Mechanical damage resistant hydrophobic and oleophobic concrete and preparation method thereof

Abstract

The invention provides mechanical damage resistant hydrophobic and oleophobic concrete and a preparation method thereof, and belongs to the technical field of building materials. The preparation method comprises the following steps: S10, dissolving a fluorine-containing monomer and a non-fluorine monomer in DMF and / or DMAC according to a ratio of (2-30) wt%: (2-30) wt%, adding (0.5-3) wt% of AIBN, and carrying out a polymerization reaction at 50-90 DEG C for 1-12 h to obtain a fluorine-containing copolymer solution; s20, pouring the fluorine-containing copolymer solution into water, and carrying out precipitation and filtration; s30, washing and filtering the precipitate with ethanol and / or isopropanol; s40, carrying out vacuum drying on the washed precipitate, grinding into powder, and sieving with a 400-mesh sieve to obtain fluorine-containing copolymer powder; s50, cement, fine sand, water and the fluorine-containing copolymer powder are mixed and stirred to form cement paste; and S60, pouring the cement paste into a mold, molding, and air-drying to obtain the mechanical damage resistant hydrophobic and oleophobic concrete.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a mechanical damage resistant hydrophobic and oleophobic concrete and a preparation method thereof. Background Art

[0002] The corrosion and deterioration of concrete is a diverse and complex process. The types of corrosion include physical degradation, chemical degradation and biological degradation. Specific examples include: dissolution, dry-wet cycle, freeze-thaw cycle, acid rain corrosion, chloride ion erosion, carbonization and microbial corrosion. The corrosion of concrete is closely related to the permeability of water. As a carrier of corrosive media, water can dissolve and transport, allowing a variety of chemical substances (acids, alkalis, salts) to penetrate into the concrete with water, directly or indirectly causing corrosion and degradation of the concrete. The penetration of water into the concrete also provides the necessary environmental conditions for the growth of microorganisms, thereby causing biological corrosion of the concrete. The preparation of super-hydrophobic concrete can greatly reduce the hydrophilicity of concrete, especially the preparation of concrete with super-hydrophobic properties on the surface and inside, which can further reduce the penetration of water into the concrete, thereby improving the concrete's ability to resist corrosion and degradation.

[0003] Chinese patent CN111410454A discloses a method for preparing efficient internally mixed nano super hydrophobic concrete or cement mortar, by mixing and diluting a nano super hydrophobic emulsion with water, and then mixing the diluted nano super hydrophobic emulsion with the raw materials for preparing cement mortar or concrete, and curing and molding to obtain efficient internally mixed nano super hydrophobic concrete, which has good hydrophobic effect and longer service life. Chinese patent CN115260384B discloses a cement-based fluorinated copolymer emulsion, a super hydrophobic concrete based on the emulsion, and a preparation method thereof, first synthesizing a cement-based fluorinated copolymer emulsion by an emulsion polymerization method, and then mixing the cement-based fluorinated copolymer emulsion in the process of preparing concrete to obtain a super hydrophobic concrete, which has super hydrophobic properties on the surface and inside, has high impermeability and super hydrophobic properties, and wear resistance, and can significantly improve the durability of concrete.

[0004] Although adding hydrophobic emulsion in the process of preparing concrete can effectively improve the hydrophobicity and wear resistance of concrete, the emulsion and its components will affect the hydration of cement, thus significantly affecting the strength and application range of concrete. Therefore, it is necessary to develop a hydrophobic and oleophobic concrete that is resistant to mechanical damage and has a low strength reduction rate. Summary of the invention

[0005] The present invention is made to solve the above problems, and aims to provide a mechanical damage resistant hydrophobic and oleophobic concrete and a preparation method thereof.

