Water permeable pressure-resistant concrete and method for producing the same

Abstract

The application relates to the technical field of concrete, and particularly discloses water-permeable compression-resistant concrete and a preparation method thereof, and the water-permeable compression-resistant concrete comprises the following raw materials in parts by weight: cement 150-200 parts, gravel 1000-1500 parts, fine sand 150-200 parts, a composite reinforcing agent 20-30 parts, a water reducing agent 3-4 parts and water 150-180 parts; the composite reinforcing agent comprises the following raw materials in parts by weight: redispersible polymer latex powder 100-200 parts and modified glass fiber 50-100 parts; and the modified glass fiber is obtained by coating and modifying glass fiber with multi-walled carbon nanotubes. The concrete obtained by the application has a 28d compression strength of 46.1-65.2 MPa, and the compression strength of the water-permeable concrete is improved under the condition of guaranteeing water permeability.

Description

Technical Field

[0001] This application relates to the field of concrete technology, and more specifically, to a permeable, compressive-resistant concrete and a method for preparing the same. Background Technology

[0002] Currently, permeable concrete is mainly no-fines porous permeable concrete. In this type of porous permeable concrete, the surface of the crushed stone is coated with a thin layer of cement paste that is bonded to the crushed stone, thus forming a honeycomb structure with uniformly distributed pores. Therefore, it has the characteristics of being breathable, having minimal capillary action, requiring less cement, and being easy to construct. It is generally used in highway slope protection and permeable brick applications.

[0003] In related technologies, permeable concrete does not add sand to increase the porosity of the concrete and thus improve its permeability. However, without sand, the bonding area between the cement paste and the aggregate is small, resulting in more defects in the interface structure. This leads to a decrease in the compressive strength of the concrete, making it difficult to meet actual use requirements, resulting in poor durability and easy cracking and deformation. Summary of the Invention

[0004] In order to improve the compressive strength of permeable concrete while ensuring permeability, this application provides a permeable compressive concrete and a method for preparing the same.

[0005] In the first aspect, this application provides a permeable compressive strength concrete, which adopts the following technical solution:

[0006] A permeable and pressure-resistant concrete, characterized in that it comprises the following raw materials in parts by weight: 150-200 parts cement, 1000-1500 parts crushed stone, 150-200 parts fine sand, 20-30 parts composite reinforcing agent, 3-4 parts water-reducing agent, and 150-180 parts water; wherein the composite reinforcing agent comprises the following raw materials in parts by weight: 100-200 parts redispersible polymer latex powder and 50-100 parts modified glass fiber; wherein the modified glass fiber is obtained by coating and modifying with carbon nanotubes.

[0007] This application discloses a permeable compressive strength concrete raw material comprising 150-200 parts cement, 1000-1500 parts crushed stone, 150-200 parts fine sand, 20-30 parts composite reinforcing agent, 3-4 parts water-reducing agent, and 150-180 parts water. The composite reinforcing agent comprises the following raw materials in parts by weight: 100-200 parts redispersible polymer latex powder and 50-100 parts modified glass fiber, any values ​​within their respective ranges can be selected, and it can improve the compressive strength of permeable concrete.

[0008] By adopting the above technical solution, the composite reinforcing agent is a mixture of redispersible polymer latex powder and modified glass fiber. The addition of modified glass fiber and redispersible polymer latex powder can reduce the amount of cement, thereby reducing the water absorption rate of concrete and improving the compressive strength of concrete. Furthermore, the mixture of redispersible polymer latex powder and modified glass fiber can improve the water resistance and mechanical properties of glass fiber, thereby improving the compressive strength of permeable concrete.

[0009] Modified glass fiber is obtained by coating glass fiber with carbon nanotubes, which can improve the tensile strength of glass fiber and the bonding strength between glass fiber and concrete, thereby improving the compressive strength of permeable concrete.

[0010] Preferably, the weight ratio of the modified glass fiber to the redispersible polymer latex powder is 1:(2-3).

