Simple and environment-friendly preparation method of integral super-hydrophobic concrete and product thereof

Abstract

The application discloses a simple and environment-friendly preparation method of integral super-hydrophobic concrete and a product, and relates to the technical field of super-hydrophobic concrete, and aims at solving the problems of super-hydrophobic concrete or complicated preparation process or containing fluorine and not having excellent super-hydrophobicity in the interior; the application comprises the following steps: after 100 parts of cement and 80-150 parts of sand are fully mixed and uniformly distributed, 40-45 parts of water is added; in the process of mixing on one side, 6-8 parts of super-hydrophobic modified silicon dioxide solid powder is uniformly added on the other side, so as to make the prepared concrete generate more dense and different-size needle-shaped products, so as to have the required layered roughness of the super-hydrophobic surface, and the concrete slurry is obtained after full stirring and uniform distribution; the obtained concrete slurry is poured and hardened to form a super-hydrophobic concrete structure; the application has the advantages of simple steps, easy operation, easy control, green and environment-friendly materials, low cost, super-hydrophobicity of the prepared concrete after rolling or breaking, and excellent ice prevention and corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of super-hydrophobic concrete, in particular to a simple and environmentally friendly method for preparing a whole super-hydrophobic concrete and the product. BACKGROUND

[0002] Concrete is the most widely used building material in infrastructure due to its excellent mechanical properties and durability. However, due to the hydrophilic porous nature of concrete, water can easily carry corrosive ions into the concrete, which will inevitably corrode the steel bars inside the concrete, resulting in a sharp decrease in service life and mechanical strength. Therefore, it is very important to improve the corrosion resistance of concrete in construction engineering.

[0003] Giving super-hydrophobicity to concrete can effectively reduce the contact area of concrete with corrosive water containing Cl － There are two main strategies to make super-hydrophobic concrete: surface spraying or coating and mixing with hydrophobic solution. In the invention patent application with the publication number CN111040625A and the title of a super-hydrophobic coating and its preparation method and application, super-hydrophobic foam concrete and its preparation method, a technical solution is disclosed in which the super-hydrophobic coating is applied to the surface of the foam concrete and then left to obtain super-hydrophobic foam concrete. However, the super-hydrophobic coating only exists on the surface of the concrete, and it can be easily damaged and lose its super-hydrophobic properties. When mixed with a hydrophobic agent, the super-hydrophobicity of the concrete can still be retained or partially retained after the surface of the concrete cracks or wears. However, at present, most of the preparation processes of super-hydrophobic concrete are complex, and liquid fluorine-containing hydrophobic agents are used, which are difficult to store and harmful to the environment. At the same time, the super-hydrophobicity of most super-hydrophobic concrete only exists on the surface, and the interior does not have excellent super-hydrophobicity. Therefore, there is an urgent need for a simple and environmentally friendly method for preparing a whole super-hydrophobic concrete to solve this problem. SUMMARY

[0004] The purpose of the present application is to provide a simple and environmentally friendly method for preparing a whole super-hydrophobic concrete to solve the problem of super-hydrophobic concrete or complex preparation process, or containing fluorine, and not having excellent super-hydrophobicity in the interior.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: a simple and environmentally friendly method for preparing a whole super-hydrophobic concrete, comprising the following specific steps:

[0006] S1. Take cement 100 parts, sand 80-150 parts, and super-hydrophobic modified silicon dioxide solid powder 6-8 parts by weight;

[0007] S2. After the cement and sand are mixed evenly, 40-45 parts by weight of water is added to start mixing; in the process of mixing on one side, the super-hydrophobic modified silicon dioxide solid powder is added evenly on the other side, for making the prepared concrete generate more dense and different size needle-shaped products to have the required hierarchical roughness of the super-hydrophobic surface; until the super-hydrophobic modified silicon dioxide solid powder is added completely, continue to mix evenly to obtain the concrete slurry;

[0008] S3. After the obtained concrete slurry is poured and hardened to form, the super-hydrophobic concrete structure is obtained.

