Silicone composite coating and modified steel fiber, preparation method and application thereof

Abstract

The present application relates to the field of solid waste resource utilization, and discloses a kind of organic silicon composite coating and modified steel fiber and its preparation method and application.The organic silicon composite coating includes component A and component B;The component A includes organic silicon and organic chlorosilane;The component B includes organic silicon, organic chlorosilane and solid waste F1;Wherein, the content of solid waste F1 in the component B is 1-30wt%.The organic silicon composite coating is combined with a certain amount of solid waste, and the surface of steel fiber is modified using the coating, and then used to prepare modified steel fiber solid waste recycled concrete, which can realize efficient utilization of solid waste, and further improve the bonding force between steel fiber and concrete matrix, thereby improving the comprehensive mechanical properties of solid waste recycled concrete.

Description

Technical Field

[0001] This invention relates to the fields of solid waste resource utilization and modified steel fiber concrete preparation, specifically to an organosilicon composite coating and modified steel fiber, their preparation method and application. Background Technology

[0002] To achieve the resource utilization of solid waste, incorporating solid waste as a filler into concrete is an effective method. Steel fiber reinforced recycled solid waste concrete is a multiphase composite concrete structure formed by incorporating randomly distributed steel fibers into recycled solid waste concrete. Due to the influence of solid waste, recycled solid waste concrete is inherently weaker than ordinary concrete under the same conditions in terms of tensile and compressive strength. The addition of steel fibers can effectively inhibit the rapid development of internal microcracks, improve the tensile, shear, flexural, and crack resistance of recycled solid waste concrete, enhance the stress-strain characteristics of the structure, and strengthen its durability.

[0003] However, steel fibers are also more prone to failure in recycled concrete. This is because the bond between steel fibers and recycled concrete is weak, and they are easily corroded and rusted by harmful ions in the solid waste, which further weakens the bond and makes the steel fibers loose and easy to pull out, thus reducing the mechanical properties and strain hardening characteristics of steel fiber concrete. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of low utilization rate of solid waste resources and poor mechanical properties of recycled solid waste concrete in the prior art. It provides a method for preparing and applying organosilicon composite coatings and modified steel fibers. This method can apply solid waste with preferred particle size and composition to organosilicon composite coatings, and then use the coatings to modify steel fibers to prepare modified steel fiber recycled solid waste concrete, thereby further improving the bonding force between the modified steel fibers and the concrete matrix. This achieves both efficient utilization of solid waste and the preparation of modified steel fiber recycled solid waste concrete with excellent mechanical properties.

[0005] To achieve the above objectives, the first aspect of the present invention provides an organosilicon composite coating, which is composed of component A and component B;

[0006] Component A contains organosilicon and organochlorosilane;

[0007] Component B contains organosilicon, organochlorosilane, and solid waste F1;

[0008] Wherein, based on the total weight of component B, the content of solid waste F1 in component B is 1-30 wt%;

[0009] Preferably, the preparation method of component A includes the following steps:

[0010] a1. Mix organosilicon with fatty alcohol, and then adjust the pH of the mixture to 3-6.

[0011] a2. Mix the organochlorosilane with the material obtained in step a1.

[0012] Preferably, the preparation method of component B includes the following steps:

[0013] b1. Mix the organosilicon with the fatty alcohol, and then adjust the pH of the mixture to 3-6.

[0014] b2. Mix the organochlorosilane with the material obtained in step b1;

[0015] b3. Mix solid waste F1 with the material obtained in step b2.

[0016] Preferably, the inorganic content in the solid waste F1 is ≥90wt%;

[0017] Preferably, the particle size of the solid waste F1 is 0.05-300 μm;

[0018] Preferably, the solid waste F1 is selected from one or more of construction solid waste, sludge and slag;

[0019] Preferably, the average particle size of the solid waste F1 is ≤30μm.

[0020] Preferably, the organosilicon is methyl orthosilicate and / or ethyl orthosilicate;

[0021] Preferably, the organochlorosilane is selected from one or more of methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, and diphenyldichlorosilane.

