Conductive cement-soil mixing pile based on industrial waste and preparation method of conductive cement-soil mixing pile

Abstract

The invention discloses a conductive cement soil mixing pile based on industrial waste and a preparation method thereof. The conductive cement soil mixing pile based on the industrial waste is prepared from the following raw materials: carbon black pretreatment liquid, modified multi-particle-size steel slag powder, sludge soil and cement, the carbon black pretreatment liquid is obtained by performing ultrasonic treatment on carbon black, a polyoxyethylene ether dispersing agent and water; the modified multi-particle-size steel slag powder is obtained by carbonizing, ball-milling and sieving steel slag, and modifying steel slag powder of 325 meshes, 200 meshes and 80 meshes according to a mass ratio of 1: 2: 1 by using an acid treatment solution. The conductive cement-soil mixing pile based on the industrial waste prepared by the invention has excellent mechanical properties and electrical properties, is low in preparation cost, can realize sludge soil foundation reinforcement, secondary utilization of the industrial waste and social sustainable development, and effectively avoids the problems of massive waste of resources, environmental pollution and the like.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering material preparation, and in particular to a conductive cement-soil mixing pile based on industrial waste and a preparation method thereof. Background Art

[0002] Steel slag is solid waste produced in the steelmaking process. It has the characteristics of huge output and complex chemical composition. Its output accounts for about 12% of crude steel output, while the resource utilization rate of steel slag is less than 30%.

[0003] Carbon black is an important industrial raw material, mainly made of incompletely burned carbonaceous materials, with high surface area, high conductivity, low cost and excellent environmental stability. Carbon black is mainly separated from waste tires through the cracking process to form a black powder with broad application prospects. Its high-value utilization is conducive to promoting the healthy development of the waste tire cracking industry and solving problems such as resource waste and environmental pollution.

[0004] In the present invention, carbon black that has been treated in a certain way is added to cement soil, which can provide good electrical conductivity for cement soil. The main component of steel slag is iron oxide, which itself has good wear resistance, durability, high activity and metallic conductivity. It can provide certain electrical conductivity and mechanical properties for cement soil, improve its durability, and at the same time improve the resource utilization rate of steel slag, and help achieve the "dual carbon" goal. Therefore, the preparation of complex conductive cement soil by utilizing the characteristics of carbon black and steel slag can not only improve the mechanical and conductive properties of cement soil, but also can perform non-destructive testing of cement soil through resistivity testing technology; the present invention mixes industrial waste into cement soil to generate a new modified cement soil-conductive cement soil mixing pile based on industrial waste, which can realize the secondary utilization of industrial waste, strengthen soft soil foundation, and improve the mechanical and electrical properties of cement soil mixing piles. Summary of the invention

[0005] In view of the status of the prior art and its shortcomings, the purpose of the present invention is to specifically relate to a conductive cement soil mixing pile based on industrial waste and a preparation method thereof. Combining steel slag with a small amount of carbon black can enhance the conductivity of cement soil and improve the mechanical properties of cement soil, thereby achieving silt soil foundation reinforcement, secondary utilization of industrial waste and social sustainable development.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A conductive cement-soil mixing pile based on industrial waste, the preparation raw materials include: carbon black pretreatment liquid, modified multi-particle steel slag powder, silt soil, cement; wherein the carbon black in the carbon black pretreatment liquid accounts for 3-9wt% of the silt soil mass, and the modified multi-particle steel slag powder and cement account for 15-25wt% and 10-30wt% of the silt soil mass, respectively.

[0007] Furthermore, the preparation of the carbon black pretreatment liquid includes: fully stirring the carbon black, polyoxyethylene ether dispersant and water, and then subjecting them to ultrasonic dispersion treatment, wherein the ultrasonic time is set to 1 hour, the temperature is 25° C., the power is 80 W, and the frequency is 40 KHz.

[0008] Furthermore, the particle size of the carbon black is 10-50 nm, and the specific surface area is 254 m 2 / g, resistivity 1.7~2.1Ω·cm, density 264kg / m 3 .

[0009] Furthermore, the effective content of the polyoxyethylene ether dispersant is 50.5%, the pH value is 6.6, and the dosage is 5wt% of the mass of carbon black.