[0009] Preferably, the cement is P.O. 42.5 ordinary portland cement.

[0010] Preferably, the sand is fine sand screened by a 35-40 mesh fine screen.

[0011] Preferably, the super-hydrophobic modified silicon dioxide solid powder is silicon dioxide soaked by 1 wt.% octadecanoic acid ethanol solution and then dried.

[0012] Another technical solution provided by the present application is: a product prepared by a simple and environmentally friendly method for preparing a whole super-hydrophobic concrete, which is composed of cement 100 parts, sand 80-150 parts, super-hydrophobic modified silicon dioxide solid powder 6-8 parts, and water 40-45 parts by weight fraction; the microstructure is dense needle-shaped, forming a Cassie-Baxter state.

[0013] Preferably, after the super-hydrophobic concrete structure of the product after hardening is broken, the static water contact angle at any position of the cross section is greater than 150°; the static water contact angle of the super-hydrophobic concrete structure of the product after hardening is greater than 150° after being rubbed for 250 centimeters.

[0014] Preferably, compared with the concrete without adding super-hydrophobic modified silicon dioxide solid powder, the corrosion potential of the product increases and the corrosion current decreases.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] 1. The simple and environmentally friendly method for preparing a whole super-hydrophobic concrete and the product, by adding super-hydrophobic modified silicon dioxide solid powder in the process of mixing the concrete, not only the hydrophobic material is uniformly distributed in the concrete, but also the addition ratio is appropriate, which can help the formation of dense structure by more hydrated calcium silicate and ettringite generated by the hydration reaction, so that the concrete generates more dense and different size multi-level micro-nano structure needle-shaped products, thereby having the required hierarchical roughness of the super-hydrophobic surface, and further obtaining super-hydrophobicity.

[0017] 2、The simple and environmentally friendly preparation method of the integral super-hydrophobic concrete has simple steps, easy operation, easy control of the ratio, no need for special equipment, green and environmentally friendly materials, low cost, and easy application in engineering practice.

[0018] 3、The product prepared by the simple and environmentally friendly preparation method of the integral super-hydrophobic concrete does not affect the super-hydrophobicity whether it is friction, cracking, damage, or breaking, can effectively prevent water from entering the interior of the concrete, can effectively ensure the waterproofness of the concrete structure, and has excellent anti-icing performance and corrosion resistance after testing, thereby improving the durability of the concrete. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 SEM image of the super-hydrophobic concrete prepared for Example 1;

[0020] Figure 2 XRD image of the super-hydrophobic concrete prepared for Example 1 and ordinary concrete without super-hydrophobic modified silica solid powder;

[0021] Figure 3 Static water contact angle of the super-hydrophobic concrete prepared for Example 1;

[0022] Figure 4 Tafel polarization curve image of the super-hydrophobic concrete prepared for Example 1 and ordinary concrete without super-hydrophobic modified silica solid powder;

[0023] Figure 5 Friction resistance test results of the super-hydrophobic concrete prepared for Example 1;

[0024] Figure 6 Anti-icing test results of the super-hydrophobic concrete prepared for Example 1 and ordinary concrete without super-hydrophobic modified silica solid powder.

[0025] Figure 7 Schematic diagram of the hydrophobicity of the super-hydrophobic concrete prepared for Example 1 after breaking. DETAILED DESCRIPTION

[0026] A simple and environmentally friendly preparation method of integral super-hydrophobic concrete includes the following specific steps:

[0027] S1. Take cement 100 parts, sand 80-150 parts, and super-hydrophobic modified silica solid powder 6-8 parts by weight fraction, wherein the cement can be common P.O. 42.5 ordinary portland cement, the sand is preferably fine sand screened by a 35-40 mesh fine screen, and the super-hydrophobic modified silica solid powder is silica soaked in 1 wt.% octadecanoic acid ethanol solution and then dried, and other commercially available super-hydrophobic modified silica without fluorine can also be used.

