Atmospheric environment self-carbonization solid waste-based neutral soil curing agent and preparation method thereof
By using a solid waste-based neutral soil solidifier composed of steel slag powder and other materials to carry out a carbonation reaction in an atmospheric environment, the problems of high energy consumption, high carbon emissions, and alkaline environment of traditional civil engineering materials are solved, achieving a high-efficiency, low-carbon, and simple soil solidification effect.
Patent Information
- Application Number
- CN202610202001.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-12
- Publication Date
- 2026-05-19
AI Technical Summary
Traditional cementitious materials used in existing civil engineering, such as cement and lime, have high energy consumption and carbon emissions during production and create an alkaline environment, making it difficult to achieve effective soil solidification in an atmospheric environment. Furthermore, existing carbonation technologies are complex and costly, making them difficult to promote.
A solid waste-based neutral soil solidifier, composed of steel slag powder, waste concrete powder, modified gasification slag, amino catalysts, and hygroscopic salts, generates neutral cementitious products through a carbonation reaction in an atmospheric environment. It is then solidified using atmospheric carbon dioxide and combined with polypropylene fibers to enhance toughness and crack resistance.
It achieves efficient soil solidification in natural environments, reduces carbon footprint, generates neutral products, reduces the risk of alkalization to the ecological environment, is easy to construct, has low cost, and exhibits excellent strength and volume stability.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of civil engineering materials technology, and in particular to a soil solidification material prepared from industrial solid waste, especially a solid waste-based soil solidification agent that can achieve self-solidification through carbonation reaction under atmospheric conditions, and whose final product is neutral, and its preparation method. Background Technology
[0002] In civil engineering construction, such as road projects, foundation treatment, and slope protection, it is often necessary to solidify and improve the in-situ soil to enhance its mechanical properties, water stability, and durability. Currently, the soil solidifying agents widely used in engineering are still mainly traditional cementing materials such as cement and lime. Although these materials can effectively improve soil strength, their production process is energy-intensive, produces large amounts of carbon dioxide, and significantly raises the pH value of the solidified soil, creating a highly alkaline environment. This alkaline environment may not only disrupt the original ecological balance of the soil and affect vegetation restoration, but also contradicts the current advocacy of green and sustainable infrastructure construction concepts.
[0003] To reduce environmental impact, developing alternative solidification materials using industrial solid waste (such as steel slag, blast furnace slag, and fly ash) has become a research hotspot. Many solid waste-based solidifiers rely on alkali activation technology to achieve gelation properties, but this does not fundamentally solve the problem of excessively high alkalinity in the system. On the other hand, carbonation solidification technology is considered a potential low-carbon pathway, utilizing the reaction of calcium-containing solid waste with carbon dioxide to generate calcium carbonate for cementation. However, existing carbonation technologies typically rely on high-concentration CO2 atmospheres (far exceeding atmospheric concentrations) and dedicated pressurization or circulation equipment, resulting in complex processes, high costs, and difficulty in widespread application in open-air, large-scale on-site engineering projects. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide an atmospheric self-carbonizing solid waste-based neutral soil solidifier and its preparation method. The solidifier can utilize carbon dioxide in the atmosphere to undergo a carbonation reaction under natural curing conditions to generate neutral cementitious products, thereby achieving effective solidification of the soil. It also has the advantages of high solid waste utilization rate, good ecological compatibility, and simple construction.
[0005] The technical solution adopted by this invention to solve its technical problem is: an atmospheric self-carbonizing solid waste-based neutral soil solidifying agent, which, by weight percentage, is composed of 40%~50% steel slag powder, 20%~30% waste concrete powder, 20%~26% modified gasification slag, 0.5%~0.8% amino catalyst, 1.0%~1.5% hygroscopic salt, and 0.1%~0.2% polypropylene fiber.
[0006] The properties and functions of each raw material are as follows: Steel slag powder: It is made from solid waste from iron and steel smelting through grinding, with a specific surface area ≥450m² / kg and a free calcium oxide content of not less than 5%. It is rich in active ingredients such as free CaO and calcium silicate, which can undergo carbonation reaction with CO2 in the atmosphere to generate calcium carbonate cement, which binds soil particles and improves the strength of the solidified body.