[0006] The invention provides a method for preparing mechanically-damaged hydrophobic and oleophobic concrete, which has the following characteristics and comprises the following steps: S10, dissolving a fluorine-containing monomer and a non-fluorine-containing monomer in DMF and / or DMAC according to (2-30) wt%: (2-30) wt%, adding (0.5-3) wt% of azobisisobutyronitrile AIBN, and carrying out polymerization reaction at a temperature of 50 DEG C-90 DEG C for 1-12 hours to obtain a fluorine-containing copolymer solution; S20, pouring the fluorine-containing copolymer solution into water, and obtaining a precipitate through precipitation and filtration; S30, repeatedly washing and filtering the precipitate with ethanol and / or isopropanol to obtain a washed precipitate; S40, vacuum drying the washed precipitate, grinding it into powder, and passing it through a 400-mesh sieve to obtain a fluorine-containing copolymer powder; S50, mixing cement, fine sand, water and the fluorine-containing copolymer powder, and stirring to form cement slurry; S60, pouring the cement slurry into a mold, molding, and naturally air-drying or curing air-drying to obtain the mechanically-damaged hydrophobic and oleophobic concrete.

[0007] The method for preparing mechanical damage resistant hydrophobic and oleophobic concrete provided by the present invention may also have the following characteristics: wherein, in step S10, the fluorine-containing monomer is selected from any one or more of perfluorononyl ethyl methacrylate, perfluorononyl ethyl acrylate, perfluorononyl ethylene, perfluorooctyl ethyl acrylate, perfluorooctyl ethyl methacrylate, perfluorooctyl ethylene, dodecafluoroheptyl methacrylate, dodecafluoroheptyl acrylate, perfluorohexyl ethyl acrylate, perfluorohexyl ethyl acrylate, perfluorohexyl ethylene, perfluorobutyl ethyl methacrylate, perfluorobutyl ethyl acrylate, perfluorobutyl ethylene, hexafluorobutyl methacrylate, and hexafluorobutyl acrylate.

[0008] The method for preparing mechanical damage resistant hydrophobic and oleophobic concrete provided by the present invention may also have the following characteristics: wherein, in step S10, the non-fluorine monomer is selected from any one or more of alkyl acrylates having a carbon chain number of 1-18 and alkyl methacrylates having a carbon chain number of 1-18.

[0009] The method for preparing mechanical damage resistant hydrophobic and oleophobic concrete provided by the present invention may also have the following characteristics: wherein, in step S50, the cement is any one or any combination of Portland cement, ordinary Portland cement, slag Portland cement, pozzolanic Portland cement, fly ash Portland cement and composite Portland cement.

[0010] The method for preparing the mechanical damage resistant hydrophobic and oleophobic concrete provided by the present invention may also have the following characteristics: wherein, in step S50, the fine sand is river sand or machine-made sand screened with 60 meshes.

[0011] The present invention provides a mechanical damage resistant hydrophobic and oleophobic concrete, which has the following characteristics: the concrete is prepared by adopting the preparation method of the mechanical damage resistant hydrophobic and oleophobic concrete.

[0012] Functions and Effects of the Invention

[0013] According to the mechanical damage resistant hydrophobic and oleophobic concrete and its preparation method involved in the present invention, because the preparation method dissolves the fluorine-containing monomer and the non-fluorine monomer in DMF and / or DMAC according to a specific ratio, and then adds AIBN, and polymerizes at a specific temperature to obtain a fluorine-containing copolymer emulsion, and the fluorine-containing copolymer emulsion is introduced into water, and after precipitation and filtration, the precipitate is repeatedly washed and filtered with ethanol and / or isopropanol crystals, and then vacuum dried, ground into powder and sieved to obtain super mechanical damage resistant hydrophobic and oleophobic concrete. The mechanical damage resistant hydrophobic and oleophobic concrete has the characteristics of hydrophobic and oleophobic surfaces and profiles, which can significantly reduce the water absorption rate of concrete; compared with ordinary hydrophobic concrete (non-oleophobic type), the hydrophobic and oleophobic concrete of the present invention is resistant to pollution by oily substances and has better durability; in addition, when the hydrophobic and oleophobic concrete of the present invention is mechanically damaged (such as knocking, scratching, and wear, etc.), the newly exposed surface still has hydrophobic and oleophobic properties.

