 1% of the mass of the terminal epoxy silicone oil, and the mass of acetone is 50% of the mass of the terminal epoxy silicone oil; the eluent used for column chromatography purification is composed of methanol and dichloromethane in a volume ratio of 0.5:25; the number average molecular weight of the terminal epoxy silicone oil is 3000, and the structure is as follows: ; The structure of double-bond-terminated epoxy silicone oil is as follows: .

[0040] (2) Add double-bond-terminated epoxy-terminated silicone oil, p-hydroxyanisole, chloroplatinic acid and toluene into a reactor, stir evenly, introduce nitrogen into the reactor, heat the temperature of the materials in the reactor and control it at 95°C, add triethoxysilane dropwise into the reactor under stirring, stir and react for 8 hours after the addition, remove toluene by vacuum distillation, and obtain an epoxy silicone oil modified silane coupling agent; wherein the molar ratio of double bonds to triethoxysilane in the double-bond-terminated epoxy-terminated silicone oil is 1:1.05, the mass of p-hydroxyanisole is 0.5% of the mass of the double-bond-terminated epoxy-terminated silicone oil, the mass of chloroplatinic acid is 0.01% of the mass of the double-bond-terminated epoxy-terminated silicone oil, and the mass of toluene is 50% of the mass of the double-bond-terminated epoxy-terminated silicone oil; the structure of the epoxy silicone oil modified silane coupling agent is as follows: .

[0041] (3) Adding epoxy silicone oil modified silane coupling agent, ethanol and deionized water in a mass ratio of 10:40:8 into a reactor, then adding hydrochloric acid into the reactor, adjusting the pH of the material in the reactor to 5, then adding 20% ​​by mass of nano-alumina ethanol dispersion into the reactor, heating the material in the reactor to 80°C, stirring and refluxing for 10 hours, filtering, washing the filter cake with ethanol, and obtaining epoxy silicone oil modified nano-alumina; wherein the mass ratio of epoxy silicone oil modified silane coupling agent to nano-alumina is 10:3, and the average particle size of nano-alumina is 70 nm.

[0042] (4) 3-mercaptopropyltriethoxysilane, ethanol and deionized water in a mass ratio of 7:40:8 were added into a reactor, and then hydrochloric acid was added into the reactor to adjust the pH of the material in the reactor to 5, and then 0.7% by mass fraction of chrysotile fiber ethanol dispersion was added into the reactor, the material in the reactor was heated to 80°C, stirred and refluxed for 8 hours, filtered, and the filter cake was washed with ethanol to obtain mercapto-modified inorganic fibers; wherein the mass ratio of 3-mercaptopropyltriethoxysilane to chrysotile fiber was 3:1, and the average length of the chrysotile fiber was 10 μm and the average diameter was 50 nm.

[0043] (5) Add tris(hydroxymethyl)aminomethane, sodium chloride, tannic acid and water in a mass ratio of 0.5:2.5:0.5:180 into a stirring tank, stir until the solid is fully dissolved to obtain a mixed solution, and adjust the pH of the mixed solution to 9 with 0.1 mol / L hydrochloric acid to obtain a modified solution; immerse the polypropylene fiber in the modified solution, place it on a shaking table oscillator and oscillate at a speed of 250 r / min. After oscillating for 30 hours, take out the polypropylene fiber, wash it with deionized water, and dry it to obtain a phenolic compound modified polypropylene fiber; the average diameter of the polypropylene fiber is 50 μm and the average length is 20 mm.

[0044] (6) 3-mercaptopropyltriethoxysilane, ethanol and deionized water in a mass ratio of 8:40:8 were added to a reactor, and hydrochloric acid was added to the reactor to adjust the pH of the material in the reactor to 5, and then an ethanol dispersion of phenolic compound modified polypropylene fiber with a mass fraction of 8% was added to the reactor, the material in the reactor was heated to 80°C, stirred and refluxed for 8 hours, filtered, and the filter cake was washed with ethanol to obtain mercapto modified polypropylene fiber; wherein the mass ratio of 3-mercaptopropyltriethoxysilane to phenolic compound modified polypropylene fiber is 5:1.

