An early-strength, crack-resistant, negative-carbon cement-stabilized soil and its preparation method and application

Abstract

The present invention relates to the technical field of cement stabilized soil preparation, and specifically discloses an early-strength, crack-resistant, negative-carbon cement stabilized soil, and its preparation method and application. The cement stabilized soil comprises the following components in parts by weight: 30 to 45 parts of blast furnace slag powder, 8 to 12 parts of modified brucite fiber steel slag powder, 20 to 35 parts of sulphoaluminate cement, 5 to 10 parts of silicate cement, 50 to 60 parts of fine aggregate, 5 to 15 parts of fluorspar, 5 to 10 parts of carbide slag, 80 to 100 parts of soil particles, 2 to 4 parts of water reducer, and 20 to 30 parts of mixing water. The above-mentioned cement stabilized soil of the present invention not only realizes green and low-carbon production and reduces costs, but also the cement stabilized soil of the present invention has significant improvements in early strength, crack resistance and long-term durability.

Description

Technical Field

[0001] The present invention relates to the technical field of cement stabilized soil preparation, and in particular to an early-strength, crack-resistant, negative-carbon cement stabilized soil, and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Cement-stabilized soil (CS) is a building material made by compacting soil, fine aggregate, and water into a compacted mixture using cement as a binder. It is widely used in the base construction of infrastructure such as highways and airport runways. It possesses excellent integrity, load-bearing capacity, and ease of construction, playing a vital role in roadbed reinforcement. As the primary material for base construction, CS exhibits high mechanical properties and long-term stability in engineering construction, and is particularly valuable under high loads and complex climatic conditions. However, with increasing engineering demands, higher requirements are being placed on the mechanical properties, durability, and environmental performance of CS.

[0004] Despite its wide application, cement-stabilized soil still has many problems with its traditional formulation. First, cement-stabilized soil mostly uses ordinary Portland cement as the main cementing material, which not only leads to high hydration heat and easily causes early shrinkage and cracking problems, but also its high carbon emissions and high energy consumption characteristics do not meet the current requirements of green and low-carbon development. Secondly, in harsh environments such as humidity and marine engineering, cement-stabilized soil has poor crack resistance and durability, and is easily affected by swelling deformation and salt erosion in seawater. Finally, the utilization rate of industrial by-products in the production process of traditional cement-stabilized soil is low, and resource recycling is not achieved, which increases production costs and environmental burdens. Therefore, there is an urgent need to develop a high-performance and environmentally friendly cement-stabilized soil to meet the needs of modern engineering. Summary of the Invention

[0005] In view of this, the present invention provides an early-strength, crack-resistant, negative-carbon cement-stabilized soil, as well as its preparation method and application. This not only achieves green, low-carbon production and reduces costs, but also significantly improves the early strength, crack resistance, and long-term durability of the cement-stabilized soil. Specifically, the technical solution of the present invention is as follows.

[0006] First, the present invention provides an early-strength, crack-resistant, negative-carbon cement-stabilized soil, which includes the following components in parts by weight: 30-45 parts of blast furnace slag powder, 8-12 parts of modified brucite fiber steel slag powder, 20-35 parts of sulphoaluminate cement, 5-10 parts of Portland cement, 50-60 parts of fine aggregate, 5-15 parts of fluorspar, 5-10 parts of carbide slag, 80-100 parts of soil particles, 2-4 parts of water reducer, and 20-30 parts of mixing water.

[0007] Furthermore, the modified brucite fiber steel slag powder is prepared by dispersing steel slag powder and brucite fibers in water, then introducing carbon dioxide under stirring. After completion, solid-liquid separation is performed, and the resulting solid product is dried and then uniformly mixed with dihydrogen phosphate powder to obtain the modified brucite fiber steel slag powder.

[0008] Furthermore, the ratio of the steel slag powder, brucite fiber powder and water is 4-7.5g: 1-1.5g: 150-220ml. Optionally, the specific surface area of the steel slag powder is 400-600m 2 / kg, and the length of the brucite fiber is 0.5~1cm.