[0014] In addition, the low surface energy component of the mechanical damage resistant hydrophobic and oleophobic concrete of the present invention is a fluorine-containing copolymer powder, which has little interaction with cement-based materials and has little effect on the mechanical properties of concrete after being added; and the added fluorine-containing copolymer powder is a macromolecular polymer, and compared with other internally added low surface energy compounds (such as small molecular fluorocarbons, silanes, fluorosilanes, alkanes, etc.), the hydrophobic and oleophobic concrete is not easy to lose during service and has better stability.

[0015] In addition, the preparation method of the mechanical damage resistant hydrophobic and oleophobic concrete of the present invention is simple and convenient for large-scale production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flowchart of a method for preparing mechanical damage resistant hydrophobic and oleophobic concrete in Example 1 of the present invention;

[0017] Figure 2 This is a photograph of the hydrophobicity and oleophobicity of the mechanically damaged hydrophobic and oleophobic concrete after crushing in Example 2 of the present invention. DETAILED DESCRIPTION

[0018] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments are combined with the accompanying drawings to specifically illustrate the mechanical damage resistant hydrophobic and oleophobic concrete and the preparation method thereof.

[0019] Example 1

[0020] Figure 1 It is a flowchart of a method for preparing mechanical damage resistant hydrophobic and oleophobic concrete in Example 1 of the present invention.

[0021] like Figure 1 As shown, this embodiment provides a mechanical damage resistant hydrophobic and oleophobic concrete and a preparation method thereof. The preparation method comprises the following steps:

[0022] Step S10, dissolving the fluorine-containing monomer and the non-fluorine-containing monomer in DMF and / or DMAC at (2-30) wt%: (2-30) wt%, adding (0.5-3) wt% azobisisobutyronitrile (AIBN), and polymerizing at a temperature of 50° C. to 90° C. for 1 to 12 hours to obtain a fluorine-containing copolymer solution.

[0023] In this step, the fluorine-containing monomer is selected from any one or any combination of perfluorononylethyl methacrylate, perfluorononylethyl acrylate, perfluorononylethylene, perfluorooctylethyl acrylate, perfluorooctylethyl methacrylate, perfluorooctylethylene, dodecafluoroheptyl methacrylate, dodecafluoroheptyl acrylate, perfluorohexylethyl acrylate, perfluorohexylethyl methacrylate, perfluorohexylethylene, perfluorobutylethyl methacrylate, perfluorobutylethyl acrylate, perfluorobutylethylene, hexafluorobutyl methacrylate, and hexafluorobutyl acrylate; and the non-fluorine-containing monomer is selected from any one or any combination of alkyl acrylates having a carbon chain number of 1 to 18 or alkyl methacrylates having a carbon chain number of 1 to 18.

[0024] Step S20, mixing water and the fluorine-containing copolymer solution in a mass ratio of (2-10):1, and obtaining a precipitate by precipitation and filtration.

[0025] Step S30, washing the precipitate three times with ethanol and / or isopropanol, and filtering to obtain a washed precipitate.

[0026] Step S40, vacuum drying the washed precipitate at 40°C for 72 hours, grinding it into powder, and passing it through a 400-mesh sieve to obtain a fluorine-containing copolymer powder.

[0027] Step S50, 135g of cement, 45g of fine sand, 47.25ml of water, and 1.35g of fluorine-containing copolymer powder are placed in a stirrer and stirred at a stirring speed of 250r / min for 240s to form a cement slurry. In this step, the cement is silicate cement, ordinary silicate cement, slag silicate cement, pozzolanic silicate cement, fly ash silicate cement, or composite silicate cement; the fine sand is 60-mesh screened river sand or machine-made sand.

[0028] S60, pouring cement slurry into a mold, shaping it, and air-drying it naturally or curing it to obtain internal and external hydrophobic and oleophobic concrete, that is, mechanical damage-resistant hydrophobic and oleophobic concrete.

