High impermeability filling concrete for bridge comb tooth plate expansion joint

Abstract

The present invention discloses a highly impermeable filling concrete for bridge comb-tooth plate expansion joints, mainly relating to the technical field of concrete, which includes portland cement, coarse aggregate, fine aggregate, water, water reducer, and modified polyvinyl alcohol fiber. Specifically, it includes 600-650 parts of portland cement, 300-350 parts of coarse aggregate, 200-250 parts of fine aggregate, 150-250 parts of water, 6-12 parts of water reducer, and 20-40 parts of modified polyvinyl alcohol fiber. The fine aggregate is one or a mixture of perlite, pearlescent sand, and quartz sand, the coarse aggregate is one or a mixture of ceramsite, crushed stone, and gravel, and the modified polyvinyl alcohol fiber contains polyvinyl alcohol fiber and modified zeolite microspheres. Compared with the prior art, the highly impermeable filling concrete prepared by the present invention has a denser structure, reduces the water absorption performance and chloride ion permeability of the concrete, and improves its impermeability and durability.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete, and particularly to a highly impermeable filling concrete for bridge comb-tooth plate expansion joints. Background Art

[0002] Concrete is a composite material formed by mixing cement, aggregates and water in a certain proportion, and is one of the most widely used building materials in the fields of construction and infrastructure at present; cement is the gelling material of concrete, which reacts with water to form a colloid, can harden in the air or in water, and can firmly bond aggregates such as sand and stone together; aggregates are the main filling materials of concrete, which can provide the strength and stability of concrete. Common aggregates include natural sand, artificial sand, pebbles, crushed stones, slag, etc. The comb-tooth plate is a common form of bridge expansion joint, which has good expansion and contraction performance and durability. The self-weight of the bridge comb-tooth plate is relatively light, and it can effectively disperse the load to provide stable structural support, thereby enhancing the overall strength and stiffness of the bridge. However, the toothed structure of the bridge comb-tooth plate may cause the surface of the bridge comb-tooth plate to be uneven during the manufacturing and processing process, and additional surface treatment is required, which increases the construction and maintenance costs. The toothed structure also brings certain difficulties to cleaning and drainage, and corresponding measures need to be taken to maintain the function and appearance of the bridge comb-tooth plate. Concrete can play multiple roles in the bridge comb-tooth plate structure, such as increasing the bearing capacity, improving the stability and durability of the bridge, protecting steel, and providing a flat surface.

[0003] In practical applications, long-term water accumulation and water penetration will affect the structural strength of the bridge, and the infiltration of chloride ions will cause corrosion of the bridge steel. In the prior art, impermeable concrete can be applied to the bridge expansion joint to prevent the intrusion of oxygen, moisture and other corrosive substances, reduce the corrosion and damage of steel, play a certain protective role in the bridge comb-tooth plate expansion joint, make the overall strength of the bridge comb-tooth plate more stable, and the bridge compressive strength higher, thereby extending the service life. The common methods for preparing impermeable concrete are as follows: adding waterproof agents to penetrate into the interior of the concrete, filling micropores and cracks to form a waterproof layer to prevent water penetration; improving the compactness of the concrete to reduce pores and cracks, thereby reducing the penetration channels and improving the impermeability; adding polymer modifiers to fill the micropores and cracks inside the concrete to improve the compactness and impermeability of the concrete; adding fiber materials such as polypropylene fibers or steel fibers to increase toughness and crack resistance, prevent the expansion of cracks, thereby reducing water penetration, and thus improving the impermeability of the concrete.

