Preparation method of high-volume shield silt concrete

Abstract

The invention relates to a preparation method of high-volume shield silt concrete, which comprises the following steps: preparing raw materials of the concrete, the raw materials of the concrete comprise 203-233 kg / m cement, 156-166 kg / m admixture, 1730-1766 kg / m aggregate, 165-180 kg / m water and 5.5-6.3 kg / m admixture, the sand rate of the aggregate is 42-45%, and the replacement rate of shield silt in the aggregate to machine-made sand is 14-17%; and mixing to obtain the C35 concrete. The shield silt is adopted to replace part of machine-made sand, the limitation of a traditional C35 concrete preparation method on use of high-mixing-amount silt is solved, and the method has the advantages that the mechanical property and the working performance of concrete are improved, and meanwhile efficient utilization of silt resources is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of C35 concrete production, and in particular to a method for preparing high-content shield silt concrete. Background Art

[0002] The shield method is a fully mechanized construction method in the dark excavation method. It pushes the shield machine into the ground, supports the surrounding rock with the shield shell and segments to prevent collapse into the tunnel, and excavates the soil in front of the excavation face with a cutting device, transports it out of the cave by the excavation machinery, pressurizes it at the rear with a jack, and assembles prefabricated concrete segments to form a mechanized construction method for the tunnel structure. A large amount of silty sand will be generated during the shield construction in the silty sand stratum. If it can be effectively utilized, it can not only reduce environmental pollution, but also reduce engineering costs. At present, C35 concrete usually uses machine-made sand as fine aggregate, and the price is about 120 yuan / ton. Due to the lack of fine particles in the machine-made sand, the fluidity of the concrete becomes poor. The use of shield silt sand to replace part of the machine-made sand costs about 25 yuan / ton, which can greatly reduce production costs. However, it is difficult to directly use high-content silt sand in traditional concrete preparation methods because the addition of silt sand will significantly affect the mechanical properties and durability of concrete. Therefore, it is of great practical significance to develop a concrete preparation method that can effectively utilize shield silt sand.

[0003] The Chinese patent with publication number CN118344045A discloses a functional additive for recycling silt layer mud shield slag in concrete, a preparation method and its application. The preparation method comprises the following steps: preparing a polyquaternary ammonium salt cationic polymer, a small molecule phosphate anionic polymer, a sodium polyacrylate viscosity regulator and an adaptive small material in a mass ratio of 1:1.0~2.0:5.0~10.0:1~2.5, and uniformly mixing them at room temperature; the concrete mix ratio parameter characteristics are as follows: The amount of shield slag in the silt layer accounts for ≤35% of the total sand usage; the 45μm sieve residue of the shield slag in the silt layer is less than 20%, the 75μm sieve residue is 35~40%, and the mud content is ≤15%; and the dosage range of the above-mentioned functional additives is 0.6~2.0%; among them, the "isolation + blocking" synergistic mud-blocking effect of the component "polyquaternary ammonium salt cationic polymer + small molecule phosphate anionic polymer" and the viscosity-reducing effect of the component sodium polyacrylate viscosity regulator effectively reduce the negative impact of shield slag on the performance of polycarboxylic acid water-reducing agent.

[0004] The above-mentioned prior art solutions have the following defects: the above-mentioned method uses polyquaternary ammonium salt cationic polymers and small molecular phosphate anionic polymers to prepare a functional additive with mud-blocking effect, which reduces the mud content of shield silt, thereby effectively reducing the adverse effects of these mud components on the performance of polycarboxylate water-reducing agent; however, the preparation process of these polymers is quite complicated, requiring multiple steps, and each step requires precise regulation and operation. This complexity will undoubtedly increase the difficulty of operation in the actual production process; in addition, although the above-mentioned functional additives can improve the durability of concrete to a certain extent, their negative impact on the mechanical properties of concrete (such as compression, tension, shear, bending, folding and bond strength) and working performance (such as slump, fluidity, cohesion, water retention) has not been fully optimized and improved, especially when a high proportion of silt is added to concrete, the performance improvement effect may not be ideal, and further research and improvement are still needed to ensure that the best performance can be achieved under various construction conditions. Summary of the invention

[0005] The problem to be solved by the present invention is to provide a method for preparing high-content shield silt sand concrete in view of the above-mentioned deficiencies in the prior art. The method solves the limitations of the traditional C35 concrete preparation method in the use of high-content silt sand by using shield silt sand to replace part of the machine-made sand. The method has the advantages of improving the mechanical properties and working performance of concrete and realizing efficient utilization of silt sand resources.

[0006] The above-mentioned object of the present invention is achieved through the following technical solutions: A method for preparing high-volume shield silt sand concrete comprises the following steps: S1 preparing the raw materials of the concrete, the raw materials of the concrete including 203-233 kg / m³ cement, 156-166 kg / m³ admixture, 1730-1766 kg / m³ aggregate, 165-180 kg / m³ water, and 5.5-6.3 kg / m³ admixture, the sand ratio of the aggregate is 42-45%, and the replacement rate of shield silt sand in the aggregate to machine-made sand is 14-17%; S2 first adds gravel in the aggregate and stirs for 1-2 minutes, then adds sand in the aggregate and stirs for 1-2 minutes, then adds cement and admixtures into the mixer and stirs for 1-2 minutes, finally adds the remaining raw materials of the concrete by the same mixing method, wet mixes for 2-3 minutes, until the mixture is evenly dispersed, to obtain C35 concrete.

[0007] Further, in the S1, the aggregate includes 639-647 kg / m³ machine-made sand, 114-120 kg / m³ shield silt sand, 755-775 kg / m³ 10-25 mm crushed stone, and 194-252 kg / m³ 5-10 mm crushed stone.

