A severe environment resistant underwater non-dispersible cementitious material

Abstract

The application relates to a kind of underwater non-dispersible cement-based materials resistant to severe environment, and belongs to the technical field of cement-based composite materials, the preparation materials of the underwater non-dispersible cement-based materials include: 25-45 parts of Portland cement, 35-55 parts of glass fiber, 40-60 parts of aluminum silicate fiber, 2-4 parts of water reducing agent, 1-3 parts of early strength agent, 4-8 parts of anti-dispersant and 10-27 parts of tap water by weight; wherein, the preparation raw materials of the anti-dispersant include: 10-20 parts of silica fume, 8-16 parts of cellulose ether, 3-6 parts of polyacrylamide and 45-65 parts of modified polyethylene short fiber by weight. The underwater non-dispersible cement-based material has excellent anti-dispersibility, and the cement paste can tightly wrap the aggregate and sink to the pouring site together. The water-land strength ratio can reach more than 70%, which can effectively ensure the design strength and ensure the safety of the structure. Through the addition of modified polyethylene short fiber, the concrete structure is uniform and dense, and the porosity is low, so it has a very high impermeability grade, can effectively resist environmental water erosion, greatly improves the service life of the structure, and is especially suitable for severe conditions such as seawater environment and hydraulic construction.

Description

Technical Field

[0001] This invention belongs to the field of cement-based composite material technology, specifically relating to a non-dispersible cement-based material that can withstand harsh underwater environments. Background Technology

[0002] Cement-based composite materials refer to composite materials made by adding fillers, chemical additives and water through a composite process, with silicate cement as the matrix, alkali-resistant glass fiber, general synthetic fiber, various ceramic fibers, carbon and aramid and other high-performance fibers, metal wires and natural plant and mineral fibers as reinforcements. Cement-based composite materials have improved performance compared to ordinary concrete.

[0003] However, when traditional cement-based materials are immersed in water, the cement paste is diluted and washed away, resulting in a sharp increase in the water-cement ratio. The actual strength is far lower than the design strength, forming a loose and porous weak layer. The loss of cement paste leads to high porosity and numerous interconnected pores inside the cement-based materials, making it easy for corrosive media such as water, chloride ions, and sulfates to penetrate and corrode the outer contact surface. This results in severe freeze-thaw damage and extremely poor durability. Summary of the Invention

[0004] The purpose of this invention is to provide a non-dispersible cementitious material resistant to harsh underwater environments in order to solve the above-mentioned problems.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] This invention provides an underwater non-dispersible cementitious material resistant to harsh environments. By weight, the materials used to prepare the underwater non-dispersible cementitious material include: 25-45 parts silicate cement, 35-55 parts glass fiber, 40-60 parts aluminosilicate fiber, 2-4 parts water-reducing agent, 1-3 parts early-strength agent, 4-8 parts anti-dispersing agent, and 10-27 parts tap water.

[0007] The raw materials for preparing the anti-dispersant, by weight, include: 10-20 parts silica fume, 8-16 parts cellulose ether, 3-6 parts polyacrylamide, and 45-65 parts modified polyethylene short fiber.

[0008] As a further optimization of the present invention, the modified polyethylene short fiber is obtained by modifying polyethylene short fiber with solvent A and solvent B. Solvent A is a mixture of ammonium mercaptoacetate, disodium EDTA and purified water; solvent B is ammonia water; and the polyethylene short fiber is a fiber with a length of 2 to 3 cm.

[0009] As a further optimization of the present invention, the preparation process of modified polyethylene short fibers is as follows: polyethylene short fibers are immersed in 0.5-1.0 mol / L solvent A with a solid-liquid ratio of 1:5-1:10, activated at 20-45℃ for 2-4 hours, and then washed and dried; the dried polyethylene short fibers are immersed in 0.5-1.0 mol / L solvent B with a solid-liquid ratio of 1:5-1:10, activated at 25-50℃ for 2-4 hours, and then washed and dried to obtain modified polyethylene short fibers.

[0010] As a further optimization of the present invention, the preparation process of the anti-dispersant is as follows: modified polyethylene short fibers are mixed with silica fume, cellulose ether and polyacrylamide, and ultrasonically vibrated for 20 to 40 minutes to obtain the anti-dispersant.

[0011] As a further optimization of the present invention, the ammonia water used is an ammonia solution with an ammonia content of 28%.