[0011] By adopting the above technical solution and adjusting the weight ratio of modified glass fiber to redispersible polymer latex powder, the water resistance and mechanical properties of glass fiber can be further improved, thereby increasing the compressive strength of permeable concrete.

[0012] Preferably, the modified glass fiber is prepared through the following steps:

[0013] First, add multi-walled carbon nanotubes to a 0.5%-1% ammonium persulfate solution at 50-70℃ and stir for 10-14 hours. Then, remove the multi-walled carbon nanotubes and add them to distilled water. Disperse the mixture by ultrasonication. Add 0.3-0.4% ethylenetriamine and 20-30% polysorbate-20 by the mass of the multi-walled carbon nanotubes. Stir at 90-110℃ for 4.5-5.5 hours to obtain a multi-walled carbon nanotube solution.

[0014] Add 5-6g of wetting agent, 3-4g of dicyandiamide formaldehyde resin and 3-4g of bisphenol A polyester resin to 100mL of water and mix well to obtain mixture B.

[0015] The multi-walled carbon nanotube solution was mixed with mixture B to obtain an impregnation solution with a multi-walled carbon nanotube concentration of 0.4-0.6%.

[0016] The glass fiber was immersed in the wetting solution, then removed and freeze-dried to obtain the modified glass fiber.

[0017] By employing the above technical solution, carbon nanotubes are first oxidized with ammonium persulfate solution at 50-70℃, generating a large number of oxygen-containing groups on the surface of multi-walled carbon nanotubes. Then, functionalization treatment with ethylenediamine is performed, resulting in hydrophilic groups covering the surface of the multi-walled carbon nanotubes. The addition of polysorbate-20 ensures that the multi-walled carbon nanotubes are stably and uniformly dispersed in the wetting solution. The surface contains carboxyl and amino groups, which can react with the silicon-oxygen bonds on the glass fiber surface to form stable chemical bonds, thus bonding the glass fiber and the multi-walled carbon nanotubes and significantly improving the tensile strength of the glass fiber. Simultaneously, it also improves the bonding strength between the glass fiber and concrete, thereby increasing the compressive strength of permeable concrete.

[0018] Preferably, the mass ratio of the glass fiber to the wetting solution is 1:(1-2).

[0019] By adopting the above technical solution and adjusting the mass ratio of glass fiber to impregnation solution, the effect of carbon nanotube coating on glass fiber can be further improved, thereby further improving the strength of concrete.

[0020] Preferably, the composite reinforcing agent further includes the following raw materials in parts by weight: 10-20 parts of ultra-high molecular weight polyvinyl alcohol fiber and 10-20 parts of polyethylene glycol octylphenyl ether.

[0021] By adopting the above technical solution and adding ultra-high molecular weight polyvinyl alcohol fiber, the compressive strength and toughness of permeable concrete can be improved.

[0022] Adding polyethylene glycol octylphenyl ether to the mixture of ultra-high molecular weight polyethylene alcohol fiber can improve the dispersion of ultra-high molecular weight polyethylene fiber in the permeable concrete raw material system, thereby further improving the compressive strength of permeable concrete.

[0023] Preferably, the composite reinforcing agent further includes the following raw material in parts by weight: 20-30 parts of polydimethylsiloxane.

[0024] By adopting the above technical solution and adding polydimethylsiloxane, the redispersible polymer latex powder becomes hydrophobic, thereby improving the dispersion stability of the redispersible polymer latex powder in the permeable concrete raw material system, and thus improving the compressive strength of the permeable concrete.

[0025] Preferably, the weight ratio of the polydimethylsiloxane to the redispersible polymer latex powder is 1:(3-5).

[0026] By adopting the above technical solution and adjusting the weight ratio of polydimethylsiloxane to redispersible polymer latex powder, the dispersion stability of redispersible polymer latex powder in permeable concrete raw material system can be further improved.

