Method for replacing part of aggregate with dredged spoil to be used as road material

Abstract

The invention provides a method for applying dredged spoil to road materials instead of part of aggregate, and relates to the technical field of road materials. The concrete is mainly prepared from the following raw materials: cement, slag, dredged spoil, gravel and a curing agent. The dredged spoil and the gravel are used as aggregates, the cement and the slag are used as cementing materials, and the spoil and the gravel aggregates are wrapped and fused under the action of the curing agent, so that the mechanical property of the novel road material reaches the national design standard for road materials, and the effect of consuming the dredged spoil can also be achieved to a certain extent; the method has important practical significance for improving the comprehensive utilization rate of solid wastes and protecting the environment.

Description

Technical Field

[0001] The invention relates to the technical field of road materials, in particular to a method for using dredged spoil to replace part of aggregates for road materials. Background Art

[0002] Since the 1980s, China's economic construction has continued to develop steadily, various infrastructures have been increasingly improved, and highway construction has also been continuously developing. However, the rapid development of highway construction has led to an increasing demand for raw materials in various regions, resulting in a serious shortage of traditional raw material resources and a gradual increase in road construction costs.

[0003] As for the mines that are the source of traditional raw materials, China has implemented the most stringent environmental inspection system. The Ministry of Ecology and Environment conducts regular inspections across the country every year and implements the "one-vote veto system for environmental protection". Therefore, all parts of the country are stepping up the remediation of mines, gradually shutting down mines with serious environmental pollution, large ecological damage and small production scale, and implementing mine greening. According to field research, the national construction sand and gravel aggregate mines still cannot meet domestic demand according to the maximum annual output, and the consumption of sand and gravel is far greater than the output. It can be seen that the limited natural resources make it increasingly difficult to obtain these materials, which also means that the supply of traditional road construction materials faces challenges.

[0004] Therefore, in order to solve the shortage of natural stone and the problem of the difficulty in disposing of the above-mentioned dredged soil, this study provides a method of using dredged soil to replace part of the stone for road materials. It can not only alleviate the shortage of road construction materials, but also consume dredged soil to a certain extent. Summary of the invention

[0005] 1. Technical issues to be resolved In view of the shortcomings of the prior art, the present invention provides a method for using dredged spoil to replace part of aggregate for road materials. (II) Technical solution To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for using dredged soil to replace part of aggregate for road materials comprises the following raw materials in parts by weight: 3-6 parts of cement, 5-8 parts of slag, 20-40 parts of soil, 49-69 parts of gravel, and 0.22-0.55 parts of curing agent.

[0006] Preferably, a method for using dredged spoil to replace part of aggregate for road materials comprises the following steps: S1. Pre-treating the waste soil; S2. Weigh cement, slag, spoil, gravel and curing agent according to the above weight parts; S3, dry-mixing the pre-treated waste soil, cement, slag and gravel; S4. Add the curing agent into an appropriate amount of water and stir evenly; S5, adding water with a curing agent to the dry mix, wet mixing, and stirring evenly to obtain a slurry; S6, the obtained slurry is loaded into a cylindrical mold of 10*10*10 cm and pressed into shape; S7, demoulding by a demoulding machine after 1 day, thus obtaining an experimental test block using the dredged soil as a road material; S8. Maintain and test the test blocks.

[0007] Preferably, the curing agent is prepared by mixing calcium aluminate, sodium aluminate and sodium sulfate in a mass ratio of 55-75:10-25:10-20.

[0008] Preferably, the pretreatment of the abandoned soil is specifically: drying the abandoned soil raw materials in an oven, manually removing soil impurities, and ball milling with a ball mill to reduce the particle size to less than 1.18 mm.

[0009] Preferably, the test block is pressed and molded to form a cylindrical specimen for compression testing at a compaction degree of 95%.

[0010] Preferably, during the curing and experiment of the experimental specimens, the curing temperature is 20±2° C. and the relative humidity is >95%.

[0011] Preferably, in the curing and experiment of the experimental test blocks, after the 6th, 27th and 89th days, the test blocks are taken out and immersed in water for 1 day before a compressive strength test is performed.

[0012] Working principle: Since slag contains more active SiO2 and Al2O3, under the action of curing agent and medium, SiO2 and Al2O3 can interact with Ca(OH)2 produced by cement hydration to generate calcium silicate hydrate and calcium aluminate hydrate. Calcium silicate hydrate can continue to be converted into needle-shaped and network-shaped CSH gel, while calcium aluminate hydrate further reacts to generate ettringite. (III) Beneficial effects

[0013] The present invention provides a method for using dredged spoil to replace part of aggregate for road materials. It has the following beneficial effects: 1. The present invention uses dredged soil and gravel as aggregates, cement and slag as cementitious materials, and wraps and fuses the soil and gravel aggregates under the action of a curing agent, so that the mechanical properties of this new type of road material meet the national design standards for road materials, and can also consume dredged soil to a certain extent, which has important practical significance for improving the comprehensive utilization rate of solid waste and environmental protection.

