A micro-expansion fast-setting green curing material

Abstract

This invention belongs to the field of geotechnical engineering materials technology and relates to a micro-expansion, fast-setting, green solidification material, composed of steel slag powder, slag powder, fly ash, desulfurized gypsum, carbide slag, fast-setting components, and micro-expansion components in specific weight proportions. This invention utilizes various industrial solid wastes, achieving rapid setting (initial setting ≤ 60 min, final setting ≤ 120 min), micro-expansion (7-day free expansion rate 0.05%~0.15%), and high early strength (7-day unconfined compressive strength ≥ 1.5 MPa) through the synergistic effect of its components. It can effectively inhibit the drying shrinkage and cracking of solidified soil, and improve the workability and long-term stability of fluidized solidified soil. The solidification material of this invention is green and low-carbon, with strong soil adaptability, and is suitable for foundation treatment projects requiring rapid construction.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering materials technology, and to a micro-expansion fast-setting green curing material. Background Technology

[0002] In projects such as soft soil foundation treatment, deep foundation pit backfilling, and roadbed reinforcement, fluidized solidified soil is widely used due to its good fluidity and controllable strength. Traditional solidification materials (such as cement and lime), while improving soil strength, suffer from problems such as slow setting speed, drying shrinkage cracking, high cement consumption, and high carbon emissions. Furthermore, the significant differences in the physicochemical properties of different soil types (such as moisture content, organic matter content, and particle size distribution) lead to unstable solidification effects.

[0003] In recent years, the preparation of green cementitious materials from industrial solid wastes such as steel slag, blast furnace slag, fly ash, desulfurization gypsum, and carbide slag has become a research hotspot. However, existing solid waste-based solidification materials often have long setting times, low early strength, and large volume shrinkage, making it difficult to meet the requirements of rapid construction and micro-expansion crack resistance. For scenarios such as variable-diameter pile composite foundations that require rapid pile formation, early load-bearing capacity, and long-term stability, there is an urgent need to develop a fast-setting, micro-expansion, low-carbon solidification material suitable for different soil conditions. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned problems and provide a micro-expansion fast-setting green curing material.

[0005] To achieve the above objectives, the present invention provides a micro-expansion rapid-setting green curing material, which is composed of the following raw materials in parts by weight: 30-50 parts of steel slag powder, 20-40 parts of blast furnace slag powder, 10-20 parts of fly ash, 5-15 parts of desulfurized gypsum, 3-10 parts of carbide slag, 2-8 parts of rapid-setting component, and 1-5 parts of micro-expansion component; wherein the rapid-setting component is at least one of aluminate cement, aluminum sulfate, or calcium fluoroaluminate; and the micro-expansion component is a calcium oxide-based expansion agent or an ettringite-based expansion agent.

[0006] Furthermore, the specific surface area of ​​both the steel slag powder and the slag powder is not less than 400 m². 2 / kg, wherein the fly ash is Grade I or Grade II fly ash. Further, the desulfurization gypsum is coal-fired flue gas desulfurization gypsum, with a CaSO4·2H2O content of not less than 85%. Further, the calcium carbide slag has a Ca(OH)2 content of not less than 80% and a moisture content of less than 5%. Further, the rapid-setting component is aluminate cement, and its addition amount is 4-6 parts. Further, the micro-expansion component is a calcium oxide-based expansive agent, and its addition amount is 2-4 parts.

[0007] The cured material, under standard curing conditions, has the following characteristics: initial setting time ≤ 60 min, final setting time ≤ 120 min, 7-day free expansion rate 0.05%~0.15%, and 7-day unconfined compressive strength ≥ 1.5 MPa.

[0008] Compared with the prior art, the present invention has the following beneficial effects: Rapid setting: By adding rapid setting components such as aluminate cement, the initial setting time is ≤60 min and the final setting time is ≤120 min, which meets the requirements for rapid construction.

[0009] Micro-expansion: Calcium oxide or ettringite-based expansion agents compensate for the drying shrinkage of solidified soil, with a free expansion rate of 0.05%~0.15% after 7 days, effectively inhibiting cracking.

[0010] Green and low-carbon: It makes extensive use of industrial solid waste such as steel slag, ore slag, fly ash, desulfurization gypsum, and carbide slag, with a solid waste utilization rate of ≥80%, which significantly reduces carbon emissions.

[0011] High early strength: 7-day unconfined compressive strength ≥1.5 MPa, improving the early bearing capacity of the pile.

