Composition for enhancing unconfined compressive strength of building waste soil, preparation method and application
By combining ultrafine auxiliary reinforcing agents and active additives with construction waste soil through multiple pozzolanic reactions, the problem of insufficient unconfined compressive strength of construction waste soil was solved, achieving efficient and stable strength improvement and resource utilization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF URBAN ENVIRONMENT CHINESE ACAD OF SCI
- Filing Date
- 2026-03-10
- Publication Date
- 2026-05-19
AI Technical Summary
In existing technologies, the resource utilization of construction waste soil is difficult to achieve efficient and stable improvement in unconfined compressive strength. Traditional cementitious materials are costly and the curing agents with single active components are not effective and cannot meet the long-term mechanical performance requirements of road subgrade and other engineering projects.
The composition employs an ultrafine auxiliary reinforcing agent and an active additive. The chemical components include SiO2, CaO, Al2O3, and Fe2O3. Through multiple pozzolanic reactions with ultrafine construction waste soil, Al-O, Fe-O, and Si-O bonds are formed, thereby improving the reactivity. The preparation methods include dry mixing, wet mixing, and molding and curing.
It significantly improves the unconfined compressive strength and splitting tensile strength of construction waste soil, meets the needs of road subgrade engineering, saves experimental cycle and economic cost, and realizes efficient and stable utilization of solid waste.
Smart Images
Figure CN122059633A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of construction solid waste recycling technology, and in particular to a composition for enhancing the unconfined compressive strength of construction waste soil, its preparation method, and its application. Background Technology
[0002] Construction waste refers to solid waste such as earth, rock, and concrete scrap generated during construction processes such as tunnel excavation and building construction. Construction waste exhibits complex soil composition and a wide particle size range, as well as engineering characteristics such as low unconfined compressive strength and high compressibility. Without treatment, it cannot be directly used in engineering construction and is currently mostly disposed of through landfilling. This not only occupies a large amount of land resources but also causes environmental problems such as soil erosion and dust pollution, making resource utilization extremely urgent.
[0003] Currently, research on the resource utilization of construction waste mainly focuses on the reuse of recycled aggregates from coarse-grained construction waste, while research on the solidification, enhancement, and high-value utilization of ultrafine construction waste is extremely limited. Existing solidification technologies for construction waste are mainly divided into two categories: one is to use traditional cementitious materials such as cement and lime for solidification, which can improve strength to a certain extent, but has problems such as high carbon emissions, high raw material costs, easy cracking, and poor compatibility with construction waste; the other is to use single industrial solid waste (such as fly ash, slag, tailings slag, etc.) as solidifying agents. Although solid waste recycling is achieved, the active components of single solid waste solidifying agents are limited and cannot fully react with the construction waste in a pozzolanic reaction. The improvement in unconfined compressive strength is limited and it is difficult to meet the requirements of long-term mechanical properties for roadbeds and other engineering projects. Moreover, existing technologies do not perform standardized ultrafine treatment of raw materials, and particle agglomerates cannot be eliminated, which easily leads to the formation of cementitious material clumps, resulting in insufficient pozzolanic reaction and unstable solidification effect. Summary of the Invention
[0004] This invention provides a composition for enhancing the unconfined compressive strength of construction waste soil, a preparation method thereof, and its application, in order to solve the problems existing in the prior art.
[0005] The technical problem solved by this invention is achieved by the following technical solution: In a first aspect, the present invention provides a composition for enhancing the unconfined compressive strength of construction waste soil, comprising an auxiliary reinforcing agent and an active additive, wherein the mass ratio of the auxiliary reinforcing agent to the active additive is 1:2, the auxiliary reinforcing agent is a mineral residue whose chemical composition includes SiO2, CaO and Al2O3; the active additive is a product of mineral beneficiation and separation operations, whose chemical composition includes SiO2, CaO and Fe2O3.
[0006] Furthermore, both the auxiliary reinforcing agent and the active additive are ultrafine powders that have passed through a 0.075 mm sieve.
