Red clay flow-state curing agent based on solid waste synergy as well as preparation method and application of red clay flow-state curing agent

Abstract

The invention discloses a red clay flow-state curing agent based on solid waste synergy as well as a preparation method and application thereof, and relates to the technical field of waste application and special soil curing. Two solid waste materials, namely the granulated blast furnace slag and the rice hull ash, are creatively compounded with the cement to form a novel curing system under the synergistic effect, namely, a slag-rice hull ash synergistic mechanism, and stable C-A-S-H gel is generated through active components (SiO2 and Al2O3) of the slag and amorphous SiO2 of the rice hull ash under the excitation of a calcium source, so that the high-strength cement is prepared. Meanwhile, pores of the red clay are filled with rice hull ash particles, a dual-curing mechanism of chemical cementation and physical filling is constructed, the problems that the curing effect is poor due to the fact that the red clay inhibits cement hydration due to an acid environment and the cementation structure is weak are effectively solved, and the strength, durability and water stability of the red clay are remarkably improved; the technical bottleneck of traditional single cement solidification or simple solid waste mixing is broken through.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of waste application and special soil solidification, in particular to a red clay fluid solidification agent based on solid waste cooperation and a preparation method and application thereof. BACKGROUND

[0002] The characteristics and application problems of red clay, which is widely distributed in southern China, especially in Guizhou, Yunnan and Guangxi. Acid red clay is red or reddish brown in color, and rich in iron oxides in the soil. Due to high rainfall and warm climate, this soil has undergone strong weathering and leaching process, resulting in a large amount of loss of alkaline substances, forming a high acidity, usually with a pH value between 4.5 and 6.0. Acid red clay has high content of clay minerals such as kaolinite and montmorillonite, which makes it have high viscosity and plasticity. Acid red clay has poor water permeability and is prone to hardening layer;

[0003] At present, the solidification agent used for solidification of soil at home and abroad is mainly traditional cement and lime. Although inorganic binder represented by cement and lime has good strength, water stability and frost resistance, it has also been widely used in many road engineering, but there are disadvantages such as high emission and high energy consumption in the production process of cement, and the solidification effect of traditional cement in red clay is significantly lower than that in other soil types, which is manifested in strength loss.

[0004] In recent years, although the alkali-activated solidification technology (such as geopolymer) reduces carbon emissions by 80% to 90% by using silicon aluminum solid waste (slag, fly ash), but its application in red clay is still limited, including not optimizing for high clay particles and high acidity of red clay, limited strength improvement after solidification; insufficient cost control, etc.

[0005] Therefore, it is urgent to develop a solidification agent and its planning material product specially used for red clay solidification, which has low cost, strong environmental protection and engineering application. SUMMARY

[0006] The purpose of the present application is to provide a red clay fluid solidification agent based on solid waste cooperation and a preparation method and application thereof, which improves the strength and durability of red clay through the synergistic effect of slag and rice husk ash; significantly reduces material cost and carbon emissions; realizes efficient resource utilization of industrial and agricultural solid waste, to solve the technical problems proposed in the background art.

[0007] To achieve the above purpose, the present application provides the following technical scheme: a red clay fluid solidification agent based on solid waste cooperation, comprising cement, granulated blast furnace slag and rice husk ash;

[0008] The mass percentage of the cement in the solidifying agent is 50%, the mass percentage of the granulated blast furnace slag in the solidifying agent is 25%, and the mass percentage of the rice husk ash in the solidifying agent is 25%.

[0009] Further, the cement is Portland cement 42.5 cement.

[0010] Further, the rice husk ash is a residue after incineration of rice husks, the loss on ignition of the rice husk ash is less than or equal to 10%, and the silicon dioxide content is greater than or equal to 85%.

[0011] A preparation method of a red clay fluidity solidifying agent based on solid waste synergy, at least comprising the following steps:

[0012] S1: grinding the granulated blast furnace slag to a specific surface area greater than or equal to 400 m2 / kg;

[0013] S2: passing the rice husk ash through a 200-mesh sieve so that the particle size of the rice husk ash is less than or equal to 75 microns;

[0014] S3: dry mixing the cement, the granulated blast furnace slag and the rice husk ash in a predetermined ratio for 3-5 minutes until the color is uniform, to form a homogeneous solidifying agent.

[0015] An application of a red clay fluidity solidifying agent based on solid waste synergy, which is mixed and incorporated into red clay according to the percentage mass, and water is added to reach a fluidity of about 200 mm, and the purpose of solidification is achieved after curing.

[0016] Further, the incorporation amount of the red clay solidifying agent during application is 20%, and the mass ratio of water to red clay solidifying agent is 0.56.