[0027] Secondly, this application provides a method for preparing permeable compressive strength concrete, which is achieved through the following technical solution:

[0028] A permeable and compressive-resistant concrete, comprising the following steps:

[0029] First, mix cement, crushed stone, fine sand and water-reducing agent, stir evenly to obtain component A;

[0030] Add the composite reinforcing agent to one-third of the total amount of water at 60-80℃, stir evenly, and obtain component B;

[0031] Mix component A and component B, add other raw materials and remaining water, and stir evenly to obtain permeable compressive concrete.

[0032] By adopting the above technical solution, the composite reinforcing agent is added to hot water to make hot water slurry, which makes the redispersible polymer latex powder in the composite reinforcing agent easier to disperse.

[0033] In summary, this application includes at least one of the following beneficial technical effects:

[0034] (1) This application improves the compressive strength of permeable concrete by controlling the type and dosage of each raw material to achieve a 28-day compressive strength of 47.5 MPa.

[0035] (2) This application improves the compressive strength of permeable concrete by adjusting the mass ratio of glass fiber to impregnation solution in modified glass fiber to achieve a 28-day compressive strength of 48.8-50.0 MPa.

[0036] (3) This application improves the compressive strength of permeable concrete by adjusting the weight ratio of modified glass fiber and redispersible polymer latex powder to achieve a 28-day compressive strength of 53.5-54.0 MPa.

[0037] (4) This application improves the compressive strength of permeable concrete by adding polyethylene glycol octylphenyl ether and ultra-high molecular weight polyvinyl alcohol fiber to the composite reinforcing agent raw materials and adjusting the amount of both, so that the 28-day compressive strength of permeable concrete is 60.5 MPa.

[0038] (5) This application improves the compressive strength of permeable concrete by adding polydimethylsiloxane to the composite reinforcing agent raw material and adjusting the weight ratio of polydimethylsiloxane to redispersible polymer latex powder, so that the 28-day compressive strength of permeable concrete is 63.7-65.2 MPa. Detailed Implementation

[0039] The present application will be further described in detail below with reference to specific embodiments.

[0040] The following raw materials used in this application are all commercially available products and are intended to fully disclose the raw materials used in this application. They should not be construed as limiting the source of the raw materials. Specifically: cement, selected from silicate cement, P42.5; crushed stone, selected from basalt gravel, with a particle size of 20-40 mm; fine sand, with a particle size of 0.35-0.25 mm; water-reducing agent, selected from polycarboxylate superplasticizer, with an effective substance content of 99%; redispersible polymer latex powder, model FX2350, with a solid content of 99.99% wt%; glass fiber, with a particle size of 12 mm; multi-walled carbon nanotubes, with a diameter of 10-30 nm and a length of 1-2 μm; ethylenediamine, with an effective substance content of 99%. Polysorbate-20, with an effective substance content of 99%; sizing agent, Poronic 6800, with an effective substance content of 99%; dicyandiamide-formaldehyde resin, with an effective substance content of 99%; bisphenol A type polyester resin, with a solid content of 99%; ultra-high molecular weight polyvinyl alcohol fiber, with a diameter of 0.15 mm, a length of 6 mm, a tensile strength ≥1200 MPa, and an initial modulus ≥8 GPa; polyethylene glycol octylphenyl ether, with an effective substance content of 99%; polydimethylsiloxane, with an effective substance content of 99%.

[0041] The following are examples of the preparation of modified glass fibers.

[0042] Preparation Example 1

[0043] The modified glass fiber of Preparation Example 1 was prepared by the following steps:

[0044] First, 1 kg of multi-walled carbon nanotubes were added to 3 L of 0.5% ammonium persulfate solution at 60℃ and stirred for 12 h. The multi-walled carbon nanotubes were then removed and added to 3 L of distilled water. The mixture was ultrasonically dispersed, and then 0.33 kg of ethylenetriamine and 0.25 kg of polysorbate-20 were added. The mixture was stirred at 100℃ for 5 h to obtain a multi-walled carbon nanotube solution.

[0045] Add 5g of wetting agent, 3g of dicyandiamide-formaldehyde resin and 3g of bisphenol A polyester resin to 100mL of water and mix well to obtain mixture B.

[0046] The multi-walled carbon nanotube solution was mixed with mixture B to obtain an impregnation solution with a multi-walled carbon nanotube concentration of 0.5%.