[0004] CN116693249A discloses a super anti-seepage comb tooth type expansion joint concrete with strong stability, which is made of raw materials in the following parts by weight: 420-480 parts of portland cement, 650-720 parts of lightweight aggregate, 1100-1200 parts of coarse aggregate, 180-200 parts of water, 100-130 parts of composite fiber, 90-100 parts of fine powder, 3-6 parts of calcium formate, and 70-100 parts of admixture; the admixture can introduce a large number of tiny closed air bubbles during the concrete mixing, reduce the surface tension of the concrete mixture, change the workability of the concrete mixture, and improve the strength of the concrete. Due to the blockage of the air bubbles, the evaporation route of the free water in the concrete becomes tortuous, fine and dispersed, reducing the seepage channels of the concrete, thereby improving the anti-seepage performance of the concrete. The network structure of the composite fiber will be damaged during the mixing to form single fibers, and these single fibers are intertwined, improving the anti-leakage performance of the concrete. Adding fine powder can reduce the porosity, and further make the structure of the concrete dense and improve the anti-seepage performance. The invention mainly realizes the anti-seepage effect by the combined action of the composite fiber and the admixture, further reducing the porosity. The proportion of water in the components is low and it is not easy to disperse the composite fiber. The composite fiber includes steel fiber, polypropylene mesh fiber and glass fiber. The surface of the carbon fiber in the composite fiber contains active groups such as carboxyl, hydroxyl and carbonyl, which will react and flocculate with the cement gel in the concrete, affecting the dispersion of the carbon fiber and ultimately resulting in unstable anti-seepage performance of the concrete.

[0005] CN116553881A discloses a high-toughness comb tooth plate expansion joint filling concrete, which contains the following components in parts by weight: 10-20 parts of cement, 5-10 parts of water, 18-36 parts of sand, 37-74 parts of gravel, 0.15-0.3 parts of aluminum alloy fiber, 0.1-0.2 parts of carbon fiber and 0.2-0.4 parts of additive; the additive includes water reducing agent, air entraining agent, quartz powder, retarder, antifreeze and expansive agent; the high-toughness comb tooth plate expansion joint filling concrete of the invention can fill the gaps between sand and gravel during the mixing and stirring, reduce the gaps after the concrete mixing and improve the density of the concrete. The anti-tensile elongation rate of the aluminum alloy fiber and the anti-tensile strength of the carbon fiber can improve the tensile and torsional strength of the concrete, reducing the phenomenon that the comb tooth plate is extruded by vehicles during the later use and the concrete cracks. The invention adds aluminum alloy fiber and carbon fiber, and the anti-tensile elongation rate of the aluminum alloy fiber and the anti-tensile strength of the carbon fiber can improve the tensile and torsional strength of the concrete, reducing the phenomenon that the comb tooth plate is extruded by vehicles during the later use and the concrete cracks. Similarly, the problem of fiber flocculation is ignored, and uneven dispersion will affect the safety of actual application. Summary of the Invention

[0006] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is the dispersibility of fiber materials in anti-seepage concrete, so as to improve the anti-seepage performance of the concrete.

[0007] To achieve the above object, the present invention provides a highly impermeable filling concrete for bridge comb tooth plate expansion joints, comprising the following components: portland cement, coarse aggregate, fine aggregate, water, water reducing agent, and modified polyvinyl alcohol fiber.

[0008] Preferably, the highly impermeable filling concrete for bridge comb tooth plate expansion joints comprises the following components in parts by weight:

[0009] 600 - 650 parts of portland cement

[0010] 300 - 350 parts of coarse aggregate

[0011] 200 - 250 parts of fine aggregate

[0012] 150 - 250 parts of water

[0013] 6 - 12 parts of water reducing agent

[0014] 20 - 40 parts of modified polyvinyl alcohol fiber.

[0015] The fine aggregate is one or a mixture of perlite, pearlescent sand, and quartz sand; preferably, the particle size of the fine aggregate is 0.1 - 4 mm.

[0016] The coarse aggregate is one or a mixture of ceramsite, crushed stone, and gravel; preferably, the particle size of the coarse aggregate is 4 - 30 mm.

[0017] The water reducing agent is a commercially available polycarboxylate water reducing agent.

[0018] The preparation method of the modified polyvinyl alcohol fiber is as follows: by weight, add 15 - 25 parts of polyvinyl alcohol fiber to 150 - 250 parts of water, stir at room temperature for 10 - 30 minutes, then add 5 - 8 parts of methyltrimethoxysilane, stir at room temperature for 4 - 5 hours, add 10 - 15 parts of modified zeolite microspheres and 1 - 3 parts of KH550, disperse for 10 - 30 minutes, centrifuge at 2000 - 2500 r / min for 1 - 2 hours, and obtain the modified polyvinyl alcohol fiber after freeze-drying.

