Cement slurry with controllable rheological property and preparation method thereof

Abstract

The invention discloses cement slurry with controllable rheological property and a preparation method thereof, and belongs to the technical field of cement. The cement slurry with the controllable rheological property is prepared from the following components in parts by weight: 35 to 55 parts of calcium aluminate cement, 40 to 70 parts of fine aggregate, 5 to 10 parts of rheological blender, 5 to 10 parts of modified silica sol, 5 to 10 parts of nano calcium carbonate, 5 to 10 parts of anti-cracking fiber and 35 to 40 parts of water. The preparation method of the cement slurry with the controllable rheological property comprises the step of mixing calcium aluminate cement, fine aggregate, a rheological blender, modified silica sol, nano calcium carbonate, anti-crack fibers and water in three steps to obtain the cement slurry with the controllable rheological property. The rheological property, the compressive strength and the breaking strength of the cement slurry are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of cement, and in particular relates to a cement slurry with controllable rheological properties and a preparation method thereof. Background Art

[0002] The rheological properties of cement slurry are directly related to the construction performance of cement slurry, the physical and mechanical properties after hardening, and the overall project quality. Rheological properties refer to the flow and deformation characteristics of materials when subjected to external forces. For cement slurry, this property is particularly important because it directly affects the pumping, pouring, and final strength and durability of the slurry after hardening.

[0003] The rheological properties of cement slurry are mainly determined by its internal structure and composition. The properties and proportions of raw materials such as cement, water, admixtures and aggregates will have a significant impact on the rheological properties of the slurry. For example, the type and fineness of cement, the amount and quality of water, the type and amount of admixtures, etc., will change the fluidity and viscosity of the slurry. In addition, the preparation process of the slurry, such as stirring method, stirring time, temperature control, etc., will also have an important impact on the rheological properties.

[0004] Cement slurry with good rheological properties usually has suitable fluidity and viscosity, can be easily pumped and poured, and is not prone to bleeding and segregation during construction. Such slurry can evenly fill the formwork to form a dense concrete structure, thereby improving the strength and durability after hardening. On the contrary, cement slurry with poor rheological properties may have problems with excessive or low fluidity, resulting in construction difficulties and even affecting the quality of the project. Slurry with too high fluidity is prone to bleeding and segregation, resulting in voids and defects inside the concrete; while slurry with too low fluidity is difficult to pump and pour, causing great inconvenience to construction. Summary of the invention

[0005] The object of the present invention is to provide a cement slurry with controllable rheological properties and a preparation method thereof, so as to solve the technical problem that the rheological properties of cement slurry are difficult to control in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The invention provides a cement slurry with controllable rheological properties, comprising the following components in parts by weight: 35-55 parts of calcium aluminate cement, 40-70 parts of fine aggregate, 5-10 parts of rheological conditioning agent, 5-10 parts of modified silica sol, 5-10 parts of nano calcium carbonate, 5-10 parts of anti-cracking fiber and 35-40 parts of water; the fine aggregate is industrial alumina, fly ash and kaolin mixed in a ratio of 1: (1-2): (0.5-1); the rheological conditioning agent is prepared by mixing and dripping methyl allyl polyoxyethylene ether, acrylic acid, acrylamide, sodium methyl propylene sulfonate, sodium formaldehyde sulfoxylate and sodium hydroxide into solutions respectively; the anti-cracking fiber is polypropylene fiber and basalt fiber mixed in a ratio of 1: (0.5-2).

[0007] Furthermore, the preparation method of the rheological adjusting agent comprises the following steps: (1) Preparing a solution: weighing methyl allyl polyoxyethylene ether, pouring it into a flask, adding deionized water, stirring thoroughly, and heating to obtain a methyl allyl polyoxyethylene ether solution; weighing sodium methyl propylene sulfonate and sodium formaldehyde sulfoxylate, dissolving them in deionized water, stirring thoroughly, and obtaining a sodium methyl propylene sulfonate solution and a sodium formaldehyde sulfoxylate solution; weighing acrylic acid and acrylamide, dissolving them in deionized water, stirring thoroughly, and obtaining an acrylic acid solution and an acrylamide solution; (2) Mixing: mixing sodium hydroxide solution with acrylic acid solution to obtain sodium acrylate solution, and then mixing methyl allyl polyoxyethylene ether solution with sodium acrylate solution to obtain a mixed solution of methyl allyl polyoxyethylene ether and sodium acrylate; mixing sodium methyl allyl sulfonate solution with sodium formaldehyde sulfoxylate solution, stirring evenly, to obtain a mixed solution of sodium methyl allyl sulfonate and sodium formaldehyde sulfoxylate; mixing acrylic acid solution with acrylamide solution, stirring evenly, to obtain a mixed solution of acrylic acid and acrylamide; (3) Dropwise addition: a mixed solution of sodium methacrylic sulfonate and sodium formaldehyde sulfoxylate and a mixed solution of acrylic acid and acrylamide are respectively added dropwise to a mixed solution of methyl allyl polyoxyethylene ether and sodium acrylate. After the addition is completed, the mixture is kept warm and the pH is adjusted to obtain a rheological adjuster.