[0047] 1 kg of glass fiber was immersed in 0.8 L of wetting solution, then removed and freeze-dried to obtain modified glass fiber.

[0048] Preparation Examples 2-5

[0049] The modified glass fibers prepared in Examples 2-5 were prepared using the same method as those prepared in Example 1, except that the amount of the impregnation solution was 1L, 1.5L, 2L, and 2.2L, respectively. The remaining operations were the same as those in Example 1.

[0050] The following are examples of the preparation of composite reinforcing agents.

[0051] Preparation Example 6

[0052] The composite reinforcing agent of Preparation Example 6 was prepared by the following steps:

[0053] According to the dosage in Table 1, the redispersible polymer latex powder was mixed with the modified glass fiber obtained in Preparation Example 1 and stirred evenly to obtain the composite reinforcing agent.

[0054] Preparation Examples 7-10

[0055] The composite reinforcing agents of Preparation Examples 7-10 were prepared using the same method as those of Preparation Example 6, except that the modified glass fibers used were the modified glass fibers prepared in Preparation Examples 2-5, and the other operations were the same as those in Preparation Example 1.

[0056] Preparation Examples 11-14

[0057] The composite reinforcing agents prepared in Examples 11-14 were prepared using the same method as those prepared in Example 8, except that the dosage of each raw material was different, as detailed in Table 1.

[0058] Table 1. Dosage of each raw material in the composite reinforcing agent (kg)

[0059]

[0060] Preparation Examples 15-19

[0061] The composite reinforcing agents prepared in Examples 15-19 were prepared using the same method as those prepared in Example 12, except that the composite reinforcing agents also included ultra-high molecular weight polyvinyl alcohol fibers and polyethylene glycol octylphenyl ether. The specific dosages are detailed in Table 2.

[0062] Table 2. Dosage of each raw material in the composite reinforcing agent (kg)

[0063]

[0064] Preparation Examples 20-24

[0065] The composite reinforcing agents prepared in Examples 20-24 were prepared using the same method as those prepared in Example 19, except that the composite reinforcing agents also included polydimethylsiloxane, the specific dosage of which is detailed in Table 3.

[0066] Table 3. Dosage of each raw material in the composite reinforcing agent (kg)

[0067]

[0068] Example 1

[0069] A permeable and compressive-resistant concrete is prepared through the following steps:

[0070] According to the dosage in Table 4, first mix the cement, crushed stone, fine sand and water-reducing agent, stir evenly, and obtain component A;

[0071] Add the composite reinforcing agent to one-third of the total volume of water, heat to 25-30℃, and stir for 20-25 minutes to obtain component B; mix component A and component B, add other raw materials and the remaining water, and stir evenly to obtain permeable compressive concrete. The composite reinforcing agent used is the one obtained in Preparation Example 6.

[0072] Example 2-3

[0073] The permeable compressive concrete of Examples 2-3 is prepared in the same way as that of Example 1, except that the dosage of each raw material is different, as detailed in Table 4.

[0074] Table 4. Dosage of each raw material in permeable compressive concrete of Examples 1-3 (unit: kg)

[0075] raw material Example 1 Example 2 Example 3 cement 180 180 180 gravel 1300 1300 1300 fine sand 180 180 180 Composite reinforcing agent 20 25 30 Water reducing agent 3.5 3.5 3.5 water 165 165 165

[0076] Example 4-21

[0077] The permeable compressive concrete of Examples 4-21 was prepared in the same way as that of Example 2, except that the composite reinforcing agent was the composite reinforcing agent prepared in Examples 7-24, and the other raw materials were the same as those in Example 2.

[0078] Comparative Example 1

[0079] The permeable compressive concrete of Comparative Example 1 was prepared in the same way as that of Example 1, except that no composite reinforcing agent was added to the permeable compressive concrete, while the other raw materials and dosages were the same as those in Example 1.

