Formula and preparation method of high-strength recycled concrete

Abstract

The invention relates to the field of recycled concrete, and discloses a high-strength recycled concrete formula and a preparation method thereof, the high-strength recycled concrete formula comprises the following raw materials by weight: 180-240 parts of cement, 600-800 parts of hydrophobic modified recycled coarse aggregate, 180-280 parts of recycled fine aggregate, 400-600 parts of sand, 300-500 parts of fly ash, 60-120 parts of silica fume, and 20-30 parts of a water reducer, the modified waste rubber powder is prepared from, by weight, 25-35 parts of modified waste rubber powder, 10-40 parts of polyethylene wax, 2-4 parts of m-phenylenediamine and 12-16 parts of tetramethyl orthosilicate. In the invention, by using a large amount of recycled aggregate (coarse aggregate and fine aggregate), the exploitation of new natural resources is effectively reduced, the reutilization rate of building wastes is improved, and by optimizing the proportion and adding a plurality of modifiers (such as silica fume, fly ash, modified waste rubber powder and the like), the mechanical properties such as compression resistance, fracture resistance and the like of the concrete are remarkably improved; by adding the hydrophobic modified recycled coarse aggregate and the penetrant, the impermeability and durability of the concrete are enhanced, so that the performance and the application range of the recycled concrete are improved.

Description

Technical Field

[0001] The invention relates to the technical field of recycled concrete, in particular to a formula of high-strength recycled concrete and a preparation method thereof. Background Art

[0002] Economic growth has promoted the rapid development of the construction industry, but it has also produced various types of construction waste. According to statistics, my country produces 3-4 billion tons of construction waste every year, which is about 40% of the total urban waste. This has had a serious impact on the ecological environment and has also caused a large waste of resources. Among them, abandoned concrete accounts for a large proportion. In order to solve this problem, the concept of recycled concrete was proposed. It mainly crushes, cleans and grades the discarded concrete materials in the construction, and reuses them as aggregates, that is, recycled aggregates, as concrete raw materials for repeated use, which better solves the problem of construction waste disposal and the shortage of natural sand and gravel resources, and is in line with the development concept of sustainable development, energy saving and green.

[0003] At present, after waste concrete is broken by external force, a large number of fine cracks will be formed inside. At the same time, a large amount of old mortar and pores are attached to the surface of the recycled aggregate, and its water absorption rate is further increased. Therefore, there are the following disadvantages: the water absorption rate of waste concrete is significantly higher than that of natural aggregate, which in turn affects its adhesion, packing density and bearing capacity, and its wear resistance becomes worse, resulting in a decrease in the performance of recycled concrete and a limited scope of application. Summary of the invention

[0004] The purpose of the present invention is to provide a formula of high-strength recycled concrete and a preparation method thereof, so as to solve the problem that the water absorption rate of waste concrete is significantly higher than that of natural aggregate, which in turn affects the decrease of its bonding strength, bulk density and bearing capacity, and the deterioration of wear resistance, resulting in the decline of recycled concrete performance and limited application scope.

[0005] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme: a formula of high-strength recycled concrete, wherein the raw materials include, by weight: 180-240 parts of cement, 600-800 parts of hydrophobically modified recycled coarse aggregate, 180-280 parts of recycled fine aggregate, 400-600 parts of sand, 300-500 parts of fly ash, 60-120 parts of silica fume, 20-30 parts of water reducer, 25-35 parts of modified waste rubber powder, 10-40 parts of polyethylene wax, 2-4 parts of meta-phenylenediamine, 12-16 parts of methyl orthosilicate, 4-6 parts of penetrant, and 100-140 parts of water.

[0006] Preferably, the hydrophobically modified recycled coarse aggregate raw material comprises the following components: 25-38 parts of acrylic resin, 8-15 parts of recycled coarse aggregate, 2-7 parts of polyethylene glycol, 30-38 parts of hydrophobic desulfurized gypsum powder, and 25-45 parts of water.

[0007] Preferably, the hydrophobic desulfurized gypsum powder raw material comprises the following components: 8-17 parts of sodium hydroxide, 20-25 parts of desulfurized gypsum, 3-6 parts of anionic surfactant, 15-25 parts of silane coupling agent, 3-10 parts of sodium sulfate, and 40-60 parts of solvent.