[0009] Furthermore, the carbon dioxide is introduced at a rate of 1 to 3 L / min, and the duration of the introduction is 45 to 60 min.

[0010] Furthermore, the drying temperature is 100-130° C., and the drying is carried out at this temperature until the weight of the solid product becomes constant.

[0011] Furthermore, the mass ratio of the dried solid product to dihydrogen phosphate is 1:0.12-0.15. Optionally, the dihydrogen phosphate includes at least one of potassium dihydrogen phosphate, ammonium dihydrogen phosphate, etc.

[0012] Furthermore, the water reducer includes at least one of a polycarboxylic acid water reducer, a naphthalene water reducer, a lignin sulfonate water reducer, and the like.

[0013] Furthermore, the fine aggregate includes at least one of quartz sand, river sand, and machine-made sand. Optionally, the fine aggregate is formed by continuously grading particles with finenesses of 20-40 mesh, 40-70 mesh, and 70-110 mesh. Optionally, the mass ratio of the particles with finenesses of 20-40 mesh, 40-70 mesh, and 70-110 mesh is 2-3:3-4:2-3.

[0014] Furthermore, the specific surface area of the blast furnace slag powder is 400-600m 2 Optionally, the soil particles have a particle size of no greater than 2 mm.

[0015] Secondly, the present invention provides a method for preparing the early-strength, crack-resistant, negative-carbon cement-stabilized soil, comprising the steps of: mixing blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, Portland cement, fine aggregate, fluorgypsum, carbide slag, and soil particles, and stirring uniformly to obtain a dry powder; then, simultaneously adding the water reducer and mixing water to the dry powder and stirring uniformly to obtain the soil.

[0016] Finally, the present invention discloses the application of the early-strength, crack-resistant, negative-carbon cement-stabilized soil in the construction of roads, airport runways, ports, etc.

[0017] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0018] (1) The cement stabilized soil of the present invention solves many deficiencies of traditional cement stabilized soil in terms of mechanical properties, durability and environmental protection by using the synergistic effect of blast furnace slag, carbide slag, sulphoaluminate cement and fluorgypsum through specific components and excitation mechanisms. The reasons are as follows: First, the alkaline environment provided by the carbide slag and the sulfate provided by the fluorgypsum fully stimulate the potential activity of the blast furnace slag, prompting the blast furnace slag to undergo hydration reaction to form a large amount of gelling products (such as CSH gel and ettringite), which significantly improves the crack resistance and long-term stability of the material stabilized soil. At the same time, the calcium ions provided by the carbide slag and the fluoride ions provided by the fluorgypsum form calcium fluoride that reacts with the aluminum ions released by the hydration of sulphoaluminate cement. The formed complex decomposes to form aluminum fluoride, which can promote cement hydration and enhance early strength, meet the requirements of rapid construction and high load-bearing capacity, and effectively solve the problem of insufficient early strength of traditional cement stabilized soil.

[0019] (2) The modified steel slag powder containing brucite fiber is added to the cement stabilized soil of the present invention, which not only overcomes the problem of poor volume stability of steel slag and realizes the stable utilization of steel slag, but also improves the mechanical strength of the prepared solidified soil. To this end, the present invention disperses brucite fiber and steel slag powder in water and then introduces carbon dioxide for treatment. In this process, on the one hand, the free calcium oxide in the steel slag is converted into calcium carbonate, which prevents the formation of calcium hydroxide after contacting water in the later stage, resulting in volume expansion, causing the prepared stabilized soil to crack during service and deteriorate its bearing capacity. On the other hand, the calcium ions provided by the steel slag and the magnesium ions provided by the brucite fiber can form magnesium carbonate and calcium carbonate on the steel slag and the surface of the brucite fiber, which can not only roughen the fiber surface, but also enhance the bonding force between the brucite fiber and the prepared stabilized soil matrix and improve the mechanical properties. At the same time, the magnesium carbonate and dihydrogen phosphate react to form struvite after releasing magnesium ions under the action of mixing water. Its high bonding property helps to further bond the brucite fiber, steel slag and stabilized soil matrix together, thereby improving the mechanical properties of the stabilized soil.