[0019] The preparation method of the modified zeolite microspheres in the above preparation method of the modified polyvinyl alcohol fiber is as follows: by weight, add 15 - 25 parts of zeolite powder to 120 - 150 parts of 25 - 30 wt.% sodium metaborate aqueous solution, stir at 30 - 35 °C for 2 - 3 hours, then after freeze-drying, calcine at 600 - 900 °C for 1 - 2 hours to obtain the modified zeolite microspheres.

[0020] Specifically, the preparation method of the high impermeability filling concrete is as follows: successively add portland cement, coarse aggregate, and fine aggregate into water, stir at room temperature for 10 - 30 minutes, and finally add modified polyvinyl alcohol fiber and water reducing agent for mixing, and stir at room temperature for 10 - 30 minutes to obtain the high impermeability filling concrete.

[0021] The high impermeability filling concrete can be applied to the expansion joint of the bridge comb tooth plate.

[0022] In the concrete, cement serves as a gelling material and reacts with water to form a colloid, endowing the concrete with certain adhesiveness and strength. The function of adding fine aggregate is to fill the voids in the cement colloid, increasing the compactness and stability of the concrete. The function of coarse aggregate is to enhance the compressive and impact resistance of the concrete. Among them, ceramsite and perlite have a relatively low density, which can reduce the weight of the concrete and improve the heat preservation performance. Pearlescent sand and quartz sand have good particle shapes and mechanical properties, which can increase the strength and durability of the concrete. Adding polycarboxylate water reducing agent can improve the fluidity of the concrete, reduce the cement consumption, and enhance the strength and durability of the concrete. It can also reduce the water-cement ratio of the concrete, improve the compactness and impermeability of the concrete, and at the same time improve the processing performance and crack resistance of the concrete.

[0023] Zeolite powder is a natural mineral composed of tetrahedral combinations with fine pores. It shows strong agglomeration phenomena in alkaline aqueous solutions and forms modified zeolite microspheres through stacking. Compared with zeolite powder, the modified zeolite particles have larger particle sizes, smoother and denser surfaces after modification. The modified zeolite microspheres have better dispersibility and can still maintain the functions of zeolite powder, effectively reducing the porosity in the concrete, improving the strength and impermeability of the concrete, reducing the drying shrinkage of the concrete, delaying the internal humidity of the concrete, etc. It can also improve the water retention of the concrete and prevent the concrete from bleeding.

[0024] Polyvinyl alcohol fiber is a synthetic fiber made from high-polymerization-degree polyvinyl alcohol as raw material through a special processing technology. It contains a large number of hydroxyl groups and has good water solubility. Modified polyvinyl alcohol fiber realizes chemical modification through the hydrolysis and condensation reaction of methyltrimethoxysilane with the hydroxyl groups of polyvinyl alcohol fiber. The Si - OCH3 of silane is easily hydrolyzed into Si - OH, and Si - OH is unstable and easily dehydroxylated. After the hydroxyl groups of polyvinyl alcohol fiber are dehydrogenated, they are condensed and connected. After the zeolite powder is modified in the present invention and incorporated into the modified polyvinyl alcohol fiber, the modified zeolite particles serve as the core therein. The water-soluble polyvinyl alcohol fiber has hydrophobicity after hydrolysis and condensation modification. After shrinkage, it wraps the modified zeolite particles. Finally, the modified polyvinyl alcohol fiber after silanization modification makes the concrete structure more compact, reduces the water absorption and chloride ion permeability of the concrete, and improves its impermeability and durability.