[0008] Furthermore, in step (1), the mass concentration of the methallyl polyoxyethylene ether solution is 1-10%, the stirring speed is 30-200 rpm, the stirring time is 15-30 min, and the temperature is heated to 30-55° C. The mass concentration of the sodium methacrylate sulfonate solution is 5-20%, the mass concentration of sodium formaldehyde sulfoxylate is 2-8%, the mass concentration of the acrylic acid solution is 5-25%, and the mass concentration of the acrylamide solution is 5-25%; in step (2), the mass concentration of the sodium hydroxide solution is 1-5 mol / L, the mass concentration of the acrylic acid solution is 5-25%, and the acrylic acid solution and the sodium hydroxide are mixed. The volume ratio of the solutions is 1:(0.5-1), the volume ratio of the methyl allyl polyoxyethylene ether solution to the sodium acrylate solution is 1:(1.2-2), the volume ratio of the sodium methyl propylene sulfonate solution to the sodium formaldehyde sulfoxylate solution is 1:(1.5-2), and the volume ratio of the acrylic acid solution to the acrylamide solution is 1:(1-5); the dripping in step (3) is 1.5-3h, the acrylic acid and acrylamide mixed solution is dripped before the sodium methyl propylene sulfonate and sodium formaldehyde sulfoxylate mixed solution, the insulation temperature is 25-35°C, the insulation time is 1-2h, and the pH is adjusted to 7-8 with a sodium hydroxide solution.

[0009] Furthermore, the preparation method of the modified silica sol comprises the following steps: S1. preparing a modified liquid: weighing methyltriethoxysilane, and dissolving it in anhydrous ethanol to obtain a methyltriethoxysilane solution; S2. Modification reaction: weigh silica sol and add it into a flask, add deionized water, heat it in a water bath, and stir to evenly disperse the silica sol to obtain a silica sol solution. While stirring, slowly drop the methyltriethoxysilane solution into the silica sol solution. After the reaction is completed, a modified silica sol solution is obtained; S3. Purification and drying: The modified silica sol solution is naturally cooled to room temperature, centrifuged to obtain a precipitate, and placed in an oven to dry to obtain a modified silica sol.

[0010] Furthermore, the mass concentration of the methyltriethoxysilane solution in S1 is 6-12%, preferably 9%; the mass ratio of the silica sol to the deionized water in S2 is 1:(0.8-2.5), the temperature of the water bath heating is 38-42°C, the stirring speed is 50-100 rpm, the volume ratio of the methyltriethoxysilane solution to the silica sol solution is 1:(0.5-1), and the reaction time is 8-16 h; the centrifugal speed in S3 is 4000-5000 rpm, the oven drying temperature is 60-65°C, and the drying time is 18-24 h.

[0011] The present invention also provides a method for preparing cement slurry with controllable rheological properties, comprising the following steps: Q1. Primary mixing: Calcium aluminate cement, fine aggregate, nano calcium carbonate and anti-cracking fiber are placed in a mixer for preliminary mixing to obtain a primary mixture; Q2. Add water: slowly add water to the initial mixture, stirring while adding to ensure that all components are evenly dispersed to obtain a wet mixture; Q3. Final mixing: Add modified silica sol and rheological adjuster to the wet mix and continue stirring to obtain a cement slurry with controllable rheological properties.

[0012] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The cement slurry prepared by the present invention by accurately proportioning calcium aluminate cement, fine aggregate, rheological modifier, modified silica sol, nano calcium carbonate, anti-cracking fiber and water not only has excellent rheological properties, but also its properties can be flexibly controlled by adjusting the proportion of each component, which not only improves the workability and plasticity of the cement slurry, but also significantly enhances its stability and durability.

