Super-hydrophobic concrete material and method for preparing the same

Abstract

This invention provides a superhydrophobic concrete material and its preparation method, relating to the field of concrete preparation technology. The superhydrophobic concrete material includes a precast concrete component and a coating; the precast concrete component comprises the following raw materials in parts by weight: 1000-1200 parts cement, 900-1300 parts sand, 10-40 parts modified fiber, 5-20 parts hydrophobic material, and 300-500 parts water; the coating is a hydrophobic coating. The preparation method of the superhydrophobic concrete material is simple, involving first preparing a precast concrete component, and then spraying a hydrophobic coating onto the surface of the precast concrete component to obtain the superhydrophobic concrete material, thus giving the concrete material a superhydrophobic effect.

Description

Technical Field

[0001] This invention relates to the field of concrete preparation technology, and in particular to a superhydrophobic concrete material and its preparation method. Background Technology

[0002] Concrete is widely used due to its abundant and inexpensive raw materials and simple production process. It also boasts high compressive strength, good durability, and a wide range of strength grades. Concrete is used not only in various civil engineering projects but also in shipbuilding, machinery manufacturing, marine development, and geothermal engineering. However, concrete has a hydrophilic and porous surface, making it susceptible to water and corrosive ions penetrating its microstructure, leading to cracking, scaling, and powdering. Therefore, there is an urgent need to develop a superhydrophobic concrete material and its preparation method, which is of great significance for large-scale practical applications. Summary of the Invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes a superhydrophobic concrete material and its preparation method.

[0004] The present invention proposes a superhydrophobic concrete material comprising precast concrete components and a coating; the precast concrete components comprise the following raw materials by weight: 1000-1200 parts cement, 900-1300 parts sand, 10-40 parts modified fiber, 5-20 parts hydrophobic material, and 300-500 parts water.

[0005] Preferably, the method for preparing the hydrophobic material includes the following steps:

[0006] S1. After stirring tetraethyl orthosilicate and ethanol evenly, add nitric acid aqueous solution, heat and stir, add zinc nitrate solution, stir evenly, let stand and keep warm, and calcine to obtain the mixture.

[0007] S2. Add polydimethylsiloxane emulsion to the mixture, mix evenly, and calcine to obtain a hydrophobic material.

[0008] More preferably, in S1, the mass fraction of the nitric acid aqueous solution is 0.01-0.03 wt%.

[0009] More preferably, in S1, the zinc nitrate solution has a mass fraction of 9-10 wt%.

[0010] More preferably, in S1, the volume ratio of tetraethyl orthosilicate, ethanol, aqueous nitric acid solution, and zinc nitrate solution is 2:(3-4):1:(1-2).

[0011] More preferably, in S1, the heat preservation temperature is 40-60℃ and the heat preservation time is 10-12h.

[0012] More preferably, in S1, the calcination temperature is 400-500℃ and the calcination time is 2-4h.

[0013] More preferably, in S2, the mass fraction of the polydimethylsiloxane emulsion is 1-3%.

[0014] More preferably, in S2, the mass ratio of the mixture to the polydimethylsiloxane emulsion is 1:(2-3).

[0015] More preferably, in S2, the calcination temperature is 200-300℃ and the calcination time is 2-4h.

[0016] Preferably, the method for preparing the modified fiber includes the following steps:

[0017] S1. Mix water, ethanol and acetone evenly to obtain mixed solution A. Soak carbon fibers in mixed solution A and sonicate them. Remove and dry them to obtain pretreated fibers.

[0018] S2. Ethanol and perfluorodecyltrichlorosilane are mixed evenly to obtain mixed solution B. Mixed solution B is dipped onto pretreated fibers and dried to obtain modified fibers.

[0019] More preferably, in S1, the volume ratio of water, ethanol, and acetone is 1:1:(1-2).

[0020] More preferably, in S2, the volume ratio of ethanol to perfluorodecyltrichlorosilane is 100:(1-2).