[0045] (7) Epoxy silicone oil modified nano alumina, mercapto modified inorganic fiber, mercapto modified polypropylene fiber and ethanol are ultrasonically dispersed to obtain a mixed solution, and then tetrabutylammonium fluoride is added to the mixed solution, stirred at room temperature for 35 minutes, and then heated to 60°C and stirred for reaction for 8 hours. The ethanol is removed by vacuum distillation and dried to obtain an alumina fiber composite; wherein the mass ratio of the mercapto modified inorganic fiber to the mercapto modified polypropylene fiber is 5:3, the ratio of the sum of the molar amounts of mercapto groups in the mercapto modified inorganic fiber and the mercapto modified polypropylene fiber to the molar amount of epoxy groups in the epoxy silicone oil modified nano alumina is 1.4:1, the mass of tetrabutylammonium fluoride is 0.08% of the mass of the epoxy silicone oil modified nano alumina, and the mass ratio of the epoxy silicone oil modified nano alumina to ethanol is 1:5.

[0046] (8) Calcium sulfate, calcium oxide, iron oxide and aluminum oxide fiber composite are uniformly stirred to obtain an anti-cracking waterproofing agent suitable for lining of long-distance water transfer tunnels in cold regions; wherein the mass ratio of calcium sulfate, calcium oxide, iron oxide and aluminum oxide fiber composite is 40:8:4:15.

[0047] Comparative Example 1 The difference between the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example and the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in Example 1 is that in step (5) of the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example, tannic acid is replaced by dopamine.

[0048] Comparative Example 2 The difference between the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example and the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in Example 1 is that in step (5) of the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example, tannic acid is replaced by resorcinol.

[0049] Comparative Example 3 The difference between the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example and the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in Example 1 is that in step (4) of the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example, the chrysotile fiber is replaced by sepiolite mineral fiber.

[0050] Comparative Example 4 The difference between the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example and the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in Example 1 is that in step (4) of the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example, the chrysotile fiber is replaced by basalt fiber.

[0051] Comparative Example 5 The difference between the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example and the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in Example 1 is that the average particle size of the nano-alumina in step (3) of the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example is 20 nm.

[0052] Comparative Example 6 The difference between the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example and the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in Example 1 is that the average particle size of the nano-alumina in step (3) of the preparation method of the anti-cracking waterproof agent suitable for the lining of long-distance water supply tunnels in cold regions in this comparative example is 100 nm.

[0053] Effect example In order to evaluate the application effect of the anti-cracking waterproofing agent prepared by the present invention in the lining of a water conveyance tunnel in a cold region, the anti-cracking waterproofing agent prepared by each embodiment and the comparative example is applied to the preparation of concrete. The cement used in the preparation of the concrete is ordinary Portland cement (labeled as P.O42.5), and the concrete is prepared by mixing cement, sand, crushed stone and water in a mass ratio of 300:900:950:170. The fineness modulus of the sand is 2.8, the average particle size of the crushed stone is 10 mm, and the amount of the anti-cracking waterproofing agent in the concrete is 7%; concrete without adding the anti-cracking waterproofing agent and concrete with adding the anti-cracking waterproofing agent are prepared into concrete test blocks, and the setting time, compressive strength, flexural strength, limited expansion rate, water seepage rate ratio, penetration height ratio, 48h water absorption ratio, crack reduction coefficient, maximum water seepage pressure and antifreeze grade of the concrete are tested. Among them, the setting time is tested according to the method in standard GB1346-2011. Each specimen is tested three times, and the average value of the test results is taken as the final result; the compressive strength and flexural strength are tested according to the method in standard GB-T50081-2002. Each specimen is tested three times, and the average value of the test results is taken as the final result; the limiting expansion rate is tested according to the method in standard GB / T 23439-2017. Each specimen is tested three times, and the average value of the test results is taken as the final result; the water seepage rate ratio, penetration height ratio, and 48h water absorption ratio are tested according to the method in standard JC-474-1999. Each specimen is tested three times, and the average value of the test results is taken as the final result; the crack reduction coefficient is tested according to the method in standard CECS 38-2004. Each specimen is tested three times, and the average value of the test results is taken as the final result; the maximum water seepage pressure and frost resistance grade are tested according to the method in standard GB / T The test was carried out according to the method in 50082-2009. Each specimen was tested three times and the average of the test results was taken as the final result. The frost resistance grade is characterized by the maximum number of freeze-thaw cycles that a 28-day-old specimen can withstand when it is saturated with water and subjected to repeated freeze-thaw cycles, with the compressive strength decreasing by no more than 25% and the mass loss not exceeding 5%.