[0020] (3) The cement stabilized soil of the present invention also achieves efficient resource utilization of industrial wastes such as blast furnace slag, calcium carbide slag, and fluorspar, significantly reduces the use of silicate cement, and reduces carbon emissions in the production process. Test results show that in complex construction environments, especially in harsh marine environmental conditions such as humidity, heat, and high salt fog, the cement stabilized soil of the present invention exhibits excellent durability and corrosion resistance, significantly extending the service life of the project. In addition, the preparation of the cement stabilized soil of the present invention is mainly based on industrial solid waste residue, which effectively reduces the cost of raw materials and is conducive to large-scale use in high-intensity engineering scenarios such as roads, airport runways, and port foundations. It has significant economic and social benefits and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute a part of the present invention, are used to provide further understanding of the present invention and are not intended to constitute an improper limitation of the present invention.

[0022] Figure 1 This is a compressive strength test diagram of the following Example 1.

[0023] Figure 2 The test piece prepared in the following Example 1 is used for shrinkage coefficient testing. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. Unless otherwise defined, all professional and scientific terms used in the present invention have the same meanings as those familiar to those skilled in the art. The preferred implementation methods and materials described in the present invention are for exemplary purposes only. The technical solutions of the present invention will now be further described with reference to specific embodiments.

[0025] Example 1

[0026] A method for preparing early-strength, crack-resistant, negative-carbon cement-stabilized soil comprises the following steps:

[0027] (1) The specific surface area is 475.1m 2 / kg of steel slag powder was mixed with 0.5-1cm long brucite fibers and clean water in a ratio of 6g:1.3g:180ml. Carbon dioxide was then continuously introduced into the resulting solid-liquid mixture at a rate of 2L / min for 50 minutes while stirring the system continuously. After completion, the solid product was filtered, dried at 100°C to a constant weight, and then mixed with potassium dihydrogen phosphate powder in a mass ratio of 1:0.12 and stirred evenly to obtain modified brucite fiber steel slag powder, which was then set aside.

[0028] (2) Take the following raw materials in proportion by weight: 40 parts of blast furnace slag powder, 10 parts of the modified brucite fiber steel slag powder, 24 parts of sulphoaluminate cement, 6 parts of Portland cement, 50 parts of quartz sand fine aggregate, 8 parts of fluorspar, 6 parts of carbide slag, 86 parts of soil particles, 2 parts of water reducer, and 26 parts of mixing water. Among them, the specific surface area of the blast furnace slag powder is 429.6m 2 / kg; the quartz sand fine aggregate is a continuous graded mix of 20-40 mesh, 40-70 mesh, and 70-110 mesh particles in a mass ratio of 3:4:3; the Portland cement is PO42.5, and the water reducer is a polycarboxylate water reducer. The soil particles have a particle size distribution below 2mm, a liquid limit of 33.65%, a plastic limit of 19.54%, and a plasticity index of 10.58%.

[0029] (3) Add the blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, silicate cement, quartz sand fine aggregate, fluorgypsum, carbide slag, and soil particles into a mixer and dry mix for 2 minutes to evenly disperse the raw materials. The resulting dry mix is then ready for use.

[0030] (4) Add the mixing water to the dry mix and add the water reducer at the same time. After completion, stir for 3 minutes to obtain cement stabilized soil.

[0031] 1. Compressive strength test: Pour the cement stabilized soil prepared in this example into a mold, and then vibrate to remove bubbles. After hardening, demould to obtain a test piece. Then place the test piece in a standard curing room for curing for the first 6 days, with the temperature controlled at 20±2°C and the relative humidity maintained at RH≥95%. On the 7th day, take the test piece out of the curing room and soak it in water controlled at 20±2°C. After curing for 1 day, measure the compressive strength of the test piece (such as Figure 1 to evaluate the compressive bearing capacity of the cement-stabilized soil.

