A method for preparing high-tensile lightweight concrete and lightweight concrete

Abstract

This invention relates to a method for preparing high-tensile lightweight concrete and the lightweight concrete itself. The method comprises the following steps: 800-1200 parts by weight of coal gangue ceramsite, 420-500 parts by weight of cement, 240-450 parts by weight of water, 0.5-1.5 parts by weight of foaming agent, 2-4 parts by weight of inorganic salt, 2-4 parts by weight of polyvinyl alcohol, and 0.2 parts by weight of water-based dispersant. Polyvinyl alcohol and water-based dispersant are immersed in water and then heated to obtain a modified liquid. The coal gangue ceramsite is then immersed in the modified liquid to obtain mixture A containing the modified coal gangue ceramsite. Cement and inorganic salt are mixed and stirred until uniformly mixed to obtain mixture B. The foaming agent is diluted and then foamed using a foaming device to generate foam. Mixture A and mixture B are mixed and stirred, incorporating foam generated by the foaming agent during the stirring process, and stirring is continued for 1-2 minutes to obtain lightweight concrete. This invention modifies coal gangue ceramsite, which slowly releases ionic additives and some moisture, allowing the chemical reaction to proceed fully and improving compressive strength.

Description

Technical Field

[0001] This invention relates to the field of building materials, specifically to a method for preparing high-tensile lightweight concrete and the lightweight concrete itself. Background Technology

[0002] Lightweight concrete, also known as foamed concrete, is a building material formed by introducing tiny closed air bubbles into a slurry through chemical or physical foaming. It has good lightweight properties, thermal insulation, fire resistance, and sound insulation, and can reduce construction steps, speed up construction progress, and reduce project costs.

[0003] In the field of building construction, lightweight concrete can be applied to integrated thermal insulation formwork for building structures and prefabricated insulated wall panels.

[0004] Building insulation layers generally suffer from low compressive strength, especially lightweight concrete, which has low early compressive strength. During routine maintenance, the insulation layer cracks and leaks due to equipment handling and personnel activity. Furthermore, the low strength of insulation layers used as interior partitions makes it impossible to install equipment on the walls.

[0005] Integrated, non-removable formwork is lighter than traditional casting formwork. Common examples include non-removable formwork represented by wire mesh. Conventional foamed concrete suffers from problems such as large slurry loss, low mechanical strength, and labor-intensive surface roughening when using non-removable wire mesh formwork. Summary of the Invention

[0006] To address the problems of low compressive strength and high loss due to loss of wire mesh material in existing lightweight concrete, this invention provides a method for preparing high-tensile lightweight concrete and lightweight concrete, which increases the compressive strength of lightweight concrete while reducing loss when applied to integrated, non-removable formwork.

[0007] The technical objective of this invention is achieved through the following technical solution:

[0008] A method for preparing high-tensile lightweight concrete, comprising the following components by weight: 800-1200 parts coal gangue ceramsite, 420-500 parts cement, 240-450 parts water, 0.5-1.5 parts foaming agent, 2-4 parts inorganic salt, 2-4 parts polyvinyl alcohol, and 0.2 parts water-based dispersant. The method includes:

[0009] Step 1: Immerse polyvinyl alcohol and an aqueous dispersant in water and then heat to obtain a modified solution;

[0010] Step 2: Immerse the coal gangue ceramsite in the modification solution to obtain mixture A containing the modified coal gangue ceramsite;

[0011] Step 3: Mix the cement and inorganic salts until they are evenly mixed to obtain mixture B;

[0012] Step 4: Dilute the foaming agent and then use a foaming device to produce foam;

[0013] Step 4: Mix mixture A and mixture B together. During the mixing process, add the foam generated by the foaming agent and continue mixing for 1-2 minutes.

[0014] Furthermore, the coal gangue ceramsite is coal gangue ceramsite with an apparent density of less than 1700 kg / m³, a fineness modulus of 1.9-2.6, a particle size of 0.15-5 mm, a water absorption rate of 5-15%, and a cylinder compressive strength of 10-15 MPa.