[0054] The test results of setting time, compressive strength, flexural strength and limited expansion rate of the concrete corresponding to the anti-cracking waterproofing agents prepared in various embodiments and comparative examples are shown in Table 1. The test results of water seepage rate ratio, penetration height ratio, 48h water absorption ratio, crack reduction coefficient, maximum water seepage pressure and antifreeze grade of the concrete corresponding to the anti-cracking waterproofing agents prepared in various embodiments and comparative examples are shown in Table 2.

[0055] Table 1 Setting time, compressive strength, flexural strength and limited expansion rate of concrete corresponding to the anti-cracking waterproofing agents prepared in various embodiments and comparative examples

[0056] Table 2 Water seepage rate ratio, penetration height ratio, 48h water absorption ratio, crack reduction coefficient, maximum water seepage pressure and antifreeze grade of concrete corresponding to the anti-cracking waterproofing agents prepared in various embodiments and comparative examples

[0057] It can be seen from the test results of Table 1 and Table 2 that the anti-cracking waterproofing agent prepared by the present invention can effectively improve the tensile strength, flexural strength, waterproof performance, crack resistance, impermeability and frost resistance of concrete, which shows that the present invention grafts hydrophobic silicone segments onto the surface of nano-alumina, and reacts the thiol-modified chrysotile fiber and the thiol-modified polypropylene fiber through the thiol group and the epoxy group grafted on the surface of the nano-alumina, so that the nano-alumina, chrysotile fiber and polypropylene fiber can be bonded together through the hydrophobic long chain, thereby improving the binding force between the three. When the anti-cracking waterproofing agent prepared by the present invention is used in concrete, the silicone oil molecular chain connected between the nano-alumina, the chrysotile fiber and the polypropylene fiber contains a large number of hydrophilic hydroxyl groups, the lipophilic organic silicon chain segment and the hydrophilic hydroxyl group cooperate with each other to form a good surface active system, improve the dispersibility of the alumina fiber composite in the aqueous concrete slurry, the chrysotile fiber and the polypropylene fiber take the nano-alumina as the central core point, and diverge outward to form a branched network structure, improve the dispersion uniformity of the chrysotile fiber and the polypropylene fiber, avoid the disordered cross entanglement of linear fibers, increase the contact area with the concrete, and then improve the support for the main structure of the concrete, and reduce the cracking of the concrete when subjected to external force. At the same time, since the nano-alumina, the chrysotile fiber and the polypropylene fiber are bonded together by chemical bonds, the three can form a stable anchoring structure, improve the tensile strength, flexural strength, waterproof performance and maximum water seepage pressure of the concrete; the hydrophobic long chain between the three can further improve the waterproof performance and maximum water seepage pressure of the concrete. In addition, the tannic acid polymer deposited on the surface of polypropylene fibers can improve the wettability and dispersibility of oleophilic polypropylene fibers in concrete slurry, and can improve the surface roughness of polypropylene fibers, improve the interlocking strength and affinity between polypropylene fibers and concrete, and thus improve the strength, waterproofness and impermeability of concrete. Finally, the long-chain silicone oil segments between nano-alumina, chrysotile fibers and polypropylene fibers and the tannic acid polymer on the surface of polypropylene fibers can give the alumina fiber composite a certain elasticity, improving the crack resistance and antifreeze grade of concrete.

[0058] It can be seen from Example 1 and Comparative Examples 1-2 that after the tannic acid polymer deposited on the surface of the polypropylene fiber is replaced with polydopamine or resorcinol polymer, the comprehensive performance of the concrete is reduced. This may be because the number of phenolic hydroxyl groups in the polymer formed by dopamine or resorcinol is small and the affinity with the concrete slurry is poor, resulting in the polypropylene fiber being unable to be well dispersed in the concrete and thus unable to play a corresponding role.