[0032] 2. Splitting tensile strength test: According to the method in the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (JTGE51-2009), a universal testing machine (MTS) was used to test the splitting tensile strength of the specimens prepared from the cement-stabilized soil described in this example in nine parallel tests.

[0033] 3. Thermal Shrinkage Performance Test: The thermal shrinkage performance (ratio of length change per unit temperature change to temperature change) of the cement-stabilized soil of this example was tested according to the method specified in the "Testing Procedures for Inorganic Binder Stabilized Materials for Highway Engineering" (JTGE51-2009). The tests were conducted within a temperature range of -35°C to 60°C, with each test set consisting of three specimens. During the test, the deformation of the material at different temperatures was recorded. By analyzing the length change data, the thermal shrinkage coefficient of the material can be calculated, thereby assessing its stability.

[0034] 4. Shrinkage performance test: Shrinkage performance test is carried out according to the method in "Test Procedure for Stabilized Materials of Inorganic Binders for Highway Engineering" (JTGE51-2009): The number of molding specimens in each group is 6, of which 3 specimens are used to determine the shrinkage coefficient (such as Figure 2 (as shown), and three other specimens were used to determine drying shrinkage and water loss. During the test, the specimens were saturated with water under standard curing conditions before shrinkage testing. The shrinkage coefficient is the ratio of the drying strain to the water loss rate, i.e., ∆ε / ∆ω. Testing the drying shrinkage and water loss rate and shrinkage coefficient can be used to assess the shrinkage and stability of the material under drying conditions. The test results for the above performance indicators are shown in the following table:

[0035] .

[0036] Example 2

[0037] A method for preparing early-strength, crack-resistant, negative-carbon cement-stabilized soil comprises the following steps:

[0038] (1) The specific surface area is 520.4m 2 / kg of steel slag powder was mixed with 0.5-1cm long brucite fibers and clean water in a ratio of 5g:1.2g:200ml. Carbon dioxide was then continuously introduced into the resulting solid-liquid mixture at a rate of 1L / min for 60 minutes while stirring the system continuously. After completion, the solid product was filtered, dried at 110°C to constant weight, and then mixed with potassium dihydrogen phosphate powder in a mass ratio of 1:0.14 and stirred evenly to obtain modified brucite fiber steel slag powder, which was then set aside.

[0039] (2) Take the following raw materials in proportion by weight: 35 parts of blast furnace slag powder, 8 parts of modified brucite fiber steel slag powder, 26 parts of sulphoaluminate cement, 9 parts of Portland cement, 56 parts of quartz sand fine aggregate, 9 parts of fluorspar, 8 parts of carbide slag, 98 parts of soil particles, 4 parts of water reducer, and 28 parts of mixing water. Among them: the specific surface area of the blast furnace slag powder is 429.6m 2 / kg; the quartz sand fine aggregate is a continuous graded mix of 20-40 mesh, 40-70 mesh, and 70-110 mesh particles in a mass ratio of 3:4:3; the Portland cement is PO42.5, and the water reducer is a polycarboxylate water reducer. The soil particles have a particle size distribution below 2mm, a liquid limit of 33.65%, a plastic limit of 19.54%, and a plasticity index of 10.58%.

[0040] (3) Add the blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, silicate cement, quartz sand fine aggregate, fluorgypsum, carbide slag, and soil particles into a mixer and dry mix for 2 minutes to evenly disperse the raw materials. The resulting dry mix is then ready for use.

[0041] (4) Add the mixing water to the dry mix and simultaneously add the water reducer. After completion, stir for 4 minutes to obtain cement stabilized soil.

[0042] The same method as in Example 1 was used to test the various performance indicators of the cement-stabilized soil prepared in this example. The results are shown in the following table:

[0043] .