[0017] Compared with the prior art, the beneficial effects of the present application are:

[0018] 1. The present application innovatively uses two kinds of solid waste materials, granulated blast furnace slag and rice husk ash, in a synergistic effect, i.e., a slag-rice husk ash synergistic mechanism, to form a new solidifying system by compounding with cement, to generate stable C-A-S-H gel through the active components (SiO2, Al2O3) of slag and amorphous SiO2 of rice husk ash under the excitation of calcium source, and at the same time, to fill the pores of red clay with rice husk ash particles, to build a dual solidification mechanism of "chemical cementation + physical filling", to effectively solve the problems of poor solidification effect of red clay due to inhibition of cement hydration by acidic environment and weak cementation structure, to significantly improve the strength, durability and water stability of red clay, and to break through the technical bottleneck of traditional single cement solidification or simple solid waste mixing;

[0019] 2、The application greatly reduces the cement dosage in the aspects of environmental protection and resource utilization, reduces carbon emissions caused by cement production through efficient recycling of industrial and agricultural solid waste, realizes the synergy of "solid waste resourceization" and "low-carbon solidification", responds to the concept of green and sustainable development, avoids environmental pressure caused by solid waste accumulation, the overall content of cement in the solidified soil is only 10%, the traditional material is replaced by solid waste, and carbon emissions are reduced by more than 50%, and the carbon emission calculation is based on "Building Carbon Emission Calculation Standard" GB / T51366-2019;

[0020] 3、The application in the aspect of engineering applicability, the red clay after solidification has good construction fluidity and long-term mechanical properties, and can be widely applied to various engineering scenes such as roadbed and slope, solves the problem that red clay is difficult to be directly applied in engineering, expands the application path of solid waste in geotechnical engineering, and forms the unity of technical performance, environmental benefit and engineering value, compared with the prior art, has significant substantial progress. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used for the description of the embodiments, and obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0022] Figure 1 For the application process of the application, the soil and the weighed and stirred solidifying agent diagram;

[0023] Figure 2 For the application solidified soil stirring state diagram;

[0024] Figure 3 For the application flow state diagram;

[0025] Figure 4 For the application red soil after adding solidifying agent and solidifying state diagram;

[0026] Figure 5 For the application red clay solidified soil XRD diagram. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application, and obviously, the described embodiments are only some embodiments of the application, not all the embodiments.

[0028] The core technical logic and core idea of the present application revolves around "solid waste synergistic activation and low-carbon solidification", and the core is to utilize the characteristics of industrial solid waste granulated blast furnace slag and agricultural solid waste rice husk ash to form a composite solidification system with cement, to generate stable cementing materials through the synergistic reaction of the active components of slag and the high-activity amorphous substances of rice husk ash under the activation of calcium source, and to optimize the microstructure of red clay by the physical filling effect of rice husk ash particles. This idea deeply combines solid waste resource utilization with the solidification demand of red clay, with the important goal of reducing the cement dosage, improving the strength and durability of red clay, realizing efficient recovery of solid waste and reduction of carbon emissions, emphasizing the synergistic effect of inorganic materials to solve the solidification problem of red clay caused by high plasticity and high acidity, and ultimately achieving the unity of "waste treatment with waste" and engineering performance improvement. The core logic is more inclined to realize the overall solidification of red clay through the dual mechanisms of chemical cementation and physical filling between materials, as follows:

[0029] Example one:

[0030] A red clay flow state solidification agent based on solid waste synergy, comprising cement, granulated blast furnace slag and rice husk ash.

[0031] The mass fraction of cement in the solidification agent is 50%, the mass fraction of granulated blast furnace slag in the solidification agent is 25%, and the mass fraction of rice husk ash in the solidification agent is 25%.

[0032] The cement adopts Portland cement 42.5 cement, and needs to meet the specification requirements of "General Portland Cement" GB / T175-2023.

[0033] The granulated blast furnace slag is a granulated blast furnace slag powder meeting the S95 performance in "Granulated Blast Furnace Slag for Use in Cement" GB / T 18046-2017 specification.

[0034] The rice husk ash is the residue after incineration of rice husk, and the loss on ignition of the rice husk ash is ≤10%, and the silicon dioxide content is ≥85%.

[0035] Example two:

[0036] The present embodiment proposes a preparation method of a red clay flow state solidification agent based on solid waste synergy based on the above-mentioned example one, at least comprising the following steps:

[0037] S1: grinding the granulated blast furnace slag to a specific surface area ≥400m2 / kg;

[0038] S2: passing the rice husk ash through a 200-mesh sieve so that the particle size of the rice husk ash is ≤75μm;

[0039] S3: dry mixing the cement, granulated blast furnace slag and rice husk ash in a predetermined ratio for 3-5 minutes until the color is uniform, to form a homogeneous solidification agent.