[0007] Furthermore, the main chemical components of the auxiliary reinforcing agent, by mass percentage, are: SiO2 54.4%, CaO 11.65%, Al2O3 11.72%; the main chemical components of the active additive, by mass percentage, are: SiO2 56.53%, CaO 10.52%, AlO3 11.7%, Fe2O3 7.12%.
[0008] Secondly, the present invention provides a method for preparing the above-mentioned composition for enhancing the unconfined compressive strength of construction waste soil, comprising the following steps: (a) Raw material preparation: Dry the construction waste soil, ball mill it, and pass it through a 0.075 mm sieve to obtain ultrafine construction waste soil powder; take the composition according to any one of claims 1-3 for later use; (b) Dry mixing: Weigh the composition at 4% to 16% of the dry weight of the construction waste soil, mix it with ultrafine construction waste soil powder and stir for 30 seconds to obtain a uniform dry mixture; (c) Wet mixing: Add water to the dry mixture from step (b), control the moisture content to 15%, stir for 3 minutes to obtain a uniform mixture; (d) Molding and curing: The mixture from step (c) is compacted and then sealed for curing.
[0009] Furthermore, the compaction molding in step (d) is static compaction with a pressure of 600 kPa, so that the specimen reaches a maximum dry density of 1.67 g / cm³; the curing conditions are a temperature of 20±2°C and a relative humidity of 95±5%, and the specimen is soaked in water before curing to the specified age.
[0010] Furthermore, the construction waste soil meets the following requirements: liquid limit ≤ 43%, plasticity index ≤ 26%, and organic matter content ≤ 5%.
[0011] Furthermore, based on the proportion of the composition being 4% to 16% of the dry weight of construction waste, the following empirical formula is established: The relationships between the 7-day and 28-day splitting tensile strength and the unconfined compressive strength of construction waste soil compositions of 4%–16% are as follows: (1) 7d: y = 1.307 - 0.980·e (-x / 10.082) , R 2 =0.999 (2) 28d: y = 0.580 + 0.038·e (x / 4.207) , R 2 =0.986; The relationships between the 7-day and 28-day elastic modulus and unconfined compressive strength of a 4%–16% composition of construction waste soil are as follows: (1) 7d: y=2616.9-2501.1·e (-x / 21.453) , R2 =0.999 (2) 28d: y = 480.0 + 21.9·e (x / 3.112) , R 2 =0.991.
[0012] Thirdly, the present invention provides the application of the above-mentioned composition for enhancing the unconfined compressive strength of construction waste soil, using the composition in the preparation of construction waste soil subgrade materials or building materials.
[0013] The beneficial effects of this invention are: 1. This invention uses ultrafine auxiliary reinforcing agent and ultrafine construction waste soil (both passed through a 200-mesh sieve) to be combined as part of the cementitious material. The mixing of ultrafine raw materials (construction waste soil, auxiliary reinforcing agent, etc.) helps to fully improve the contact between the two, thereby minimizing the formation of harmful voids in the cementitious material and ensuring the stability of the final structure.
[0014] 2. The ultrafine auxiliary reinforcing agent (containing SiO2, CaO and Al2O3) and ultrafine active additive (containing active SiO2, CaO and Fe2O3) used in this invention can fully undergo multiple pozzolanic reactions with ultrafine construction waste soil. This includes using ultrafine grinding of the auxiliary reinforcing agent and active additive to facilitate the breaking of Al-O, Fe-O and Si-O bonds, releasing lattice energy to improve reaction activity, and solving the problem of insufficient unconfined compressive strength when construction waste soil is used for road paving.
[0015] 3. This invention establishes the relationship between the 7-day and 28-day unconfined compressive strength (UCS) of the blocks prepared from the composition and the 7-day and 28-day splitting tensile strength (STS) and elastic modulus of 7-day and 28-day. Under the same conditions, this relationship can be applied to directly derive the corresponding splitting tensile strength and elastic modulus from the unconfined compressive strength, saving experimental time and economic costs.