[0022] Preferably, in component A and component B, the molar ratio of the organochlorosilane to the organosilicon is 1-8:10, and the molar amounts of the organochlorosilane and the organosilicon are both calculated based on silicon element.

[0023] Preferably, in steps a1 and b1, the molar ratio of the organosilicon and the fatty alcohol is 1:1-9, and the molar amount of the organosilicon is calculated in terms of silicon element.

[0024] Preferably, the weight ratio of component A to component B is 1:0.5-4, and more preferably 1:1-3.

[0025] A second aspect of the present invention provides a method for preparing modified steel fibers, the method comprising: sequentially coating the surface of steel fibers with components A and B of the organosilicon composite coating, and drying to obtain modified steel fibers.

[0026] A third aspect of the present invention provides a modified steel fiber prepared by the above method.

[0027] A fourth aspect of the present invention provides the application of the above-mentioned modified steel fibers in the preparation of concrete.

[0028] The fifth aspect of the present invention provides a method for preparing modified steel fiber concrete, the method comprising: mixing cement, fly ash, silica fume, solid waste F2, kaolin and water, and then mixing the mixed materials, polycarboxylate superplasticizer and the modified steel fiber;

[0029] The weight ratio of cement, fly ash, silica fume, solid waste F2, kaolin, and polycarboxylate superplasticizer is 0.25:0.27:0.03:0.15-0.55:0.02:0.0015.

[0030] The weight ratio of the modified steel fiber to the total weight of cement, fly ash, silica fume, solid waste F2 and kaolin is 0.5-5:100.

[0031] Preferably, the solid waste F2 contains 15-40 wt% silicon, 2-20 wt% iron, 5-20 wt% aluminum and 4-40 wt% calcium.

[0032] In this invention, solid waste is used to prepare an organosilicon composite coating, resulting in a high-performance organosilicon composite coating that can block harmful ion corrosion and is also less expensive. The organosilicon composite coating is then applied to the surface of steel fibers to obtain modified steel fibers. These modified steel fibers can be used to prepare steel fiber-recycled solid waste concrete. More importantly, the steel fiber-recycled solid waste concrete prepared using the modified steel fibers of this invention exhibits significantly improved tensile strength and strain hardening characteristics, and further enhances the bonding force between the modified steel fibers and the concrete substrate, making the modified steel fibers less prone to loosening and pull-out, thus maintaining the stability of the performance of the prepared modified steel fiber-recycled solid waste concrete. Furthermore, a large amount of solid waste is also added to the steel fiber-recycled solid waste concrete of this invention, enabling large-scale solid waste disposal and further realizing the efficient utilization of solid waste. Detailed Implementation

[0033] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0034] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0035] This invention discloses an organosilicon composite coating, which is composed of component A and component B; component A contains organosilicon and organochlorosilane, and component B contains organosilicon, organochlorosilane and solid waste F1.

[0036] In a preferred embodiment, the organosilicon is methyl orthosilicate and / or ethyl orthosilicate.

[0037] In a preferred embodiment, the organochlorosilane is selected from one or more of methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, and diphenyldichlorosilane, and is more preferably methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, or diphenyldichlorosilane.

[0038] In a specific implementation, the organosilicon and organochlorosilane are selected in the same way in components A and B, that is, the organosilicon and organochlorosilane components in components A and B are equivalent. For example, when the organosilicon in component A is methyl orthosilicate and the organochlorosilane is methyltrichlorosilane, the organosilicon in component B is also methyl orthosilicate and the organochlorosilane is also methyltrichlorosilane.

[0039] In a preferred embodiment, the weight ratio of component A to component B needs to be controlled. If the proportion of component B is too low, the utilization rate of solid waste will be too low; if the proportion of component B is too high, the barrier performance of the coating will be reduced. The ratio of A to B is controlled to be 1:0.5-4, preferably 1:1-3. Specifically, the ratio of A to B can be 1:1, 1:2, or 1:3.

