Gypsum-based self-leveling material, preparation method and strength testing method

Abstract

The invention relates to a gypsum-based self-leveling material as well as a preparation method and a strength testing method thereof. The gypsum-based self-leveling material is prepared from the following raw materials in parts by weight: 60 to 85 parts of desulfurized gypsum, 4.5 to 5.0 parts of cement, 10 to 30.5 parts of mineral powder, 0.035 to 0.045 part of retarder, 0.037 to 0.048 part of cellulose, 0.226 to 0.315 part of water reducing agent and 0.093 to 0.114 part of defoaming agent. The preparation method comprises the following steps: S1, removing scrap iron impurities mixed in the raw materials in the production process through an iron remover; s2, the raw materials are separately dried, and the water content is lower than 8%; and S3, putting the raw materials into a dry powder stirrer according to the ratio, adding a proper amount of water, and fully and uniformly stirring to prepare the gypsum-based self-leveling material. The material strength is improved, the cost is reduced, and the material is more environment-friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of self-leveling materials, and particularly relates to a gypsum-based self-leveling material, a preparation method and a strength testing method. Background Art

[0002] Industrial by-product gypsum is a large-scale industrial waste. For example, desulfurization gypsum is a by-product of the flue gas desulfurization process in thermal power plants, and phosphogypsum is waste residue from the production of phosphate fertilizers. If these industrial by-products are not properly utilized, they not only occupy a large amount of land resources but also cause environmental pollution. With the development of the construction industry, the requirements for floor smoothness and construction efficiency are becoming increasingly stringent. Traditional floor leveling methods, such as cement mortar leveling, are inefficient, labor-intensive, and difficult to ensure floor smoothness. The emergence of self-leveling materials has addressed these issues, offering simple and fast construction and effective improvement in floor smoothness. Initially, cement-based self-leveling was the predominant self-leveling material due to its high strength and durability. However, with increasing demands for environmental protection, energy conservation, and building comfort, the shortcomings of cement-based self-leveling have gradually become apparent. Gypsum-based self-leveling has begun to attract attention as a new self-leveling material, providing an effective way to recycle industrial by-product gypsum. By properly treating and processing industrial by-product gypsum, high-quality building gypsum can be made, and then gypsum-based self-leveling materials with excellent performance can be produced. This not only realizes the resource utilization of solid waste and reduces environmental pollution, but also reduces the production cost of gypsum-based self-leveling and improves its market competitiveness.

[0003] Gypsum-based self-leveling is a powdered material made of building gypsum as the main cementitious material, mixed with an appropriate amount of light aggregate, additives, etc., and formed into a slurry with good fluidity and plasticity after adding water and stirring. It can automatically level on the ground and form a flat ground layer after hardening.

[0004] The raw materials of existing gypsum-based self-leveling rely on a large amount of conventional materials such as cement and additives, which are relatively expensive and have poor flexural and compressive properties. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a gypsum-based self-leveling material, a preparation method and a strength testing method, which solve the technical problems of the prior art such as high cost and poor performance.

[0006] In order to solve the above problems, the technical solution of the present invention is: a gypsum-based self-leveling material, comprising the following raw materials in parts by weight: 60-85 parts of desulfurized gypsum, 4.5-5.0 parts of cement, 10-30.5 parts of mineral powder, 0.035-0.045 parts of retarder, 0.037-0.048 parts of cellulose, 0.226-0.315 parts of water reducer, and 0.093-0.114 parts of defoaming agent.

[0007] Another object of the present invention is to provide a method for preparing a gypsum-based self-leveling material, comprising the following steps: Step S1: passing the raw materials through a deironing device to remove iron filings and impurities mixed in during the production process; Step S2: drying the raw materials separately to obtain a moisture content of less than 8%; Step S3: Put the raw materials into a dry powder mixer according to the proportion and add appropriate amount of water to fully stir them to prepare a gypsum-based self-leveling material.

[0008] Another object of the present invention is to provide a method for testing the flexural and compressive strength of a gypsum-based self-leveling material, wherein the gypsum-based self-leveling material is selected for testing, and the method comprises the following steps: Pour the evenly stirred gypsum-based self-leveling material sample into the triple test mold. After the sample is full, lift one end of the mold and let it fall freely. Vibrate it multiple times to eliminate bubbles in the sample. Use a scraper to scrape off the surface slurry until the specified demolding time. After the sample is hydrated to the specified age, dry it in an oven to constant weight, and then perform flexural and compressive tests according to the "Determination of Mechanical Properties of Building Gypsum" (GB / T 17669.3-1999).

[0009] Preferably, the mold lifting height is 10mm-30mm.