[0040] Example Three

[0041] Referring to Figures 1-4 , the present embodiment is based on the above-mentioned embodiments to propose an application of red clay fluidity solidification agent based on solid waste cooperation. The red clay fluidity solidification agent based on solid waste cooperation is mixed and incorporated into red clay according to percentage mass, water is added to reach a fluidity of about 200 mm, and after curing, the purpose of solidification is achieved.

[0042] Red clay is a carbonate rock formed by weathering under subtropical warm and humid climate conditions, and is a residual, slope or residual-slope high-plasticity clay with brownish red, reddish brown or yellowish brown color, liquid limit > 45%, and clay content > 25%.

[0043] The incorporation amount of the red clay solidification agent in the application process is 20%, and the mass ratio of water to red clay solidification agent is 0.56.

[0044] The fluidity of the red clay fluidity solidification soil based on solid waste cooperation is 200 mm, the 7d unconfined compressive strength is greater than 0.5 MPa, and the strength retention rate after dry-wet cycle is greater than 80%.

[0045] Example Four

[0046] The present embodiment is based on the above-mentioned embodiments one to three, and proposes a comprehensive application and corresponding experimental demonstration of the above-mentioned technical effects.

[0047] An application of a solid waste-based red clay solidification agent, the solidification agent is incorporated into red clay at a mixing amount of 20% to achieve the purpose of stabilizing soil.

[0048] S1: Take Nanchang red clay (liquid limit 52%, plastic limit 28%), air dry and crush;

[0049] S2: Prepare the solidification agent according to the proportion of cement 50% + slag 25% + rice husk ash 25%;

[0050] S3: The solidification agent mixing amount is 20% of the red clay, and water is added to reach a slump spread of 200 mm to make 70.7x70.7x70.7mm test pieces;

[0051] S4: Standard curing (25℃, humidity 95%) for 7 days.

[0052] Results:

[0053] The test piece is solidified within 24 hours, the 7d unconfined compressive strength is 0.66 MPa, and XRD detection shows that C-A-S-H gel characteristic peaks appear at 2θ = 29.3°, 50.1° (see Figure 5 ), confirming the synergistic cementation effect of slag-rice husk ash.

[0054] Test method: Dry-wet cycle test was carried out according to the Highway Engineering Inorganic Binder Stabilized Material Test Regulation JTG E51-2009 T0845:

[0055] Drying stage: room temperature drying (25±2℃) for 12h;

[0056] Wetting stage: 25℃ deionized water immersion for 24h (water surface is 50mm higher than the test piece);

[0057] Cycle times: 15 times;

[0058] Result: strength retention rate: 85%; no visible cracks, proving excellent environmental erosion resistance.

[0059] Based on the above examples, the following comparative experiments are proposed:

[0060] Comparative experiment:

[0061] Using pure cement solidifying agent (cement content is 20% of red clay), the result is:

[0062] The test piece is solidified within 24h, and the 7d unconfined compressive strength is 0.6MPa.

[0063]

[0064]

[0065] From the above comparison, it can be obviously known that the new solidifying agent has higher solidifying performance and environmental protection performance.

[0066] As shown in the comparative experiment: when the cement content is 20%, the 7d strength of red clay solidified soil is only 0.6MPa, while the strength of cement solidified sand soil under the same conditions is usually more than 1.5MPa (referring to JTG 3442-2024), and the strength loss is more than 60%; water stability is poor, and the product Ca (OH) 2 is consumed in the acidic environment, which inhibits the hydration of cement, and the cementing structure is weak. +

[0067] Performance advantages of the solidifying agent of the application:

[0068] 1. Mechanical property improvement: 7d unconfined compressive strength reaches 0.66MPa, which is increased by 10% compared with pure cement solidifying agent (0.6MPa);

[0069] 2. Environmental benefits: carbon emission is reduced to 89kgCO2 / t, and the material cost is only ￥210 / ton, which is reduced by 40%;

[0070] 3. Engineering applicability:

[0071] ​Cracking resistance: no cracks appeared after 28 days of curing, prolonging the service life of the subgrade and meeting the requirements of the Highway Subgrade Design Specification JTGD30-2015;

[0072] Wear resistance: dense microstructure resists long-term wear;

[0073] Durability: stable crystal structure resists water erosion, and the strength retention rate is greater than or equal to 80%.

[0074] 4. Low cost and easy construction: by using cheap industrial and agricultural waste as raw materials, the cost of the curing agent is relatively low, and the construction process is simple, which is suitable for the economic and technical conditions of rural areas.