[0044] Example 3

[0045] A method for preparing early-strength, crack-resistant, negative-carbon cement-stabilized soil comprises the following steps:

[0046] (1) The specific surface area is 401.8m 2 / kg steel slag powder was mixed with 0.5-1cm long brucite fibers and clean water in a ratio of 7.5g:1.5g:220ml. Carbon dioxide was then continuously introduced into the resulting solid-liquid mixture at a rate of 2.5L / min for 50 minutes while stirring the system. After completion, the solid product was filtered, dried at 130°C to constant weight, and then mixed with ammonium dihydrogen phosphate powder in a mass ratio of 1:0.15 and stirred evenly to obtain modified brucite fiber steel slag powder, which was then set aside.

[0047] (2) Take the following raw materials in proportion by weight: 42 parts of blast furnace slag powder, 9 parts of modified brucite fiber steel slag powder, 30 parts of sulphoaluminate cement, 5 parts of Portland cement, 58 parts of quartz sand fine aggregate, 12 parts of fluorspar, 8 parts of carbide slag, 92 parts of soil particles, 3 parts of water reducer, and 22 parts of mixing water. Among them: the specific surface area of the blast furnace slag powder is 429.6m 2 / kg; the quartz sand fine aggregate is a continuous graded mix of 20-40 mesh, 40-70 mesh, and 70-110 mesh particles in a mass ratio of 3:4:3; the Portland cement is PO42.5, and the water reducer is a polycarboxylate water reducer. The soil particles have a particle size distribution below 2mm, a liquid limit of 33.65%, a plastic limit of 19.54%, and a plasticity index of 10.58%.

[0048] (3) Add the blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, silicate cement, quartz sand fine aggregate, fluorgypsum, carbide slag, and soil particles into a mixer and dry mix for 2 minutes to evenly disperse the raw materials. The resulting dry mix is then ready for use.

[0049] (4) Add the mixing water to the dry mix and simultaneously add the water reducer. After completion, stir for 4 minutes to obtain cement stabilized soil.

[0050] The same method as in Example 1 was used to test the various performance indicators of the cement-stabilized soil prepared in this example. The results are shown in the following table:

[0051] .

[0052] Example 4

[0053] A method for preparing early-strength, crack-resistant, negative-carbon cement-stabilized soil comprises the following steps:

[0054] (1) The specific surface area is 599.3m 2 Mix 1000 kg of steel slag powder with 0.5-1 cm long brucite fibers and clean water in a ratio of 4 g:1 g:150 ml. Then, introduce carbon dioxide into the resulting solid-liquid mixture continuously for 45 minutes at a rate of 3 L / min while stirring the system. After completion, filter the solid product, dry it at 120°C to constant weight, and then mix it with ammonium dihydrogen phosphate powder in a mass ratio of 1:0.14 and stir thoroughly to obtain modified brucite fiber steel slag powder, which is then set aside.

[0055] (2) Take the following raw materials in proportion by weight: 45 parts of blast furnace slag powder, 12 parts of modified brucite fiber steel slag powder, 35 parts of sulphoaluminate cement, 10 parts of Portland cement, 60 parts of river sand fine aggregate, 15 parts of fluorspar, 10 parts of carbide slag, 100 parts of soil particles, 3.5 parts of water reducer, and 30 parts of mixing water. Among them: the specific surface area of the blast furnace slag powder is 601.7m 2 / kg; the river sand fine aggregate is a continuous graded mix of 20-40 mesh, 40-70 mesh, and 70-110 mesh particles in a mass ratio of 2:3:2; the Portland cement is PO42.5, and the water reducer is sodium lignin sulfonate. The soil particles have a particle size distribution below 2mm, a liquid limit of 33.65%, a plastic limit of 19.54%, and a plasticity index of 10.58%.

[0056] (3) Add the blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, silicate cement, river sand fine aggregate, fluorgypsum, carbide slag, soil particles, and polypropylene fiber into a mixer and dry mix for 2 minutes to evenly disperse the raw materials. The resulting dry mix is then ready for use.

[0057] (4) Add the mixing water to the dry mix and simultaneously add the water reducer. After completion, stir for 4 minutes to obtain cement stabilized soil.

[0058] The same method as in Example 1 was used to test the various performance indicators of the cement-stabilized soil prepared in this example. The results are shown in the following table:

[0059] .