[0028] S2. After the cement and sand are mixed well, 40-45 parts by weight of water are added to start mixing; while mixing on one side, the super-hydrophobic modified silica solid powder is added evenly on the other side to make the prepared concrete generate more dense and different size needle-shaped products to have the required hierarchical roughness for the super-hydrophobic surface; after the super-hydrophobic modified silica solid powder is added completely, the concrete slurry is obtained by further mixing well;

[0029] S3. The obtained concrete slurry is poured and hardened to form a super-hydrophobic concrete structure.

[0030] The concrete prepared by the above method has a dense needle-shaped microstructure and forms a Cassie-Baxter state; the static water contact angle of the super-hydrophobic concrete structure after the product is hardened is still greater than 150° at any position of the cross section, and the super-hydrophobic performance is maintained at each position; the static water contact angle of the super-hydrophobic concrete structure after the product is hardened is still greater than 150° after 250 cm of friction.

[0031] Example 1

[0032] S1. In parts by weight, 100 parts of P.O. 42.5 ordinary Portland cement, 150 parts of fine sand screened by a 40-mesh fine screen, and 6 parts of silica soaked in a 1 wt.% ethanolic solution of octadecanoic acid and then dried are taken;

[0033] S2. After the cement and sand are mixed well, 40 parts by weight of water are added to start mixing; while mixing on one side, the super-hydrophobic modified silica solid powder is added evenly on the other side; after the super-hydrophobic modified silica solid powder is added completely, the concrete slurry is obtained by further mixing well;

[0034] S3. The obtained concrete slurry is poured and hardened to form a super-hydrophobic concrete structure.

[0035] Example 2

[0036] S1. In parts by weight, 100 parts of P.O. 42.5 ordinary Portland cement, 130 parts of fine sand screened by a 40-mesh fine screen, and 7 parts of silica soaked in a 1 wt.% ethanolic solution of octadecanoic acid and then dried are taken;

[0037] S2. After the cement and sand are mixed well, 45 parts by weight of water are added to start mixing; while mixing on one side, the super-hydrophobic modified silica solid powder is added evenly on the other side; after the super-hydrophobic modified silica solid powder is added completely, the concrete slurry is obtained by further mixing well;

[0038] S3. The obtained concrete slurry is poured and hardened to form a super-hydrophobic concrete structure.

[0039] Example 3

[0040] S1. Take P.O. 42.5 ordinary Portland cement 100 parts, fine sand screened by 35 mesh fine screen 80 parts, and 8 parts of silica which is soaked in 1wt.% octadecanoic acid ethanol solution and then dried;

[0041] S2. After the cement and sand are mixed uniformly, 40 parts of water are added to start mixing; while mixing on one side, the super-hydrophobic modified silica solid powder is added uniformly; after the super-hydrophobic modified silica solid powder is added completely, the mixing is continued to obtain a concrete slurry;

[0042] S3. The obtained concrete slurry is poured and hardened to form a super-hydrophobic concrete structure.

[0043] Comparative Example

[0044] P.O. 42.5 ordinary Portland cement 100 parts, fine sand screened by 40 mesh fine screen 150 parts, and 40 parts of water are stirred uniformly to obtain a common concrete slurry, which is poured and hardened to form a concrete structure.

[0045] Figure 1 The SEM image of the super-hydrophobic concrete prepared in Example 1 shows that the super-hydrophobic concrete has a dense needle-like structure and a multi-level micro-nano structure with different sizes, which provides the required hierarchical roughness of the super-hydrophobic surface, forms a Cassie-Baxter state, and makes the water droplets more likely to form a larger contact angle and roll off the surface. Other examples also have a dense needle-like structure.

[0046] Figure 2 The XRD pattern of the super-hydrophobic concrete prepared in Example 1 and the comparative example shows that the peak intensity of the super-hydrophobic concrete is significantly higher than that of the common concrete, indicating that the addition of the solid hydrophobic powder promotes the hydration reaction to produce more C-S-H and AFt. Combined with the dense structure, the addition ratio of the method of the present application can help the formation of more hydrated calcium silicate and ettringite produced by the hydration reaction, which further helps to improve the performance of the super-hydrophobic concrete. Other examples also have more C-S-H and AFt than common concrete. Figure 1

[0047] Figure 3 The static wetting image of the super-hydrophobic concrete prepared in Example 1 shows that the super-hydrophobic surface has a water contact angle as high as 154.27°, showing good non-wetting property. The present application also conducts a large number of tests, and the obtained contact angle is all above 154°.

