Low-carbon polymer modified all-solid waste premixed fluid soil and preparation method thereof

Abstract

The invention discloses a low-carbon polymer modified all-solid waste premixed fluid-state soil, which is prepared from the following components in parts by weight: 10-30 parts of low-carbon polymer modified all-solid waste premixed fluid-state soil, the concrete is prepared from the following components in parts by weight: 5-10 parts of a modifier, 5-10 parts of an exciting agent, 1-5 parts of an additive, 1-5 parts of a retarder, 10-20 parts of coal gangue powder, 10-20 parts of carbide slag, 10-20 parts of bentonite, 35-40 parts of fly ash, 35-40 parts of slag powder, 100 parts of clay powder, 145 parts of machine-made medium sand and 150 parts of water. According to the invention, the polymer polyacrylamide is added into the fluid soil, so that the compressive strength of the fluid soil stone body is improved; when the polyacrylamide is mixed with the fluid soil, active components in the polymer emulsion and components in the fluid soil are subjected to a cross-linking reaction to form a more complex network structure, so that a dispersion system of the slurry can be remarkably improved, the repulsive potential energy among particles in a multiphase dispersion is reduced, and the integrity and the stability of the slurry are enhanced; the slurry is not easy to separate when being injected into underground rock strata or fractures, and good uniformity and flowability are maintained.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a low-carbon polymer modified all-solid waste premixed fluidized soil and a preparation method thereof. Background Art

[0002] At present, my country has a variety of technical means to deal with soft soil foundations. Among them, soil solidification technology has the advantages of fast consolidation speed, good impermeability, simple construction, low construction noise, and little impact on adjacent buildings. However, there are also problems in actual projects, mainly manifested as follows: in early projects, the choice of curing agent is relatively single, mainly using cement and lime to solidify the soil, which has a high dependence on the amount of cement or lime, and greatly increases the project cost; the selection of moisture content of ordinary soil solidification technology usually adopts the optimal moisture content of soil materials, and the construction is basically loose materials, which are difficult to mix evenly, resulting in different strengths of various parts and prone to uneven settlement; for the problems of narrow backfill space, deep backfill depth, great construction difficulty, and difficulty in compaction in the pipeline corridor project, the application of ordinary soil solidification technology is limited, and the backfill quality is difficult to guarantee.

[0003] From the above analysis, it can be seen that the problems of single curing agent, uneven material mixing and difficulty in backfilling narrow space in the solidification soil technology need to be solved urgently, so the fluidized solidification soil technology was further developed. Fluidized solidification soil refers to the process of digging out the original soft soil for projects that need to be reinforced, adding soil curing agent, water and other materials to mix evenly, and then pouring or filling and curing to form a new type of geotechnical engineering material with certain strength, water stability and low permeability. Generally speaking, solidified soil with a slump greater than 90mm can be called fluidized solidification soil. When the slump is greater than 160mm, the pumping construction method can be used, and generally no vibration or only slight vibration is required during pouring. Fluidized solidification soil has good construction convenience and has unique technical advantages in filling projects, especially in narrow space filling projects. Among the new geotechnical engineering materials, fluidized solidification soil has broad application prospects and has been actually applied in the backfill project of the Sichuan Tianfu International Airport tunnel foundation trench.