[0021] More preferably, in S2, the drying process includes first heating to 80-90℃ at 3-5℃ / min and holding for 1-2 hours, and then heating to 140-160℃ at 3-5℃ / min and holding for 0.5-2 hours.

[0022] Preferably, the coating is a hydrophobic coating.

[0023] More preferably, the coating is a fluorosilane-based hydrophobic coating.

[0024] This invention also proposes a method for preparing superhydrophobic concrete material, comprising the following steps:

[0025] S1. Mix cement, sand, and hydrophobic materials evenly to obtain a mixture;

[0026] S2. Add modified fiber and water to the mixture, mix evenly, compact, demold, and cure to obtain precast concrete components;

[0027] S3. A hydrophobic coating is sprayed onto the surface of precast concrete components to obtain superhydrophobic concrete material.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention proposes a superhydrophobic concrete material comprising precast concrete components and a coating. The precast concrete components include cement, sand, modified fibers, hydrophobic materials, and water. The raw materials work synergistically to produce precast concrete components with excellent hydrophobic properties. The modified fibers are pretreated with a mixture of water, ethanol, and acetone to remove surface contaminants, making them easier to combine with perfluorodecyltrichlorosilane to obtain hydrophobic modified fibers. The hydrophobic material is generated by the hydrolysis and condensation of tetraethyl orthosilicate, producing silica and a large number of hydroxyl radicals. This allows zinc ions from zinc nitrate solution to be adsorbed and deposited on the silica surface. After calcination, a mixture is obtained. This mixture is then uniformly mixed with a polydimethylsiloxane emulsion. Under high temperature conditions, the silanol groups of polydimethylsiloxane covalently bond with the surface groups of the mixture to form a stable hydrophobic material. This hydrophobic material not only improves the hydrophobic properties of the concrete material but also enhances its durability. A simple method for preparing superhydrophobic concrete material involves first preparing precast concrete components, and then spraying a hydrophobic coating onto the surface of the precast concrete components to obtain the superhydrophobic concrete material, thus giving the concrete material a superhydrophobic effect. Detailed Implementation

[0030] The technical solution of the present invention will be described in detail through specific embodiments.

[0031] Example 1

[0032] A method for preparing a superhydrophobic concrete material includes the following steps:

[0033] S1. Mix 1100 parts of cement, 1000 parts of sand, and 15 parts of hydrophobic material evenly to obtain a mixture.

[0034] S2. Add 25 parts of modified fiber and 450 parts of water to the mixture, mix evenly, compact, demold, and cure to obtain precast concrete components.

[0035] S3. A superhydrophobic concrete material is obtained by spraying fluorosilane onto the surface of precast concrete components to form a hydrophobic coating.

[0036] The preparation method of hydrophobic materials includes the following steps:

[0037] S1. After stirring tetraethyl orthosilicate and ethanol evenly, add 0.02% nitric acid aqueous solution, heat and stir, add 10% zinc nitrate solution, stir evenly, let stand at 50℃ for 12h, and calcine at 450℃ for 2h to obtain a mixture; wherein, the volume ratio of tetraethyl orthosilicate, ethanol, nitric acid aqueous solution and zinc nitrate solution is 2:3:1:1;

[0038] S2. Add 2% by mass of polydimethylsiloxane emulsion to the mixture, mix evenly, and calcine at 240°C for 2 hours to obtain a hydrophobic material; wherein the mass ratio of the mixture to the polydimethylsiloxane emulsion is 1:2.

[0039] The method for preparing modified fibers includes the following steps:

[0040] S1. Mix water, ethanol and acetone in a volume ratio of 1:1:1 to obtain mixed solution A. Soak carbon fibers in mixed solution A and sonicate them. Remove them and dry them at 65°C to obtain pretreated fibers.