[0025] The beneficial effects of the present invention:

[0026] Compared with the prior art, the present invention adds modified zeolite microspheres. Compared with zeolite powder, the modified zeolite particles have larger particle size, smoother and denser surface after modification. The modified zeolite microspheres have better dispersibility, which can improve the strength and impermeability of concrete by reducing the porosity in the concrete, as well as reduce the drying shrinkage of the concrete and delay the internal humidity of the concrete; the modified zeolite microspheres are also incorporated into the modified polyvinyl alcohol fibers. Among them, the modified zeolite particles act as the core. After hydrolysis and condensation modification, the water-soluble polyvinyl alcohol fibers become hydrophobic and wrap the modified zeolite particles after shrinkage. Finally, the modified polyvinyl alcohol fibers after silanization modification make the concrete structure more dense, reduce the water absorption performance and chloride ion permeability of the concrete, and improve its impermeability and durability. Detailed implementation mode

[0027] The parameters and sources of the specific chemical substances used in the examples are as follows:

[0028] The portland cement is a commercially available 52.5-grade portland cement;

[0029] The quartz sand is purchased from Henan Yuyan Environmental Protection Technology Co., Ltd., with a particle size specification of 2mm, a silicon content of 99%, a moisture content of 5%, a hardness of 6, and a porosity of 86%;

[0030] The perlite is purchased from Langfang Sanxin Perlite Products Co., Ltd., with a particle size specification of 2mm, a silicon dioxide content of 71.2%, an MgO content of 9.3%, a moisture content of 3%, and a hardness of 5.5;

[0031] The ceramsite is purchased from Wuhan Yuanrun Environmental Protection Technology Co., Ltd., with a particle size specification of 28mm, a compressive strength of 1.2 MPa, and the number rrhb0067; [[ID=*21]]

[0032] The gravel is purchased from Xubang Mineral Products Processing Factory in Lingshou County, with a particle size specification of 10mm.

[0033] The polycarboxylate water reducer is purchased from Wuhan Runxingyuan Technology Co., Ltd., with the model QSC-polycarboxylate water reducer B.

[0034] The zeolite powder is purchased from Ningbo Mineral Products Co., Ltd. in Lingshou County, with a hardness of 5-6, a particle size of 325 mesh, and the model 010123.

[0035] The polyvinyl alcohol fiber is purchased from Taian Haoda New Materials Co., Ltd., with a particle size specification of 6mm, a breaking strength of 1200 MPa, and the model SH-PVA-6.

[0036] Example 1

[0037] It should be noted that there seems to be a small error in the content you provided. In the description of the perlite in item , the MgO content should be 9.3% instead of 93% as it is not possible to have such a high MgO content in perlite under normal circumstances. This translation is based on the corrected content for better understanding. If you have any other questions, please feel free to let me know.A high anti-seepage filling concrete for the bridge comb tooth plate expansion joint, comprising the following raw materials: 620 g of 52.5-grade portland cement, 130 g of ceramsite with a particle size of 28 mm, 200 g of gravel with a particle size of 10 mm, 100 g of quartz sand with a particle size of 2 mm, 120 g of pearlescent sand with a particle size of 2 mm, 250 g of water, and 10 g of polycarboxylate water reducer.

[0038] Specifically, the preparation method of the high anti-seepage filling concrete for the bridge comb tooth plate expansion joint is as follows: sequentially add the portland cement, quartz sand, pearlescent sand, ceramsite, and gravel into water, stir at room temperature for 20 minutes, and finally add the polycarboxylate water reducer for mixing, and stir at room temperature for 30 minutes to obtain the high anti-seepage filling concrete.

[0039] Example 2

[0040] A high anti-seepage filling concrete for the bridge comb tooth plate expansion joint, comprising the following raw materials: 620 g of 52.5-grade portland cement, 130 g of ceramsite with a particle size of 28 mm, 200 g of gravel with a particle size of 10 mm, 100 g of quartz sand with a particle size of 2 mm, 120 g of pearlescent sand with a particle size of 2 mm, 250 g of water, 10 g of polycarboxylate water reducer, and 30 g of polyvinyl alcohol fiber.