[0008] Preferably, the osmotic agent is one or more of a non-ionic osmotic agent, a compound osmotic agent or an anionic osmotic agent.

[0009] Preferably, the water reducer is one or more of a naphthalene-based water reducer, a phosphate-based water reducer or a microbead mineral water reducer.

[0010] The present invention also provides a method for preparing high-strength recycled concrete and a method for preparing hydrophobically modified recycled coarse aggregate, comprising the following steps:

[0011] S1: Take waste concrete, crush, clean, dry and screen it to obtain recycled coarse aggregate after crushing;

[0012] S2: preparing a modifier: uniformly mixing a certain proportion of hydrophobic desulfurized gypsum powder, polyethylene glycol, acrylic resin and water to obtain a modifier;

[0013] S3: The recycled coarse aggregate is immersed in a modifier for modification. After the modification is completed, the recycled coarse aggregate is filtered and dried to obtain a hydrophobic modified recycled coarse aggregate.

[0014] Preferably, the method for preparing the hydrophobic desulfurized gypsum powder comprises the following steps:

[0015] S1: Grind and sieve the desulfurized gypsum to obtain desulfurized gypsum powder;

[0016] S2: calcining the desulfurized gypsum powder to obtain anhydrous desulfurized gypsum powder;

[0017] S3: mixing anhydrous desulfurized gypsum powder with sodium hydroxide and sodium sulfate, and heating the mixture to obtain pretreated desulfurized gypsum powder;

[0018] S4: mixing the pretreated desulfurized gypsum powder with a silane coupling agent, an anionic surfactant and a solvent, and performing a heating treatment to obtain a hydrophobic desulfurized gypsum powder.

[0019] Preferably, the method for treating the modified waste rubber powder comprises the following steps:

[0020] S1: washing and drying the waste rubber, crushing and sieving to obtain waste rubber powder;

[0021] S2: adding silane coupling agent and calcium carbonate to the waste rubber powder, stirring and dispersing, and then drying to obtain modified waste rubber powder.

[0022] Preferably, the method comprises the following steps:

[0023] S1: Mix cement, hydrophobic modified recycled coarse aggregate, recycled fine aggregate, sand, fly ash, silica fume, water reducing agent, modified waste rubber powder, polyethylene wax, m-phenylenediamine, methyl orthosilicate and a portion of water, and stir evenly;

[0024] S2: Add penetrant and continue stirring to mix evenly;

[0025] S3: adding the remaining water, stirring and mixing again to obtain a recycled concrete mixture;

[0026] S4: Pour the recycled concrete mixture evenly on the construction surface and cure it to obtain high-strength recycled concrete.

[0027] Compared with the prior art, the formula of a high-strength recycled concrete using the above technical solution has the following beneficial effects:

[0028] 1. In use, by using a large amount of recycled aggregates (coarse aggregates and fine aggregates), the exploitation of new natural resources is effectively reduced, and the recycling rate of construction waste is increased. By optimizing the mix ratio and adding a variety of modifiers (such as silica fume, fly ash, modified waste rubber powder, etc.), the mechanical properties of concrete such as compression and flexural strength are significantly improved, so that it can meet the needs of high-standard buildings. The addition of hydrophobic modified recycled coarse aggregates and penetrants enhances the impermeability and durability of concrete, thereby improving the performance and application range of recycled concrete;

[0029] 2. During use, through the treatment of modifiers such as acrylic resin, a hydrophobic layer is formed on the surface of the recycled coarse aggregate, which effectively prevents the intrusion of moisture and harmful substances and improves the anti-permeability of concrete. The introduction of additives such as polyethylene glycol improves the bonding performance between aggregate and cement paste and enhances the overall strength of concrete. The addition of hydrophobic desulfurized gypsum powder further enhances the stability and durability of aggregate, enabling it to maintain stable performance in harsh environments. Through the treatment of modifiers such as silane coupling agents, the desulfurized gypsum powder has excellent hydrophobic properties, which can effectively prevent the erosion of concrete by moisture. The introduction of additives such as sodium hydroxide and sodium sulfate improves the mechanical properties of the desulfurized gypsum powder, enabling it to better combine with the concrete matrix. Desulfurized gypsum is a kind of industrial waste. It can be reused through modification, which not only reduces waste emissions but also saves resources. Penetrants can penetrate into the concrete, fill pores and cracks, form a dense waterproof layer, and significantly improve the concrete's anti-seepage performance. By improving the concrete's microstructure, penetrants can also improve the concrete's durability and extend its service life. At the same time, the use of penetrants simplifies the construction process and reduces construction time and cost.