[0013] 2. The present invention significantly improves the rheological properties of cement slurry by adding a rheological adjuster through the synergistic effect of complex components. Among them, methyl allyl polyoxyethylene ether, as a high-efficiency water reducer, can significantly reduce the friction between cement particles and increase the fluidity and stability of the slurry. The polymers of acrylic acid and acrylamide provide additional viscosity, enhancing the thixotropy and shear resistance of the slurry. The addition of sodium methyl propylene sulfonate and sodium formaldehyde sulfoxylate further optimizes the rheological behavior of the slurry and improves its adaptability to construction conditions. By precisely controlling the concentration and reaction conditions of these components, the rheological adjuster can significantly improve the rheological properties of the cement slurry while maintaining good workability and stability.

[0014] 3. The present invention significantly enhances its compatibility and bonding with the cement matrix by adding modified silica sol, which uses methyltriethoxysilane for surface modification. Methyltriethoxysilane reacts with the silanol groups on the surface of silica sol to form a stable siloxane network, which not only improves the stability of silica sol, but also enhances its dispersibility and reactivity in cement slurry. This helps to form a more dense and uniform microstructure during the hardening process, thereby significantly improving the early strength, crack resistance and durability of cement slurry. At the same time, the addition of modified silica sol can also optimize the rheological properties of the slurry, so that it has higher durability while maintaining good fluidity. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present invention are described clearly and completely below. 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.

[0016] Embodiment 1:

[0017] The present embodiment provides a cement slurry with controllable rheological properties, comprising the following components in parts by weight: 55 kg of calcium aluminate cement, 70 kg of fine aggregate, 5 kg of rheological conditioning agent, 5 kg of modified silica sol, 5 kg of nano calcium carbonate, 5 kg of anti-cracking fiber and 35 kg of water.

[0018] The preparation method of the rheological adjusting agent comprises the following steps: (1) Preparation of solution: weigh 10 g of methyl allyl polyoxyethylene ether and pour it into a flask, add 1000 mL of deionized water, stir thoroughly at a stirring speed of 30 rpm for 30 min, and heat to 30°C to obtain a methyl allyl polyoxyethylene ether solution; weigh 50 g of sodium methyl propylene sulfonate and 20 g of sodium formaldehyde sulfoxylate, respectively, dissolve them in 1000 mL of deionized water, stir thoroughly to obtain a sodium methyl propylene sulfonate solution and a sodium formaldehyde sulfoxylate solution; weigh 50 g of acrylic acid and 50 g of acrylamide, respectively, dissolve them in 1000 mL of deionized water, stir thoroughly to obtain an acrylic acid solution and an acrylamide solution; (2) Mixing: Mix 100 mL of 1 mol / L sodium hydroxide solution with 50 mL of 5% acrylic acid solution to obtain a sodium acrylate solution, then mix the methyl allyl polyoxyethylene ether solution with the sodium acrylate solution to obtain a mixed solution of 100 mL of methyl allyl polyoxyethylene ether and 120 mL of sodium acrylate; mix 100 mL of sodium methyl allyl sulfonate solution with 150 mL of sodium formaldehyde sulfoxylate solution and stir evenly to obtain a mixed solution of sodium methyl allyl sulfonate and sodium formaldehyde sulfoxylate; then mix 100 mL of 5% acrylic acid solution with 100 mL of acrylamide solution and stir evenly to obtain a mixed solution of acrylic acid and acrylamide; (3) Adding drops: add the mixed solution of sodium methacrylate sulfonate and sodium formaldehyde sulfoxylate and the mixed solution of acrylic acid and acrylamide to the mixed solution of methyl allyl polyoxyethylene ether and sodium acrylate respectively, and add the drops for 1.5 hours. The mixed solution of acrylic acid and acrylamide is added before the mixed solution of sodium methacrylate sulfonate and sodium formaldehyde sulfoxylate. After the addition is completed, keep the mixture warm at 25°C for 1 hour. Then adjust the pH to 7 with sodium hydroxide solution to obtain a rheological adjuster.