[0004] At the same time, with the continuous acceleration of urbanization, the amount of construction waste generated and discharged in cities is also growing rapidly, and solid waste treatment and utilization has become a major issue. Alkali-activated inorganic geopolymers such as coal gangue powder, carbide slag, slag powder, fly ash, etc. can be used as solid waste. They have the characteristics of low cost, high strength, low energy consumption in the preparation process, low carbon emissions, and can provide similar performance to silicate cement-based cementitious materials. It is a low-carbon cementitious material; coal gangue is a complex solid waste with a huge stockpile in the world produced during coal mining. Using calcined coal gangue powder to replace cement as a new building material can not only reduce the consumption of clinker, but also promote the development of mechanical properties of fluid soil in synergy with other solid wastes; bentonite is a cheap clay mineral with montmorillonite as the main component, which has excellent suspension and thixotropy in aqueous solution. In order to reduce the cost of solidification and improve environmental benefits, technicians in this field usually react alkali liquid with fly ash and coal-fired waste residue in solid waste to form a solidifying agent, such as a solidifying agent for shield mud and its preparation method disclosed in Chinese patent CN116177909, but the reaction speed of the solidifying agent with the mud is slow, which cannot meet the requirements of the operable time on the construction site, and the improvement of the strength of the mud solidified soil is limited. Therefore, the present invention uses desulfurized gypsum and microsilica powder as activators, and the combined action of the two can adjust the gelling time of the fluidized soil and significantly improve the compressive strength of the stone body of the fluidized soil. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art. The present invention provides a low-carbon polymer modified all-solid waste premixed fluidized soil and a preparation method. The present invention can improve the compressive strength of the fluidized soil stone body by adding polymer polyacrylamide to the fluidized soil; polyacrylamide as a high molecular compound has good bonding performance and stability. When polyacrylamide is mixed with the fluidized soil, the active ingredients in the polymer emulsion react with the components in the fluidized soil to form a more complex network structure, which can significantly improve the dispersion system of the slurry, reduce the repulsive potential energy between particles in the multiphase dispersion, and increase the attractive potential energy between particles, thereby contributing to the coagulation and stabilization of the particles, and also enhancing the integrity and stability of the slurry, so that the slurry is not easy to segregate when injected into underground rock formations or cracks, and maintains good uniformity and fluidity.

[0006] In order to achieve the above invention purpose, the technical solution provided by the present invention is as follows:

[0007] A low-carbon polymer modified all-solid waste premixed fluidized soil, which consists of the following components in parts by weight: 5-10 parts of a modifier, 5-10 parts of an activator, 1-5 parts of an admixture, 1-5 parts of a retarder, 10-20 parts of coal gangue powder, 10-20 parts of carbide slag, 10-20 parts of bentonite, 35-40 parts of fly ash, 35-40 parts of slag powder, 100 parts of clay powder, 145 parts of machine-made medium sand and 150 parts of water.

[0008] Furthermore, the modifier is polyacrylamide, which is a glassy solid, white powder or granular. The molecular formula of polyacrylamide is (C 3 H 5 NO) n , density is 1.302g / cm 3 , the solid content of polyacrylamide is 91.2%.

[0009] Furthermore, the activator is desulfurized gypsum and microsilica powder, the particle size of the desulfurized gypsum is less than 0.074 mm, the microsilica powder is off-white powder, and the particle size of the microsilica powder is 0.2 μm.

[0010] Furthermore, the admixture includes calcium carbonate, magnesium carbonate, calcium hydroxide, iron oxide and silicon dioxide, and the proportion of each component in the admixture is: 85.87% of calcium carbonate, 6.53% of magnesium carbonate, 3.93% of calcium hydroxide, 1.86% of iron oxide and 1.81% of silicon dioxide.

[0011] Furthermore, the retarder is disodium hydrogen phosphate, which is a white powder of analytical grade with a purity greater than 99%. The molecular formula of disodium hydrogen phosphate is Na 2 HP0 4 12H 2 0, molecular weight is 358.1.

[0012] Furthermore, the gangue powder is obtained by grinding the gangue, calcining it at high temperature, and then activating it. The composition of the gangue powder is SiO 2 and Al 2 O 3 ; The content of calcium oxide in the carbide slag is greater than 70wt%.

[0013] Furthermore, the bentonite is sodium-based bentonite, no less than 95% of the bentonite passes through a 400-mesh sieve, the pH value of the bentonite is 9.3, and the expansion multiple of the bentonite is greater than 80.

[0014] Furthermore, the fly ash fineness is not more than 2.5%, the slag powder is S95 grade or above; the clay powder is powdered clay obtained by drying, crushing and sieving silt clay; the fineness modulus of the machine-made sand is 2.0; and the water is deionized water.