[0012] As a further optimization of the present invention, the cross-sectional radius of the glass fiber is 3-8 μm; the cross-sectional radius of the aluminum silicate fiber is 2-5 μm.

[0013] As a further optimization of the present invention, the water-reducing agent is calcium lignosulfonate; the early strength agent is calcium chloride.

[0014] As a further optimization of the present invention, the preparation process of solvent A is as follows: ammonium mercaptoacetate and disodium EDTA are added to a stirred tank and stirred at 25 r / min for 5 to 10 min. After uniform mixing, purified water is added and ultrasonically vibrated for 30 min to obtain solvent A.

[0015] As a further optimization of the present invention, the mass ratio of ammonium mercaptoacetate, disodium EDTA, and purified water is 0.1:0.2:1.

[0016] This invention also provides a method for preparing a non-dispersible cementitious material resistant to harsh underwater environments, comprising the following steps:

[0017] S1, use tap water to wet the glass fiber and aluminum silicate fiber, and set aside;

[0018] S2, Silicate cement, glass fiber and aluminum silicate fiber are placed in a cement mixer and tap water is added. The mixture is stirred at 75 r / min. At the 5th minute of stirring, an anti-dispersing agent is added, at the 10th minute, a water-reducing agent is added, and at the 20th minute, an early-strength agent is added. Stirring is continued for 20 minutes to obtain an underwater non-dispersible cementitious material.

[0019] The beneficial effects of this invention are as follows: The underwater non-dispersible cementitious material prepared by this invention has excellent anti-dispersion properties, and the cement paste can tightly wrap the aggregate and sink together to the casting site. Its water-to-land strength ratio can reach over 70%, which can effectively guarantee the design strength and ensure structural safety. By adding modified polyethylene short fibers, the concrete structure becomes uniform and dense with low porosity, thus having an extremely high impermeability level, effectively resisting environmental water erosion, and significantly improving the service life of the structure. It is particularly suitable for harsh conditions such as seawater environments and hydraulic structures. Detailed Implementation

[0020] The present application will now be described in further detail. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0021] Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art, and all reagents and materials used are commercially available products.

[0022] The silicate cement used in the experiment was purchased from Wuxi Jianghuai Building Materials Technology Co., Ltd.

[0023] Example 1

[0024] The preparation process of modified polyethylene short fibers is as follows: polyethylene short fibers are impregnated in 0.5 mol / L solvent A (polyethylene short fibers with a length of 2 cm), with a solid-liquid ratio of 1:5, activated at 20℃ for 2 h, and then washed and dried; the dried polyethylene short fibers are impregnated in 0.5 mol / L ammonia water (ammonia water with an ammonia content of 28% is used), with a solid-liquid ratio of 1:5, activated at 25℃ for 2 h, and then washed and dried to obtain modified polyethylene short fibers;

[0025] The preparation process of the anti-dispersant is as follows: 45 parts of modified polyethylene short fiber are mixed with 10 parts of silica fume, 8 parts of cellulose ether and 3 parts of polyacrylamide, and ultrasonically vibrated for 20 minutes to obtain the anti-dispersant.

[0026] The preparation process of solvent A is as follows: ammonium thioglycolate and disodium EDTA are added to a stirred tank and stirred at 25 r / min for 5 min. After uniform mixing, purified water is added and ultrasonically vibrated for 30 min to obtain solvent A (the mass ratio of ammonium thioglycolate, disodium EDTA and purified water is 0.1:0.2:1).

[0027] 35 parts of glass fiber (cross-sectional radius of 3-8 μm) and 40 parts of aluminosilicate fiber (cross-sectional radius of 2-5 μm) were sprayed with tap water and set aside for later use.

[0028] 25 parts of silicate cement, glass fiber and aluminosilicate fiber were placed in a cement mixer and 10 parts of tap water were added. The mixture was stirred at 75 r / min. At the 5th minute of stirring, 4 parts of anti-dispersing agent were added, at the 10th minute, 2 parts of calcium lignosulfonate were added, and at the 20th minute, 1 part of calcium chloride was added. The mixture was stirred for another 20 minutes to obtain an underwater non-dispersible cementitious material.