[0010] Furthermore, the preparation of the modified multi-particle-size steel slag powder includes: the raw steel slag needs to be carbonized, and 99.9 vol% pure CO2 gas is controlled to be injected, the carbonization process temperature is 500°C, and the carbonization duration is 3 hours. After the carbonization is completed, the steel slag is placed in a 105°C oven for drying, and the carbonized steel slag is ground by a ball mill, and sieved through 80 mesh, 200 mesh and 325 mesh sieves respectively, and configured into multi-particle-size steel slag powder in a mass ratio of 1:2:1, and then the multi-particle-size steel slag powder and the acid treatment liquid are mixed and stirred at a solid-liquid ratio of 1:5g / ml for 2 hours, and then centrifuged to obtain the modified multi-particle-size steel slag powder.

[0011] Furthermore, the acid treatment liquid is a mixed solution of magnesium phosphate and potassium persulfate, the mass ratio of magnesium phosphate to potassium persulfate is 1:0.5-2, the purity of magnesium phosphate is 98%, and the concentration of potassium persulfate is 40g / L.

[0012] Furthermore, the silt soil needs to be oven-dried and then ground through a 5 mm sieve, with a natural moisture content of 40%-70%, and SiO2, Al2O3, and Fe2O3 contents of 61.81%, 23.70%, and 6.00%, respectively.

[0013] Furthermore, the cement is ordinary Portland cement with a PO of 42.5 and SiO2, Al2O3, Fe2O3 and CaO contents of They are 20.90%, 4.76%, 3.41% and 65.41%.

[0014] A method for preparing conductive cement soil mixing piles based on industrial waste comprises the following steps: Step 1: Mix cement, modified multi-size steel slag powder, carbon black pretreatment liquid and appropriate amount of water, stir at a low speed of 140 r / min for 2 minutes and then stir at a high speed of 285 r / min for 3 minutes to obtain a conductive slurry; Step 2: Start the deep mixer, sink the mixing head to mix the silt soil, start lifting from the designed elevation, add the conductive slurry prepared in step 1 to the silt soil, and perform a two-spray and four-mixing mixing process to obtain the conductive cement soil mixing pile based on industrial waste.

[0015] Compared with the prior art, the present invention has the following significant advantages: The present invention realizes the large-scale utilization of carbon black and steel slag, and solves the problem of environmental pollution. The conductive cement soil mixing pile based on industrial waste has excellent mechanical and electrical properties, and the preparation cost is low. It can realize the reinforcement of silt foundation, the secondary utilization of industrial waste and the sustainable development of society, and effectively avoids the problems of large-scale waste of resources and environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flow chart of the preparation method of carbon black pretreatment liquid and multi-size steel slag powder.

[0017] Figure 2 The present invention is a flow chart of the method for preparing conductive soil-cement mixing piles based on industrial waste.

[0018] Figure 3 Schematic diagram of resistivity testing method. DETAILED DESCRIPTION

[0019] A conductive cement-soil mixing pile based on industrial waste, the raw material mix ratio is: silt soil: 1200g, carbon black accounts for 3-9wt% of the silt soil mass, polyoxyethylene ether dispersant accounts for 5wt% of the carbon black mass, modified multi-particle size steel slag powder, cement, and water account for 15-25wt%, 10-30wt%, and 70-140wt% of the silt soil mass, respectively.

[0020] Furthermore, the preparation of the carbon black pretreatment liquid includes: fully stirring the carbon black, polyoxyethylene ether dispersant and half of the amount of water, and then subjecting the mixture to ultrasonic dispersion treatment, wherein the ultrasonic time is set to 1 hour, the temperature is 25° C., the power is 80 W, and the frequency is 40 KHz.

[0021] Furthermore, the particle size of the carbon black is 10-50 nm, and the specific surface area is 254 m 2 / g, resistivity 1.7~2.1Ω·cm, density 264kg / m 3 .

[0022] Furthermore, the dispersant is a polyoxyethylene ether dispersant, the effective content is 50.5%, the pH value is 6.6, and the dosage is 5wt% of the carbon black.

[0023] Furthermore, the raw steel slag needs to be ground by a ball mill to obtain 325 mesh, 200 mesh and 80 mesh multi-size steel slag powder, the mass ratio of which is 1:2:1. The basic properties are shown in Table 1: Table 1 Basic properties of steel slag

[0024] Furthermore, the preparation of the modified multi-particle-size steel slag powder includes: the raw steel slag needs to be carbonized, and 99.9 vol% pure CO2 gas is controlled to be injected, the carbonization process temperature is 500°C, and the carbonization duration is 3 hours. After the carbonization is completed, the steel slag is placed in a 105°C oven for drying, and the carbonized steel slag is ground by a ball mill, and sieved through 80 mesh, 200 mesh and 325 mesh sieves respectively, and configured into multi-particle-size steel slag powder in a mass ratio of 1:2:1, and then the multi-particle-size steel slag powder and the acid treatment liquid are mixed and stirred at a solid-liquid ratio of 1:5g / ml for 2 hours, and then centrifuged to obtain the modified multi-particle-size steel slag powder.