[0041] S2. Mix ethanol and perfluorodecyltrichlorosilane at a volume ratio of 100:1 to obtain mixed solution B. Apply mixed solution B to the pretreated fiber and heat it to 85℃ at 5℃ / min for 2 hours. Then heat it to 150℃ at 3℃ / min for 1 hour to obtain modified fiber.

[0042] Example 2

[0043] A method for preparing a superhydrophobic concrete material includes the following steps:

[0044] S1. Mix 1200 parts of cement, 1200 parts of sand, and 20 parts of hydrophobic material evenly to obtain a mixture.

[0045] S2. Add 40 parts of modified fiber and 500 parts of water to the mixture, mix evenly, compact, demold, and cure to obtain precast concrete components.

[0046] S3. A superhydrophobic concrete material is obtained by spraying fluorosilane onto the surface of precast concrete components to form a hydrophobic coating.

[0047] The preparation method of hydrophobic materials includes the following steps:

[0048] S1. After stirring tetraethyl orthosilicate and ethanol evenly, add 0.02% nitric acid aqueous solution, heat and stir, add 10% zinc nitrate solution, stir evenly, let stand at 50℃ for 12h, and calcine at 450℃ for 2h to obtain a mixture; wherein, the volume ratio of tetraethyl orthosilicate, ethanol, nitric acid aqueous solution and zinc nitrate solution is 2:3:1:2;

[0049] S2. Add 3% by mass of polydimethylsiloxane emulsion to the mixture and mix evenly. Calcine at 240°C for 2 hours to obtain a hydrophobic material. The mass ratio of the mixture to the polydimethylsiloxane emulsion is 1:2.

[0050] The method for preparing modified fibers includes the following steps:

[0051] S1. Mix water, ethanol and acetone in a volume ratio of 1:1:1 to obtain mixed solution A. Soak carbon fibers in mixed solution A and sonicate them. Remove them and dry them at 65°C to obtain pretreated fibers.

[0052] S2. Ethanol and perfluorodecyltrichlorosilane are mixed evenly at a volume ratio of 100:2 to obtain mixed solution B. Mixed solution B is then coated onto pretreated fibers and heated to 90℃ at 5℃ / min and kept at that temperature for 2 hours. The temperature is then increased to 150℃ at 5℃ / min and kept at that temperature for 2 hours to obtain modified fibers.

[0053] Example 3

[0054] A method for preparing a superhydrophobic concrete material includes the following steps:

[0055] S1. Mix 1000 parts of cement, 1200 parts of sand, and 15 parts of hydrophobic material evenly to obtain a mixture.

[0056] S2. Add 30 parts of modified fiber and 450 parts of water to the mixture, mix evenly, compact, demold, and cure to obtain precast concrete components.

[0057] S3. A superhydrophobic concrete material is obtained by spraying fluorosilane onto the surface of precast concrete components to form a hydrophobic coating.

[0058] The preparation method of hydrophobic materials includes the following steps:

[0059] S1. After stirring tetraethyl orthosilicate and ethanol evenly, add 0.02% nitric acid aqueous solution, heat and stir, add 9% zinc nitrate solution, stir evenly, let stand at 50℃ for 12h, and calcine at 450℃ for 2h to obtain a mixture; wherein, the volume ratio of tetraethyl orthosilicate, ethanol, nitric acid aqueous solution and zinc nitrate solution is 2:4:1:2;

[0060] S2. Add 2% by mass of polydimethylsiloxane emulsion to the mixture and mix evenly. Calcine at 240°C for 2 hours to obtain a hydrophobic material. The mass ratio of the mixture to the polydimethylsiloxane emulsion is 1:3.

[0061] The method for preparing modified fibers includes the following steps:

[0062] S1. Mix water, ethanol and acetone in a volume ratio of 1:1:1 to obtain mixed solution A. Soak carbon fibers in mixed solution A and sonicate them. Remove them and dry them at 65°C to obtain pretreated fibers.