[0060] Example 5

[0061] A method for preparing early-strength, crack-resistant, negative-carbon cement-stabilized soil comprises the following steps:

[0062] (1) The specific surface area is 566.3m 2 / kg of steel slag powder was mixed with brucite fibers 0.5-1cm in length and clean water in a ratio of 4.5g:1.2g:180ml. Carbon dioxide was then continuously introduced into the resulting solid-liquid mixture at a rate of 1.5L / min for 50 minutes while stirring the system continuously. After completion, the solid product was filtered, dried at 100°C to constant weight, and then mixed with potassium dihydrogen phosphate powder in a mass ratio of 1:0.13 and stirred evenly to obtain modified brucite fiber steel slag powder, which was then set aside.

[0063] (2) Take the following raw materials in proportion by weight: 30 parts of blast furnace slag powder, 8 parts of modified brucite fiber steel slag powder, 20 parts of sulphoaluminate cement, 7 parts of Portland cement, 52 parts of quartz sand fine aggregate, 5 parts of fluorspar, 5 parts of carbide slag, 80 parts of soil particles, 2.5 parts of water reducer, and 20 parts of mixing water. Among them: the specific surface area of the blast furnace slag powder is 399.2m 2 / kg; the quartz sand fine aggregate is a continuous graded mix of 20-40 mesh, 40-70 mesh, and 70-110 mesh particles in a mass ratio of 3:4:3; the Portland cement is PO42.5, and the water reducer is a naphthalene-based water reducer. The soil particles have a particle size distribution below 2mm, a liquid limit of 33.65%, a plastic limit of 19.54%, and a plasticity index of 10.58%.

[0064] (3) Add the blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, silicate cement, quartz sand fine aggregate, fluorgypsum, carbide slag, soil particles, and polyvinyl alcohol fiber into a mixer and dry mix for 2 minutes to evenly disperse the raw materials. The resulting dry mix is then ready for use.

[0065] (4) Add the mixing water to the dry mix and simultaneously add the water reducer. After completion, stir for 4 minutes to obtain cement stabilized soil.

[0066] The same method as in Example 1 was used to test the various performance indicators of the cement-stabilized soil prepared in this example. The results are shown in the following table:

[0067] .

[0068] Example 6

[0069] A method for preparing early-strength, crack-resistant, negative-carbon cement-stabilized soil comprises the following steps:

[0070] (1) Take the following raw materials in proportion by weight: 40 parts of blast furnace slag powder, 10 parts of modified brucite fiber steel slag powder of Example 1, 24 parts of sulphoaluminate cement, 6 parts of Portland cement, 50 parts of quartz sand fine aggregate, 86 parts of soil particles, 2 parts of water reducer, and 26 parts of mixing water. The specific surface area of the blast furnace slag powder is 429.6 m 2 / kg; the quartz sand fine aggregate is a continuous graded mix of 20-40 mesh, 40-70 mesh, and 70-110 mesh particles in a mass ratio of 3:4:3; the Portland cement is PO42.5, and the water reducer is a polycarboxylate water reducer. The soil particles have a particle size distribution below 2mm, a liquid limit of 33.65%, a plastic limit of 19.54%, and a plasticity index of 10.58%.

[0071] (2) Add the blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, silicate cement, quartz sand fine aggregate, and soil particles into a mixer and dry mix for 2 minutes to evenly disperse the raw materials. The resulting dry mix is then ready for use.

[0072] (3) Add the mixing water to the dry mix and simultaneously add the water reducer. After completion, stir for 3 minutes to obtain cement stabilized soil.

[0073] The same method as in Example 1 was used to test the various performance indicators of the cement-stabilized soil prepared in this example. The results are shown in the following table:

[0074] .