[0015] A method for preparing low-carbon polymer modified all-solid waste premixed fluidized soil, the method specifically comprising the following steps:

[0016] S1, weigh 10-20 parts of coal gangue powder, 10-20 parts of carbide slag, 10-20 parts of bentonite, 35-40 parts of fly ash, 35-40 parts of slag powder, 100 parts of clay powder, 1-5 parts of admixture, 1-5 parts of retarder, 145 parts of machine-made sand and 100 parts of water, and mix them evenly with mechanical stirring to obtain slurry A;

[0017] S2, weighing 2-4 parts of desulfurized gypsum, 3-6 parts of microsilica powder and 25 parts of water and stirring and mixing them uniformly to obtain an activator solution, and then adding the activator solution to slurry A, mixing them uniformly under mechanical stirring to obtain slurry B;

[0018] S3, weigh 5-10 parts of polyacrylamide and 25 parts of water and stir and mix them evenly to obtain a modifier solution, then add the modifier solution to slurry B, mix them evenly under mechanical stirring to obtain slurry C, which is polymer-modified all-solid waste premixed fluidized soil.

[0019] Based on the above technical scheme, the low-carbon polymer modified all-solid waste premixed fluidized soil and preparation method of the present invention have achieved the following technical effects through practical application:

[0020] 1. The low-carbon polymer modified all-solid waste premixed fluidized soil of the present invention can improve the compressive strength of the fluidized soil stone body by adding the polymer polyacrylamide to the fluidized soil; polyacrylamide, as a high molecular compound, has good bonding performance and stability. When polyacrylamide is mixed with the fluidized soil, the active ingredients in the polymer emulsion react with the ingredients in the fluidized soil to form a more complex network structure, which can significantly improve the dispersion system of the slurry, reduce the repulsive potential energy between particles in the multiphase dispersion, and increase the attractive potential energy between particles, thereby contributing to the coagulation and stabilization of the particles, and also enhancing the integrity and stability of the slurry, so that the slurry is not easy to segregate when injected into underground rock formations or cracks, and maintains good uniformity and fluidity.

[0021] 2. The low-carbon polymer modified all-solid waste premixed fluidized soil of the present invention uses desulfurized gypsum and microsilica powder as activators to improve the compressive strength of the fluidized soil stone body and adjust the gelling time of the fluidized soil; under the combined action of sulfate activation of gypsum and alkali activation of microsilica powder, the silicon oxygen bonds and aluminum oxygen bonds in the aluminosilicate raw materials are broken and reorganized; the sulfate radicals in the gypsum combine with calcium ions to form ettringite, which reacts and expands and combines with the soil body, which can significantly improve the compressive strength of the fluidized soil stone body; [SiO 4 ]tetrahedron and [AlO 4]tetrahedron dissolves in an alkaline environment to form [Si(OH) 4 ] and [Al(OH) 4 ] - The monomer then diffuses and penetrates into the solid particles based on the principle of chemical equilibrium, polymerizes to form a gel phase, condenses and solidifies into a geopolymer, and the active silica (SiO 2 ) and aluminum oxide (Al 2 O 3 ) is continuously dissolved to participate in the hydration reaction to form calcium silicate hydrate (CSH) gel and hydraulic ettringite (CaO·Al 2 O 3 ·3CaSO 4 ·32H 2 O), and then mixed evenly with silt clay powder to obtain premixed fluidized soil, which further improves the compressive strength of the fluidized soil stone body. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and effect of the present invention clearer, the present invention is described below by specific examples. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0023] Example 1

[0024] A low-carbon polymer modified all-solid waste premixed fluidized soil is obtained by the following preparation steps:

[0025] Step 1: Pour 10 parts of coal gangue powder, 10 parts of carbide slag, 10 parts of bentonite, 35 parts of fly ash, 35 parts of slag powder, 100 parts of clay powder, 5 parts of admixture, 2.5 parts of retarder, and 145 parts of machine-made sand into 100 parts of water, and mix them evenly under mechanical stirring to obtain slurry A;

[0026] Step 2: Pour 4 parts of desulfurized gypsum and 6 parts of microsilica powder into 25 parts of water, stir to mix evenly, to obtain an activator solution, then add the activator solution into slurry A, mix evenly under mechanical stirring, to obtain slurry B;

[0027] Step three, pour 5 parts of polyacrylamide into 25 parts of water, stir to mix evenly, obtain a modifier solution, then add it to slurry B, mix evenly under mechanical stirring, and obtain slurry C, which is the polymer-modified all-solid waste premixed fluidized soil.