[0063] S2. Mix ethanol and perfluorodecyltrichlorosilane at a volume ratio of 100:1 to obtain mixed solution B. Apply mixed solution B to the pretreated fiber and heat it to 85℃ at 5℃ / min for 2 hours. Then heat it to 150℃ at 3℃ / min for 1 hour to obtain modified fiber.

[0064] Comparative Example 1

[0065] A method for preparing concrete material includes the following steps:

[0066] S1. Mix 1100 parts of cement, 1000 parts of sand, and 15 parts of hydrophobic material evenly to obtain a mixture.

[0067] S2. Add 25 parts of carbon fiber and 450 parts of water to the mixture, mix evenly, compact, demold, and cure to obtain precast concrete components.

[0068] S3. A hydrophobic coating is formed by spraying fluorosilane onto the surface of precast concrete components to obtain concrete material.

[0069] The preparation method of hydrophobic materials includes the following steps:

[0070] S1. After stirring tetraethyl orthosilicate and ethanol evenly, add 0.02% nitric acid aqueous solution, heat and stir, add 10% zinc nitrate solution, stir evenly, let stand at 50℃ for 12h, and calcine at 450℃ for 2h to obtain a mixture; wherein, the volume ratio of tetraethyl orthosilicate, ethanol, nitric acid aqueous solution and zinc nitrate solution is 2:3:1:1;

[0071] S2. Add 2% by mass of polydimethylsiloxane emulsion to the mixture, mix evenly, and calcine at 240°C for 2 hours to obtain a hydrophobic material; wherein the mass ratio of the mixture to the polydimethylsiloxane emulsion is 1:2.

[0072] Comparative Example 2

[0073] A method for preparing concrete material includes the following steps:

[0074] S1. Mix 1100 parts of cement and 1000 parts of sand evenly to obtain a mixture.

[0075] S2. Add 25 parts of modified fiber and 450 parts of water to the mixture, mix evenly, compact, demold, and cure to obtain precast concrete components.

[0076] S3. A hydrophobic coating is formed by spraying fluorosilane onto the surface of precast concrete components to obtain concrete material.

[0077] The preparation method of hydrophobic materials includes the following steps:

[0078] After stirring tetraethyl orthosilicate and ethanol evenly, add 0.02% nitric acid aqueous solution, heat and stir, add 10% zinc nitrate solution, stir evenly, let stand at 50℃ for 12h, and calcine at 450℃ for 2h to obtain hydrophobic material; wherein, the volume ratio of tetraethyl orthosilicate, ethanol, nitric acid aqueous solution and zinc nitrate solution is 2:3:1:1.

[0079] The method for preparing modified fibers includes the following steps:

[0080] S1. Mix water, ethanol and acetone in a volume ratio of 1:1:1 to obtain mixed solution A. Soak carbon fibers in mixed solution A and sonicate them. Remove them and dry them at 65°C to obtain pretreated fibers.

[0081] S2. Mix ethanol and perfluorodecyltrichlorosilane at a volume ratio of 100:1 to obtain mixed solution B. Apply mixed solution B to the pretreated fiber and heat it to 85℃ at 5℃ / min for 2 hours. Then heat it to 150℃ at 3℃ / min for 1 hour to obtain modified fiber.

[0082] After the concrete materials of Examples 1-3 and Comparative Examples 1-2 were left to stand naturally for 7 days, their compressive strength and flexural strength were tested according to the "GB / T50081-2019 Standard for Test Methods of Physical and Mechanical Properties of Concrete". The contact angle of the concrete materials was tested using a contact angle measuring instrument, and the water contact angle after 80 cycles of friction was recorded. The surface of the concrete material was placed against sandpaper, and a 50g weight was placed on top of the concrete material with a friction angle of 5mm·s⁻¹. -1 The sample was dragged at a constant speed, with each wear cycle lasting 20 cm. The test results are shown in Table 1.