[0030] 3. In use, water reducers can significantly reduce the water-cement ratio of concrete, improve the fluidity and plasticity of concrete, and facilitate construction operations. By reducing water consumption, water reducers can also increase the strength and density of concrete and improve mechanical properties. Through the steps of crushing, cleaning, drying, screening, etc., the effective recycling of waste concrete is achieved, and the preparation process is simplified. At the same time, the introduction of modifiers significantly improves the performance of recycled coarse aggregate, enabling it to meet the needs of high-strength recycled concrete. The entire preparation process reduces energy consumption and waste emissions, which is in line with the concept of green manufacturing;

[0031] 4. During use, the quality and stability of desulfurized gypsum powder are ensured through grinding, screening, calcination and other steps. At the same time, the introduction of modifiers significantly improves the hydrophobicity and mechanical properties of desulfurized gypsum powder, converting industrial waste desulfurized gypsum into high-performance building materials, realizing resource recycling. Through crushing, screening and other steps, the effective recycling of waste rubber is achieved. Secondly, the introduction of silane coupling agent and calcium carbonate improves the performance of waste rubber powder, enabling it to better combine with the concrete matrix, reducing the pollution of waste rubber to the environment, and saving resources. Through precise proportioning and mixing, the quality and performance of recycled concrete are ensured, while the construction process is simplified, the construction time and cost are reduced, and by optimizing the proportion and adding a variety of modifiers, the construction requirements of high strength and high durability are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The invention is a flow chart of the formula of high-strength recycled concrete and its preparation method. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0034] like Figure 1 As shown, a formula of high-strength recycled concrete includes the following raw materials by weight: 180-240 parts of cement, 600-800 parts of hydrophobically modified recycled coarse aggregate, 180-280 parts of recycled fine aggregate, 400-600 parts of sand, 300-500 parts of fly ash, 60-120 parts of silica fume, 20-30 parts of water reducer, 25-35 parts of modified waste rubber powder, 10-40 parts of polyethylene wax, 2-4 parts of meta-phenylenediamine, 12-16 parts of methyl orthosilicate, 4-6 parts of penetrant, and 100-140 parts of water.

[0035] In use, the large-scale use of recycled aggregates (coarse aggregate and fine aggregate) effectively reduces the exploitation of new natural resources and increases the recycling rate of construction waste. By optimizing the mix ratio and adding a variety of modifiers (such as silica fume, fly ash, modified waste rubber powder, etc.), the compressive and flexural mechanical properties of concrete are significantly improved, enabling it to meet the needs of high-standard buildings. The addition of hydrophobic modified recycled coarse aggregate and penetrant enhances the impermeability and durability of concrete, reduces the deterioration of concrete caused by water intrusion, enhances the impermeability and durability of concrete, and thus improves the performance and application range of recycled concrete.

[0036] like Figure 1 As shown, the hydrophobic modified recycled coarse aggregate raw material includes the following components: 25-38 parts of acrylic resin, 8-15 parts of recycled coarse aggregate, 2-7 parts of polyethylene glycol, 30-38 parts of hydrophobic desulfurized gypsum powder, and 25-45 parts of water. The hydrophobic desulfurized gypsum powder raw material includes the following components: 8-17 parts of sodium hydroxide, 20-25 parts of desulfurized gypsum, 3-6 parts of anionic surfactant, 15-25 parts of silane coupling agent, 3-10 parts of sodium sulfate, and 40-60 parts of solvent. The penetrant is one or more of a non-ionic penetrant, a compound penetrant or an anionic penetrant, and the water reducer is one or more of a naphthalene-based water reducer, a phosphate-type water reducer or a microbead mineral water reducer.