[0040] In this invention, it is necessary to control the content of solid waste F1 in component B. When the content of solid waste F1 is too low, the utilization rate of solid waste is too low, and the barrier effect is not significant enough. When it is too high, the organosilicon coating cannot be densified and formed, thus affecting the barrier performance. Preferably, in component B, based on the total weight of component B, the content of solid waste F1 is 1-30 wt%, preferably 20-25 wt%. Specifically, the content of sludge can be 20 wt%, 23 wt%, or 25 wt%.

[0041] In this invention, by utilizing the volcanic ash effect and filling effect of solid waste F1, not only was a dense and highly effective organosilicon composite coating prepared, but the resource utilization of solid waste F1 was also realized, opening up new avenues for the disposal of solid waste F1 and providing a new method for the preparation of organosilicon coatings.

[0042] In this invention, to ensure excellent shielding performance of the prepared organosilicon composite coating, the particle size of the solid waste F1 is controlled to be 0.05-300 μm, preferably 1-100 μm; more preferably 1-50 μm. In this invention, the addition of micro-nano-level solid waste to the organosilicon composite coating further enhances the bonding force between the subsequently prepared modified steel fibers and concrete, thereby further improving the comprehensive mechanical properties of the prepared modified steel fiber solid waste recycled concrete. Specifically, the particle size of the solid waste F1 can be 1 μm, 10 μm, 50 μm, 100 μm, 150 μm, or 200 μm.

[0043] In a preferred embodiment, the average particle size of the solid waste F1 is ≤30μm, preferably 0.1-10μm.

[0044] In a preferred embodiment, the solid waste F1 is selected from one or more of construction solid waste, sludge, and slag, preferably slag. Specifically, the main components of the construction solid waste are silicate substances; the main components of the sludge are oxides of silicon, iron, aluminum, and calcium; and the main elements contained in the slag are Si, Al, Ca, and Mg.

[0045] In a preferred embodiment, to further improve the barrier properties of the subsequently prepared organosilicon composite coating, the content of inorganic matter in the solid waste F1 is controlled to be ≥90wt%. In this invention, the composition of inorganic matter contained in the solid waste F1 is not limited; only the content of inorganic matter in the solid waste F1 needs to be limited.

[0046] In a preferred embodiment, the molar ratio of the organochlorosilane to the organosilicon in component A and component B is 1-8:10, preferably 4-7:10, and the molar amounts of both the organochlorosilane and the organosilicon are calculated based on silicon elemental mass. Specifically, the molar ratio of the organochlorosilane to the organosilicon can be 4:10, 5:10, 6:10, or 7:10. Furthermore, in this invention, the molar ratio of the organochlorosilane to the organosilicon is the same in components A and B. For example, when the molar ratio of the organochlorosilane to the organosilicon in component A is 5:10, the molar ratio of the organochlorosilane to the organosilicon in component B is also 5:10.

[0047] In a preferred embodiment, the preparation method of component A includes the following steps:

[0048] a1. Mix organosilicon with fatty alcohol, and then adjust the pH of the mixture to 3-6.

[0049] a2. Mix the organochlorosilane with the material obtained in step a1.

[0050] In a preferred embodiment, the preparation method of component B includes the following steps:

[0051] b1. Mix the organosilicon with the fatty alcohol, and then adjust the pH of the mixture to 3-6.

[0052] b2. Mix the organochlorosilane with the material obtained in step b1;

[0053] b3. Mix solid waste F1 with the material obtained in step b2.

[0054] In this invention, in steps a1 and b1, the molar ratio of organosilicon to fatty alcohol is 1:1-9, preferably 1:3-5, and the molar amount of organosilicon is calculated in terms of silicon element. Specifically, the molar ratio of the silicon source to fatty alcohol can be 1:3, 1:4, or 1:5.