[0028] Comparative Example 1

[0029] A low-carbon polymer modified all-solid waste premixed fluidized soil is obtained by the following preparation steps:

[0030] Step 1: Pour 10 parts of coal gangue powder, 10 parts of carbide slag, 10 parts of bentonite, 35 parts of fly ash, 35 parts of slag powder, 100 parts of clay powder, 5 parts of admixture, 2.5 parts of retarder, and 145 parts of machine-made sand into 100 parts of water, and mix them evenly under mechanical stirring to obtain slurry A;

[0031] Step 2: Pour 4 parts of desulfurized gypsum and 6 parts of microsilica powder into 25 parts of water, stir to mix evenly, to obtain an activator solution, then add the activator solution into slurry A, mix evenly under mechanical stirring, to obtain slurry B;

[0032] Step three, pour 0 parts of polyacrylamide into 25 parts of water, stir to mix evenly, obtain a modifier solution, then add it to slurry B, mix evenly under mechanical stirring, and obtain slurry C, which is the polymer-modified all-solid waste premixed fluidized soil.

[0033] Comparative Example 2

[0034] A low-carbon polymer modified all-solid waste premixed fluidized soil is obtained by the following preparation steps:

[0035] Step 1: Pour 10 parts of coal gangue powder, 10 parts of carbide slag, 10 parts of bentonite, 35 parts of fly ash, 35 parts of slag powder, 100 parts of clay powder, 5 parts of admixture, 2.5 parts of retarder, and 145 parts of machine-made sand into 100 parts of water, and mix them evenly under mechanical stirring to obtain slurry A;

[0036] Step 2: Pour 0 parts of desulfurized gypsum and 0 parts of microsilica powder into 25 parts of water, stir to mix evenly, to obtain an activator solution, then add the activator solution into slurry A, mix evenly under mechanical stirring, to obtain slurry B;

[0037] Step three, pour 5 parts of polyacrylamide into 25 parts of water, stir to mix evenly, obtain a modifier solution, then add it to slurry B, mix evenly under mechanical stirring, and obtain slurry C, which is the polymer-modified all-solid waste premixed fluidized soil.

[0038] Comparative Example 3

[0039] A low-carbon polymer modified all-solid waste premixed fluidized soil is obtained by the following preparation steps:

[0040] Step 1: Pour 50 parts of fly ash, 50 parts of slag powder, 100 parts of clay powder, 5 parts of admixture, 2.5 parts of retarder, and 145 parts of machine-made sand into 100 parts of water, and mix them evenly under mechanical stirring to obtain slurry A;

[0041] Step 2: Pour 4 parts of desulfurized gypsum and 6 parts of microsilica powder into 25 parts of water, stir to mix evenly, to obtain an activator solution, then add the activator solution into slurry A, mix evenly under mechanical stirring, to obtain slurry B;

[0042] Step three, pour 5 parts of polyacrylamide into 25 parts of water, stir to mix evenly, obtain a modifier solution, then add it to slurry B, mix evenly under mechanical stirring, and obtain slurry C, which is the polymer-modified all-solid waste premixed fluidized soil.

[0043] Comparative Example 4

[0044] A low-carbon polymer modified all-solid waste premixed fluidized soil is obtained by the following preparation steps:

[0045] Step 1: Pour 50 parts of fly ash, 50 parts of slag powder, 100 parts of clay powder, 5 parts of admixture, 2.5 parts of retarder, and 145 parts of machine-made sand into 100 parts of water, and mix them evenly under mechanical stirring to obtain slurry A;

[0046] Step 2: Pour 0 parts of desulfurized gypsum and 0 parts of microsilica powder into 25 parts of water, stir to mix evenly, to obtain an activator solution, then add the activator solution into slurry A, mix evenly under mechanical stirring, to obtain slurry B;

[0047] Step three, pour 0 parts of polyacrylamide into 25 parts of water, stir to mix evenly, obtain a modifier solution, then add it to slurry B, mix evenly under mechanical stirring, and obtain slurry C, which is the polymer-modified all-solid waste premixed fluidized soil.