[0075] In summary:

[0076] The present application applies industrial solid waste slag and agricultural solid waste rice husk ash to red clay curing, forming a unique composite curing system. Traditional curing technology relies on cement or single solid waste material, but this technology breaks through this limitation and fully utilizes the differences in characteristics of the two types of solid waste to achieve complementary advantages. The active ingredients provided by the slag and the high-activity amorphous material contained in the rice husk ash react synergistically under the excitation of the cement calcium source to generate stable cementing materials, effectively solving the curing problem of red clay caused by the acidic environment. This idea of combining industrial and agricultural solid waste not only expands the way of solid waste resource utilization, but also optimizes the characteristics of high clay particles and high acidity of red clay, changing the situation of not adapting to the characteristics of red clay in the past solid waste application, forming a new and more targeted curing scheme, and showing significant novelty in the field of solid waste synergistic curing of red clay.

[0077] The present application is not simply mixed materials in technical design, but improves the curing effect through the dual action mechanism of micropore filling and chemical cementation: the rice husk ash particles fill the pores of the red clay and block the crack propagation, while the slag cooperates to generate cementing gel, which enhances the structural stability of the cured soil from physical and chemical aspects. This design breaks through the limitation of traditional curing technology relying on a single action mechanism, greatly improves the mechanical properties and durability of red clay. At the same time, by reducing the cement dosage and increasing the solid waste proportion, the carbon emissions and material cost are reduced under the premise of ensuring performance, solving the problems of high emission and high cost of traditional cement curing and limited effect of single solid waste application, forming an innovative technical scheme that takes into account performance, environmental protection and economy, and embodies outstanding creativity.

[0078] The present application is aimed at the whole-chain optimization of the engineering application of red clay, so that the red clay which is originally difficult to utilize realizes the engineering value. The red clay is limited in engineering application due to its own characteristics, and the present technology develops around the characteristics of red clay from the aspects of solidifying agent formula, preparation process and application method: the solidifying agent components adapt to the acidic environment of red clay, the treatment of slag and rice husk ash in the preparation process ensures that they can effectively play a role, and the fluidization design in application is convenient for construction operation. This whole-chain targeted optimization changes the previous "one-size-fits-all" treatment of red clay in solidification technology, so that the solidified red clay can meet the engineering requirements in terms of mechanical properties, durability and other aspects, and especially shows good applicability in roadbed backfilling and other engineering. Through this precise adaptation and system optimization, the present technology successfully converts the disadvantages of special soil into usable engineering resources, and has significant innovation and practicality in the field of red clay engineering application.

[0079] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, and the scope of the application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and range of the equivalent elements of the claims are intended to be embraced in the application. Any reference signs in the claims should not be considered as limiting the claims involved.

Claims

1. A red clay fluidity solidification agent based on solid waste synergy, characterized by: The cement, the granulated blast furnace slag and the rice husk ash; The mass ratio of the cement in the solidifying agent is 50%, the mass ratio of the granulated blast furnace slag in the solidifying agent is 25%, and the mass ratio of the rice husk ash in the solidifying agent is 25%.

2. The red clay fluidizing solidification agent based on solid waste synergy according to claim 1, characterized by: The cement is Portland cement 42.5 cement.

3. The red clay fluidizing solidification agent based on solid waste synergy according to claim 1, characterized by: The rice husk ash is the residue after incineration of rice husk, the loss on ignition of the rice husk ash is less than or equal to 10%, and the content of silicon dioxide is greater than or equal to 85%.

4. A preparation method of red clay fluid solidification agent based on solid waste synergy, for the red clay fluid solidification agent based on solid waste synergy according to any one of claims 1-2, characterized in that: At least comprising the following steps: S1 : grinding granulated blast furnace slag to a specific surface area of > 400 m 2 / kg; S2: passing the rice husk ash through a 200-mesh sieve so that the particle size of the rice husk ash is less than or equal to 75 μm; S3: dry mixing the cement, the granulated blast furnace slag and the rice husk ash in a predetermined ratio for 3-5 minutes until the color is uniform to form a homogeneous solidifying agent.

5. The use of a red clay fluidity solidification agent based on solid waste synergy, characterized by: A red clay fluidized solidifying agent based on solid waste cooperation prepared according to claim 4 is mixed and added into red clay according to the percentage mass, water is added until the fluidity reaches about 200 mm, and after curing, the purpose of solidification is achieved.

6. The use of a red clay fluidizing agent based on solid waste according to claim 5, characterized in that: The mixing amount of the red clay solidifying agent in the application process is 20%, and the mass ratio of water to the red clay solidifying agent is 0.56.

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