[0010] Preferably, the prescribed demoulding time is 24 hours.

[0011] Preferably, the temperature in the oven is 45°C.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. High solid waste content, significant environmental benefits: In existing technologies, gypsum-based self-leveling materials also utilize some industrial solid waste, but the content is usually limited, making it difficult to dispose of solid waste on a large scale. This invention uses desulfurized gypsum as the main base material, with a content of 65%-80%.

[0013] 2. Significant performance improvement and outstanding comprehensive advantages: The present invention significantly enhances the strength and durability of the material; further optimizes the material's setting time, fluidity and other properties, overcoming the defects of the existing technology.

[0014] 3. Reduce production costs and improve economic benefits: Existing technologies rely on large amounts of conventional materials such as cement and additives, which are relatively costly. This invention uses a large amount of desulfurized gypsum, significantly reducing raw material costs. At the same time, the improved overall performance of the material reduces losses during construction and subsequent maintenance costs. DETAILED DESCRIPTION

[0015] The present invention is described in further detail below with reference to the embodiments.

[0016] Example 1: This example provides a gypsum-based self-leveling material, comprising the following raw materials in parts by weight: 65 parts of desulfurized gypsum, 5 parts of cement, 30 parts of mineral powder, 0.04 parts of retarder, 0.04 parts of cellulose, 0.25 parts of water reducer, and 0.1 parts of defoaming agent.

[0017] The preparation method of the gypsum-based self-leveling material comprises the following steps: Step S1: passing the raw materials through a deironing device to remove iron filings and impurities mixed in during the production process; Step S2: drying the raw materials separately to obtain a moisture content of less than 8%; Step S3: Put the raw materials into a dry powder mixer according to the proportion and add appropriate amount of water to fully stir them to prepare a gypsum-based self-leveling material.

[0018] This method of solid waste utilization not only achieves efficient resource utilization of industrial waste, reduces production costs, reasonably optimizes setting time, and improves material strength, but also significantly improves the comprehensive performance of gypsum-based self-leveling materials, providing the construction industry with a green, environmentally friendly and high-performance ground leveling solution.

[0019] Example 2: This example provides a gypsum-based self-leveling material, comprising the following raw materials in parts by weight: 70 parts of desulfurized gypsum, 5 parts of cement, 25 parts of mineral powder, 0.04 parts of retarder, 0.04 parts of cellulose, 0.25 parts of water reducer, and 0.1 parts of defoaming agent.

[0020] The preparation method of the gypsum-based self-leveling material comprises the following steps: Step S1: passing the raw materials through a deironing device to remove iron filings and impurities mixed in during the production process; Step S2: drying the raw materials separately to obtain a moisture content of less than 8%; Step S3: Put the raw materials into a dry powder mixer according to the proportion and add appropriate amount of water to fully stir them to prepare a gypsum-based self-leveling material.

[0021] This solid waste utilization method not only achieves efficient resource utilization of industrial waste, reduces production costs, reasonably optimizes setting time, and improves material strength, but also significantly improves the comprehensive performance of gypsum-based self-leveling materials, providing a green, environmentally friendly and high-performance ground leveling solution for the construction industry. Example 3: This example provides a gypsum-based self-leveling material, comprising the following raw materials in parts by weight: 70 parts of desulfurized gypsum, 5 parts of cement, 25 parts of mineral powder, 0.04 parts of retarder, 0.04 parts of cellulose, 0.25 parts of water reducer, and 0.1 parts of defoaming agent.

[0022] The preparation method of the gypsum-based self-leveling material comprises the following steps: Step S1: passing the raw materials through a deironing device to remove iron filings and impurities mixed in during the production process; Step S2: drying the raw materials separately to obtain a moisture content of less than 8%; Step S3: Put the raw materials into a dry powder mixer according to the proportion and add appropriate amount of water to fully stir them to prepare a gypsum-based self-leveling material.

[0023] This solid waste utilization method not only achieves efficient resource utilization of industrial waste, reduces production costs, reasonably optimizes setting time, and improves material strength, but also significantly improves the comprehensive performance of gypsum-based self-leveling materials, providing a green, environmentally friendly and high-performance ground leveling solution for the construction industry. Example 4: This example provides a method for testing the flexural and compressive strength of a gypsum-based self-leveling material. The gypsum-based self-leveling material in Examples 1-3 is selected for testing, and the method includes the following steps: Pour a well-mixed sample of gypsum-based self-leveling material into a triple test mold. Once filled, manually lift one end of the mold approximately 10-30 mm and allow it to fall freely. Vibrate the mold several times to remove air bubbles from the sample. Use a scraper to remove any excess slurry until the specified demolding time (24 hours) is reached. Samples hydrated to the specified age are dried in a 45°C oven to constant weight. Flexural and compressive strength tests are then performed according to "Determination of Mechanical Properties of Building Gypsum" (GB / T 17669.3-1999).