[0059] It can be seen from Example 1 and Comparative Examples 3-4 that after the chrysotile fiber is replaced with sepiolite mineral fiber or basalt fiber, the comprehensive performance of the concrete is also reduced. This may be because the adsorption capacity of sepiolite mineral fiber and basalt fiber is too strong. When used together with the polypropylene fiber coated with tannic acid polymer, the sepiolite mineral fiber and basalt fiber will form a strong adsorption effect on the phenolic hydroxyl groups on the surface of the tannic acid polymer, resulting in the polypropylene fiber being unable to disperse well and unable to form a divergent structure, resulting in a decrease in overall performance.

[0060] It can be seen from Example 1 and Comparative Examples 5-6 that after increasing or decreasing the particle size of nano-alumina, the comprehensive performance of concrete is significantly reduced, indicating that the particle size of nano-alumina is crucial to the performance of the alumina fiber composite. When the particle size of nano-alumina is too large, a good equilibrium system cannot be formed between chrysotile fiber, polypropylene fiber and nano-alumina, resulting in the inability of chrysotile fiber and polypropylene fiber to be well dispersed in concrete and form a network divergent structure with nano-alumina, thereby weakening the effect of the alumina fiber composite; when the particle size of nano-alumina is too small, it cannot form a good central core point, resulting in the chrysotile fiber and polypropylene fiber being easy to move and entangle, and unable to form a good network divergent structure, which also leads to a decrease in concrete performance.

Claims

1. A method for preparing an anti-cracking waterproofing agent suitable for lining of long-distance water transfer tunnels in cold regions, characterized in that: The following steps are involved: Calcium sulfate, calcium oxide, iron oxide and aluminum oxide fiber composite are mixed to obtain an anti-cracking waterproof agent suitable for lining of long-distance water conveyance tunnels in cold regions; the mass ratio of the calcium sulfate, calcium oxide, iron oxide and aluminum oxide fiber composite is 30-40:5-8:3-4:10-15; the preparation method of the aluminum oxide fiber composite is as follows: (1) The double-bond-terminated epoxy silicone oil and triethoxysilane are reacted to obtain an epoxy silicone oil-modified silane coupling agent; the structure of the double-bond-terminated epoxy silicone oil is as follows: ； The structure of epoxy silicone oil modified silane coupling agent is as follows: ； (2) reacting the epoxy silicone oil modified silane coupling agent with nano-alumina to obtain epoxy silicone oil modified nano-alumina; the average particle size of the nano-alumina is 40-70 nm; (3) reacting 3-mercaptopropyltriethoxysilane with chrysotile fiber to obtain mercapto-modified inorganic fiber; (4) reacting tannic acid with polypropylene fiber to obtain phenol compound modified polypropylene fiber; then reacting the phenol compound modified polypropylene fiber with 3-mercaptopropyltriethoxysilane to obtain mercapto modified polypropylene fiber; (5) The epoxy silicone oil modified nano alumina, the mercapto modified inorganic fiber and the mercapto modified polypropylene fiber are reacted to obtain an alumina fiber composite; the mass ratio of the mercapto modified inorganic fiber and the mercapto modified polypropylene fiber is 3-5:2-3, and the ratio of the sum of the molar amounts of the mercapto groups in the mercapto modified inorganic fiber and the mercapto modified polypropylene fiber to the molar amount of the epoxy groups in the epoxy silicone oil modified nano alumina is 1.2-1.4:

1.

2. The method for preparing the anti-cracking waterproofing agent suitable for lining of long-distance water conveyance tunnels in cold regions according to claim 1, characterized in that: The double-bond-terminated epoxy-terminated silicone oil is prepared by mixing epoxy-terminated silicone oil and acrylic acid under the catalytic action of tetrabutylammonium bromide at 90-100° C. for 5-7 hours; the molar ratio of epoxy group to acrylic acid in the epoxy-terminated silicone oil is 2:

1.

3. The method for preparing the anti-cracking waterproofing agent suitable for lining of long-distance water conveyance tunnels in cold regions as claimed in claim 2, characterized in that: The number average molecular weight of the epoxy-terminated silicone oil is 1500-3000.