[0080] Comparative Example 2

[0081] The permeable compressive concrete of Comparative Example 2 was prepared in the same way as that of Example 1, except that the redispersible polymer latex powder in the composite reinforcing agent was replaced with modified glass fiber in equal amounts, while the other raw materials and dosages were the same as those in Example 1.

[0082] Comparative Example 3

[0083] The permeable compressive concrete of Comparative Example 3 was prepared in the same way as that of Example 1, except that the modified glass fiber in the composite reinforcing agent was replaced with redispersible polymer latex powder in equal amounts, while the other raw materials and dosages were the same as those in Example 1.

[0084] Performance testing

[0085] The permeable compressive concrete obtained in different Examples 1-21 and Comparative Examples 1-3 were tested using the following testing standards or methods. The test results are detailed in Table 5.

[0086] 28-day compressive strength: The 28-day compressive strength of permeable concrete was tested according to GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete".

[0087] Permeability coefficient: The permeability coefficient of permeable concrete is tested according to GB / T25993-2010 "Instructions for Test Device of Permeability Coefficient of Standard Permeable Cement Concrete".

[0088] Bleeding rate: The bleeding rate of permeable concrete is tested according to the bleeding test in GB / T50080-2002 "Standard for Test Methods of Performance of Ordinary Concrete Mixture".

[0089] Table 5 Performance test results of different permeable compressive concretes

[0090]

[0091]

[0092] The test results in Table 5 show that the permeability coefficient and bleeding rate of the permeable concrete obtained in this application are 7.2-8.7 mm / s, the bleeding rate is 5-10%, and the 28-day compressive strength is 46.1-65.2 MPa. While ensuring permeability, the compressive strength of the permeable concrete is improved.

[0093] Of the examples 1-3, the 28-day compressive strength of the permeable concrete in Example 2 was 47.5 MPa, which was higher than that in Examples 1 and 3. This indicates that the dosage of the composite reinforcing agent in Example 2 was appropriate, improving the compressive strength of the permeable concrete. This may be related to the fact that the composite reinforcing agent was a mixture of redispersible polymer latex powder and modified glass fiber. The addition of modified glass fiber and redispersible polymer latex powder can reduce the amount of cement used, thereby reducing the water absorption rate of the concrete and improving its compressive strength. Furthermore, the mixture of redispersible polymer latex powder and modified glass fiber can improve the water resistance and mechanical properties of the glass fiber, thus increasing the compressive strength of the permeable concrete.

[0094] Combining the performance test data of permeable concrete from Examples 2 and 4-7, it was found that the 28-day compressive strength of the permeable concrete from Examples 4-6 was 48.8-50.0 MPa, which was higher than that of Examples 2 and 7. This indicates that a mass ratio of glass fiber to impregnation solution of 1:(1-2) is more suitable, improving the compressive strength of the permeable concrete. This may be related to the fact that adjusting the mass ratio of glass fiber to impregnation solution can further enhance the effect of carbon nanotube coating on glass fiber, thereby further improving the strength of the concrete.

[0095] Based on the performance test data of the permeable concrete in Examples 8-12, the 28-day compressive strength of the permeable concrete in Examples 9-11 was 53.5-54.0 MPa, which was higher than that in Examples 8 and 12. This indicates that a weight ratio of modified glass fiber to redispersible polymer latex powder of 1:(2-3) is more suitable, improving the compressive strength of the permeable concrete. This may be related to the fact that adjusting the weight ratio of modified glass fiber to redispersible polymer latex powder can further improve the water resistance and mechanical properties of glass fiber, thereby increasing the compressive strength of the permeable concrete.

[0096] Based on the performance test data of permeable concrete in Examples 13-17, the 28-day compressive strength of permeable concrete in Example 16 was 60.5 MPa, which was higher than that of Examples 13-15 and Example 17. This indicates that the ultra-high molecular weight polyvinyl alcohol fiber and polyethylene glycol octylphenyl ether in the raw materials of permeable concrete in Example 16 were more suitable, thus improving the compressive strength of the permeable concrete. This may be related to the fact that the addition of polyethylene glycol octylphenyl ether to mix with ultra-high molecular weight polyvinyl alcohol fiber can improve the dispersion of ultra-high molecular weight polyethylene fiber in the permeable concrete raw material system, thereby further improving the compressive strength of the permeable concrete.