[0083] Table 1. Test data of concrete material properties in Examples 1-3 and Comparative Examples 1-2

[0084]

[0085] As can be seen from the data in Table 1, the concrete material prepared by this invention has a large water contact angle, and the water contact angle only slightly decreases after 80 cycles of friction, indicating that the concrete material prepared by this invention has excellent hydrophobic properties. From the data of Comparative Examples 1-2 and the Examples, it can be seen that Comparative Example 1 is a concrete material prepared by adding unmodified carbon fibers, and Comparative Example 2 is a concrete material prepared without adding polydimethylsiloxane emulsion to the hydrophobic material. Both Comparative Examples 1 and 2 show poor hydrophobic properties. However, it is obvious that the compressive strength and flexural strength of the concrete material prepared by Comparative Example 2 are higher than those of the concrete material prepared by the Examples. The main reason is that the addition of polydimethylsiloxane in the Examples inhibits the hydration of cement in the concrete, reducing cement hydration products and thus causing a decrease in mechanical properties. However, the compressive strength and flexural strength of the concrete material prepared by the Examples still meet the requirements for practical use and have excellent hydrophobic properties.

[0086] In summary, the concrete material provided by this invention has excellent hydrophobic properties and maintains good hydrophobic properties even after 80 friction cycles.

[0087] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A superhydrophobic concrete material, characterized in that, It includes precast concrete components and a hydrophobic coating; the precast concrete components include the following raw materials by weight: 1000-1200 parts cement, 900-1300 parts sand, 10-40 parts modified fiber, 5-20 parts hydrophobic material, and 300-500 parts water. The method for preparing the hydrophobic material includes the following steps: S1. After stirring tetraethyl orthosilicate and ethanol evenly, add nitric acid aqueous solution, heat and stir, add zinc nitrate solution, stir evenly, let stand and keep warm, and calcine to obtain the mixture. S2. Add polydimethylsiloxane emulsion to the mixture, mix evenly, and calcine to obtain a hydrophobic material; In S1, the volume ratio of tetraethyl orthosilicate, ethanol, nitric acid aqueous solution, and zinc nitrate solution is 2:(3-4):1:(1-2); the mass fraction of nitric acid aqueous solution is 0.01-0.03wt%; the mass fraction of zinc nitrate solution is 9-10wt%; the holding temperature is 40-60℃, the holding time is 10-12h; the calcination temperature is 400-500℃, and the calcination time is 2-4h. In the S2, the mass fraction of polydimethylsiloxane emulsion is 1-3%; the mass ratio of the mixture to the polydimethylsiloxane emulsion is 1:(2-3); the calcination temperature is 200-300℃, and the calcination time is 2-4h. The method for preparing the modified fiber includes the following steps: S1. Mix water, ethanol and acetone evenly to obtain mixed solution A. Soak carbon fibers in mixed solution A and sonicate them. Remove and dry them to obtain pretreated fibers. S2. Ethanol and perfluorodecyltrichlorosilane are mixed evenly to obtain mixed solution B. Mixed solution B is dipped onto pretreated fibers and dried to obtain modified fibers.

2. The superhydrophobic concrete material according to claim 1, characterized in that, In S1, the volume ratio of water, ethanol, and acetone is 1:1:(1-2).

3. The superhydrophobic concrete material according to claim 1, characterized in that, In S2, the volume ratio of ethanol to perfluorodecyltrichlorosilane is 100:(1-2); the drying process includes first heating to 80-90℃ at 3-5℃ / min and holding for 1-2 hours, and then heating to 140-160℃ at 3-5℃ / min and holding for 0.5-2 hours.

4. The superhydrophobic concrete material according to claim 1, characterized in that, The hydrophobic coating is a fluorosilane-based hydrophobic coating.

5. A method for preparing the superhydrophobic concrete material according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Mix cement, sand, and hydrophobic materials evenly to obtain a mixture; S2. Add modified fiber and water to the mixture, mix evenly, compact, demold, and cure to obtain precast concrete components; S3. A hydrophobic coating is sprayed onto the surface of precast concrete components to obtain superhydrophobic concrete material.

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