[0025] Furthermore, the acid treatment solution is a mixed solution of magnesium phosphate and potassium persulfate, the mass ratio of magnesium phosphate to potassium persulfate is 1:0.5-2, and the concentration of potassium persulfate is 40g / L.

[0026] Furthermore, the silt soil needs to be oven dried and then ground through a 5 mm sieve to obtain the SiO2, Al2O3, and Fe2O3 contents. The amounts are 61.81%, 23.70% and 6.00% respectively. The basic properties are shown in Table 2: Table 2 Basic properties of silt soil

[0027] Further, the cement is ordinary Portland cement with PO 42.5, and the contents of SiO2, Al2O3, Fe2O3 and CaO are 20.90%, 4.76%, 3.41% and 65.41% respectively. Specific embodiments

[0028] A conductive cement soil-cement soil mixing pile based on industrial waste and a preparation method thereof, comprising the following steps: Step 1: Mix cement, modified multi-size steel slag powder, carbon black pretreatment liquid and the remaining half of the water, stir at a low speed (140r / min) for 2min and then stir at a high speed (285r / min) for 3min to obtain a conductive slurry; Step 2: Start the deep mixer and sink the mixing head to mix the silt soil. Start lifting from the design elevation, add the conductive slurry prepared in step 1 to the silt soil, and perform a two-spray and four-mixing mixing process to obtain the conductive cement soil mixing pile based on industrial waste. At the same time, cast the conductive cement soil based on industrial waste into a cubic mold, insert two copper mesh sheets into the test block with a spacing of 5 cm, and perform 28d resistivity and unconfined compressive strength tests.

[0029] Specific implementation case 1: Step 1: Prepare the raw materials by weight including: 1200g dry silt soil, 245.6g cement, 163.6g modified multi-size steel slag powder, 49.1g carbon black, 847.6g water, and the dispersant dosage is 5wt% of the total mass of carbon black; Step 2: Place the carbon black weighed in step 1 in a beaker, add a polymer dispersant accounting for 5 wt% of the carbon black mass and half of the water, mix and stir manually for 1 minute, and then perform ultrasonic treatment to obtain a carbon black pretreatment solution; Step 3: Mix the cement, modified multi-size steel slag powder, carbon black pretreatment liquid and the remaining half of the water in the raw materials weighed in step 1, stir at a low speed (140 r / min) for 2 minutes and then stir at a high speed (285 r / min) for 3 minutes to obtain a conductive slurry; Step 4: Start the deep mixer and sink the mixing head to mix the silt soil. Start lifting from the design elevation, add the conductive slurry prepared in step 3 to the silt soil, and perform a two-spray and four-mixing mixing process to obtain a conductive cement soil mixing pile based on industrial waste. At the same time, cast the conductive cement soil based on industrial waste into a cubic mold, insert two copper mesh sheets into the test block with a spacing of 5 cm, and conduct 28d resistivity and unconfined compressive strength tests.

[0030] The test results are as follows: the unconfined compressive strength of the conductive cement-soil mixing pile based on industrial waste prepared in this embodiment is 1.48 MPa at 28 days, and the resistivity is 386.40 Ω·m.

[0031] Specific implementation case 2: The components of the conductive cement soil mixing pile based on industrial waste in this embodiment are different from those in the specific implementation case 1 only in that: 327.3 g of cement, 327.3 g of modified multi-size steel slag powder, and 970.4 g of water.

[0032] The preparation method of the conductive cement soil mixing pile based on industrial waste in this embodiment is the same as that in the specific implementation case 1, and the only difference is that the amount of cement, modified multi-size steel slag powder and water added in the corresponding steps is different.

[0033] The test results are as follows: the unconfined compressive strength of the conductive cement-soil mixing pile based on industrial waste prepared in this embodiment is 2.23 MPa at 28 days, and the resistivity is 160.77 Ω·m.

[0034] Specific implementation case three: The components of the conductive cement soil mixing pile based on industrial waste in this embodiment are different from those in the specific implementation case 1 only in that: 409.1 g of cement, 490.9 g of modified multi-size steel slag powder, and 1093.1 g of water.