[0097] Based on the performance test data of the permeable concrete in Examples 18-22, the 28-day compressive strength of the permeable concrete in Examples 19-21 was 63.7-65.2 MPa, all higher than that in Examples 18 and 22. This indicates that a weight ratio of polydimethylsiloxane to redispersible polymer latex powder of 1:(3-5) is more suitable, improving the compressive strength of the permeable concrete. This may be related to the fact that adjusting the weight ratio of polydimethylsiloxane to redispersible polymer latex powder can further improve the dispersion stability of redispersible polymer latex powder in the permeable concrete raw material system.

[0098] Based on the performance test data of permeable concrete in Example 1 and Comparative Examples 1-3, it was found that adding composite reinforcing agents to permeable concrete raw materials, as well as adding redispersible polymer latex powder and modified glass fiber to composite reinforcing agents, can improve the compressive strength of permeable concrete to varying degrees.

[0099] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A permeable, compressive-resistant concrete, characterized in that, It comprises the following raw materials in parts by weight: 150-200 parts cement, 1000-1500 parts crushed stone, 150-200 parts fine sand, 20-30 parts composite reinforcing agent, 3-4 parts water-reducing agent, and 150-180 parts water; the composite reinforcing agent comprises the following raw materials in parts by weight: 100-200 parts redispersible polymer latex powder and 50-100 parts modified glass fiber; the modified glass fiber is obtained by coating and modifying glass fiber with multi-walled carbon nanotubes. The modified glass fiber is specifically prepared through the following steps: First, add multi-walled carbon nanotubes to a 0.5%-1% ammonium persulfate solution at 50-70℃ and stir for 10-14 hours. Then, remove the multi-walled carbon nanotubes and add them to distilled water. Disperse the mixture by ultrasonication. Add 0.3-0.4% ethylenedienetriamine and 20-30% polysorbate-20 by the mass of the multi-walled carbon nanotubes. Stir at 90-110℃ for 4.5-5.5 hours to obtain a multi-walled carbon nanotube solution. Add 5-6g of wetting agent, 3-4g of dicyandiamide formaldehyde resin and 3-4g of bisphenol A polyester resin to 100mL of water and mix well to obtain mixture B. The multi-walled carbon nanotube solution was mixed with mixture B to obtain an impregnation solution with a multi-walled carbon nanotube concentration of 0.4-0.6%. The glass fiber was immersed in the wetting solution, then removed and freeze-dried to obtain the modified glass fiber.

2. The permeable compressive concrete according to claim 1, characterized in that, The weight ratio of the modified glass fiber to the redispersible polymer latex powder is 1:(2-3).

3. The permeable compressive strength concrete according to claim 1, characterized in that, The mass ratio of the glass fiber to the impregnation solution is 1:(1-2).

4. The permeable compressive concrete according to claim 1, characterized in that: The composite reinforcing agent also includes the following raw materials in parts by weight: 10-20 parts of ultra-high molecular weight polyvinyl alcohol fiber and 10-20 parts of polyethylene glycol octylphenyl ether.

5. The permeable compressive strength concrete according to claim 1, characterized in that, The composite reinforcing agent also includes the following raw materials in parts by weight: 20-30 parts of polydimethylsiloxane.

6. The permeable compressive strength concrete according to claim 5, characterized in that, The weight ratio of the polydimethylsiloxane to the redispersible polymer latex powder is 1:(3-5).

7. A method for preparing permeable compressive strength concrete according to any one of claims 1-6, characterized in that, The following steps are included: First, mix cement, crushed stone, fine sand and water-reducing agent, stir evenly to obtain component A; Add the composite reinforcing agent to one-third of the total volume of water, heat to 25-30℃, and stir for 20-25 minutes to obtain component B; Mix component A and component B, add other raw materials and remaining water, and stir evenly to obtain permeable compressive concrete.

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