[0019] The preparation method of modified silica sol comprises the following steps: S1. Prepare a modified liquid: weigh 60 g of methyltriethoxysilane and dissolve it in 1000 mL of anhydrous ethanol to obtain a methyltriethoxysilane solution; S2, modification reaction: weigh 400g of silica sol and add it into a flask, add 500mL of deionized water, heat in a water bath, and stir to evenly disperse the silica sol to obtain a silica sol solution. While stirring, slowly drop the methyltriethoxysilane solution into the silica sol solution. After the reaction is completed, a modified silica sol solution is obtained; S3. Purification and drying: the modified silica sol solution is naturally cooled to room temperature, centrifuged to obtain a precipitate at a centrifugal speed of 4000 rpm, and placed in an oven for drying at a temperature of 60° C. for 18 h to obtain a modified silica sol.

[0020] This embodiment also provides a method for preparing a cement slurry with controllable rheological properties, comprising the following steps: Q1. Primary mixing: Put calcium aluminate cement, fine aggregate, nano calcium carbonate and anti-cracking fiber into a mixer and perform preliminary mixing to obtain a primary mix.

[0021] Q2. Add water: Slowly add water to the initial mixture, stirring while adding to ensure that all components are evenly dispersed to obtain a wet mixture.

[0022] Q3. Final mixing: Add modified silica sol and rheological adjuster to the wet mix and continue stirring to obtain a cement slurry with controllable rheological properties.

[0023] Embodiment 2:

[0024] The present embodiment provides a cement slurry with controllable rheological properties, comprising the following components in parts by weight: 40 kg of calcium aluminate cement, 60 kg of fine aggregate, 6 kg of rheological conditioning agent, 6 kg of modified silica sol, 6 kg of nano calcium carbonate, 6 kg of anti-cracking fiber and 37 kg of water.

[0025] The preparation method of the rheological adjusting agent comprises the following steps: (1) Preparation of solution: weigh 25 g of methyl allyl polyoxyethylene ether and pour it into a flask, add 1000 mL of deionized water, stir thoroughly at a stirring speed of 50 rpm for 18 min, and heat to 35°C to obtain a methyl allyl polyoxyethylene ether solution; weigh 80 g of sodium methyl propylene sulfonate and 30 g of sodium formaldehyde sulfoxylate, respectively, dissolve them in 1000 mL of deionized water, stir thoroughly to obtain a sodium methyl propylene sulfonate solution and a sodium formaldehyde sulfoxylate solution; weigh 100 g of acrylic acid and 100 g of acrylamide, respectively, dissolve them in 1000 mL of deionized water, stir thoroughly to obtain an acrylic acid solution and an acrylamide solution; (2) Mixing: Mix 100 mL of 2 mol / L sodium hydroxide solution with 60 mL of 10% acrylic acid solution to obtain a sodium acrylate solution, then mix the methyl allyl polyoxyethylene ether solution with the sodium acrylate solution to obtain a mixed solution of 100 mL of methyl allyl polyoxyethylene ether and 150 mL of sodium acrylate; mix 100 mL of sodium methyl allyl sulfonate solution with 160 mL of sodium formaldehyde sulfoxylate solution and stir evenly to obtain a mixed solution of sodium methyl allyl sulfonate and sodium formaldehyde sulfoxylate; then mix 100 mL of 10% acrylic acid solution with 200 mL of acrylamide solution and stir evenly to obtain a mixed solution of acrylic acid and acrylamide; (3) Adding drops: add the mixed solution of sodium methacrylate sulfonate and sodium formaldehyde sulfoxylate and the mixed solution of acrylic acid and acrylamide to the mixed solution of methyl allyl polyoxyethylene ether and sodium acrylate respectively, and add the drops for 2 hours. The mixed solution of acrylic acid and acrylamide is added before the mixed solution of sodium methacrylate sulfonate and sodium formaldehyde sulfoxylate. After the addition is completed, keep the mixture warm at 28°C for 1.5 hours. Then adjust the pH to 7.5 with sodium hydroxide solution to obtain a rheological adjuster.

[0026] The preparation method of modified silica sol comprises the following steps: S1. Prepare a modified liquid: weigh 80 g of methyltriethoxysilane and dissolve it in 1000 mL of anhydrous ethanol to obtain a methyltriethoxysilane solution; S2, modification reaction: weigh 600g of silica sol and add it into a flask, add 1000mL of deionized water, heat in a water bath, and stir to evenly disperse the silica sol to obtain a silica sol solution. While stirring, slowly dropwise add the methyltriethoxysilane solution into the silica sol solution. After the reaction is completed, a modified silica sol solution is obtained; S3. Purification and drying: The modified silica sol solution is naturally cooled to room temperature, centrifuged to obtain a precipitate at a centrifugal speed of 5000 rpm, and placed in an oven for drying at a temperature of 65° C. for 24 hours to obtain a modified silica sol.