[0035] The preparation method of conductive cement soil mixing piles based on industrial waste in this embodiment is the same as that in the specific implementation case 1, and the only difference is that the amounts of cement, steel slag and water added in the corresponding steps are different.

[0036] The test results are as follows: the unconfined compressive strength of the conductive cement-soil mixing pile based on industrial waste prepared in this embodiment is 2.61 MPa at 28 days, and the resistivity is 108.36 Ω·m.

[0037] Specific implementation case 4: The components of the conductive cement soil mixing pile based on industrial waste in this embodiment are different from those in the specific implementation case 1 only in that: 327.3 g of cement, 163.6 g of modified multi-size steel slag powder, 98.2 g of carbon black, and 986.7 g of water.

[0038] The preparation method of conductive cement soil mixing piles based on industrial waste in this embodiment is the same as that in the specific implementation case 1, the only difference is that the amounts of carbon black, cement, modified multi-size steel slag powder, water and dispersant added in the corresponding steps are different.

[0039] The test results are as follows: the unconfined compressive strength of the conductive cement-soil mixing pile based on industrial waste prepared in this embodiment is 1.78 MPa at 28 days, and the resistivity is 8.15 Ω·m.

[0040] Specific implementation case five: The components of the conductive cement soil mixing pile based on industrial waste in this embodiment are different from those in the specific implementation case 1 only in that: 409.1 g of cement, 327.3 g of modified multi-particle steel slag powder, 98.2 g of carbon black, and 1109.5 g of water.

[0041] The preparation method of conductive cement soil mixing piles based on industrial waste in this embodiment is the same as that in the specific implementation case 1, the only difference is that the amounts of carbon black, cement, modified multi-size steel slag powder, water and dispersant added in the corresponding steps are different.

[0042] The test results are as follows: the unconfined compressive strength of the conductive cement-soil mixing pile based on industrial waste prepared in this embodiment is 2.39 MPa at 28 days, and the resistivity is 100.80 Ω·m.

[0043] Specific implementation case six: The components of the conductive cement soil mixing pile based on industrial waste in this embodiment are different from those in the specific implementation case 1 only in that: 245.5 g of cement, 490.9 g of modified multi-particle steel slag powder, 98.2 g of carbon black, and 1109.5 g of water.

[0044] The preparation method of conductive cement soil mixing piles based on industrial waste in this embodiment is the same as that in the specific implementation case 1, the only difference is that the amounts of carbon black, cement, modified multi-size steel slag powder, water and dispersant added in the corresponding steps are different.

[0045] The test results are as follows: the unconfined compressive strength of the conductive cement-soil mixing pile based on industrial waste prepared in this embodiment is 1.14 MPa at 28 days, and the resistivity is 161.28 Ω·m.

[0046] Specific implementation case seven: The components of the conductive cement soil mixing pile based on industrial waste in this embodiment are different from those in the specific implementation case 1 only in that: 409.1 g of cement, 163.6 g of modified multi-size steel slag powder, 163.6 g of carbon black, and 1485.8 g of water.

[0047] The preparation method of conductive cement soil mixing piles based on industrial waste in this embodiment is the same as that in the specific implementation case 1, the only difference is that the amounts of carbon black, cement, modified multi-size steel slag powder, water and dispersant added in the corresponding steps are different.

[0048] The test results are as follows: the unconfined compressive strength of the conductive cement-soil mixing pile based on industrial waste prepared in this embodiment is 1.13 MPa at 28 days, and the resistivity is 1.39 Ω·m.

[0049] Specific implementation case eight: The components of the conductive cement soil mixing pile based on industrial waste in this embodiment are different from those in the specific implementation case 1 only in that: 245.5 g of cement, 327.3 g of modified multi-particle steel slag powder, 163.6 g of carbon black, and 1485.8 g of water.

[0050] The preparation method of conductive cement soil mixing piles based on industrial waste in this embodiment is the same as that in the specific implementation case 1, the only difference is that the amounts of carbon black, cement, modified multi-size steel slag powder, water and dispersant added in the corresponding steps are different.

[0051] The test results are as follows: the unconfined compressive strength of the conductive cement-soil mixing pile based on industrial waste prepared in this embodiment is 0.77 MPa at 28 days, and the resistivity is 73.96 Ω·m.

[0052] Specific implementation case nine: The components of the conductive cement soil mixing pile based on industrial waste in this embodiment are different from those in the specific implementation case 1 only in that: 327.3 g of cement, 490.6 g of modified multi-particle steel slag powder, 163.6 g of carbon black, and 1608.5 g of water.