[0037] During use, through the treatment of modifiers such as acrylic resin, a hydrophobic layer is formed on the surface of the recycled coarse aggregate, which effectively prevents the intrusion of moisture and harmful substances and improves the anti-permeability of concrete. The introduction of additives such as polyethylene glycol improves the bonding performance between aggregate and cement paste and enhances the overall strength of concrete. The addition of hydrophobic desulfurized gypsum powder further enhances the stability and durability of aggregate, enabling it to maintain stable performance in harsh environments. Through the treatment of modifiers such as silane coupling agents, the desulfurized gypsum powder has excellent hydrophobic properties, which can effectively prevent moisture from corroding concrete. The introduction of additives such as sodium hydroxide and sodium sulfate improves the mechanical properties of the desulfurized gypsum powder, enabling it to better combine with the concrete matrix. Desulfurized gypsum is a kind of industrial waste. It can be reused through modification, which not only reduces waste emissions but also saves resources. Penetrants can penetrate into the concrete, fill pores and cracks, form a dense waterproof layer, and significantly improve the concrete's anti-seepage performance. By improving the concrete's microstructure, penetrants can also improve the concrete's durability and extend its service life. At the same time, the use of penetrants simplifies the construction process, reducing construction time and costs. Water reducers can significantly reduce the concrete's water-cement ratio, improve the concrete's fluidity and plasticity, and facilitate construction operations. By reducing water consumption, water reducers can also improve the concrete's strength and density and improve its mechanical properties.

[0038] The present invention also provides a method for preparing high-strength recycled concrete and a method for preparing hydrophobically modified recycled coarse aggregate, comprising the following steps:

[0039] S1: Take waste concrete, crush, clean, dry and screen it to obtain recycled coarse aggregate after crushing;

[0040] S2: preparing a modifier: uniformly mixing a certain proportion of hydrophobic desulfurized gypsum powder, polyethylene glycol, acrylic resin and water to obtain a modifier;

[0041] S3: The recycled coarse aggregate is immersed in a modifier for modification. After the modification is completed, the recycled coarse aggregate is filtered and dried to obtain a hydrophobic modified recycled coarse aggregate.

[0042] During use, effective recycling of waste concrete is achieved through crushing, cleaning, drying, screening and other steps, which simplifies the preparation process. At the same time, the introduction of modifiers significantly improves the performance of recycled coarse aggregate, enabling it to meet the needs of high-strength recycled concrete. The entire preparation process reduces energy consumption and waste emissions, which is in line with the concept of green manufacturing.

[0043] The preparation method of hydrophobic desulfurized gypsum powder comprises the following steps:

[0044] S1: Grind and sieve the desulfurized gypsum to obtain desulfurized gypsum powder;

[0045] S2: calcining the desulfurized gypsum powder to obtain anhydrous desulfurized gypsum powder;

[0046] S3: mixing anhydrous desulfurized gypsum powder with sodium hydroxide and sodium sulfate, and heating the mixture to obtain pretreated desulfurized gypsum powder;

[0047] S4: mixing the pretreated desulfurized gypsum powder with a silane coupling agent, an anionic surfactant and a solvent, and performing a heating treatment to obtain a hydrophobic desulfurized gypsum powder.

[0048] During use, the quality and stability of the desulfurized gypsum powder are ensured through steps such as grinding, screening, and calcination. At the same time, the introduction of the modifier significantly improves the hydrophobicity and mechanical properties of the desulfurized gypsum powder, converting industrial waste desulfurized gypsum into high-performance building materials and realizing the recycling of resources.

[0049] The method for treating modified waste rubber powder comprises the following steps:

[0050] S1: washing and drying the waste rubber, crushing and sieving to obtain waste rubber powder;

[0051] S2: adding silane coupling agent and calcium carbonate to the waste rubber powder, stirring and dispersing, and then drying to obtain modified waste rubber powder.

[0052] During use, the effective recycling of waste rubber is achieved through steps such as crushing and screening. Secondly, the introduction of silane coupling agent and calcium carbonate improves the performance of waste rubber powder, enabling it to better combine with the concrete matrix, reducing the pollution of waste rubber to the environment and saving resources.

[0053] The following steps are involved:

[0054] S1: Mix cement, hydrophobic modified recycled coarse aggregate, recycled fine aggregate, sand, fly ash, silica fume, water reducing agent, modified waste rubber powder, polyethylene wax, m-phenylenediamine, methyl orthosilicate and a portion of water, and stir evenly;

[0055] S2: Add penetrant and continue stirring to mix evenly;

[0056] S3: adding the remaining water, stirring and mixing again to obtain a recycled concrete mixture;

[0057] S4: Pour the recycled concrete mixture evenly on the construction surface and cure it to obtain high-strength recycled concrete.