[0027] This embodiment also provides a method for preparing a cement slurry with controllable rheological properties, comprising the following steps: Q1. Primary mixing: Put calcium aluminate cement, fine aggregate, nano calcium carbonate and anti-cracking fiber into a mixer and perform preliminary mixing to obtain a primary mix.

[0028] Q2. Add water: Slowly add water to the initial mixture, stirring while adding to ensure that all components are evenly dispersed to obtain a wet mixture.

[0029] Q3. Final mixing: Add modified silica sol and rheological adjuster to the wet mix and continue stirring to obtain a cement slurry with controllable rheological properties.

[0030] Embodiment 3:

[0031] The present embodiment provides a cement slurry with controllable rheological properties, comprising the following components in parts by weight: 45 kg of calcium aluminate cement, 55 kg of fine aggregate, 10 kg of rheological conditioning agent, 10 kg of modified silica sol, 7 kg of nano calcium carbonate, 7 kg of anti-cracking fiber and 40 kg of water.

[0032] The preparation method of the rheological adjusting agent comprises the following steps: (1) Preparation of solution: weigh 50 g of methyl allyl polyoxyethylene ether and pour it into a flask, add 1000 mL of deionized water, stir thoroughly at a stirring speed of 100 rpm for 30 min, and heat to 55° C. to obtain a methyl allyl polyoxyethylene ether solution; weigh 200 g of sodium methyl propylene sulfonate and 80 g of sodium formaldehyde sulfoxylate, respectively, dissolve them in 1000 mL of deionized water, stir thoroughly, to obtain a sodium methyl propylene sulfonate solution and a sodium formaldehyde sulfoxylate solution; weigh 250 g of acrylic acid and 250 g of acrylamide, respectively, dissolve them in 1000 mL of deionized water, stir thoroughly, to obtain an acrylic acid solution and an acrylamide solution; (2) Mixing: Mix 100 mL of 5 mol / L sodium hydroxide solution with 100 mL of 25% acrylic acid solution to obtain a sodium acrylate solution, then mix the methyl allyl polyoxyethylene ether solution with the sodium acrylate solution to obtain a mixed solution of 100 mL of methyl allyl polyoxyethylene ether and 200 mL of sodium acrylate; mix 100 mL of sodium methyl allyl sulfonate solution with 200 mL of sodium formaldehyde sulfoxylate solution and stir evenly to obtain a mixed solution of sodium methyl allyl sulfonate and sodium formaldehyde sulfoxylate; then mix 100 mL of 25% acrylic acid solution with 500 mL of acrylamide solution and stir evenly to obtain a mixed solution of acrylic acid and acrylamide; (3) Adding drops: add the mixed solution of sodium methacrylate sulfonate and sodium formaldehyde sulfoxylate and the mixed solution of acrylic acid and acrylamide to the mixed solution of methyl allyl polyoxyethylene ether and sodium acrylate respectively, and add the drops for 1.5 to 3 hours. The mixed solution of acrylic acid and acrylamide is added before the mixed solution of sodium methacrylate sulfonate and sodium formaldehyde sulfoxylate. After the addition is completed, keep the mixture warm at 35°C for 2 hours. Then adjust the pH to 7.5 with sodium hydroxide solution to obtain a rheological adjuster.

[0033] The preparation method of modified silica sol comprises the following steps: S1. Prepare a modified liquid: weigh 120 g of methyltriethoxysilane and dissolve it in 1000 mL of anhydrous ethanol to obtain a methyltriethoxysilane solution; S2, modification reaction: weigh 1250g of silica sol into a flask, add 1000mL of deionized water, heat in a water bath, and stir to evenly disperse the silica sol to obtain a silica sol solution. While stirring, slowly dropwise add the methyltriethoxysilane solution into the silica sol solution. After the reaction is completed, a modified silica sol solution is obtained; S3. Purification and drying: The modified silica sol solution is naturally cooled to room temperature, centrifuged to obtain a precipitate at a centrifugal speed of 5000 rpm, and placed in an oven for drying at a temperature of 65° C. for 24 hours to obtain a modified silica sol.