[0048] ​Figure 4 The corrosion resistance test result graph of the super-hydrophobic concrete prepared in Example 1 is shown. In a 3.5wt% NaCl solution, the corrosion resistance test is carried out in a standard three-electrode system using an electrochemical workstation, with a steel bar as the working electrode, a platinum electrode and a saturated calomel electrode as the counter electrode and the reference electrode, respectively. It can be seen from the Tafel polarization curve that the super-hydrophobic concrete surface has good corrosion resistance, the corrosion potential increases, and the corrosion current decreases. Other examples also have the same excellent corrosion resistance.

[0049] Figure 5 The friction resistance test result graph of the super-hydrophobic concrete surface prepared in Example 1 is shown. It can be observed that the super-hydrophobic concrete still has a high contact angle of 156.85° after 250 cm of friction, proving that it has good post-friction super-hydrophobicity. Other examples also have the same excellent post-friction super-hydrophobicity.

[0050] Figure 6 The anti-icing performance test result graph of the super-hydrophobic concrete prepared in Example 1 is shown. A refrigeration device is used to observe the surface anti-icing performance. The experiment is carried out at room temperature, the sample is placed on the sample stage, and then 10 μl of water droplets are dropped on the sample surface using a micro-needle. There is no obvious change in the morphology before and after icing, the super-hydrophobic concrete reduces the contact area between the droplets and the concrete surface, which is conducive to the deicing and anti-icing of the concrete surface.

[0051] Figure 7 The hydrophobicity diagram of the super-hydrophobic concrete prepared in Example 1 of the present application after breaking is shown. It can be observed that the droplets on the broken surface are still spherical and have a high contact angle of 151.34°. All test results of the present application show that the contact angle of each part after breaking is greater than 150°, and the overall hydrophobicity is excellent.

[0052] The above is only a preferred embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be limited by the protection scope defined in the claims.

[0053] The details not described in the present application are well-known to those skilled in the art.

Claims

1. A simple and environmentally friendly method for preparing monolithic superhydrophobic concrete, characterized in that, The specific steps include the following: S1. By weight, take 100 parts of cement, 80-150 parts of sand, and 6-8 parts of superhydrophobic modified silica solid powder. The cement is P.O42.5 ordinary silicate cement, the sand is fine sand screened through a 35-40 mesh sieve, and the superhydrophobic modified silica solid powder is silica that has been soaked in 1wt.% octadecanoic acid ethanol solution and then dried. S2. Mix the cement and sand thoroughly and evenly, add 40-45 parts by weight of water, and start mixing; while mixing, add the superhydrophobic modified silica solid powder evenly to make the concrete produce more dense needle-like products of different sizes, so as to have the layered roughness required for the superhydrophobic surface; after the superhydrophobic modified silica solid powder is added, continue to mix thoroughly to obtain the concrete slurry. S3. The obtained concrete slurry is poured and hardened to form a superhydrophobic concrete structure. After the superhydrophobic concrete structure is broken, the static water contact angle at any point on the cross-section is greater than 150°. After the superhydrophobic concrete structure is rubbed for 250 cm, the static water contact angle is greater than 150°.

2. The product obtained by the simple and environmentally friendly integral superhydrophobic concrete preparation method according to claim 1, characterized in that: The raw materials of the product, by weight, consist of 100 parts cement, 80-150 parts sand, 6-8 parts superhydrophobic modified silica solid powder, and 40-45 parts water; its microstructure is dense needle-like, forming a Cassie-Baxter state.

3. The product according to claim 2, characterized in that: Compared to concrete without the addition of superhydrophobic modified silica solid powder, the product exhibits an increased corrosion potential and a decreased corrosion current.

Images