[0007] Waste concrete powder: made from construction demolition waste through crushing, impurity removal, and grinding, with a specific surface area ≥400m² / kg. It is rich in calcium hydroxide and unhydrated cement particles, and can react with atmospheric CO2 under the action of a catalyst to generate neutral calcium carbonate crystals with cementing ability, providing early and late strength to the solidified body.
[0008] Modified gasification slag: It is made from coarse coal gasification slag through crushing and screening, with a particle size of 0.15mm~4.75mm and a total porosity of not less than 40%. Its well-developed porous structure can construct transport channels for CO2 and moisture within the solidified body, providing reaction surface area, while its own active components can participate in the carbonation reaction.
[0009] Amino-based catalysts: One or more of triethanolamine, diethanolamine, and urea can be selected to reduce the activation energy of the carbonation reaction, accelerate the dissolution and ionization of CO2 in water, promote the combination of Ca²⁺ and CO3²⁻, and achieve efficient carbonation in a low-concentration atmospheric CO2 environment.
[0010] Hygroscopic salt: Select one of calcium chloride, magnesium chloride, or calcium nitrate. It can actively absorb moisture from the air, maintain stable internal humidity of the cured body, and avoid reaction cessation caused by surface drying during natural curing.
[0011] Polypropylene fiber: can improve the toughness and crack resistance of the cured body, and improve the volume stability of the cured body.
[0012] This invention also discloses the preparation and application method of the curing agent, including the following steps: (1) Raw material pretreatment: Steel slag is ground to a specific surface area ≥450m² / kg; Demolition waste is crushed and cleaned and then ground to a specific surface area ≥400m² / kg; Coal gasification coarse slag is crushed and screened to a particle size of 0.15mm~4.75mm.
[0013] (2) Mixing and batching: Weigh each component according to the weight percentage, stir and mix evenly to obtain solid waste-based neutral soil solidification agent.
[0014] (3) Soil solidification construction: Dry mix the solidifier and soil at a mass ratio of 10%~15% for 2 minutes, add water accounting for 11%~13% of the total mass of solidifier and soil and wet mix for 4 minutes; fill the construction area and compact to a compaction degree ≥95%; cover with plastic film for curing in a natural environment with a temperature of 15℃~30℃ and humidity of 40%~70% for a curing period of not less than 7 days.
[0015] The beneficial effect of this invention is that it solves the defects existing in the prior art. 1. Using steel slag, waste concrete, and gasification slag as main raw materials, this method achieves high-value synergistic utilization of various industrial solid wastes, replacing traditional cement and significantly reducing the carbon footprint of material production. The solidification process can also absorb and seal CO2 from the atmosphere, demonstrating negative carbon potential.
[0016] 2. Through complete carbonation reaction, the alkaline components in the raw materials are completely consumed, making the pH value of the leachate of the final solidified product neutral, eliminating the risk of alkalization to the soil ecological environment, and facilitating ecological restoration after the project.
[0017] 3. It breaks through the dependence of carbonation curing on high concentrations of CO2 and special equipment. It only requires conventional covering and maintenance in a natural environment. The construction process is simple and compatible with the existing construction system, which greatly reduces the cost and threshold for the promotion and application of the technology.
[0018] 4. The solidified soil exhibits stable strength development in both the early and later stages, with an unconfined compressive strength of over 2.0 MPa after 28 days, meeting general engineering requirements. Furthermore, its drying shrinkage is significantly lower than that of traditional cement-solidified soil, resulting in superior volume stability. Detailed Implementation
[0019] The present invention will be further described below with reference to specific embodiments. The described embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention. Example
[0020] An atmospheric self-carbonizing solid waste-based neutral soil solidifying agent, by weight percentage, is composed of the following components: 45% steel slag powder, 23% waste concrete powder, 20% modified gasification furnace slag, 0.7% triethanolamine, 1.2% calcium chloride, and 0.1% polypropylene fiber.
[0021] Its preparation and construction methods are as follows: Raw material pretreatment: Steel slag is ground to a specific surface area of 450 m² / kg; demolition waste is crushed, impurities removed, and then ground to a specific surface area of 400 m² / kg; coarse slag from coal gasification is crushed and screened to a particle size of 0.15 mm to 4.75 mm.
[0022] Mixing ingredients: Weigh each component according to the above weight percentages, stir and mix evenly to obtain the curing agent.