[0055] In a specific embodiment, the fatty alcohol used to dissolve organosilicon can be a fatty alcohol reagent commonly used in the art, preferably a C1-C5 fatty alcohol, and more preferably one or more of methanol, ethanol, propanol and isopropanol.

[0056] In this invention, adjusting the pH of the mixture to acidic levels in steps a1 and b1 is to slow down the rate of organosilicon hydrolysis. Hydrochloric acid or acetic acid can be added to adjust the pH of the mixture to 3-6. Specifically, the pH of the mixture can be adjusted to 3, 4, 5, or 6.

[0057] In one specific implementation, component B can be obtained by directly removing a portion of component A and mixing the removed component A directly with solid waste F1.

[0058] In this invention, the A and B components of the organosilicon composite coating do not need to be mixed during use. Instead, the two components are applied as a primer and a topcoat on the substrate surface, respectively, and the organosilicon coating is obtained after drying. Specifically, component A is the primer and component B is the topcoat.

[0059] The present invention further provides a method for preparing modified steel fibers, the method comprising: sequentially coating the surface of steel fibers with components A and B of the organosilicon composite coating, and drying to obtain modified steel fibers.

[0060] In a specific embodiment, component A of the organosilicon composite coating is applied to the surface of the steel fiber as a primer, and after drying, component B is applied as a topcoat. By using a primer and a topcoat, the modified steel fiber achieves superior corrosion resistance.

[0061] In this invention, to further improve the performance of the modified steel fiber, the coating thickness of the organosilicon composite coating is limited to 60-500 μm, preferably 200-400 μm. Furthermore, this invention does not limit the relationship between the coating thickness of component A and component B; it only requires ensuring that the coating order of components A and B and the final coating thickness of the organosilicon composite coating meet the requirements.

[0062] In this invention, when the organosilicon composite coating is applied to the surface of steel fibers, the coating method is not limited. For example, it can be conventional methods such as spraying, brushing, or dipping.

[0063] In this invention, the modified steel fiber is coated with the aforementioned organosilicon composite coating. The modified steel fiber obtained after coating has stronger corrosion resistance, and the modified steel fiber can also enhance the adhesion between the modified steel fiber and the matrix when used to prepare concrete.

[0064] The present invention further provides an application of the above-mentioned modified steel fiber in the preparation of concrete.

[0065] The present invention can also provide a method for preparing modified steel fiber solid waste recycled concrete, the method comprising: mixing cement, fly ash, silica fume, solid waste F2, kaolin and water, and then mixing the mixed materials, polycarboxylate superplasticizer and the modified steel fiber.

[0066] In a preferred embodiment, cement, fly ash, silica fume, solid waste F2 and kaolin are mixed, the mixed materials are mixed with water, then mixed with polycarboxylate superplasticizer, and then mixed with the modified steel fiber.

[0067] In this invention, adding too much water will result in high porosity of the prepared modified steel fiber reinforced concrete, while adding too little water will prevent it from hardening into a cohesive whole, affecting the concrete's molding. Therefore, it is necessary to control the water-cement ratio during the preparation process. The water-cement ratio refers to the weight ratio of water to cementitious materials (cement, fly ash, kaolin). In a preferred embodiment, the water-cement ratio is controlled to be 0.3-0.5 in the preparation method of the modified steel fiber reinforced concrete, that is, the weight ratio of water to cement is 0.3-0.5:1.

[0068] In a preferred embodiment, the mixing can be a stirring mixture.

[0069] In a preferred embodiment, the polycarboxylate superplasticizer can be a common polycarboxylate superplasticizer in the art, such as HPEG2400, PCE-101 or SPC-100.

[0070] In this invention, the weight ratio of cement, fly ash, silica fume, solid waste F2, kaolin, and polycarboxylate superplasticizer is 0.25:0.27:0.03:0.15-0.55:0.02:0.0015, preferably 0.25:0.27:0.03:0.3-0.5:0.02:0.0015.