[0015] Furthermore, during the heating process in step 1, the water temperature is heated to no more than 60°C until the polyvinyl alcohol and the aqueous dispersant are completely dissolved in the water.

[0016] Furthermore, in step 2, the soaking time of the coal gangue ceramsite is controlled at 5-10 minutes.

[0017] Furthermore, it also includes adding silica fume and / or fly ash to replace 10%-20% of the cement by weight.

[0018] Furthermore, the specific surface area of ​​the silica fume is above 23,000 m² / kg, and the silica content in the silica fume is greater than 75%; the mineral powder is at least one of S95 mineral powder or S105 mineral powder.

[0019] Furthermore, the foaming agent is a saponin-type plant protein foaming agent.

[0020] Furthermore, the inorganic salt is at least one of calcium sulfate and sodium thiosulfate.

[0021] The present invention also provides a high-tensile lightweight concrete, comprising coal gangue ceramsite, cement, water, foaming agent, inorganic salt, polyvinyl alcohol and aqueous dispersant, wherein the coal gangue ceramsite, cement, water, foaming agent, inorganic salt, polyvinyl alcohol and aqueous dispersant are prepared according to the preparation method described above.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The lightweight concrete prepared by the method of the present invention modifies the coal gangue ceramsite, allowing the adsorption of ionic additives in the coal gangue ceramsite. During the hardening process of the concrete, the coal gangue ceramsite slowly releases the ionic additives and some water, enabling the chemical reaction to proceed fully. This improves the interfacial strength between the aggregate and the paste, and the compressive strength can reach more than 10 MPa. Compared with existing foamed concrete and polystyrene particle concrete, it can withstand more gravity loads from mechanical equipment.

[0024] 2. The high-tensile lightweight concrete of the present invention, while ensuring good fluidity, makes the concrete slurry less prone to leakage due to the addition of surface-active additives, thus solving the problem of slurry loss and large consumption in the application of wire mesh in existing foamed concrete.

[0025] 3. The foaming agent used in this invention is a saponin-type plant protein foaming agent, which has a simple manufacturing process and is not sensitive to hard water rich in calcium ions, ensuring that the performance of the foaming agent is not affected by changes in water quality. If necessary, water can be recycled at a mixing plant, which is beneficial to environmental protection. In addition, as a plant-based foaming agent, it has a relatively low odor. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to specific embodiments: Example 1

[0027] Take 1200 parts by weight of coal gangue ceramsite, 420 parts of cement, 1.5 parts of foaming agent, and 360 parts of water; wherein, the coal gangue ceramsite is coal gangue ceramsite with an apparent density of less than 1700 kg / m³, a fineness modulus of 1.9-2.6, a particle size of 0.15-5 mm, a water absorption rate of 5-15%, and a cylinder compressive strength of 10-15 MPa; the foaming agent is a saponin-type plant protein foaming agent.

[0028] Coal gangue ceramsite, cement, and water were mixed and stirred. Foam generated by a foaming agent was then incorporated and stirred until homogeneous to obtain lightweight concrete. The various performance parameters of this lightweight concrete were tested, as shown in the table below:

[0029] Example 2

[0030] A method for preparing high-tensile lightweight concrete, comprising the following components by weight: 1200 parts coal gangue ceramsite, 420 parts cement, 360 parts water, 1.5 parts foaming agent, 2 parts calcium sulfate, 2 parts polyvinyl alcohol, and 0.2 parts water-based dispersant, wherein sodium polyacrylate is selected as the water-based dispersant.

[0031] Among them, coal gangue ceramsite is coal gangue ceramsite with an apparent density of less than 1700 kg / m³, a fineness modulus of 1.9-2.6, a particle size of 0.15-5 mm, a water absorption rate of 5-15%, and a cylinder compressive strength of 10-15 MPa.

[0032] The foaming agent is a saponin-type plant protein foaming agent.