[0041] Specifically, the preparation method of the high anti-seepage filling concrete for the bridge comb tooth plate expansion joint is as follows: sequentially add the portland cement, quartz sand, pearlescent sand, ceramsite, and gravel into water, stir at room temperature for 20 minutes, and finally add the polyvinyl alcohol fiber and the polycarboxylate water reducer for mixing, and stir at room temperature for 30 minutes to obtain the high anti-seepage filling concrete.

[0042] Example 3

[0043] A high anti-seepage filling concrete for the bridge comb tooth plate expansion joint, comprising the following raw materials: 620 g of 52.5-grade portland cement, 130 g of ceramsite with a particle size of 28 mm, 200 g of gravel with a particle size of 10 mm, 100 g of quartz sand with a particle size of 2 mm, 120 g of pearlescent sand with a particle size of 2 mm, 250 g of water, 10 g of polycarboxylate water reducer, and 30 g of modified polyvinyl alcohol fiber.

[0044] Specifically, the preparation method of the high anti-seepage filling concrete for the bridge comb tooth plate expansion joint is as follows: sequentially add the portland cement, quartz sand, pearlescent sand, ceramsite, and gravel into water, stir at room temperature for 20 minutes, and finally add the modified polyvinyl alcohol fiber and the polycarboxylate water reducer for mixing, and stir at room temperature for 30 minutes to obtain the high anti-seepage filling concrete.

[0045] The preparation method of the modified polyvinyl alcohol fiber is as follows: Add 32 g of polyvinyl alcohol fiber to 400 g of water, stir at room temperature for 30 minutes, then add 12 g of methyltrimethoxysilane, stir at room temperature for 4 hours, add 4 g of KH550 and disperse for 30 minutes, centrifuge at 2500 r / min for 2 hours, and obtain the modified polyvinyl alcohol fiber after freeze-drying.

[0046] Example 4

[0047] A high anti-seepage filling concrete for bridge comb-tooth plate expansion joints comprises the following raw materials: 620 g of 52.5-grade portland cement, 130 g of ceramsite with a particle size of 28 mm, 200 g of gravel with a particle size of 10 mm, 100 g of quartz sand with a particle size of 2 mm, 120 g of pearlescent sand with a particle size of 2 mm, 250 g of water, 10 g of polycarboxylate water reducer, and 30 g of modified polyvinyl alcohol fiber.

[0048] Specifically, the preparation method of the high anti-seepage filling concrete for bridge comb-tooth plate expansion joints is as follows: Add portland cement, quartz sand, pearlescent sand, ceramsite, and gravel to water in sequence, stir at room temperature for 20 minutes, and finally add the modified polyvinyl alcohol fiber and polycarboxylate water reducer for mixing, and stir at room temperature for 30 minutes to obtain the high anti-seepage filling concrete.

[0049] The preparation method of the modified polyvinyl alcohol fiber is as follows: Add 32 g of polyvinyl alcohol fiber to 400 g of water, stir at room temperature for 30 minutes, then add 12 g of methyltrimethoxysilane, stir at room temperature for 4 hours, add 25 g of zeolite powder and 4 g of KH550 and disperse for 30 minutes, centrifuge at 2500 r / min for 2 hours, and obtain the modified polyvinyl alcohol fiber after freeze-drying.

[0050] Example 5

[0051] A high anti-seepage filling concrete for bridge comb-tooth plate expansion joints comprises the following raw materials: 620 g of 52.5-grade portland cement, 130 g of ceramsite with a particle size of 28 mm, 200 g of gravel with a particle size of 10 mm, 100 g of quartz sand with a particle size of 2 mm, 120 g of pearlescent sand with a particle size of 2 mm, 250 g of water, 10 g of polycarboxylate water reducer, and 30 g of modified polyvinyl alcohol fiber.

[0052] Specifically, the preparation method of the high anti-seepage filling concrete for bridge comb-tooth plate expansion joints is as follows: Add portland cement, quartz sand, pearlescent sand, ceramsite, and gravel to water in sequence, stir at room temperature for 20 minutes, and finally add the modified polyvinyl alcohol fiber and polycarboxylate water reducer for mixing, and stir at room temperature for 30 minutes to obtain the high anti-seepage filling concrete.