[0016] 4. The raw materials of the construction waste soil composition proposed in this invention are all derived from solid waste. It has the characteristics of low price, environmental protection, high efficiency and stability, and good strength improvement effect. The use of this composition not only helps to reduce the accumulation of solid waste and is beneficial to the environment, but also effectively enhances the unconfined compressive strength of construction waste soil, thus bringing potential economic advantages. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0018] Figure 1 This is a SEM image of a 7-day solidified test block of construction waste soil with 16% admixture of the present invention. Figure 2 This is a SEM image of a 28-day solidified test block of construction waste soil with a 16% admixture content according to the present invention. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below with reference to the accompanying drawings and specific embodiments. However, it should be understood that these embodiments are only for explaining the invention and are not intended to limit the scope of protection of the invention.
[0020] The construction waste soil used in this invention was taken from a construction site in Xiamen City, Fujian Province. Its basic physical properties are shown in Table 1, and the chemical composition of the auxiliary reinforcing agent and active additives used is shown in Table 2. Before the experiment, all raw materials were pretreated as follows: dried in an oven at 105°C for 24 hours to constant weight, then ground in a ball mill at 500 rpm for 6 hours, and finally passed through a 0.075 mm (200 mesh) sieve for later use.
[0021] Table 1. Physical properties of the foundation soil
[0022] Table 2. Chemical composition of raw materials for reinforcing agents
[0023] The specimen preparation and testing methods for all embodiments and comparative examples were carried out in accordance with the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). The specific steps were as follows: Pretreated raw materials were weighed according to the specified ratio, dry-mixed for 30 seconds, then wet-mixed with deionized water for 3 minutes, controlling the moisture content to 15%. The mixture was then statically pressed into a cylindrical mold with a diameter of 50 mm and a height of 100 mm at approximately 600 kPa to achieve a maximum dry density of 1.67 g / cm³. The molded specimens were sealed with plastic wrap and placed in a curing room at a temperature of 20 ± 2℃ and a relative humidity of 95 ± 5%. After 6 days of curing, the specimens were soaked in water for 24 hours, removed, and their surface moisture was wiped dry before testing for unconfined compressive strength (UCS), splitting tensile strength (STS), and modulus of elasticity. The proportions and test results for each embodiment and comparative example are shown in Table 3. Example 1
[0024] First, the construction waste soil, auxiliary reinforcing agent, and active additive were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm, 6 hours), the mixture was passed through a 0.075 mm sieve. Soil reinforcing agent (based on soil dry weight, the ratio of auxiliary reinforcing agent to active additive was 1:2) was weighed at 4% of the dry weight of the construction waste soil and mixed for 30 seconds. Then, the optimum moisture content was determined according to the requirements and controlled at 15%. The mixture was stirred for 3 minutes to ensure uniform mixing. The blocks were then prepared, cured, and tested according to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were measured. Example 2
[0025] First, the construction waste soil, auxiliary reinforcing agent, and active additive were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm, 6 hours), the mixture was passed through a 0.075 mm sieve. Soil reinforcing agent (based on soil dry weight, the ratio of auxiliary reinforcing agent to active additive is 1:2) was weighed at 6% of the dry weight of the construction waste soil and mixed for 30 seconds. Then, the optimum moisture content was determined according to the requirements and controlled at 15%. The mixture was stirred for 3 minutes to ensure uniform mixing. The blocks were then prepared, cured, and tested according to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were measured. Example 3
[0026] First, the construction waste soil, auxiliary reinforcing agent, and active additive were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm, 6 hours), the mixture was passed through a 0.075 mm sieve. 8% of the dry weight of the construction waste soil was weighed as soil reinforcing agent (the ratio of auxiliary reinforcing agent to active additive was 1:2 based on the dry weight of the soil) and mixed for 30 seconds. Then, the optimum moisture content was determined as required and controlled at 15%. The mixture was stirred for 3 minutes to ensure uniform mixing. The blocks were then prepared, cured, and tested according to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were measured. Example 4