[0075] Example 7

[0076] A method for preparing early-strength, crack-resistant, negative-carbon cement-stabilized soil comprises the following steps:

[0077] (1) Take the following raw materials in proportion by weight: 35 parts of blast furnace slag powder, 8 parts of modified brucite fiber steel slag powder of Example 2, 26 parts of sulphoaluminate cement, 9 parts of Portland cement, 56 parts of quartz sand fine aggregate, 9 parts of fluorgypsum, 98 parts of soil particles, 4 parts of water reducer, and 28 parts of mixing water. The specific surface area of the blast furnace slag powder is 429.6 m 2 / kg; the quartz sand fine aggregate is a continuous graded mix of 20-40 mesh, 40-70 mesh, and 70-110 mesh particles in a mass ratio of 3:4:3; the Portland cement is PO42.5, and the water reducer is a polycarboxylate water reducer. The soil particles have a particle size distribution below 2mm, a liquid limit of 33.65%, a plastic limit of 19.54%, and a plasticity index of 10.58%.

[0078] (2) Add the blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, silicate cement, quartz sand fine aggregate, fluorgypsum and soil particles into a mixer and dry mix for 2 minutes to evenly disperse the raw materials together. The resulting dry mix is then ready for use.

[0079] (3) Add the mixing water to the dry mix and add the water reducer at the same time. After completion, stir for 4 minutes to obtain cement stabilized soil.

[0080] The same method as in Example 1 was used to test the various performance indicators of the cement-stabilized soil prepared in this example. The results are shown in the following table:

[0081] .

[0082] Example 8

[0083] A method for preparing early-strength, crack-resistant, negative-carbon cement-stabilized soil comprises the following steps:

[0084] (1) Take the following raw materials in proportion by weight: 42 parts of blast furnace slag powder, 9 parts of modified brucite fiber steel slag powder of Example 3, 30 parts of sulphoaluminate cement, 5 parts of Portland cement, 58 parts of quartz sand fine aggregate, 8 parts of calcium carbide slag, 92 parts of soil particles, 3 parts of water reducer, and 22 parts of mixing water. The specific surface area of the blast furnace slag powder is 429.6 m 2 / kg; the quartz sand fine aggregate is a continuous graded mix of 20-40 mesh, 40-70 mesh, and 70-110 mesh particles in a mass ratio of 3:4:3; the Portland cement is PO42.5, and the water reducer is a polycarboxylate water reducer. The soil particles have a particle size distribution below 2mm, a liquid limit of 33.65%, a plastic limit of 19.54%, and a plasticity index of 10.58%.

[0085] (2) Add the blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, silicate cement, quartz sand fine aggregate, carbide slag, and soil particles into a mixer and dry mix for 2 minutes to evenly disperse the raw materials. The resulting dry mix is then ready for use.

[0086] (3) Add the mixing water to the dry mix and add the water reducer at the same time. After completion, stir for 4 minutes to obtain cement stabilized soil.

[0087] The same method as in Example 1 was used to test the various performance indicators of the cement-stabilized soil prepared in this example. The results are shown in the following table:

[0088] .

[0089] Example 9

[0090] A method for preparing early-strength, crack-resistant, negative-carbon cement-stabilized soil comprises the following steps:

[0091] (1) The specific surface area is 599.3m 2 / kg steel slag powder and 0.5~1cm long brucite fiber are mixed in a ratio of 4g:1g to obtain modified brucite fiber steel slag powder, which is set aside.

[0092] (2) Take the following raw materials in proportion by weight: 45 parts of blast furnace slag powder, 12 parts of the modified brucite fiber steel slag powder of this embodiment, 35 parts of sulphoaluminate cement, 10 parts of Portland cement, 60 parts of river sand fine aggregate, 15 parts of fluorspar, 10 parts of carbide slag, 100 parts of soil particles, 3.5 parts of water reducer, and 30 parts of mixing water. Among them, the specific surface area of the blast furnace slag powder is 601.7m 2 / kg; the river sand fine aggregate is a continuous graded mix of 20-40 mesh, 40-70 mesh, and 70-110 mesh particles in a mass ratio of 2:3:2; the Portland cement is PO42.5, and the water reducer is sodium lignin sulfonate. The soil particles have a particle size distribution below 2mm, a liquid limit of 33.65%, a plastic limit of 19.54%, and a plasticity index of 10.58%.