[0053] The preparation method of the modified polyvinyl alcohol fiber is as follows: Add 32 g of polyvinyl alcohol fiber to 400 g of water, stir at room temperature for 30 minutes, then add 12 g of methyltrimethoxysilane, stir at room temperature for 4 hours, add 25 g of modified zeolite microspheres and 4 g of KH550, disperse for 30 minutes, centrifuge at 2500 r / min for 2 hours, and obtain the modified polyvinyl alcohol fiber after freeze-drying.

[0054] The preparation method of the modified zeolite microspheres in the above preparation method of the modified polyvinyl alcohol fiber is as follows: Add 30 g of zeolite powder to 250 g of 28 wt.% sodium metaborate aqueous solution, stir at 30 °C for 2 hours, then after freeze-drying, calcine at 650 °C for 1 hour to obtain the modified zeolite microspheres.

[0055] Test Example 1

[0056] Impermeability performance test

[0057] The high impermeability filling concrete obtained in Examples 1-5 was respectively subjected to impermeability performance tests on the 3rd, 7th, 14th, and 28th days. Each group was set with 6 parallel test specimens, and the test data were averaged. The test method was based on the impermeability performance test in JGJ∕T70-2009 "Standard for Test Methods of Basic Properties of Building Mortars", and the test data are as described in Table 1.

[0058] The test steps are as follows:

[0059] (1) Load the high impermeability filling concrete obtained in Examples 1-5 into the mold, and evenly tamp it 15 times with a plastering trowel, then tamp it 5 times again. When the filling mortar is slightly higher than the edge of the test mold, use a trowel to scrape off the excess concrete on the surface of the test mold at a 45° angle at one time, and then use a trowel to scrape the concrete flat on the surface of the test mold in the opposite direction at a flatter angle. 6 test specimens are made in each group;

[0060] (The test specimens should be left to stand at room temperature for 24 hours before demolding after molding. After the test specimens are demolded, they are placed in a constant temperature room at 20 °C and a humidity of 90% and cured until the 3rd, 7th, 14th, and 28th days. After the test specimens are taken out and the surface is dried, they are sealed with a sealing material and installed in a permeameter for impermeability test;

[0061] (3) During the impermeability test, the pressure should be started from 0.2 MPa, increased to 0.3 MPa after 2 hours of constant pressure, and then increased by 0.1 MPa every 1 hour. When water seepage appears on the surfaces of 3 out of 6 test specimens, the test should be stopped and the water pressure at that time should be recorded. During the test process, when it is found that water seeps out from the periphery of the test specimen, the test should be stopped, resealed, and then continued.

[0062] The impermeability pressure value of the concrete should be based on the maximum pressure when 4 out of 6 test specimens in each group do not show water seepage, and should be calculated according to the following formula:

[0063] P = H - 0.1

[0064] Where:

[0065] P —— Impermeability pressure value (MPa), accurate to 0.1 MPa;

[0066] H —— Water pressure when water seepage occurs in 3 out of 6 specimens (MPa).

[0067] Table 1 Impermeability pressure value

[0068] Example 1 Example 2 Example 3 Example 4 Example 5 3d 0.3 0.4 0.6 0.6 0.8 7d 0.4 0.5 0.7 0.7 0.9 14d 0.6 0.6 0.8 0.9 1.2 28d 1.0 1.1 1.2 1.2 1.5

[0069] It can be seen from the comparison in Table 1 that the impermeability pressures of the concrete specimens in Examples 1 - 4 are all lower than that in Example 5. Therefore, the impermeability effect of the concrete proportioned according to Example 5 is better.

[0070] Test Example 2

[0071] Water absorption test

[0072] The highly impermeable filling concrete obtained in Examples 1 - 5 was subjected to water absorption test. 3 parallel test specimens were set for each group, and the test data were averaged. The test method was based on the water absorption test in "Standard for Test Methods of Basic Properties of Building Mortars" JGJ∕T70 - 2009. The test data are as described in Table 1.