[0071] In a specific embodiment, the weight ratio of the modified steel fiber to the total weight of cement, fly ash, silica fume, solid waste F2, and kaolin is 0.5-5:100, preferably 1-3:100. Specifically, the weight ratio of the modified steel fiber to the total weight of cement, fly ash, silica fume, solid waste F2, and kaolin can be 1:100, 2:100, and 3:100.

[0072] In this invention, the solid waste F2 is selected from one or more of construction solid waste, sludge and slag.

[0073] In this invention, the solid waste F2 contains 15-40 wt% silicon, 2-20 wt% iron, 5-20 wt% aluminum, and 4-40 wt% calcium. Silicon mainly exists in the form of silicon oxides and silicates; iron mainly exists in the form of iron oxides and iron salts; aluminum mainly exists in the form of aluminum oxides and aluminates; and calcium mainly exists in the form of calcium oxides and calcium salts. The solid waste F2 also contains other components, but the types and contents of these other components are not limited in this invention.

[0074] In a preferred embodiment, the particle size of the solid waste F2 is 0.05-20000 μm, more preferably 0.1-350 μm.

[0075] In a preferred embodiment, the length of the modified steel fiber is controlled to be 34-40 mm and the diameter to be 0.4-0.8 mm.

[0076] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto.

[0077] In the following examples and comparative examples, the cement is PII52.5 silicate cement.

[0078] Example 1

[0079] (1) Mix methyl orthosilicate and ethanol at a molar ratio of 1:2 until homogeneous, and then add hydrochloric acid (concentration of 1 mol / L) to adjust the pH of the mixture to 4.

[0080] (2) Mix methyltrichlorosilane (the molar ratio of methyl orthosilicate to methyltrichlorosilane is 5:10) with the material obtained in step (1) to obtain component A;

[0081] (3) Mix methyl orthosilicate and ethanol at a molar ratio of 1:2 until homogeneous, and then add hydrochloric acid (concentration of 1 mol / L) to adjust the pH of the mixture to 4.

[0082] (4) Methyltrichlorosilane (the molar ratio of methyl orthosilicate to methyltrichlorosilane is 5:10) is mixed with the material obtained in step (1), and then mixed with solid waste F1 (slag, inorganic content 100%, particle size 1-50μm, average particle size 7.8μm) to obtain component B; wherein, the content of solid waste F1 (slag) in component B is 25wt%;

[0083] (5) Component A of the organosilicon composite coating is coated onto the surface of the steel fiber and dried at 80°C. Then, component B is used for a second coating. The mass ratio of A to B is 1:2. The coating is also dried at 80°C. After drying, modified steel fiber is obtained (the coating thickness of the organosilicon composite coating is 300 μm).

[0084] (6) Mix cement, fly ash, silica fume, solid waste F2 (slag, particle size 5-200μm, containing 31.3wt% silicon, 10.2wt% iron, 13.6wt% aluminum and 33.7wt% calcium), and kaolin for 1 min. Then add water (water-cement ratio 0.35) and continue mixing for 2 min. Next, add polycarboxylate superplasticizer (HPEG2400) and mix for 3 min. Finally, add the modified steel fiber (35m in length). (m, diameter 0.55mm, with hooks at both ends) Mix for 3 minutes; then pour the slurry into the mold and vibrate to compact it to obtain modified steel fiber solid waste recycled concrete; the weight ratio of cement, fly ash, silica fume, solid waste F2 (slag), kaolin, and polycarboxylate superplasticizer is 0.25:0.22:0.03:0.50:0.02:0.0015; the weight ratio of modified steel fiber to the total weight of cement, fly ash, silica fume, solid waste F2, and kaolin is 2:100.

[0085] Example 2

[0086] (1) Mix methyl orthosilicate and ethanol at a molar ratio of 1:2 until homogeneous, and then add hydrochloric acid (concentration of 1 mol / L) to adjust the pH of the mixture to 4.