[0048] The weight percentages of the components in Example 1 and Comparative Examples 1-4 are summarized in Table 1.

[0049] Table 1: Weight parts of each component in Example 1 and Comparative Examples 1-4

[0050] Components Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Modifier 5 0 5 5 0 Stimulant 10 10 0 10 0 Admixtures 5 5 5 5 5 Coal Gangue Powder 10 10 10 0 0 Carbide slag 10 10 10 0 0 Bentonite 10 10 10 0 0 Fly ash 35 35 35 50 50 Slag powder 35 35 35 50 50 Retarder 2.5 2.5 2.5 2.5 2.5 Clay powder 100 100 100 100 100 Mechanism medium sand 145 145 145 145 145 water 150 150 150 150 150

[0051] The test data are shown in Table 2.

[0052] Table 2: Test data

[0053]

[0054] Implementation effect:

[0055] From Example 1 and Comparative Example 1, it can be seen that adding polyacrylamide to fluidized soil can shorten the gelation time of fluidized soil, increase viscosity, and slightly increase the compressive strength of 28d stone body. When polyacrylamide is mixed with fluidized soil, a cross-linking reaction occurs to form a more complex network structure, which is conducive to the aggregation and stability of particles.

[0056] From Example 1 and Comparative Example 2, it can be seen that adding desulfurized gypsum and microsilica powder to fluidized soil can shorten the gelling time of fluidized soil, increase viscosity, and significantly increase the compressive strength of the 28d stone body;

[0057] From Example 1 and Comparative Example 3, it can be seen that using equal amounts of gangue powder, carbide slag and bentonite to replace fly ash and slag powder to prepare fluidized soil can shorten the gelation time of the fluidized soil, keep the viscosity basically the same, and keep the 28d stone body compressive strength basically the same. Gangue powder, carbide slag and bentonite can adsorb and exchange ions in the solution to form micelle structure and network structure, control the slurry stability, increase the cementation ability and strength of the fluidized soil, and maintain the uniformity and dispersibility of the fluidized soil.

[0058] From Comparative Examples 3 and 4, it can be seen that adding polyacrylamide, desulfurized gypsum and microsilica powder to the fluidized soil can shorten the gelling time of the fluidized soil, increase the viscosity, and significantly increase the compressive strength of the 28d stone body;

[0059] The green and low-carbon polymer-modified all-solid waste premixed fluidized soil prepared by the present invention is prepared by adding a modifier and an activator to the all-solid waste premixed fluidized soil. A variety of substances cooperate with each other to regulate the gelation time, fluidity and 28d stone body compressive strength of the polymer-modified fluidized soil. The durability of the fluidized soil is improved, the coagulation time is controllable, the fluidity is good, the stone body compressive strength is high, the cost is low, the environment is environmentally friendly, pollution-free, low energy consumption and easy preparation are advantages.

[0060] The green and low-carbon polymer-modified all-solid waste premixed fluidized soil in the present invention can make full use of construction solid waste, and the coal gangue powder, carbide slag, slag powder and fly ash undergo depolymerization and polycondensation reactions to form a gel material with fluidity and a certain strength after hardening; the amount of cement used and the energy consumption of building materials, the emission of carbon dioxide gas can be reduced, and the working performance of the modified fluidized soil can be enhanced and the construction requirements can be met; bentonite has strong adsorption and water absorption properties, which can increase the viscosity of the fluidized soil and maintain the fluidity of the fluidized soil; the layered structure of bentonite has ion exchange capacity, which can adsorb and exchange ions in the solution, and this ion exchange capacity can control the ion concentration and stability of the mud; at the same time, there are adsorption forces and electrostatic forces between bentonite particles, which can form micelle structures and network structures, increase the cementation capacity and strength of the fluidized soil, and maintain the uniformity and dispersibility of the fluidized soil.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should all be covered by the scope of the technical solution for protection of the present invention.