[0023] Soil solidification construction: Dry mix the solidifying agent and soil at a mass ratio of 90:10 for 2 minutes, add water accounting for 12% of the total mass of solid raw materials and wet mix for 4 minutes; fill the test mold and compact to a compaction degree of 95%; cover with plastic film for 7 days and 28 days in a natural environment with a temperature of 15℃~30℃ and a humidity of 40%~70%. Example
[0024] An atmospheric self-carbonizing solid waste-based neutral soil solidifying agent, by weight percentage, is composed of the following components: 50% steel slag powder, 20% waste concrete powder, 22.5% modified gasification furnace slag, 0.5% urea, 1.5% calcium nitrate, and 0.2% polypropylene fiber.
[0025] Its preparation and construction methods are as follows: Raw material pretreatment: Same as in Example 1.
[0026] Mixing ingredients: Weigh each component according to the above weight percentages, stir and mix evenly to obtain the curing agent.
[0027] Soil consolidation construction: Dry mix the solidifying agent and soil at a mass ratio of 88:12 for 2 minutes, add water accounting for 11% of the total mass of solid raw materials and wet mix for 4 minutes; fill the test mold and compact to a compaction degree of 95%; cover with plastic film for 7 days and 28 days in a natural environment with a temperature of 15℃~30℃ and a humidity of 40%~70%. Example
[0028] An atmospheric self-carbonizing solid waste-based neutral soil solidifying agent, by weight percentage, is composed of the following components: 40% steel slag powder, 30% waste concrete powder, 25% modified gasification furnace slag, 0.8% diethanolamine, 1.0% magnesium chloride, and 0.2% polypropylene fiber.
[0029] Its preparation and construction methods are as follows: Raw material pretreatment: Same as in Example 1.
[0030] Mixing ingredients: Weigh each component according to the above weight percentages, stir and mix evenly to obtain the curing agent.
[0031] Soil solidification construction: Dry mix the solidifying agent and soil at a mass ratio of 85:15 for 2 minutes, add water accounting for 13% of the total mass of solid raw materials and wet mix for 4 minutes; fill the test mold and compact to a compaction degree of 95%; cover with plastic film for 7 days and 28 days in a natural environment with a temperature of 15℃~30℃ and a humidity of 40%~70%. Example
[0032] An atmospheric self-carbonizing solid waste-based neutral soil solidifying agent, by weight percentage, is composed of the following components: 43% steel slag powder, 25% waste concrete powder, 26% modified gasification slag, 0.6% triethanolamine, 1.3% calcium chloride, and 0.1% polypropylene fiber.
[0033] Its preparation and construction methods are as follows: Raw material pretreatment: Same as in Example 1.
[0034] Mixing ingredients: Weigh each component according to the above weight percentages, stir and mix evenly to obtain the curing agent.
[0035] Soil solidification construction: Dry mix the solidifying agent and soil at a mass ratio of 87:13 for 2 minutes, add water accounting for 12% of the total mass of solid raw materials and wet mix for 4 minutes; fill the test mold and compact to a compaction degree of 95%; cover with plastic film for 7 days and 28 days in a natural environment with a temperature of 15℃~30℃ and a humidity of 40%~70%.
[0036] Comparative Example 1 The solid waste-based solidifier composition is the same as in Example 1, but it does not contain amino-based catalysts or hygroscopic salts; the mass ratio of soil to solidifier is 90:10, and the water mass is 12% of the total mass of solid raw materials; the preparation and construction methods are the same as in Example 1.
[0037] Comparative Example 2 The curing agent used was P·O 42.5 cement; the mass ratio of soil to cement was 90:10, and the water mass was 12% of the total mass of solid raw materials; the soil and cement were dry-mixed for 2 minutes, and then wet-mixed with water for 4 minutes; the mixture was poured into a test mold and compacted to a compaction degree of 95%; and cured for 7 days and 28 days under standard curing conditions.