[0034] This embodiment also provides a method for preparing a cement slurry with controllable rheological properties, comprising the following steps: Q1. Primary mixing: Put calcium aluminate cement, fine aggregate, nano calcium carbonate and anti-cracking fiber into a mixer and perform preliminary mixing to obtain a primary mix.

[0035] Q2. Add water: Slowly add water to the initial mixture, stirring while adding to ensure that all components are evenly dispersed to obtain a wet mixture.

[0036] Q3. Final mixing: Add modified silica sol and rheological adjuster to the wet mix and continue stirring to obtain a cement slurry with controllable rheological properties.

[0037] Embodiment 4:

[0038] The present embodiment provides a cement slurry with controllable rheological properties, comprising the following components in parts by weight: 35 kg of calcium aluminate cement, 40 kg of fine aggregate, 10 kg of rheological adjuster, 10 kg of modified silica sol, 10 kg of nano calcium carbonate, 10 kg of anti-cracking fiber and 40 kg of water.

[0039] The preparation method of the rheological adjusting agent comprises the following steps: (1) Preparation of solution: weigh 100 g of methyl allyl polyoxyethylene ether and pour it into a flask, add 1000 mL of deionized water, stir thoroughly at a stirring speed of 200 rpm for 30 min, and heat to 55° C. to obtain a methyl allyl polyoxyethylene ether solution; weigh 200 g of sodium methyl propylene sulfonate and 80 g of sodium formaldehyde sulfoxylate, respectively, dissolve them in 1000 mL of deionized water, stir thoroughly, to obtain a sodium methyl propylene sulfonate solution and a sodium formaldehyde sulfoxylate solution; weigh 250 g of acrylic acid and 250 g of acrylamide, respectively, dissolve them in 1000 mL of deionized water, stir thoroughly, to obtain an acrylic acid solution and an acrylamide solution; (2) Mixing: Mix 100 mL of 5 mol / L sodium hydroxide solution with 100 mL of 25% acrylic acid solution to obtain a sodium acrylate solution, then mix the methyl allyl polyoxyethylene ether solution with the sodium acrylate solution to obtain a mixed solution of 100 mL of methyl allyl polyoxyethylene ether and 200 mL of sodium acrylate; mix 100 mL of sodium methyl allyl sulfonate solution with 200 mL of sodium formaldehyde sulfoxylate solution and stir evenly to obtain a mixed solution of sodium methyl allyl sulfonate and sodium formaldehyde sulfoxylate; then mix 100 mL of 25% acrylic acid solution with 500 mL of acrylamide solution and stir evenly to obtain a mixed solution of acrylic acid and acrylamide; (3) Adding drops: add the mixed solution of sodium methacrylate sulfonate and sodium formaldehyde sulfoxylate and the mixed solution of acrylic acid and acrylamide to the mixed solution of methyl allyl polyoxyethylene ether and sodium acrylate respectively, and add the drops for 1.5 to 3 hours. The mixed solution of acrylic acid and acrylamide is added before the mixed solution of sodium methacrylate sulfonate and sodium formaldehyde sulfoxylate. After the addition is completed, keep the mixture warm at 35°C for 2 hours. Then adjust the pH to 8 with sodium hydroxide solution to obtain a rheological adjuster.

[0040] The preparation method of modified silica sol comprises the following steps: S1. Prepare a modified liquid: weigh 120 g of methyltriethoxysilane and dissolve it in 1000 mL of anhydrous ethanol to obtain a methyltriethoxysilane solution; S2, modification reaction: weigh 400g of silica sol and add it into a flask, add 500mL of deionized water, heat in a water bath, and stir to evenly disperse the silica sol to obtain a silica sol solution. While stirring, slowly drop the methyltriethoxysilane solution into the silica sol solution. After the reaction is completed, a modified silica sol solution is obtained; S3. Purification and drying: the modified silica sol solution is naturally cooled to room temperature, centrifuged to obtain a precipitate at a centrifugal speed of 4000-5000 rpm, and placed in an oven for drying at a temperature of 60-65°C for a drying time of 18-24 hours to obtain a modified silica sol.

[0041] This embodiment also provides a method for preparing a cement slurry with controllable rheological properties, comprising the following steps: Q1. Primary mixing: Put calcium aluminate cement, fine aggregate, nano calcium carbonate and anti-cracking fiber into a mixer and perform preliminary mixing to obtain a primary mix.