[0029] Example 2

[0030] The preparation process of modified polyethylene short fibers is as follows: polyethylene short fibers are impregnated in 0.8 mol / L solvent A (polyethylene short fibers with a length of 2.5 cm), with a solid-liquid ratio of 1:8, activated at 30℃ for 3 h, and then washed and dried; the dried polyethylene short fibers are impregnated in 0.9 mol / L ammonia water (ammonia water with an ammonia content of 28% is used), with a solid-liquid ratio of 1:6, activated at 45℃ for 3 h, and then washed and dried to obtain modified polyethylene short fibers;

[0031] The preparation process of the anti-dispersant is as follows: 50 parts of modified polyethylene short fiber are mixed with 15 parts of silica fume, 12 parts of cellulose ether and 4 parts of polyacrylamide, and ultrasonically vibrated for 30 minutes to obtain the anti-dispersant.

[0032] The preparation process of solvent A is as follows: ammonium thioglycolate and disodium EDTA are added to a stirred tank and stirred at 25 r / min for 8 min. After uniform mixing, purified water is added and ultrasonically vibrated for 30 min to obtain solvent A (the mass ratio of ammonium thioglycolate, disodium EDTA and purified water is 0.1:0.2:1).

[0033] 40 parts of glass fiber (cross-sectional radius of 3-8μm) and 50 parts of aluminosilicate fiber (cross-sectional radius of 2-5μm) were sprayed with tap water and set aside for later use.

[0034] 32 parts of silicate cement, glass fiber and aluminosilicate fiber were placed in a cement mixer and 18 parts of tap water were added. The mixture was stirred at 75 r / min. At the 5th minute of stirring, 6 parts of anti-dispersing agent were added, at the 10th minute, 3 parts of calcium lignosulfonate were added, and at the 20th minute, 2 parts of calcium chloride were added. The mixture was stirred for another 20 minutes to obtain an underwater non-dispersible cementitious material.

[0035] Example 3

[0036] The preparation process of modified polyethylene short fibers is as follows: polyethylene short fibers are immersed in 1.0 mol / L solvent A (the polyethylene short fibers are 3 cm in length), with a solid-liquid ratio of 1:10, activated at 45℃ for 4 h, and then washed and dried; the dried polyethylene short fibers are immersed in 1.0 mol / L ammonia water (the ammonia water is an ammonia solution with an ammonia content of 28%), with a solid-liquid ratio of 1:10, activated at 50℃ for 4 h, and then washed and dried to obtain modified polyethylene short fibers;

[0037] The preparation process of the anti-dispersant is as follows: 65 parts of modified polyethylene short fiber are mixed with 20 parts of silica fume, 16 parts of cellulose ether and 6 parts of polyacrylamide, and ultrasonically vibrated for 40 minutes to obtain the anti-dispersant.

[0038] The preparation process of solvent A is as follows: ammonium thioglycolate and disodium EDTA are added to a stirred tank and stirred at 25 r / min for 10 min. After uniform mixing, purified water is added and ultrasonically vibrated for 30 min to obtain solvent A (the mass ratio of ammonium thioglycolate, disodium EDTA and purified water is 0.1:0.2:1).

[0039] 55 parts of glass fiber (cross-sectional radius of 3-8 μm) and 60 parts of aluminosilicate fiber (cross-sectional radius of 2-5 μm) were sprayed with tap water and set aside for later use.

[0040] 45 parts of silicate cement, glass fiber and aluminosilicate fiber were placed in a cement mixer and 27 parts of tap water were added. The mixture was stirred at 75 r / min. At the 5th minute of stirring, 8 parts of anti-dispersing agent were added, at the 10th minute, 4 parts of calcium lignosulfonate were added, and at the 20th minute, 3 parts of calcium chloride were added. The mixture was stirred for another 20 minutes to obtain an underwater non-dispersible cementitious material.

[0041] Comparative Example 1

[0042] The preparation process of modified polyethylene short fibers is as follows: polyethylene short fibers are impregnated in 0.5 mol / L solvent A (polyethylene short fibers with a length of 2 cm), with a solid-liquid ratio of 1:5, activated at 20℃ for 2 h, and then washed and dried; the dried polyethylene short fibers are impregnated in 0.5 mol / L ammonia water (ammonia water with an ammonia content of 28% is used), with a solid-liquid ratio of 1:5, activated at 25℃ for 2 h, and then washed and dried to obtain modified polyethylene short fibers;

[0043] The preparation process of solvent A is as follows: ammonium thioglycolate and disodium EDTA are added to a stirred tank and stirred at 25 r / min for 5 min. After uniform mixing, purified water is added and ultrasonically vibrated for 30 min to obtain solvent A (the mass ratio of ammonium thioglycolate, disodium EDTA and purified water is 0.1:0.2:1).