[0012] High adaptability to soil types: When used with a rapid compatibility model for fluidized solidified soil, it is applicable to a variety of soil types such as silt, clay, and weathered residual soil. Detailed Implementation

[0013] Example 1: This invention provides a micro-expansion, fast-setting, green curing material, composed of the following parts by weight: 40 parts steel slag powder, 30 parts blast furnace slag powder, 15 parts fly ash, 8 parts desulfurized gypsum, 5 parts carbide slag, 5 parts aluminate cement, and 3 parts calcium oxide-based expanding agent. The steel slag powder has a specific surface area of ​​450 m². 2 / kg, slag powder specific surface area 420 m² 2 / kg, fly ash grade I, desulfurized gypsum CaSO4·2H2O content 88%, carbide slag Ca(OH)2 content 85%. Preparation method: Weigh all raw materials according to the formula, put them into a forced mixer, speed 70 rpm, dry powder mix for 4 minutes, mix evenly and then package.

[0014] Example 2: 35 parts steel slag powder, 35 parts slag powder, 12 parts fly ash, 10 parts desulfurized gypsum, 4 parts calcium carbide slag, 4 parts aluminum sulfate, and 4 parts ettringite-based expanding agent. All other conditions are the same as in Example 1.

[0015] Example 3: 45 parts steel slag powder, 25 parts slag powder, 18 parts fly ash, 6 parts desulfurized gypsum, 6 parts calcium carbide slag, 3 parts calcium fluoroaluminate, and 2 parts calcium oxide-based expanding agent. All other conditions are the same as in Example 1.

[0016] Comparative Example 1: No fast-setting or micro-expansion components were added; the rest was the same as in Example 1 (i.e., only steel slag powder, slag powder, fly ash, desulfurized gypsum, and carbide slag were added, with the total amount remaining unchanged).

[0017] Performance testing: The solidification materials from Examples 1-3 and Comparative Example 1 were mixed with a certain silty clay (dry weight) at a dosage of 10%, and water was added to a fluidity of 180±10 mm to prepare fluidized solidified soil test blocks. These blocks were then cured under standard conditions (20±2℃, humidity ≥95%), and their performance was tested as follows: The results show that the initial setting time of the embodiment of the present invention is ≤60 min, the final setting time is ≤120 min, there is slight expansion at 7 days, and the strength at 7 days is ≥1.68 MPa, which is far superior to the comparative example. This demonstrates the advantages of rapid setting, slight expansion, and high early strength.

[0018] The above description is merely one embodiment of the present invention and is not intended to limit the invention. Those skilled in the art will recognize that the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A micro-expansion, fast-setting, green curing material, composed of the following raw materials in parts by weight: The mixture comprises 30-50 parts of steel slag powder, 20-40 parts of blast furnace slag powder, 10-20 parts of fly ash, 5-15 parts of desulfurized gypsum, 3-10 parts of carbide slag, 2-8 parts of rapid-setting component, and 1-5 parts of micro-expansion component; wherein the rapid-setting component is at least one of aluminate cement, aluminum sulfate, or calcium fluoroaluminate; and the micro-expansion component is a calcium oxide-based expansion agent or an ettringite-based expansion agent.

2. The micro-expansion rapid-setting green curing material according to claim 1, characterized in that, The specific surface area of ​​both the steel slag powder and the slag powder is not less than 400 m². 2 / kg, wherein the fly ash is Grade I or Grade II fly ash.

3. The micro-expansion rapid-setting green curing material according to claim 1, characterized in that, The desulfurization gypsum is a coal-fired flue gas desulfurization gypsum with a CaSO4·2H2O content of not less than 85%.

4. The micro-expansion rapid-setting green curing material according to claim 1, characterized in that, The calcium carbide slag contains no less than 80% Ca(OH)2 and less than 5% moisture.

5. The micro-expansion rapid-setting green curing material according to claim 1, characterized in that, The rapid-setting component is aluminate cement, and its addition amount is 4 to 6 parts.

6. The micro-expansion rapid-setting green curing material according to claim 1, characterized in that, The micro-expansion component is a calcium oxide-based expansion agent, and its addition amount is 2 to 4 parts.

7. The micro-expansion rapid-setting green curing material according to claim 1, characterized in that, Under standard curing conditions, the cured material has an initial setting time of ≤60 min, a final setting time of ≤120 min, a 7-day free expansion rate of 0.05%~0.15%, and a 7-day unconfined compressive strength of ≥1.5 MPa.

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