[0087] (2) Mix methyltrichlorosilane (the molar ratio of methyl orthosilicate to methyltrichlorosilane is 6:10) with the material obtained in step (1) to obtain component A;

[0088] (3) Mix methyl orthosilicate and ethanol at a molar ratio of 1:2 until homogeneous, and then add hydrochloric acid (concentration of 1 mol / L) to adjust the pH of the mixture to 4.

[0089] (4) Methyltrichlorosilane (the molar ratio of methyl orthosilicate to methyltrichlorosilane is 6:10) is mixed with the material obtained in step (1), and then mixed with solid waste F1 (incinerated sludge, inorganic content 98.5%, particle size 1-30 μm, average particle size 9.5 μm) to obtain component B; wherein, the content of solid waste F1 (incinerated sludge) in component B is 23 wt%;

[0090] (5) Component A of the organosilicon composite coating is coated onto the surface of the steel fiber and dried at 80°C. Then, component B is used for a second coating. The mass ratio of A to B is 1:2. The coating is also dried at 80°C. After drying, modified steel fiber is obtained (the coating thickness of the organosilicon composite coating is 330 μm).

[0091] (6) Mix cement, fly ash, silica fume, solid waste F2 (sludge, particle size 5-250μm, containing 20.8wt% silicon, 15.9wt% iron, 18.6wt% aluminum and 22.3wt% calcium), and kaolin for 1 min. Then add water (water-cement ratio 0.35) and continue mixing for 2 min. Next, add polycarboxylate superplasticizer (PCE-101) and mix for 3 min. Finally, add the modified steel fiber (length... Mix the 35mm thick, 0.55mm diameter, hooked ends of the steel fiber reinforced concrete (SFRP) for 3 minutes; then pour the slurry into the mold and vibrate to compact it to obtain modified steel fiber reinforced concrete; the weight ratio of cement, fly ash, silica fume, solid waste F2, kaolin, and polycarboxylate superplasticizer is 0.22:0.27:0.03:0.48:0.02:0.0015; the weight ratio of modified steel fiber to the total weight of cement, fly ash, silica fume, solid waste F2, and kaolin is 1.5:100.

[0092] Example 3

[0093] (1) Mix methyl orthosilicate and ethanol at a molar ratio of 1:3 until homogeneous, and then add hydrochloric acid (concentration of 1 mol / L) to adjust the pH of the mixture to 4.

[0094] (2) Mix methyltrichlorosilane (the molar ratio of methyl orthosilicate to methyltrichlorosilane is 5:10) with the material obtained in step (1) to obtain component A;

[0095] (3) Mix methyl orthosilicate and ethanol at a molar ratio of 1:3 until homogeneous, and then add hydrochloric acid (concentration of 1 mol / L) to adjust the pH of the mixture to 4.

[0096] (4) Methyltrichlorosilane (the molar ratio of methyl orthosilicate to methyltrichlorosilane is 5:10) is mixed with the material obtained in step (1), and then mixed with solid waste F1 (crushed construction solid waste, inorganic content 97%, particle size 1-80μm, average particle size 10.4μm) to obtain component B; wherein, the content of solid waste F1 (crushed construction solid waste) in component B is 22wt%;

[0097] (5) Component A of the organosilicon composite coating is coated onto the surface of the steel fiber and dried at 80°C. Then, component B is used for a second coating. The mass ratio of A to B is 1:2. The coating is also dried at 80°C. After drying, modified steel fiber is obtained (the coating thickness of the organosilicon composite coating is 300 μm).

[0098] (6) Mix cement, fly ash, silica fume, solid waste F2 (crushed construction solid waste with a particle size of 120-280μm, containing 36.3wt% silicon, 15.5wt% iron, 8.3wt% aluminum and 15.1wt% calcium), and kaolin for 1 min. Then add water (water-cement ratio of 0.35) and continue mixing for 2 min. Next, add polycarboxylate superplasticizer (SPC-100) and mix for 3 min. Finally, add the modified steel fibers (length 3... Mix the 5mm thick, 0.55mm diameter, hooked ends of the steel fiber reinforced concrete for 3 minutes; then pour the slurry into the mold and vibrate to compact it to obtain modified steel fiber reinforced concrete; the weight ratio of cement, fly ash, silica fume, solid waste F2, kaolin, and polycarboxylate superplasticizer is 0.25:0.27:0.03:0.45:0.02:0.0015; the weight ratio of modified steel fiber to the total weight of cement, fly ash, silica fume, solid waste F2 (crushed construction solid waste) and kaolin is 3:100.