[0053] The preparation method of conductive cement soil mixing piles based on industrial waste in this embodiment is the same as that in the specific implementation case 1, the only difference is that the amounts of carbon black, cement, modified multi-size steel slag powder, water and dispersant added in the corresponding steps are different.

[0054] The test results are as follows: the unconfined compressive strength of the conductive cement-soil mixing pile based on industrial waste prepared in this embodiment is 1.06 MPa at 28 days, and the resistivity is 167.66 Ω·m.

[0055] The specific mix ratios of cement, carbon black, and modified multi-size steel slag powder in implementation cases 1 to 9 are shown in Table 3.

[0056] Table 3 Mixing ratio of carbon black, modified multi-size steel slag powder and cement (%)

[0057] Although the present invention has been disclosed as above in terms of preferred embodiments, they are not intended to limit the present invention. Anyone skilled in the art can make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined by the claims of this application.

Claims

1. A conductive cement soil mixing pile based on industrial waste, characterized by: The raw materials for preparing conductive cement soil mixing piles based on industrial waste include: carbon black pretreatment liquid, modified multi-particle size steel slag powder, silt soil, and cement.

2. The conductive cement soil mixing pile based on industrial waste according to claim 1, characterized in that: In the carbon black pretreatment solution, the carbon black accounts for 3-9 wt% of the silt soil mass, and the modified multi-size steel slag powder and cement account for 15-25wt% and 10-30wt% of the silt soil mass, respectively.

3. The conductive cement soil mixing pile based on industrial waste according to claim 1, characterized in that: The preparation of the carbon black pretreatment liquid includes: fully stirring the carbon black, polyoxyethylene ether dispersant and water, and then subjecting the mixture to ultrasonic dispersion treatment, wherein the ultrasonic time is set to 1 hour, the temperature is 25° C., the power is 80 W, and the frequency is 40 KHz.

4. The conductive cement soil mixing pile based on industrial waste according to claim 3, characterized in that: The particle size of the carbon black used is 10~50nm and the specific surface area is 254m 2 / g, resistivity 1.7~2.1Ω·cm, density 264kg / m 3 .

5. The conductive cement soil mixing pile based on industrial waste according to claim 3, characterized in that: The effective content of the polyoxyethylene ether dispersant is 50.5%, the pH value is 6.6, and the usage is 5wt% of the carbon black mass.

6. The conductive cement soil mixing pile based on industrial waste according to claim 1, characterized in that: The preparation of modified multi-particle size steel slag powder includes: the raw steel slag needs to be carbonized, and 99.9 vol% pure CO2 gas is controlled to be injected. The carbonization process temperature is 500°C and the carbonization duration is 3 hours. After the carbonization is completed, the steel slag is placed in a 105°C oven for drying. The carbonized steel slag is ground by a ball mill and sieved through 80 mesh, 200 mesh and 325 mesh sieves respectively, and configured into multi-particle size steel slag powder in a mass ratio of 1:2:

1. Then, the multi-particle size steel slag powder and the acid treatment liquid are mixed and stirred for 2 hours at a solid-liquid ratio of 1:5 g / ml, and then centrifuged and dried to obtain the modified multi-particle size steel slag powder.

7. The conductive cement soil mixing pile based on industrial waste according to claim 6, characterized in that: The acid treatment solution is a mixed solution of magnesium phosphate and potassium persulfate, the mass ratio of magnesium phosphate to potassium persulfate is 1:0.5-2, and the concentration of potassium persulfate is 40g / L.

8. The conductive cement soil mixing pile based on industrial waste according to claim 1, characterized in that: The silt soil was dried and ground and passed through a 5 mm sieve, with a natural moisture content of 40%-70%, and SiO2, Al2O3 and Fe2O3 contents of 61.81%, 23.70% and 6.00% respectively.

9. The conductive cement soil mixing pile based on industrial waste according to claim 1, characterized in that: The cement is ordinary Portland cement with PO 42.

5.

10. A method for preparing conductive cement soil mixing piles based on industrial waste according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Mix cement, modified multi-size steel slag powder, carbon black pretreatment liquid and appropriate amount of water, stir at a low speed of 140 r / min for 2 minutes and then stir at a high speed of 285 r / min for 3 minutes to obtain a conductive slurry; Step 2: Start the deep mixer, sink the mixing head to mix the silt soil, start lifting from the designed elevation, add the conductive slurry prepared in step 1 to the silt soil, and perform a two-spray and four-mixing mixing process to obtain the conductive cement soil mixing pile based on industrial waste.

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