[0014] 2. The present invention uses a certain amount of dredged soil to replace part of the gravel aggregate for road materials, so that the aggregate particles of different sizes are matched and inlaid with each other to play a skeleton role. Among them, the gaps formed by the large particles are filled by the next level particles; the gaps formed by the next level particles are filled by the next level particles, and the filling is continued level by level to achieve the most compact stacking and the minimum void ratio, thereby improving the strength of the specimen. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the experimental flow chart of the present invention; Figure 2 It is a flow chart of the compressive strength experiment of the present invention. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0017] The weight ratio of cement and mineral powder was controlled at 3:8, the weight ratio of curing agent was 0.66, and the weight ratio of dredged soil and gravel was set to 20:69, 30:59, and 40:49 respectively. After the experimental test blocks were made, their compressive strength was tested, and the rest of the steps were the same; Example 2

[0018] The weight ratio of cement to mineral powder was controlled at 4:7, the weight ratio of curing agent was 0.66, and the weight ratio of dredged soil and gravel was set to 20:69, 30:59, and 40:49 respectively. After the experimental test blocks were made, their compressive strength was tested, and the rest of the steps were the same; Example 3

[0019] The weight ratio of cement and mineral powder was controlled at 5:6, the weight ratio of curing agent was 0.66, and the weight ratio of dredged soil and gravel was set to 20:69; 30:59; 40:49 respectively. After the experimental test blocks were made, their compressive strength was tested, and the rest of the steps were the same; Example 4

[0020] The weight ratio of cement and mineral powder was controlled at 6:5, the weight ratio of curing agent was 0.66, the weight ratio of dredged soil and gravel was set to 20:69; 30:59; 40:49 respectively, and the compressive strength of the experimental blocks was tested after they were made. The rest of the steps were the same.

[0021] Table 1 shows the compressive strength test results of the experimental test blocks in each group of embodiments.

[0022]

[0023] The results in Table 1 above show that when the amount of dredged soil is fixed, the strength of the test block increases with the increase of slag content; when the amount of cement and mineral powder is fixed, the strength of the test block increases with the increase of dredged soil content. After analysis, the main reason is that under the action of the curing agent and the medium, the active substances SiO2 and Al2O3 in the slag can be fully activated, and interact with Ca(OH)2 produced by cement hydration to generate hydrated calcium silicate and hydrated calcium aluminate. The hydrated calcium silicate can continue to be converted into needle-shaped and network-shaped CSH gel, while the hydrated calcium aluminate further reacts to generate calcium sulfonate, which provides strength for the specimen; the main reason is that during the reaction process, the active substances SiO2 and Al2O3 in the dredged soil are also activated to participate in the reaction, and the small amount of CaO contained in the dredged soil can provide Ca2+ for the CSH gel and calcium sulfonate that are finally generated by the reaction and provide strength. "Changed to "The small amount of CaO contained in the dredged soil can provide Ca2+ for the reaction, and finally generate CSH gel and ettringite which provide strength.

[0024] In summary, the research on using dredged soil as road materials in the present invention is feasible, and the appropriate proportion can be selected according to the compressive strength requirements of different roads.

[0025] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for using dredged spoil to replace part of aggregate as road material, characterized in that: The invention is prepared from the following raw materials in parts by weight: 3-6 parts of cement, 5-8 parts of slag, 20-40 parts of abandoned soil, 49-69 parts of gravel and 0.22-0.55 parts of curing agent.

2. A method for using dredged soil to replace part of aggregate for road materials according to claim 1, characterized in that: The steps include: S1. Pre-treating the waste soil; S2. Weigh cement, slag, spoil, gravel and curing agent according to the above weight parts; S3, dry-mixing the pre-treated waste soil, cement, slag and gravel; S4. Add the curing agent into an appropriate amount of water and stir evenly; S5, adding water with a curing agent to the dry mix, wet mixing, and stirring evenly to obtain a slurry; S6, the obtained slurry is loaded into a cylindrical mold of 10*10*10 cm and pressed into shape; S7, demoulding by a demoulding machine after 1 day, thus obtaining an experimental test block using the dredged soil as a road material; S8. Maintain and test the test blocks.

3. A method for using dredged spoil to replace part of aggregate for road materials according to claim 2, characterized in that: The pretreatment of the abandoned soil specifically includes: drying the abandoned soil raw materials in an oven, manually removing soil impurities, and grinding the abandoned soil with a ball mill to reduce the particle size to less than 1.18 mm.

4. The method of using dredged soil to replace part of aggregate for road materials according to claim 2, characterized in that: The test block is pressed and formed to form a cylindrical test piece for compression test at a compaction degree of 95%.

5. The method of using dredged soil to replace part of aggregate for road materials according to claim 2, characterized in that: During the curing and testing of the test blocks, the curing temperature is 20±2° C. and the relative humidity is >95%.

6. The method of using dredged soil to replace part of aggregate for road materials according to claim 2, characterized in that: In the curing and experiment of the test blocks, after the 6th, 27th and 89th days, the test blocks were taken out and immersed in water for 1 day before the compressive strength test was performed.

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