Claims

1. A low-carbon polymer modified all-solid waste premixed fluidized soil, characterized in that: The all-solid waste premixed fluidized soil is composed of the following components by weight: 5-10 parts of modifier, 5-10 parts of activator, 1-5 parts of admixture, 1-5 parts of retarder, 10-20 parts of coal gangue powder, 10-20 parts of carbide slag, 10-20 parts of bentonite, 35-40 parts of fly ash, 35-40 parts of slag powder, 100 parts of clay powder, 145 parts of machine-made medium sand and 150 parts of water.

2. The low-carbon polymer modified all-solid waste premixed fluidized soil according to claim 1, characterized in that: The modifier is polyacrylamide, which is a glassy solid, white powder or granular. The molecular formula of polyacrylamide is (C3H5NO) n , density is 1.302g / cm 3 , the solid content of polyacrylamide is 91.2%.

3. The low-carbon polymer modified all-solid waste premixed fluidized soil according to claim 1, characterized in that: The activator is desulfurized gypsum and microsilica powder. The particle size of the desulfurized gypsum is less than 0.074 mm. The microsilica powder is off-white powder with a particle size of 0.2 μm.

4. The low-carbon polymer modified all-solid waste premixed fluidized soil according to claim 1, characterized in that: The admixture includes calcium carbonate, magnesium carbonate, calcium hydroxide, iron oxide and silicon dioxide, and the proportion of each component in the admixture is: 85.87% of calcium carbonate, 6.53% of magnesium carbonate, 3.93% of calcium hydroxide, 1.86% of iron oxide and 1.81% of silicon dioxide.

5. The low-carbon polymer modified all-solid waste premixed fluidized soil according to claim 1, characterized in that: The retarder is disodium hydrogen phosphate, which is white powder and analytically pure. The purity of disodium hydrogen phosphate is greater than 99%. The molecular formula of disodium hydrogen phosphate is Na2HP04·12H20, and the molecular weight is 358.

1.

6. The low-carbon polymer modified all-solid waste premixed fluidized soil according to claim 1, characterized in that: The gangue powder is obtained by grinding gangue, calcining it at high temperature and then activating it. The components of the gangue powder are SiO2 and Al2O3. The content of calcium oxide in the carbide slag is greater than 70wt%.

7. The low-carbon polymer modified all-solid waste premixed fluidized soil according to claim 1, characterized in that: The bentonite is sodium-based bentonite, no less than 95% of the bentonite passes through a 400-mesh sieve, the pH value of the bentonite is 9.3, and the expansion multiple of the bentonite is greater than 80.

8. The low-carbon polymer modified all-solid waste premixed fluidized soil according to claim 1, characterized in that: The fly ash fineness is not more than 2.5%, the slag powder is S95 grade or above; the clay powder is powdered clay obtained by drying, crushing and sieving silt clay; the fineness modulus of the machine-made medium sand is 2.0; and the water is deionized water.

9. A method for preparing low-carbon polymer modified all-solid waste premixed fluidized soil, characterized in that: The method specifically comprises the following steps: S1, weigh 10-20 parts of coal gangue powder, 10-20 parts of carbide slag, 10-20 parts of bentonite, 35-40 parts of fly ash, 35-40 parts of slag powder, 100 parts of clay powder, 1-5 parts of admixture, 1-5 parts of retarder, 145 parts of machine-made sand and 100 parts of water, and mix them evenly with mechanical stirring to obtain slurry A; S2, weighing 2-4 parts of desulfurized gypsum, 3-6 parts of microsilica powder and 25 parts of water and stirring and mixing them uniformly to obtain an activator solution, and then adding the activator solution to slurry A, mixing them uniformly under mechanical stirring to obtain slurry B; S3, weigh 5-10 parts of polyacrylamide and 25 parts of water and stir and mix them evenly to obtain a modifier solution, then add the modifier solution to slurry B, mix them evenly under mechanical stirring to obtain slurry C, which is polymer-modified all-solid waste premixed fluidized soil.

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