[0033] The process includes the following steps:

[0034] Step 1: Immerse polyvinyl alcohol and sodium polyacrylate in water and then heat to obtain a modified solution;

[0035] Step 2: Soak the coal gangue ceramsite in the modification solution for 5-10 minutes to obtain mixture A containing modified coal gangue ceramsite;

[0036] Step 3: Mix the cement and calcium sulfate together until they are evenly mixed to obtain mixture B;

[0037] Step 4: Dilute the foaming agent and then use a foaming device to produce foam;

[0038] Step 4: Mix mixture A and mixture B together, incorporating foam generated by the foaming agent during the mixing process, and continue mixing for 1-2 minutes to obtain lightweight concrete. The various performance parameters of this lightweight concrete are tested, as shown in the table below:

[0039] Example 3

[0040] A method for preparing high-tensile lightweight concrete comprises, by weight, 800 parts of coal gangue ceramsite, 420 parts of cement, 360 parts of water, 1.5 parts of foaming agent, 2 parts of calcium sulfate, 2 parts of polyvinyl alcohol, and 0.2 parts of water-based dispersant, wherein the water-based dispersant is sodium polyacrylate.

[0041] Among them, coal gangue ceramsite is coal gangue ceramsite with an apparent density of less than 1700 kg / m³, a fineness modulus of 1.9-2.6, a particle size of 0.15-5 mm, a water absorption rate of 5-15%, and a cylinder compressive strength of 10-15 MPa.

[0042] The foaming agent is a saponin-type plant protein foaming agent.

[0043] The preparation process includes the following steps:

[0044] Step 1: Immerse polyvinyl alcohol and sodium polyacrylate in water and then heat to obtain a modified solution;

[0045] Step 2: Soak the coal gangue ceramsite in the modification solution for 5-10 minutes to obtain mixture A containing modified coal gangue ceramsite;

[0046] Step 3: Mix the cement and calcium sulfate together until they are evenly mixed to obtain mixture B;

[0047] Step 4: Dilute the foaming agent and then use a foaming device to produce foam;

[0048] Step 4: Mix mixture A and mixture B together, incorporating foam generated by the foaming agent during the mixing process, and continue mixing for 1-2 minutes to obtain lightweight concrete. The various performance parameters of this lightweight concrete are tested, as shown in the table below:

[0049] Example 4

[0050] Based on Example 3, silica fume and / or mineral powder are added to replace 10%-20% of the cement content to improve the mechanical properties of concrete. A method for preparing high-tensile lightweight concrete comprises, by weight, 800 parts coal gangue ceramsite, 340 parts cement, 30 parts silica fume, 50 parts mineral powder, 360 parts water, 1.5 parts foaming agent, 2 parts calcium sulfate, 2 parts polyvinyl alcohol, and 0.2 parts water-based dispersant, wherein sodium polyacrylate is selected as the water-based dispersant.

[0051] Among them, coal gangue ceramsite is coal gangue ceramsite with an apparent density of less than 1700 kg / m³, a fineness modulus of 1.9-2.6, a particle size of 0.15-5 mm, a water absorption rate of 5-15%, and a cylinder compressive strength of 10-15 MPa.

[0052] The foaming agent is a saponin-type plant protein foaming agent.

[0053] The preparation process includes the following steps:

[0054] Step 1: Immerse polyvinyl alcohol and sodium polyacrylate in water and then heat to obtain a modified solution;

[0055] Step 2: Soak the coal gangue ceramsite in the modification solution for 5-10 minutes to obtain mixture A containing the modified coal gangue ceramsite;

[0056] Step 3: Mix the cement and calcium sulfate together until they are evenly mixed to obtain mixture B;

[0057] Step 4: Dilute the foaming agent and then use a foaming device to produce foam;

[0058] Step 4: Mix mixture A and mixture B together, incorporating foam generated by the foaming agent during the mixing process, and continue mixing for 1-2 minutes to obtain lightweight concrete. The various performance parameters of this lightweight concrete are tested, as shown in the table below:

[0059]

[0060] As demonstrated in Examples 1-4, the sulfate and polyvinyl alcohol in the mix proportions, acting as dispersants and surfactants, reduce the contact angle of the cement paste, thus increasing the surface tension of the liquid and making it less likely for the liquid to spread on the solid surface. This improves the concrete's encapsulation properties while reducing paste loss during construction, i.e., reducing liquid overflow from the mesh. Furthermore, since the insulation layer is a non-structural component and does not come into contact with reinforcing steel, it will not corrode. The relatively small amount of sulfate added has little impact on the mechanical properties of the high-tensile lightweight concrete.