[0099] Example 4

[0100] The method was implemented according to Example 1, except that the inorganic content in the solid waste F1 (sludge) was 85 wt%.

[0101] Example 5

[0102] The method was implemented according to Example 1, except that the weight ratio of cement, fly ash, silica fume, solid waste F2 (slag), kaolin, and polycarboxylate superplasticizer was 0.25:0.22:0.03:0.6:0.02:0.0015.

[0103] Comparative Example 1

[0104] The method was implemented according to Example 1, except that the content of solid waste F1 was 40 wt%.

[0105] Comparative Example 2

[0106] The method described in Example 1 is followed, except that the silicone composite coating contains only component B.

[0107] Comparative Example 3

[0108] The method of Example 1 was implemented, except that the proportion of material with a particle size distribution of 350-600μm in the solid waste F1 was 30-80wt%.

[0109] Comparative Example 4

[0110] The method of Example 1 was implemented, except that in step (6), the modified steel fiber was replaced with an equal weight of ordinary steel fiber.

[0111] Comparative Example 5

[0112] The method of Example 1 was implemented, except that the modified steel fibers were not added in step (6) during preparation.

[0113] Test case

[0114] Test Example 1

[0115] Test Method: The corrosion resistance of the modified steel fibers prepared in Examples 1-4 and Comparative Examples 1-3 was tested. A standard three-electrode system was established. The uncoated portion of the modified steel fibers was coated with epoxy resin and led out with wires. Electrochemical corrosion performance was tested using an electrochemical workstation. A calomel electrode was used as the reference electrode, a graphite electrode as the counter electrode, and the modified steel fiber as the working electrode. The electrolyte was a 3.5 wt.% NaCl solution. The EIS test range was 10... -2 -10 5 The AC excitation signal amplitude was 10mV, the potential scan test range was set between -500mV and +500mV of the open circuit potential, the scan rate was 0.5mV / s, and the coating was immersed for 90 days to test the equivalent resistance of the coating. The results are shown in Table 1.

[0116] Table 1

[0117] Example number <![CDATA[Coating equivalent resistance / Ω·cm 2 > Example 1 <![CDATA[1.25×10 10 ]]> Example 2 <![CDATA[1.21×10 10 <!-- 7 -->]]> Example 3 <![CDATA[1.12×10 10 ]]> Example 4 <![CDATA[3.63×10 9 ]]> Comparative Example 1 <![CDATA[5.35×10 6 ]]> Comparative Example 2 <![CDATA[2.28×10 8 ]]> Comparative Example 3 <![CDATA[1.06×10 7 ]]>

[0118] As can be seen from the results in Table 1, the anti-corrosion performance of the modified steel fibers prepared by coating with the organosilicon composite coating described in this invention is significantly increased.

[0119] Test Example 2

[0120] The bond strength between the modified steel fibers prepared in Examples 1-5 and Comparative Examples 1-5 and the concrete matrix, the compressive / tensile strength and ultimate tensile strain of the finally prepared modified steel fiber recycled solid waste concrete were tested.

[0121] Test methods: The compressive strength, tensile strength and stress-strain characteristics of concrete were tested according to standard GB-T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete".

[0122] The bond strength between modified steel fibers and concrete matrix was tested according to CECS13:2009 "Standard Test Methods for Fiber Reinforced Concrete". The results are shown in Table 2.