[0073] The test steps are as follows:

[0074] (1) Fill the highly impermeable filling concrete obtained in Examples 1 - 5 into the mold, and insert it evenly with a plastering trowel 15 times, then tamp it 5 times. When the filling mortar is slightly higher than the edge of the test mold, use a trowel to scrape off the excess concrete on the surface of the test mold at a 45° angle at one time, and then use the trowel to scrape the concrete flat on the surface of the test mold in the opposite direction at a flatter angle. 6 test specimens were made for each group;

[0075] (2) After the specimens are formed, they should be left standing at room temperature for 24 hours before demolding. After demolding, the specimens are placed in a constant temperature room at 20°C and a humidity of 90% for curing until the 28th day and then taken out, dried at 105°C for 48 hours, and weighed as m0;

[0076] (3) Place the specimens with the formed surface facing down in the water tank, pad them up with two steel bars, and completely immerse the specimens in water, and the height of the upper surface from the water surface should be not less than 20 mm. Take out the specimens at the 24th, 48th, and 72nd hours of immersion, wipe off the surface water with a wrung - out damp cloth, and weigh them as m1.

[0077] The water absorption rate is calculated by the following formula:

[0078] W x = (m1 - m0) / m0

[0079] Where:

[0080] W x ——Water absorption rate (%)

[0081] m1——Mass of the specimen after water absorption (g);

[0082] m0——Mass of the dry specimen (g).

[0083] Table 2 Water absorption rate test

[0084] Example 1 Example 2 Example 3 Example 4 Example 5 24h 3.4% 3.2% 3.0% 2.9% 2.5% 48h 4.1% 4.0% 3.8% 3.7% 2.7% 72h 5.0% 4.8% 4.6% 4.4% 3.1%

[0085] It can be seen from the comparison in Table 2 that the water absorption rates of the concrete specimens in Examples 1 - 4 are all higher than that in Example 5. Therefore, the water resistance effect of the concrete formulated according to Example 5 is better.

Claims

1. A highly impermeable filling concrete for a bridge comb tooth plate expansion joint, characterized in that, Comprising the following components in parts by weight: Portland cement 600 - 650 parts Coarse aggregate 300 - 350 parts Fine aggregate 200 - 250 parts Water 150 - 250 parts Water reducing agent 6 - 12 parts Modified polyvinyl alcohol fiber 20 - 40 parts; The preparation method of the modified polyvinyl alcohol fiber is as follows, in parts by weight: Add 15 - 25 parts of polyvinyl alcohol fiber to 150 - 250 parts of water, stir at room temperature, then add 5 - 8 parts of methyltrimethoxysilane, stir for 4 - 5 hours, add 10 - 15 parts of modified zeolite microspheres, 1 - 3 parts of KH550 for dispersion, centrifuge for 1 - 2 hours, and obtain the modified polyvinyl alcohol fiber after freeze-drying; The preparation method of the modified zeolite microspheres in the above preparation method of the modified polyvinyl alcohol fiber is as follows, in parts by weight: Add 15 - 25 parts of zeolite powder to 120 - 150 parts of 25 - 30 wt.% sodium metaborate aqueous solution, stir at 30 - 35 °C for 2 - 3 hours, and then after freeze-drying, calcine at 600 - 900 °C for 1 - 2 hours to obtain the modified zeolite microspheres.

2. The high anti-seepage filling concrete of the bridge comb tooth plate expansion joint according to claim 1, characterized in that, The fine aggregate is one or a mixture of perlite, pearlite sand, and quartz sand.

3. The high anti-seepage filling concrete for the bridge comb tooth plate expansion joint according to claim 2, wherein, The particle size of the fine aggregate is 0.1 - 4 mm.

4. The high anti-seepage filling concrete for the bridge comb tooth plate expansion joint according to claim 1, characterized in that, The coarse aggregate is one or a mixture of ceramsite, crushed stone, and gravel.

5. The high anti-seepage filling concrete for the bridge comb tooth plate expansion joint according to claim 4, wherein The particle size of the coarse aggregate is 4 - 30 mm.