[0038] The solidified soils prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to performance tests, including 7-day unconfined compressive strength, 28-day unconfined compressive strength, 28-day leachate pH value, and 28-day drying shrinkage coefficient. The test results are shown in the table below:
[0039] The test results show that: The solidified soils prepared in Examples 1-4 exhibited an unconfined compressive strength of 0.9-1.2 MPa at 7 days and 2.0-2.5 MPa at 28 days, with the strength steadily increasing with age, meeting the strength requirements for solidified soils in civil engineering. The pH value of the leachate at 28 days was 7.3-7.6, indicating neutrality and excellent ecological compatibility. The drying shrinkage coefficient was significantly lower than that of Comparative Example 1 and Comparative Example 2, demonstrating better volume stability.
[0040] Comparing Example 1 with Comparative Example 1, it can be seen that amino-based catalysts and hygroscopic salts are key components for achieving efficient self-carbonization and system neutralization. Without these two components, the strength of the cured body decreases significantly and the system becomes alkaline.
[0041] Comparing Example 2 with Comparative Example 2, it can be seen that the early strength of the curing agent of the present invention is slightly lower than that of traditional cement, but the 28-day strength can meet the engineering requirements. It also has the significant advantages of being neutral and having low drying shrinkage, making it more suitable for green and ecological engineering projects.
[0042] In Example 2, the content of steel slag powder was 50%, and the strength and volume stability of the solidified body were optimal, which is the optimal ratio of the present invention.
[0043] The above description is only a specific embodiment of the present invention. Various examples and illustrations do not constitute a limitation on the substantive content of the present invention. Those skilled in the art can make modifications or variations to the above-described specific embodiments after reading the specification without departing from the substance and scope of the invention.
Claims
1. A neutral soil solidification agent based on atmospheric self-carbonization solid waste, characterized in that, By weight percentage, it consists of the following components: 40%~50% steel slag powder, 20%~30% waste concrete powder, 20%~26% modified gasification slag, 0.5%~0.8% amino catalyst, 1.0%~1.5% hygroscopic salt, and 0.1%~0.2% polypropylene fiber; The steel slag powder is made from solid waste from iron and steel smelting through grinding, with a specific surface area ≥450m² / kg and a free calcium oxide content of not less than 5%; The waste concrete powder is made from building demolition solid waste through crushing, impurity removal, and grinding, with a specific surface area ≥400m² / kg; The modified gasification slag is produced by crushing and screening coarse coal gasification slag, with a particle size of 0.15mm~4.75mm and a total porosity of not less than 40%.
2. The atmospheric self-carbonizing solid waste-based neutral soil solidifier according to claim 1, characterized in that, The amino-based catalyst is one or more of triethanolamine, diethanolamine, and urea.
3. The atmospheric self-carbonizing solid waste-based neutral soil solidifier according to claim 1, characterized in that, The hygroscopic salt is one of calcium chloride, magnesium chloride, and calcium nitrate.
4. The atmospheric self-carbonizing solid waste-based neutral soil solidifier according to claim 1, characterized in that, The composition of each component by weight percentage is as follows: 50% steel slag powder, 20% waste concrete powder, 22.5% modified gasification slag, 0.5% urea, 1.5% calcium nitrate, and 0.2% polypropylene fiber.
5. A neutral soil solidification agent for atmospheric self-carbonizing solid waste as described in any one of claims 1 to 4, characterized in that, The mass ratio of the curing agent to the soil is 10% to 15%.
6. A method for preparing the curing agent according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Raw material pretreatment: Steel slag is ground to a specific surface area ≥450m² / kg; Construction demolition waste is crushed and cleaned and then ground to a specific surface area ≥400m² / kg; Coal gasification coarse slag is crushed and screened to a particle size of 0.15mm~4.75mm; (2) Mixing and batching: Weigh each component according to the weight percentage, stir and mix evenly to obtain a solid waste-based neutral soil solidification agent; (3) Soil solidification construction: Dry mix the solidifying agent with the soil, add water and mix wet, fill the construction area and compact, and cure in natural environment until the design age.
7. The method for preparing and applying the curing agent according to claim 6, characterized in that, In step (3), the dry mixing time is 2 minutes and the wet mixing time is 4 minutes; the mass of water is 11% to 13% of the total mass of the curing agent and the soil.
8. The method for preparing and applying the curing agent according to claim 6, characterized in that, In step (3), the compaction degree after compaction is ≥95%.
9. The method according to claim 6, characterized in that, In step (3), the natural curing environment is a temperature of 15℃~30℃ and a humidity of 40%~70%. During curing, the plant is covered with plastic film and the curing period is no less than 7 days.