[0042] Q2. Add water: Slowly add water to the initial mixture, stirring while adding to ensure that all components are evenly dispersed to obtain a wet mixture.

[0043] Q3. Final mixing: Add modified silica sol and rheological adjuster to the wet mix and continue stirring to obtain a cement slurry with controllable rheological properties.

[0044] Comparative Example 1: Compared with Example 3, in Comparative Example 1, no rheological adjuster is added to a cement slurry with controllable rheological properties, and other conditions remain unchanged.

[0045] Comparative Example 2: Comparative Example 2 Compared with Example 3, in Comparative Example 1, no modified silica sol is added to a cement slurry with controllable rheological properties, and other conditions remain unchanged.

[0046] Experimental example 1. Flow performance test The samples prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were tested for fluidity. The setting time of the samples was tested according to GB / T 1346-2011; the fluidity of the samples was tested according to GB / T 2419-2005. The larger the fluidity value tested by the fluidity tester, the better the fluidity of the cement slurry and the better the construction performance. The test results are shown in Table 1: Table 1

[0047] According to the test results in Table 1, the cement slurries with controllable rheological properties in Examples 1 to 4 of the present invention have short initial setting time and short final setting time, and improved fluidity. By comparing Examples 1 to 4 with Comparative Examples 1 to 2, it can be seen that the addition of rheological modifiers and modified silica sol significantly improves the rheological properties of the cement slurry, indicating that the rheological properties of the cement slurry can be regulated by controlling the addition amount of the rheological modifiers and modified silica sol.

[0048] 2. Mechanical properties test According to GB / T 17671-1999, the flexural strength and compressive strength of the samples were tested for mechanical properties. The test blocks were prepared according to the size of 40mm×40mm×160mm. The prepared test blocks were cured under standard curing conditions (20±1℃, relative humidity ≥90%) to 3 days, 7 days, and 28 days. The test results are shown in Table 2: Table 2

[0049] According to the test results in Table 2, the flexural strength and compressive strength of the cement slurries with controllable rheological properties of Examples 1 to 4 of the present invention are significantly improved. By comparing Examples 1 to 4 with Comparative Examples 1 to 2, it can be seen that the mechanical properties of the cement slurry are significantly improved after adding the rheological modifier and the modified silica sol.

[0050] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0051] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A cement slurry with controllable rheological properties, characterized in that: The invention comprises the following components in parts by weight: 35-55 parts of calcium aluminate cement, 40-70 parts of fine aggregate, 5-10 parts of rheological modifier, 5-10 parts of modified silica sol, 5-10 parts of nano calcium carbonate, 5-10 parts of anti-cracking fiber and 35-40 parts of water; the fine aggregate is industrial alumina, fly ash and kaolin mixed in a mass ratio of 1: (1-2): (0.5-1); the rheological modifier is prepared by mixing and dripping methyl allyl polyoxyethylene ether, acrylic acid, acrylamide, sodium methyl propylene sulfonate, sodium formaldehyde sulfoxylate and sodium hydroxide into solutions respectively; the anti-cracking fiber is polypropylene fiber and basalt fiber mixed in a mass ratio of 1: (0.5-2).

2. A cement slurry with controllable rheological properties according to claim 1, characterized in that: The preparation method of the rheological adjusting agent comprises the following steps: (1) Preparing a solution: weighing methyl allyl polyoxyethylene ether, pouring it into a flask, adding deionized water, stirring thoroughly, and heating to obtain a methyl allyl polyoxyethylene ether solution; weighing sodium methyl propylene sulfonate and sodium formaldehyde sulfoxylate, dissolving them in deionized water, stirring thoroughly, and obtaining a sodium methyl propylene sulfonate solution and a sodium formaldehyde sulfoxylate solution; weighing acrylic acid and acrylamide, dissolving them in deionized water, stirring thoroughly, and obtaining an acrylic acid solution and an acrylamide solution; (2) Mixing: mixing sodium hydroxide solution with acrylic acid solution to obtain sodium acrylate solution, and then mixing methyl allyl polyoxyethylene ether solution with sodium acrylate solution to obtain a mixed solution of methyl allyl polyoxyethylene ether and sodium acrylate; mixing sodium methyl allyl sulfonate solution with sodium formaldehyde sulfoxylate solution, stirring evenly, to obtain a mixed solution of sodium methyl allyl sulfonate and sodium formaldehyde sulfoxylate; mixing acrylic acid solution with acrylamide solution, stirring evenly, to obtain a mixed solution of acrylic acid and acrylamide; (3) Dropwise addition: a mixed solution of sodium methacrylic sulfonate and sodium formaldehyde sulfoxylate and a mixed solution of acrylic acid and acrylamide are respectively added dropwise to a mixed solution of methyl allyl polyoxyethylene ether and sodium acrylate. After the addition is completed, the mixture is kept warm and the pH is adjusted to obtain a rheological adjuster.