[0044] 35 parts of glass fiber (cross-sectional radius of 3-8 μm) and 40 parts of aluminosilicate fiber (cross-sectional radius of 2-5 μm) were sprayed with tap water and set aside for later use.

[0045] 25 parts of silicate cement, glass fiber and aluminosilicate fiber were placed in a cement mixer and 10 parts of tap water were added. The mixture was stirred at 75 r / min. At the 5th minute of stirring, 4 parts of anti-dispersing agent were added, at the 10th minute, 2 parts of calcium lignosulfonate were added, and at the 20th minute, 1 part of calcium chloride was added. The mixture was stirred for another 20 minutes to obtain an underwater non-dispersible cementitious material.

[0046] Comparative Example 2

[0047] The preparation process of the anti-dispersant is as follows: 45 parts of polyethylene short fiber are mixed with 10 parts of silica fume, 8 parts of cellulose ether and 3 parts of polyacrylamide, and ultrasonically vibrated for 20 minutes to obtain the anti-dispersant.

[0048] The preparation process of solvent A is as follows: ammonium thioglycolate and disodium EDTA are added to a stirred tank and stirred at 25 r / min for 5 min. After uniform mixing, purified water is added and ultrasonically vibrated for 30 min to obtain solvent A (the mass ratio of ammonium thioglycolate, disodium EDTA and purified water is 0.1:0.2:1).

[0049] 35 parts of glass fiber (cross-sectional radius of 3-8 μm) and 40 parts of aluminosilicate fiber (cross-sectional radius of 2-5 μm) were sprayed with tap water and set aside for later use.

[0050] 25 parts of silicate cement, glass fiber and aluminosilicate fiber were placed in a cement mixer and 10 parts of tap water were added. The mixture was stirred at 75 r / min. At the 5th minute of stirring, 4 parts of anti-dispersing agent were added, at the 10th minute, 2 parts of calcium lignosulfonate were added, and at the 20th minute, 1 part of calcium chloride was added. The mixture was stirred for another 20 minutes to obtain an underwater non-dispersible cementitious material.

[0051] Comparative Example 3

[0052] The preparation process of the anti-dispersant is as follows: 25 parts silica fume, 23 parts cellulose ether and 18 parts polyacrylamide are mixed and ultrasonically vibrated for 20 minutes to obtain the anti-dispersant;

[0053] The preparation process of solvent A is as follows: ammonium thioglycolate and disodium EDTA are added to a stirred tank and stirred at 25 r / min for 5 min. After uniform mixing, purified water is added and ultrasonically vibrated for 30 min to obtain solvent A (the mass ratio of ammonium thioglycolate, disodium EDTA and purified water is 0.1:0.2:1).

[0054] 35 parts of glass fiber (cross-sectional radius of 3-8 μm) and 40 parts of aluminosilicate fiber (cross-sectional radius of 2-5 μm) were sprayed with tap water and set aside for later use.

[0055] 25 parts of silicate cement, glass fiber and aluminosilicate fiber were placed in a cement mixer and 10 parts of tap water were added. The mixture was stirred at 75 r / min. At the 5th minute of stirring, 4 parts of anti-dispersing agent were added, at the 10th minute, 2 parts of calcium lignosulfonate were added, and at the 20th minute, 1 part of calcium chloride was added. The mixture was stirred for another 20 minutes to obtain an underwater non-dispersible cementitious material.

[0056] Performance testing

[0057] (a) The compressive strength and flexural strength of the underwater non-dispersible cementitious material samples prepared by the methods of Examples 1-3 and Comparative Examples 1-3 were tested according to GB175-2020 "General Silicate Cement". The test results are shown in Table 1.

[0058] Table 1

[0059]

[0060] As can be seen from the table above, the underwater non-dispersible cementitious material samples prepared by the method in Example 1 have good compressive strength and flexural strength.

[0061] (ii) The underwater non-dispersible cementitious material samples prepared by the methods of Examples 1-3 and Comparative Examples 1-3 were tested for their water-land strength ratio, suspended solids content and bleeding rate in accordance with DL / T 5117 "Test Procedure for Underwater Non-dispersible Concrete". The test results are shown in Table 2.