[0024] The flexural and compressive strength indices measured for the three groups of examples are shown in the following table: Absolute dry flexural strength (Mpa) (average value) Absolute dry compressive strength (Mpa) (average value) Example 1 13.9 51.97 Example 2 14.8 41.25 Example 3 13.3 41.78 The absolute dry flexural and compressive strength (MPa) of the G25 self-leveling material after 28 days is 7 / 25. The gypsum-based self-leveling material of the present invention has better performance.

[0025] The gypsum-based self-leveling material of the present invention has the following advantages: 1. Good fluidity and construction performance: Gypsum-based self-leveling has good fluidity. After adding water and stirring, it can automatically level on the ground without excessive external force. It is easy to apply and fast, which can effectively improve construction efficiency. Moreover, its construction thickness can be adjusted as needed, from a few millimeters to tens of millimeters.

[0026] 2. Improved water resistance: After 28 days of standard curing, the sample was immersed in water for 7 days, and its strength loss rate was significantly reduced compared to existing technologies. This shows that the material can still maintain high strength after absorbing water, can better adapt to humid environments, effectively avoid problems such as softening and powdering caused by water erosion, and greatly extend the service life of the material.

[0027] 3. Low shrinkage: The shrinkage is extremely small, almost negligible. This makes it less likely to crack during the hardening process, ensuring the flatness and integrity of the ground, and is especially suitable for large-scale construction.

[0028] 4. Fast drying and high early strength: The mortar dries quickly and generally reaches a certain strength within 24 hours after construction, allowing for subsequent construction and significantly shortening the project period. At the same time, its early strength is also high, meeting the requirements for ground use.

[0029] 5. Good thermal insulation performance: With good thermal insulation performance, it can effectively reduce the energy consumption of buildings and improve indoor comfort. This is of great significance to the development of energy-saving buildings and green buildings.

[0030] 6. Good sound absorption and noise reduction performance: It can absorb and reduce the spread of sound, has good sound absorption and noise reduction performance, and can provide people with a quiet indoor environment.

[0031] 7. Excellent environmental performance: It realizes the resource utilization of solid waste, reduces the dependence on natural gypsum resources, and solves the problem of stacking and pollution of industrial by-product gypsum. It does not release harmful substances during use and meets environmental protection requirements.

[0032] 8. Good adhesion to the base layer: It has strong adhesion to the base layer and can be firmly attached to the base layer. It is not prone to hollowing and falling off, ensuring the quality and stability of the ground.

Claims

1. A gypsum-based self-leveling material, characterized in that: It includes the following raw materials in parts by weight: 60-85 parts of desulfurized gypsum, 4.5-5.0 parts of cement, 10-30.5 parts of mineral powder, 0.035-0.045 parts of retarder, 0.037-0.048 parts of cellulose, 0.226-0.315 parts of water reducer, and 0.093-0.114 parts of defoaming agent.

2. The method for preparing a gypsum-based self-leveling material according to claim 1, characterized in that: The following steps are involved: Step S1: passing the raw materials through a deironing device to remove iron filings and impurities mixed in during the production process; Step S2: drying the raw materials separately to obtain a moisture content of less than 8%; Step S3: Put the raw materials into a dry powder mixer according to the proportion and add appropriate amount of water to fully stir them to prepare a gypsum-based self-leveling material.

3. A method for testing the flexural and compressive strength of gypsum-based self-leveling materials, characterized in that: The gypsum-based self-leveling material of claim 1 is selected for testing, comprising the following steps: Pour the evenly stirred gypsum-based self-leveling material sample into the triple test mold. After the sample is full, lift one end of the mold and let it fall freely. Vibrate it multiple times to eliminate bubbles in the sample. Use a scraper to scrape off the surface slurry until the specified demolding time. After the sample is hydrated to the specified age, dry it in an oven to constant weight, and then perform flexural and compressive tests according to the "Determination of Mechanical Properties of Building Gypsum" (GB / T 17669.3-1999).

4. The method for testing the flexural and compressive strength of a gypsum-based self-leveling material according to claim 3, characterized in that: The mold lifting height is 10mm-30mm.

5. The method for testing the flexural and compressive strength of a gypsum-based self-leveling material according to claim 3, wherein: The specified demoulding time is 24h.

6. The method for testing the flexural and compressive strength of a gypsum-based self-leveling material according to claim 3, wherein: The temperature in the oven was 45°C.