[0027] First, the construction waste soil, auxiliary reinforcing agent, and active additive were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm, 6 hours), the mixture was passed through a 0.075 mm sieve. Soil reinforcing agent (based on soil dry weight, the ratio of auxiliary reinforcing agent to active additive was 1:2) was weighed at 10% of the dry weight of the construction waste soil and mixed for 30 seconds. Then, the optimum moisture content was determined as required and controlled at 15%. The mixture was stirred for 3 minutes to ensure uniform mixing. The blocks were then prepared, cured, and tested according to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were measured. Example 5
[0028] First, the construction waste soil, auxiliary reinforcing agent, and active additive were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm, 6 hours), the mixture was passed through a 0.075 mm sieve. Soil reinforcing agent (based on soil dry weight, the ratio of auxiliary reinforcing agent to active additive is 1:2) was weighed at 12% of the dry weight of the construction waste soil and mixed for 30 seconds. Then, the optimum moisture content was determined as required and controlled at 15%. The mixture was stirred for 3 minutes to ensure uniform mixing. The blocks were then prepared, cured, and tested according to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were measured. Example 6
[0029] First, the construction waste soil, auxiliary reinforcing agent, and active additive were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm, 6 hours), the mixture was passed through a 0.075 mm sieve. Soil reinforcing agent (based on soil dry weight, the ratio of auxiliary reinforcing agent to active additive is 1:2) was weighed at 14% of the dry weight of the construction waste soil and mixed for 30 seconds. Then, the optimum moisture content was determined according to the requirements and controlled at 15%. The mixture was stirred for 3 minutes to ensure uniform mixing. The blocks were then prepared, cured, and tested according to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were measured. Example 7
[0030] First, the construction waste soil, auxiliary reinforcing agent, and active additive were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm, 6 hours), the mixture was passed through a 0.075 mm sieve. Soil reinforcing agent (based on soil dry weight, the ratio of auxiliary reinforcing agent to active additive is 1:2) was weighed at 16% of the dry weight of the construction waste soil and mixed for 30 seconds. Then, the optimum moisture content was determined as required and controlled at 15%. The mixture was stirred for 3 minutes to ensure uniform mixing. The blocks were then prepared, cured, and tested according to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were measured.
[0031] Comparative Example 1 First, the construction waste soil, auxiliary reinforcing agent, and active additives were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm for 6 hours), the mixture was passed through a 0.075 mm sieve. Soil reinforcing agent (100% active additive by dry weight) was weighed at 4% of the dry weight of the construction waste soil and mixed for 30 seconds. Then, the optimum moisture content was determined and controlled at 15%, and the mixture was stirred for 3 minutes. After ensuring uniform mixing, blocks were prepared, cured, and tested according to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were measured.
[0032] Comparative Example 2 First, the construction waste soil, auxiliary reinforcing agent, and active additives were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm, 6 hours), the mixture was passed through a 0.075 mm sieve. Soil reinforcing agent (100% active additive by dry weight of soil) was weighed at 16% of the dry weight of the construction waste soil and mixed for 30 seconds. Then, the optimum moisture content was determined as required and controlled at 15%. The mixture was stirred for 3 minutes to ensure uniform mixing. Blocks were then prepared, cured, and tested according to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were measured.
[0033] Comparative Example 3 First, the construction waste soil, auxiliary reinforcing agent, and active additives were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm for 6 hours), the mixture was passed through a 0.075 mm sieve. Soil reinforcing agent (100% by dry weight of soil) was weighed at 4% of the dry weight of the construction waste soil and mixed for 30 seconds. Then, the optimum moisture content was determined as required and controlled at 15%. The mixture was stirred for 3 minutes to ensure uniform mixing. The blocks were then prepared, cured, and tested according to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were measured.
[0034] Comparative Example 4 First, the construction waste soil, auxiliary reinforcing agent, and active additives were dried at 105°C for 24 hours until completely dry. After ball milling (500 rpm for 6 hours), the mixture was passed through a 0.075 mm sieve. Soil reinforcing agent (100% by dry weight of soil) was weighed at 16% of the dry weight of the construction waste soil and mixed for 30 seconds. Then, the optimum moisture content was determined and controlled at 15%. The mixture was stirred for 3 minutes to ensure uniform mixing. Blocks were then prepared, cured, and tested according to the "Test Procedures for Inorganic Binder Stabilized Materials in Highway Engineering" (T 0805-1994). After the specified age, the unconfined compressive strength, splitting tensile strength, and modulus of elasticity were determined. Table 3. Sample ratios and mechanical property test results of the examples and comparative examples.