[0061] Because low water-cement ratio concrete may suffer from incomplete hydration of cement particles, adjusting the paste-aggregate ratio can alter the workability of high-tensile lightweight concrete to some extent. Modified coal gangue ceramsite, through the slow release of moisture and ionic additives stored during pre-wetting, participates in the hydration reaction of cement particles, increasing concrete strength. Simultaneously, it provides moisture to reduce foam loss and lower the dry density of the finished concrete. This provides internal curing for the cement paste, improving the mechanical properties of the concrete. It solves the problems of easy grout leakage and high waste in lightweight concrete applications requiring no formwork removal, and thus has a wider application prospect in building insulation layers and other construction fields.

[0062] This embodiment is merely a further explanation of the present invention and is not intended to limit the present invention. Those skilled in the art can make non-inventive modifications to this embodiment as needed after reading this specification, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for preparing high-tensile lightweight concrete, characterized in that, The following ingredients are used in the following weight ratios: 800-1200 parts coal gangue ceramsite, 420-500 parts cement, 240-450 parts water, 0.5-1.5 parts foaming agent, 2-4 parts inorganic salt, 2-4 parts polyvinyl alcohol, and 0.2 parts aqueous dispersant. The inorganic salt is at least one of calcium sulfate and sodium thiosulfate. The method includes: Step 1: Immerse polyvinyl alcohol and an aqueous dispersant in water and then heat to obtain a modified solution; Step 2: Immerse the coal gangue ceramsite in the modification solution to obtain mixture A containing the modified coal gangue ceramsite; Step 3: Mix the cement and inorganic salts until they are evenly mixed to obtain mixture B; Step 4: Dilute the foaming agent and then use a foaming device to produce foam; Step 5: Mix mixture A and mixture B together. During the mixing process, add the foam generated by the foaming agent and continue mixing for 1-2 minutes.

2. The method for preparing high-tensile lightweight concrete according to claim 1, characterized in that, The coal gangue ceramsite is coal gangue ceramsite with an apparent density of less than 1700 kg / m³, a fineness modulus of 1.9-2.6, a particle size of 0.15-5 mm, a water absorption rate of 5-15%, and a cylinder compressive strength of 10-15 MPa.

3. The method for preparing high-tensile lightweight concrete according to claim 1, characterized in that, In step 1, the water temperature is heated to no more than 60°C until the polyvinyl alcohol and the aqueous dispersant are completely dissolved in the water.

4. The method for preparing high-tensile lightweight concrete according to claim 1, characterized in that, In step 2, the soaking time of the coal gangue ceramsite is controlled at 5-10 minutes.

5. The method for preparing high-tensile lightweight concrete according to claim 1, characterized in that, The method also includes replacing 10%-20% of the cement by weight with silica fume and / or fly ash.

6. The method for preparing high-tensile lightweight concrete according to claim 5, characterized in that, The silica fume has a specific surface area of ​​over 23,000 m² / kg and a silica content of over 75%; the mineral powder is at least one of S95 mineral powder or S105 mineral powder.

7. The method for preparing high-tensile lightweight concrete according to claim 1, characterized in that, The foaming agent is a saponin-type plant protein foaming agent.

8. A high-tensile lightweight concrete, characterized in that, The product comprises coal gangue ceramsite, cement, water, foaming agent, inorganic salt, polyvinyl alcohol, and aqueous dispersant, and is prepared by means of any one of claims 1-7.

Images