[0093] (3) Add the blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, silicate cement, river sand fine aggregate, fluorgypsum, carbide slag, soil particles, and polypropylene fiber into a mixer and dry mix for 2 minutes to evenly disperse the raw materials. The resulting dry mix is then ready for use.

[0094] (4) Add the mixing water to the dry mix and simultaneously add the water reducer. After completion, stir for 4 minutes to obtain cement stabilized soil.

[0095] The same method as in Example 1 was used to test the various performance indicators of the cement-stabilized soil prepared in this example. The results are shown in the following table:

[0096] .

[0097] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that they may modify the technical solutions described in the foregoing embodiments or substitute equivalents for some of the technical features. Any such modifications, equivalent substitutions, and improvements shall be within the scope of protection of the present invention.

Claims

1. An early-strength, crack-resistant, negative-carbon cement-stabilized soil, characterized in that: The invention comprises the following components in parts by weight: 30-45 parts of blast furnace slag powder, 8-12 parts of modified brucite fiber steel slag powder, 20-35 parts of sulphoaluminate cement, 5-10 parts of Portland cement, 50-60 parts of fine aggregate, 5-15 parts of fluorgypsum, 5-10 parts of carbide slag, 80-100 parts of soil particles, 2-4 parts of water reducer, and 20-30 parts of mixing water. The modified brucite fiber steel slag powder is prepared by the following method: dispersing steel slag powder and brucite fiber in water, then introducing carbon dioxide under stirring for treatment; after completion of solid-liquid separation, drying the obtained solid product and uniformly mixing it with dihydrogen phosphate powder to obtain the modified brucite fiber steel slag powder.

2. The early-strength, crack-resistant, negative-carbon cement-stabilized soil according to claim 1, characterized in that: In the preparation method of the modified brucite fiber steel slag powder, the ratio of steel slag powder, brucite fiber powder and water is 4-7.5g:1-1.5g:150-220mL.

3. The early strength and crack resistance negative carbon cement stabilized soil according to claim 1, characterized in that: The carbon dioxide is introduced at a rate of 1 to 3 L / min, and the duration of the introduction is 45 to 60 min.

4. The early-strength, crack-resistant, negative-carbon cement-stabilized soil according to claim 1, characterized in that: The mass ratio of the dried solid product to dihydrogen phosphate is 1:0.12-0.15, and the dihydrogen phosphate includes at least one of potassium dihydrogen phosphate and ammonium dihydrogen phosphate.

5. The early strength and crack resistance negative carbon cement stabilized soil according to claim 1, characterized in that: The water reducer includes at least one of a polycarboxylic acid water reducer, a naphthalene water reducer, and a lignin sulfonate water reducer.

6. The early-strength, crack-resistant, negative-carbon cement-stabilized soil according to claim 1, characterized in that: The fine aggregate is graded by particles with fineness of 20-40 mesh, 40-70 mesh and 70-110 mesh in a mass ratio of 2-3:3-4:2-3.

7. The early-strength, crack-resistant, negative-carbon cement-stabilized soil according to any one of claims 1 to 5, characterized in that: The specific surface area of the blast furnace slag powder is 400~600m 2 / kg; the particle size of the soil particles is not greater than 2mm.

8. The method for preparing the early-strength, crack-resistant, negative-carbon cement-stabilized soil according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: mixing blast furnace slag powder, modified brucite fiber steel slag powder, sulphoaluminate cement, silicate cement, fine aggregate, fluorgypsum, carbide slag and soil particles and stirring evenly to obtain a dry powder; and then adding the water reducer and mixing water to the dry powder and stirring evenly to obtain the dry powder.

9. Use of the early-strength, crack-resistant, negative-carbon cement-stabilized soil according to any one of claims 1 to 7, or the early-strength, crack-resistant, negative-carbon cement-stabilized soil obtained by the preparation method according to claim 8 in the construction of roads, airport runways or ports.

Images