[0035] Table 4 Summary of Overall Mechanical Properties of Construction Waste Soil under Different Solidification Systems
[0036] Comparative Examples 1-4: The operating steps of Comparative Examples 1-4 are the same as those of the Examples, except that the composition of the reinforcing agent is different; The reinforcing agents in Comparative Examples 1 and 2 were only active additives (accounting for 100% of the reinforcing agents). The reinforcing agents in Comparative Examples 3 and 4 were only auxiliary reinforcing agents (accounting for 100% of the reinforcing agents).
[0037] As can be seen from the data in Table 3: Synergistic effect: Comparing Example 1 (4% dosage) with Comparative Example 1 (4% active additive) and Comparative Example 3 (4% auxiliary reinforcing agent), the 7-day UCS (3.0 MPa) of Example 1 was significantly higher than that of Comparative Example 1 (2.6 MPa) and Comparative Example 3 (2.7 MPa). At a dosage of 16%, the 7-day UCS (7.3 MPa) and 28-day UCS (9.9 MPa) of Example 7 were significantly higher than those of Comparative Example 2 (6.3 MPa) and Comparative Example 4 (6.4 MPa, 7.8 MPa). This fully demonstrates that there is a significant "1+1>2" synergistic enhancement effect between the auxiliary reinforcing agent and the active additive in the composition of the present invention.
[0038] Strength improvement pattern: In Examples 1-7, as the dosage of the composition of the present invention increases, the 7-day and 28-day unconfined compressive strength, splitting tensile strength and elastic modulus of the construction waste soil all show a continuous upward trend. When the dosage is 16% (Example 7), all mechanical properties reach the optimal level, and the 28-day unconfined compressive strength reaches 9.9 MPa, which far exceeds the strength requirement of ≥2.5 MPa for road subgrade engineering.
[0039] At the same dosage, the curing effect of the compound composition of the present invention is significantly better than that of the single curing agent in the comparative example. At a dosage of 16%, the 28-day unconfined compressive strength of Example 7 is increased by 26.9% compared with Comparative Example 4 (single auxiliary reinforcing agent), and the 7-day splitting tensile strength is increased by 20.3% compared with Comparative Example 2 (single active additive). This fully demonstrates that the 1:2 compound of auxiliary reinforcing agent and active additive has a significant synergistic effect, which is the core innovation of the present invention.
[0040] Microstructure verification: like Figure 1 As shown, curing with 4%–16% reinforcing agent ratios over 7 days revealed a dense, uniform matrix with reduced cracks. This early microstructural advantage provides clear evidence that the active additives actively accelerate the pozzolanic reaction. The silica and alumina added to the active additives promote rapid and abundant formation of the initial CSH gel, resulting in earlier strength increases and a more complete structure. like Figure 2 As shown, when 4% to 16% reinforcing agent is added, the cured test blocks exhibit a completely different state after 28 days: a dense and interconnected structure is formed, characterized by the growth of a large number of needle-like ettringite and the appearance of a ubiquitous CSH gel, which completely encapsulates the soil particles and eliminates the void space.
[0041] Establishment of empirical formulas: Based on the test data from Example 7 (optimal dosage of 4%–16%), this invention further fitted the relationships between 7-day and 28-day unconfined compressive strength (x) and splitting tensile strength (y) and elastic modulus (y), as follows: Figure 1 As shown in the formula below, the goodness of fit R² for all relationships is greater than 0.98, indicating extremely high prediction accuracy.
[0042] For reinforcing agent dosages of 4% to 16%: Relationship between 7-day splitting tensile strength (STS) and 7-day unconfined compressive strength (UCS): y = 1.307 - 0.980·e (-x / 10.082) , R 2 =0.999 Relationship between 28-day splitting tensile strength (STS) and 28-day unconfined compressive strength (UCS): y = 0.580 + 0.038·e (x / 4.207) , R 2 =0.986 Relationship between 7-day elastic modulus and 7-day unconfined compressive strength (UCS): y = 2616.9 - 2501.1·e (-x / 21.453) , R 2 =0.999 Relationship between 28-day elastic modulus and 28-day unconfined compressive strength (UCS): y = 480.0 + 21.9·e (x / 3.112) , R 2 =0.991 These formulas greatly facilitate engineering applications, allowing for rapid and accurate evaluation of a material's STS and elastic modulus simply by measuring the UCS.