4. The method for preparing the anti-cracking waterproofing agent suitable for lining of long-distance water conveyance tunnels in cold regions according to claim 1, characterized in that: When the double-bond-terminated epoxy-terminated silicone oil and triethoxysilane react, chloroplatinic acid is used as a catalyst, p-hydroxyanisole is used as an inhibitor, the reaction temperature is 85-95° C., and the reaction time is 6-8 hours. The molar ratio of the double bond and triethoxysilane in the double-bond-terminated epoxy-terminated silicone oil is 1:1.02-1.05, the mass of p-hydroxyanisole is 0.2-0.5% of the mass of the double-bond-terminated epoxy-terminated silicone oil, and the mass of chloroplatinic acid is 0.007-0.01% of the mass of the double-bond-terminated epoxy-terminated silicone oil.

5. The method for preparing the anti-cracking waterproofing agent suitable for lining of long-distance water conveyance tunnels in cold regions according to claim 1, characterized in that: The method for reacting epoxy silicone oil modified silane coupling agent and nano alumina is as follows: mix epoxy silicone oil modified silane coupling agent, ethanol and water in a mass ratio of 10:30~40:5~8, then adjust the pH to 4~5 with hydrochloric acid, add ethanol dispersion of nano alumina with a mass fraction of 15~20%, heat to 70~80°C, mix for 7~10h, and obtain epoxy silicone oil modified nano alumina; the mass ratio of epoxy silicone oil modified silane coupling agent and nano alumina is 10:2~3.

6. The method for preparing the anti-cracking waterproofing agent suitable for lining of long-distance water conveyance tunnels in cold regions according to claim 1, characterized in that: The method for reacting 3-mercaptopropyltriethoxysilane and chrysotile fiber is as follows: 3-mercaptopropyltriethoxysilane, ethanol and water in a mass ratio of 7:30~40:5~8 are mixed, and then the pH is adjusted to 4~5 with hydrochloric acid, and then an ethanol dispersion of chrysotile fiber with a mass fraction of 0.4~0.7% is added, and the mixture is heated to 70~80°C, mixed and reacted for 5~8h to obtain mercapto-modified inorganic fiber; the mass ratio of 3-mercaptopropyltriethoxysilane to chrysotile fiber is 2~3:1, and the average length of the chrysotile fiber is 7~10μm and the average diameter is 30~50nm.

7. The method for preparing the anti-cracking waterproofing agent suitable for lining of long-distance water conveyance tunnels in cold regions according to claim 1, characterized in that: The method for reacting tannic acid and polypropylene fiber is as follows: tris(hydroxymethyl)aminomethane, sodium chloride, tannic acid and water in a mass ratio of 0.5:2.5:0.5:150-180 are mixed to obtain a mixed solution, and then the pH of the mixed solution is adjusted to 8-9 to obtain a modified solution; The polypropylene fiber is immersed in the modification liquid and subjected to an oscillating reaction at a rotation speed of 200-250 r / min for 24-30 hours to obtain the phenol compound modified polypropylene fiber.

8. The method for preparing the anti-cracking waterproofing agent suitable for lining of long-distance water conveyance tunnels in cold regions as claimed in claim 7, characterized in that: The average diameter of the polypropylene fiber is 30-50 μm, and the average length is 15-20 mm.

9. The method for preparing the anti-cracking waterproofing agent suitable for lining of long-distance water conveyance tunnels in cold regions according to claim 1, characterized in that: The method for reacting phenolic compound modified polypropylene fiber and 3-mercaptopropyltriethoxysilane is as follows: 3-mercaptopropyltriethoxysilane, ethanol and water in a mass ratio of 8:30~40:5~8 are mixed, and then the pH is adjusted to 4~5 with hydrochloric acid, and then an ethanol dispersion of phenolic compound modified polypropylene fiber with a mass fraction of 5~8% is added, heated to 70~80°C, and mixed for reaction for 5~8h to obtain mercapto modified polypropylene fiber; the mass ratio of 3-mercaptopropyltriethoxysilane and phenolic compound modified polypropylene fiber is 3~5:

1.

10. The method for preparing the anti-cracking waterproofing agent suitable for lining of long-distance water conveyance tunnels in cold regions according to claim 1, characterized in that: When epoxy silicone oil modified nano alumina, mercapto modified inorganic fiber and mercapto modified polypropylene fiber are reacted, tetrabutylammonium fluoride is used as a catalyst, the reaction temperature is 50-60°C, the reaction time is 6-8h, and the mass of tetrabutylammonium fluoride is 0.05-0.08% of the mass of epoxy silicone oil modified nano alumina.

Images