[0062] Table 2

[0063]

[0064] As can be seen from the table above, the underwater non-dispersible cementitious material samples prepared by the method in Example 1 not only have good compressive strength and flexural strength, but also exhibit superior performance underwater. Comparing Example 1 with Comparative Examples 1-3, it can be seen that Comparative Example 1 directly uses modified polyethylene short fibers without adding silica fume, cellulose ether, and polyacrylamide, resulting in the modified polyethylene short fibers not being able to work synergistically with them; Comparative Example 2 uses unmodified ordinary polyethylene short fibers, resulting in relatively low water and land strength values ​​in the experimental values ​​of Comparative Example 2; Comparative Example 3 does not use polyethylene short fibers or modified polyethylene short fibers at all, thus making its performance the worst among all the test groups.

[0065] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A non-dispersible cementitious material resistant to harsh underwater environments, characterized in that, The underwater non-dispersible cementitious material, by weight, comprises: 25-45 parts silicate cement, 35-55 parts glass fiber, 40-60 parts aluminosilicate fiber, 2-4 parts water-reducing agent, 1-3 parts early-strength agent, 4-8 parts anti-dispersing agent, and 10-27 parts tap water; wherein, by weight, the anti-dispersing agent comprises: 10-20 parts silica fume, 8-16 parts cellulose ether, 3-6 parts polyacrylamide, and 45-65 parts modified polyethylene short fiber; the modified polyethylene short fiber is obtained by modifying polyethylene short fiber with solvent A and solvent B, wherein solvent A is a mixture of ammonium mercaptoacetate, disodium EDTA, and purified water; and solvent B is ammonia water. The polyethylene short fibers are 2-3 cm in length. The preparation process of the modified polyethylene short fibers is as follows: the polyethylene short fibers are immersed in 0.5-1.0 mol / L solvent A with a solid-liquid ratio of 1:5-1:10, activated at 20-45℃ for 2-4 hours, and then washed and dried. The dried polyethylene short fibers are immersed in 0.5-1.0 mol / L solvent B with a solid-liquid ratio of 1:5-1:10, activated at 25-50℃ for 2-4 hours, and then washed and dried to obtain modified polyethylene short fibers. The preparation process of the anti-dispersant is as follows: the modified polyethylene short fibers are mixed with silica fume, cellulose ether and polyacrylamide, and ultrasonically vibrated for 20-40 minutes to obtain the anti-dispersant.

2. The underwater non-dispersible cementitious material resistant to harsh environments according to claim 1, characterized in that, The ammonia solution used is an ammonia solution with an ammonia content of 28%.

3. The underwater non-dispersible cementitious material resistant to harsh environments according to claim 1, characterized in that, The cross-sectional radius of the glass fiber is 3-8 μm; the cross-sectional radius of the aluminum silicate fiber is 2-5 μm.

4. The underwater non-dispersible cementitious material resistant to harsh environments according to claim 1, characterized in that, The water-reducing agent is calcium lignosulfonate; the early-strength agent is calcium chloride.

5. The underwater non-dispersible cementitious material resistant to harsh environments according to claim 1, characterized in that, The preparation process of solvent A is as follows: ammonium mercaptoacetate and disodium EDTA are added to a stirred tank and stirred at 25 r / min for 5-10 min. After homogenization, purified water is added and the mixture is ultrasonically vibrated for 30 min to obtain solvent A.

6. The underwater non-dispersible cementitious material resistant to harsh environments according to claim 1, characterized in that, The mass ratio of ammonium thioglycolate, disodium EDTA, and purified water is 0.1:0.2:

1.

7. A method for preparing an underwater non-dispersible cementitious material resistant to harsh environments as described in any one of claims 1-6, characterized in that, Includes the following steps: S1, use tap water to wet the glass fiber and aluminum silicate fiber, and set aside; S2, Silicate cement, glass fiber and aluminum silicate fiber are placed in a cement mixer and tap water is added. The mixture is stirred at 75 r / min. At the 5th minute of stirring, an anti-dispersing agent is added, at the 10th minute, a water-reducing agent is added, and at the 20th minute, an early-strength agent is added. Stirring is continued for 20 minutes to obtain an underwater non-dispersible cementitious material.

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