[0043] In summary, the present invention provides a composition for enhancing the unconfined compressive strength of construction waste soil, its preparation method and application. Through the synergistic effect of two-component solid waste, ultrafine activation and precise process control, the mechanical properties of construction waste soil are improved, and it has extremely high value for promotion and application.
[0044] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.
Claims
1. A composition for enhancing the unconfined compressive strength of construction waste soil, characterized in that, It includes an auxiliary reinforcing agent and an active additive, wherein the mass ratio of the auxiliary reinforcing agent to the active additive is 1:
2. The auxiliary reinforcing agent is a mineral residue whose chemical composition includes SiO2, CaO and Al2O3. The active additive is a product of mineral beneficiation and separation operations, whose chemical composition includes SiO2, CaO and Fe2O3.
2. The composition for enhancing the unconfined compressive strength of construction waste soil according to claim 1, characterized in that, Both the auxiliary reinforcing agent and the active additive are ultrafine powders that have passed through a 0.075 mm sieve.
3. The composition for enhancing the unconfined compressive strength of construction waste soil according to claim 1, characterized in that, The main chemical components of the auxiliary reinforcing agent, by mass percentage, are: SiO2 54.4%, CaO 11.65%, Al2O3 11.72%; the main chemical components of the active additive, by mass percentage, are: SiO2 56.53%, CaO 10.52%, Al2O3 11.7%, Fe2O3 7.12%.
4. The method for preparing the composition for enhancing the unconfined compressive strength of construction waste soil as described in any one of claims 1-3, characterized in that, Includes the following steps: (a) Raw material preparation: Dry the construction waste soil, ball mill it, and pass it through a 0.075 mm sieve to obtain ultrafine construction waste soil powder; take the composition according to any one of claims 1-3 for later use; (b) Dry mixing: Weigh the composition at 4% to 16% of the dry weight of the construction waste soil, mix it with ultrafine construction waste soil powder and stir for 30 seconds to obtain a uniform dry mixture; (c) Wet mixing: Add water to the dry mixture from step (b), control the moisture content to 15%, stir for 3 minutes to obtain a uniform mixture; (d) Molding and curing: The mixture from step (c) is compacted and then sealed for curing.
5. The method for preparing the composition for enhancing the unconfined compressive strength of construction waste soil according to claim 4, characterized in that, The compaction molding in step (d) is static compaction with a pressure of 600 kPa, so that the specimen reaches the maximum dry density of 1.67 g / cm³; the curing conditions are a temperature of 20±2°C and a relative humidity of 95±5%, and the specimen is soaked in water before curing to the specified age.
6. The method for preparing the composition for enhancing the unconfined compressive strength of construction waste soil according to claim 4, characterized in that, The construction waste soil meets the following requirements: liquid limit ≤ 43%, plasticity index ≤ 26%, and organic matter content ≤ 5%.
7. The method for preparing the composition for enhancing the unconfined compressive strength of construction waste soil according to claim 4, characterized in that, Based on the composition dosage of 4% to 16% of the dry weight of construction waste, the following empirical formula is established: The relationships between the 7-day and 28-day splitting tensile strength and the unconfined compressive strength of construction waste soil compositions of 4%–16% are as follows: (1)7d:y=1.307-0.980·e (-x / 10.082) , R 2 =0.999 (2)28d:y=0.580+0.038·e (x / 4.207) , R 2 =0.986; The relationships between the 7-day and 28-day elastic modulus and unconfined compressive strength of a 4%–16% composition of construction waste soil are as follows: (1)7d:y=2616.9-2501.1·e (-x / 21.453) , R 2 =0.999 (2)28d:y=480.0+21.9·e (x / 3.112) , R 2 =0.991。 8. The composition for enhancing the unconfined compressive strength of construction waste soil according to any one of claims 1-3, or the preparation method according to any one of claims 4-7, is used in the preparation of construction waste soil subgrade materials or building materials.