[0058] During use, the quality and performance of recycled concrete are ensured through precise proportioning and mixing, while the construction process is simplified, construction time and cost are reduced. By optimizing the proportion and adding a variety of modifiers, construction requirements such as high strength and high durability are met.

[0059] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A formula of high-strength recycled concrete, characterized in that: The raw materials include, by weight: 180-240 parts of cement, 600-800 parts of hydrophobically modified recycled coarse aggregate, 180-280 parts of recycled fine aggregate, 400-600 parts of sand, 300-500 parts of fly ash, 60-120 parts of silica fume, 20-30 parts of water reducer, 25-35 parts of modified waste rubber powder, 10-40 parts of polyethylene wax, 2-4 parts of meta-phenylenediamine, 12-16 parts of methyl orthosilicate, 4-6 parts of penetrant, and 100-140 parts of water.

2. The formula of a high-strength recycled concrete according to claim 1, characterized in that: The hydrophobic modified recycled coarse aggregate raw material comprises the following components: 25-38 parts of acrylic resin, 8-15 parts of recycled coarse aggregate, 2-7 parts of polyethylene glycol, 30-38 parts of hydrophobic desulfurized gypsum powder, and 25-45 parts of water.

3. The formula of a high-strength recycled concrete according to claim 2, characterized in that: The hydrophobic desulfurized gypsum powder raw material comprises the following components: 8-17 parts of sodium hydroxide, 20-25 parts of desulfurized gypsum, 3-6 parts of anionic surfactant, 15-25 parts of silane coupling agent, 3-10 parts of sodium sulfate and 40-60 parts of solvent.

4. The formula of a high-strength recycled concrete according to claim 1, characterized in that: The permeabilizing agent is one or more of a non-ionic permeabilizing agent, a compound permeabilizing agent or an anionic permeabilizing agent.

5. The formula of a high-strength recycled concrete according to claim 1, characterized in that: The water reducer is one or more of a naphthalene-based water reducer, a phosphate-based water reducer or a microbead mineral water reducer.

6. A method for preparing high-strength recycled concrete, characterized in that: The method for preparing hydrophobically modified recycled coarse aggregate comprises the following steps: S1: Take waste concrete, crush, clean, dry and screen it to obtain recycled coarse aggregate after crushing; S2: preparing a modifier: uniformly mixing a certain proportion of hydrophobic desulfurized gypsum powder, polyethylene glycol, acrylic resin and water to obtain a modifier; S3: The recycled coarse aggregate is immersed in a modifier for modification. After the modification is completed, the recycled coarse aggregate is filtered and dried to obtain a hydrophobic modified recycled coarse aggregate.

7. The method for preparing high-strength recycled concrete according to claim 6, characterized in that: The method for preparing the hydrophobic desulfurized gypsum powder comprises the following steps: S1: Grind and sieve the desulfurized gypsum to obtain desulfurized gypsum powder; S2: calcining the desulfurized gypsum powder to obtain anhydrous desulfurized gypsum powder; S3: mixing anhydrous desulfurized gypsum powder with sodium hydroxide and sodium sulfate, and heating the mixture to obtain pretreated desulfurized gypsum powder; S4: mixing the pretreated desulfurized gypsum powder with a silane coupling agent, an anionic surfactant and a solvent, and performing a heating treatment to obtain a hydrophobic desulfurized gypsum powder.

8. The method for preparing high-strength recycled concrete according to claim 7, characterized in that: The method for treating the modified waste rubber powder comprises the following steps: S1: washing and drying the waste rubber, crushing and sieving to obtain waste rubber powder; S2: adding silane coupling agent and calcium carbonate to the waste rubber powder, stirring and dispersing, and then drying to obtain modified waste rubber powder.

9. A method for preparing high-strength recycled concrete according to claims 6-8, characterized in that: The following steps are involved: S1: Mix cement, hydrophobic modified recycled coarse aggregate, recycled fine aggregate, sand, fly ash, silica fume, water reducing agent, modified waste rubber powder, polyethylene wax, m-phenylenediamine, methyl orthosilicate and a portion of water, and stir evenly; S2: Add penetrant and continue stirring to mix evenly; S3: adding the remaining water, stirring and mixing again to obtain a recycled concrete mixture; S4: Pour the recycled concrete mixture evenly on the construction surface and cure it to obtain high-strength recycled concrete.

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