[0029] Example 2

[0030] This embodiment provides a mechanical damage resistant hydrophobic and oleophobic concrete, which is prepared by the preparation method of the mechanical damage resistant hydrophobic and oleophobic concrete of Example 1.

[0031] Specifically, the specific parameters of each step are selected as follows: in step S10, the fluorine-containing monomer is 150g of perfluorohexylethyl acrylate, the non-fluorine monomer is 150g of octadecyl methacrylate, the solvent is 1000g of DMAC, the amount of azobisisobutyronitrile (AIBN) is 5g, the polymerization temperature is 80°C, and the polymerization time is 6h; in step S20, the amount of water is 500g, and the amount of the fluorine-containing copolymer solution is 100g; in step S30, the alcohol is ethanol; the cement in step S50 is PO52.5 ordinary Portland cement; and the fine sand is 60-mesh screened machine-made sand.

[0032] Figure 2 This is a photograph of the hydrophobicity and oleophobicity of the mechanically damaged hydrophobic and oleophobic concrete after crushing in Example 2 of the present invention.

[0033] like Figure 2 As shown, the mechanical damage resistant hydrophobic and oleophobic concrete of this embodiment has excellent mechanical damage resistance and still has good hydrophobic and oleophobic properties even if it is broken into pieces.

[0034] Example 3

[0035] This example uses the method for preparing mechanical damage resistant hydrophobic and oleophobic concrete in Example 1 to prepare 30 kinds of mechanical damage resistant hydrophobic and oleophobic concretes, and the 30 kinds of mechanical damage resistant hydrophobic and oleophobic concretes are respectively recorded as samples 1 to 30. The specific parameters in the preparation process of the 30 samples are shown in Table 1.

[0036] Table 1 (Specific parameters during the preparation of samples 1 to 30)

[0037]

[0038]

[0039]

[0040]

[0041] This embodiment also refers to the prior art Chinese patents CN111410454A, CN108341635B, CN115260384B, and CN107244847B to prepare four types of hydrophobic concrete, which are respectively recorded as sample 31, sample 32, sample 33, and sample 34.

[0042] In this example, the prepared samples 1 to 34 were characterized by the following properties:

[0043] (1) The static water contact angle (WCA) and mineral oil contact angle (OCA) of the samples were measured using a contact angle meter.

[0044] (2) Test the water absorption and mineral oil absorption of samples in accordance with the standard JC474-2008 "Mortar and Concrete Waterproofing Agent".

[0045] (3) Mechanical strength reduction rate: The 28d flexural strength and 28d bending strength of concrete were measured using GBJ 107-87 “Standard for Testing and Evaluation of Concrete Strength”. The mechanical strength reduction rates of samples 1 to 34 were calculated as follows: flexural strength reduction rate = flexural strength of sample / flexural strength of ordinary concrete*100%; compressive strength reduction rate = compressive strength of sample / compressive strength of ordinary concrete*100%.

[0046] (4) The wear resistance of the hydrophobic property of the sample is characterized by testing the water and mineral oil contact angles after the surface is worn by sandpaper, as follows: After rubbing the surface of the mechanical damage-resistant hydrophobic and oleophobic concrete of the present invention with 1500-grit sandpaper 50 times, the water contact angle (WCA) and mineral oil contact angle (OCA) of the concrete surface are tested.

[0047] The above corresponding performance characterization results are shown in Table 2.

[0048] Table 2 (Performance characterization results of samples 1 to 34)

[0049]

[0050]

[0051] As shown in Table 1 and Table 2, combined with the performance characterization test of samples 1 to 30, the hydrophobicity of the surface of the mechanical damage resistant hydrophobic and oleophobic concrete of the present invention is greater than 150°, and the oleophobicity is also around 150°, with super hydrophobic and strong oleophobic properties, and the water absorption rate is less than 2%, which is more resistant to water and oily substance pollution than ordinary concrete, and has better durability. After 50 frictions with 1500 mesh sandpaper, the hydrophobicity of the newly exposed surface of the mechanical damage resistant hydrophobic and oleophobic concrete of the present invention is still above 140°, and has good mechanical damage resistance.