3. A cement slurry with controllable rheological properties according to claim 2, characterized in that: In step (1), the mass concentration of the methallyl polyoxyethylene ether solution is 1-10%, the stirring speed is 30-200 rpm, the stirring time is 15-30 min, and the temperature is heated to 30-55° C. The mass concentration of the sodium methacrylate sulfonate solution is 5-20%, the mass concentration of sodium formaldehyde sulfoxylate is 2-8%, the mass concentration of the acrylic acid solution is 5-25%, and the mass concentration of the acrylamide solution is 5-25%.

4. The cement slurry with controllable rheological properties according to claim 2, characterized in that: In step (2), the mass concentration of the sodium hydroxide solution is 1-5 mol / L, the mass concentration of the acrylic acid solution is 5-25%, the volume ratio of the acrylic acid solution to the sodium hydroxide solution is 1:(0.5-1), the volume ratio of the methyl allyl polyoxyethylene ether solution to the sodium acrylate solution is 1:(1.2-2), the volume ratio of the sodium methacrylate sulfonate solution to the sodium formaldehyde sulfoxylate solution is 1:(1.5-2), and the volume ratio of the acrylic acid solution to the acrylamide solution is 1:(1-5).

5. The cement slurry with controllable rheological properties according to claim 2, characterized in that: In step (3), the dripping time is 1.5 to 3 hours. The mixed solution of acrylic acid and acrylamide is added before the mixed solution of sodium methyl methacrylate sulfonate and sodium formaldehyde sulfoxylate. The temperature is kept at 25 to 35°C for 1 to 2 hours. The pH is adjusted to 7 to 8 with sodium hydroxide solution.

6. The cement slurry with controllable rheological properties according to claim 2, characterized in that: The preparation method of modified silica sol comprises the following steps: S1. preparing a modified liquid: weighing methyltriethoxysilane, and dissolving it in anhydrous ethanol to obtain a methyltriethoxysilane solution; S2. Modification reaction: weigh silica sol and add it into a flask, add deionized water, heat it in a water bath, and stir to evenly disperse the silica sol to obtain a silica sol solution. While stirring, slowly drop the methyltriethoxysilane solution into the silica sol solution. After the reaction is completed, a modified silica sol solution is obtained; S3. Purification and drying: The modified silica sol solution is naturally cooled to room temperature, centrifuged to obtain a precipitate, and placed in an oven to dry to obtain a modified silica sol.

7. The cement slurry with controllable rheological properties according to claim 6, characterized in that: The mass concentration of methyltriethoxysilane solution in S1 is 6~12%.

8. The cement slurry with controllable rheological properties according to claim 6, characterized in that: The mass ratio of silica sol to deionized water in S2 is 1:(0.8~2.5), the water bath heating temperature is 38~42°C, the stirring speed is 50~100rpm, the volume ratio of methyltriethoxysilane solution to silica sol solution is 1:(0.5~1), and the reaction time is 8~16h.

9. The cement slurry with controllable rheological properties according to claim 6, characterized in that: The centrifugal speed in S3 is 4000~5000rpm, the oven drying temperature is 60~65℃, and the drying time is 18~24h.

10. A method for preparing cement slurry with controllable rheological properties, characterized in that: The following steps are involved: Q1. Primary mixing: Calcium aluminate cement, fine aggregate, nano calcium carbonate and anti-cracking fiber are placed in a mixer for preliminary mixing to obtain a primary mixture; Q2. Add water: slowly add water to the initial mixture, stirring while adding to ensure that all components are evenly dispersed to obtain a wet mixture; Q3. Final mixing: Add modified silica sol and rheological adjuster to the wet mix and continue stirring to obtain cement slurry with controllable rheological properties.

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