[0123] Table 2

[0124] Example number Bond strength / MPa 28-day compressive strength / MPa 28-day tensile strength / MPa Ultimate tensile strain / % Example 1 9.55 68.2 4.46 1.23 Example 2 9.47 67.4 4.40 1.21 Example 3 9.38 67.2 4.37 1.19 Example 4 9.15 64.5 4.33 1.11 Example 5 9.19 64.1 4.31 1.09 Comparative Example 1 8.98 63.8 4.21 1.08 Comparative Example 2 9.18 63.3 4.22 1.09 Comparative Example 3 9.14 63.4 4.25 1.10 Comparative Example 4 8.01 60.3 4.18 1.08 Comparative Example 5 / 54.2 1.68 0.32

[0125] As can be seen from the results in Table 2, the bond strength between the modified steel fiber and concrete prepared by coating with the organosilicon composite coating described in this invention is significantly increased, and the compressive / tensile strength of the prepared concrete is also increased.

[0126] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An organosilicon composite coating, characterized in that, The organosilicon composite coating is composed of component A and component B; Component A contains organosilicon and organochlorosilane; Component B contains organosilicon, organochlorosilane, and solid waste F1; The content of solid waste F1 in component B is 1-30 wt%. The particle size of the solid waste F1 is 0.05-300μm, the average particle size of the solid waste F1 is ≤30μm, the content of inorganic matter in the solid waste F1 is ≥90wt%, and the solid waste F1 is selected from one or more of construction solid waste, sludge and slag. The organosilicon is methyl orthosilicate and / or ethyl orthosilicate; the organochlorosilane is selected from one or more of methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, and diphenyldichlorosilane. The weight ratio of component A to component B is 1:0.5-4. In components A and B, the molar ratio of organochlorosilane to organosilicon is 1-8:

10. The molar amounts of organochlorosilane and organosilicon are both calculated based on silicon element, and the molar ratio of organochlorosilane and organosilicon is the same in components A and B. When using the organosilicon composite coating, components A and B are applied as a primer and topcoat respectively on the substrate surface. Component A is the primer and component B is the topcoat.

2. The organosilicon composite coating according to claim 1, characterized in that, The preparation method of component A includes the following steps: a1. Mix the organosilicon with the fatty alcohol, and then adjust the pH of the mixture to 3-6; a2. Mix the organochlorosilane with the material obtained in step a1.

3. The organosilicon composite coating according to claim 1, characterized in that, The preparation method of component B includes the following steps: b1. Mix the organosilicon with the fatty alcohol, and then adjust the pH of the mixture to 3-6; b2. Mix the organochlorosilane with the material obtained in step b1; b3. Mix the solid waste F1 with the material obtained in step b2.

4. The organosilicon composite coating according to claim 1, characterized in that, The weight ratio of component A to component B is 1:1-3.

5. A method for preparing modified steel fibers, characterized in that, The preparation method includes: sequentially coating the A component and B component of the organosilicon composite coating according to any one of claims 1-4 onto the surface of steel fibers, and obtaining modified steel fibers after drying.

6. A modified steel fiber prepared by the method for preparing modified steel fiber according to claim 5.

7. The application of the modified steel fiber as described in claim 6 in the preparation of concrete.

8. A method for preparing modified steel fiber reinforced solid waste recycled concrete, characterized in that, The preparation method includes: mixing cement, fly ash, silica powder, solid waste F2, kaolin and water, and then mixing the mixed materials, polycarboxylate superplasticizer and the modified steel fiber as described in claim 6. The weight ratio of cement, fly ash, silica fume, solid waste F2, kaolin, and polycarboxylate superplasticizer is 0.25:0.27:0.03:0.15-0.55:0.02:0.0015. The weight ratio of the modified steel fiber to the total weight of cement, fly ash, silica fume, solid waste F2, and kaolin is 0.5-5:

100.

9. The method for preparing modified steel fiber reinforced solid waste recycled concrete according to claim 8, characterized in that, The solid waste F2 contains 15-40 wt% silicon, 2-20 wt% iron, 5-20 wt% aluminum and 4-40 wt% calcium.