[0052] As shown in Table 1 and Table 2, the mechanical strength reduction rate of samples 1 to 30 of the present invention is lower than that of samples 31 to 34 prepared under the prior art, that is, the mechanical damage-resistant hydrophobic and oleophobic concrete of the present invention has higher compressive strength and higher flexural strength, and is more widely and safely applied.

[0053] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing mechanical damage resistant hydrophobic and oleophobic concrete, characterized in that: include: S10, dissolving the fluorine-containing monomer and the non-fluorine-containing monomer in DMF and / or DMAC at a ratio of (2-30) wt %: (2-30) wt %, adding (0.5-3) wt % of azobisisobutyronitrile AIBN, and polymerizing at a temperature of 50° C.-90° C. for 1-12 h to obtain a fluorine-containing copolymer solution; S20, pouring the fluorinated copolymer solution into water, and obtaining a precipitate by precipitation and filtration; S30, repeatedly washing and filtering the precipitate with ethanol and / or isopropanol to obtain a washed precipitate; S40, vacuum drying the washed precipitate, grinding it into powder, and passing it through a 400-mesh sieve to obtain a fluorine-containing copolymer powder; S50, mixing cement, fine sand, water and the fluorine-containing copolymer powder, and stirring to form cement slurry; S60, pouring the cement slurry into a mold, forming it, and air-drying it naturally or curing it to obtain a mechanical damage-resistant hydrophobic and oleophobic concrete.

2. The method for preparing the mechanical damage resistant hydrophobic and oleophobic concrete according to claim 1, characterized in that: in, In step S10, the fluorine-containing monomer is selected from any one or more of perfluorononylethyl methacrylate, perfluorononylethyl acrylate, perfluorononylethylene, perfluorooctylethyl acrylate, perfluorooctylethyl methacrylate, perfluorooctylethylene, dodecafluoroheptyl methacrylate, dodecafluoroheptyl acrylate, perfluorohexylethyl acrylate, perfluorohexylethyl methacrylate, perfluorohexylethylene, perfluorobutylethyl methacrylate, perfluorobutylethyl acrylate, perfluorobutylethylene, hexafluorobutyl methacrylate, and hexafluorobutyl acrylate.

3. The method for preparing mechanical damage resistant hydrophobic and oleophobic concrete according to claim 1, characterized in that: in, In step S10, the non-fluorine monomer is selected from any one or more of alkyl acrylates having a carbon chain number of 1-18 and alkyl methacrylates having a carbon chain number of 1-18.

4. The method for preparing the mechanical damage resistant hydrophobic and oleophobic concrete according to any one of claims 1 to 3, characterized in that: in, In step S50, the cement is any one or any combination of Portland cement, ordinary Portland cement, slag Portland cement, pozzolanic Portland cement, fly ash Portland cement and composite Portland cement.

5. The method for preparing mechanical damage resistant hydrophobic and oleophobic concrete according to claim 4, characterized in that: in, In step S50, the fine sand is river sand or machine-made sand screened with 60 mesh.

6. A mechanical damage resistant hydrophobic and oleophobic concrete, characterized by: The concrete is prepared by the method for preparing the mechanical damage resistant hydrophobic and oleophobic concrete according to any one of claims 1 to 5.

7. The mechanical damage resistant hydrophobic and oleophobic concrete according to claim 6, characterized in that: include: Conventional concrete; as well as Fluorine-containing copolymer powder is mixed in the conventional concrete.

8. The mechanical damage resistant hydrophobic and oleophobic concrete according to claim 7, characterized in that: in, The surface and cross section of the mechanical damage resistant hydrophobic and oleophobic concrete are hydrophobic and oleophobic, and can reduce the water absorption rate of the concrete.

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