[0008] Furthermore, in S1, the admixture includes 78-88 kg / m³ fly ash and 75-80 kg / m³ slag powder.

[0009] Furthermore, in said S1, the raw materials of the concrete include 203, 205, 208, 215, 220, 225, 230 or 233 kg / m³ cement, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87 or 88 kg / m³ fly ash, 75, 76, 77, 78, 79 or 80 kg / m³ slag powder, 639, 640, 641, 642, 643, 644, 645, 646 or 647 kg / m³ machine-made sand, 114, 115, 116, 117, 118, 119 or 120 kg / m³ cement, 121, 122, 123, 124, 125, 126 or 127 kg / m³ fly ash, 127, 128, 129 or 130 kg / m³ slag powder, 131, 132, 133, 134, 135 20kg / m³ shield silt sand, 755, 760, 765, 770 or 775kg / m³ 10-25mm gravel, 194, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250 or 252kg / m³ 5-10mm gravel, 165, 168, 170, 172, 175, 178 or 180kg / m³ water, and 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2 or 6.3kg / m³ admixture.

[0010] Furthermore, in S1, the mass ratio of cement, fly ash and slag powder is controlled to be 1:0.33~0.44:0.33~0.39, the mass ratio of the mixture of cement and admixture, and water is controlled to be 1:0.44~0.47, and the mass ratio of 10~25mm crushed stone and 5~10mm crushed stone is about 1:3~4.

[0011] Furthermore, in the S1, the raw materials of the concrete include 203kg / m³ cement, 88kg / m³ fly ash, 78kg / m³ slag powder, 639kg / m³ machine-made sand, 120kg / m³ shield sand, 755kg / m³ 10~25mm crushed stone, 252kg / m³ 5~10mm crushed stone, 165kg / m³ water, and 5.5kg / m³ admixture.

[0012] Alternatively, in S1, the raw materials of concrete include 233kg / m³ cement, 78kg / m³ fly ash, 78kg / m³ slag powder, 647kg / m³ machine-made sand, 114kg / m³ shield sand, 775kg / m³ 10-25mm crushed stone, 194kg / m³ 5-10mm crushed stone, 180kg / m³ water, and 6.3kg / m³ admixture.

[0013] Furthermore, in the S1, silty sand with a mud content of ≤30% and a water content of ≤18% is soaked in a modifier until it is saturated with water, and stirring is continued and an auxiliary agent is added dropwise during the soaking period. After the soaking is completed, the sand is filtered and dried, and then mixed with abrasive, ball milled and sieved to obtain the shield silt sand; wherein the modifier is composed of the following raw materials in parts by weight: 10 to 15 parts of bis-PEG-18 methyl ether dimethyl silane, 5 to 8 parts of aluminum lactate, 4 to 6 parts of attapulgite, 5 to 10 parts of triethoxyoctylsilane, and water is added to 100 parts.

[0014] Furthermore, during the soaking process, the modifier is composed of the following raw materials in parts by weight: 5, 6, 7, 8, 9 or 10 parts of triethoxycaprylylsilane, 10, 11, 12, 13, 14 or 15 parts of bis-PEG-18 methyl ether dimethyl silane, 5, 6, 7 or 8 parts of aluminum lactate, 4, 5 or 6 parts of attapulgite, and water is added to 100 parts.

[0015] Furthermore, during the soaking process, the auxiliary agent is composed of the following raw materials in parts by weight: 20 to 30 parts of sodium carboxymethyl cellulose, 30 to 40 parts of hydroxyethyl urea, and water is added to 100 parts.

[0016] Furthermore, during the soaking process, the auxiliary agent is composed of the following raw materials in parts by weight: 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 parts of sodium carboxymethyl cellulose, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40 parts of hydroxyethyl urea, and water is added to 100 parts.

[0017] Furthermore, during the soaking process, the volume ratio of silty sand, modifier and auxiliary agent is controlled to be 1:5~15:0.5~1.5.

[0018] Furthermore, during the soaking process, the volume ratio of silty sand, modifier and additive is controlled to be 1:5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15:0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4 or 1.5.

[0019] Furthermore, during the soaking process, the height difference between the auxiliary agent addition port and the liquid level of the modifier is controlled to be 0.3 m.

[0020] Furthermore, during the soaking process, the soaking time is controlled to be 4-6 hours and the stirring speed is controlled to be 1000-1250 r / min.

[0021] Furthermore, during the ball milling process, the abrasive is composed of the following raw materials in parts by weight: 38 to 45 parts of hydrated silica, 30 to 35 parts of talc, and 20 to 32 parts of microcrystalline cellulose.

[0022] Furthermore, during the ball milling process, the abrasive is composed of the following raw materials in parts by weight: 38, 39, 40, 41, 42, 43, 44 or 45 parts of hydrated silica, 30, 31, 32, 33, 34 or 35 parts of talc, and 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 or 32 parts of microcrystalline cellulose.

[0023] Furthermore, in the process of ball milling, ceramic balls are used as ball milling media, and water is added for wet milling, and the mass ratio of silty sand, abrasive, ball milling media and water obtained by soaking is controlled to be 1:0.08~0.12:0.5~1.5:0.5~1.0.

[0024] Furthermore, in the process of ball milling, ceramic balls are used as ball milling media, and water is added for wet milling, and the mass ratio of silt sand, abrasive, ball milling media and water obtained by soaking is controlled to be 1:0.08, 0.09, 0.10, 0.11 or 0.12:0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.3, 1.4 or 1.5:0.5, 0.6, 0.7, 0.8, 0.9 or 1.0.

[0025] Furthermore, during the ball milling process, the ball milling speed is controlled to be 10-15 r / min, and the ball milling time is 2-3 h.

[0026] In summary, the beneficial technical effects of the present invention are: 1. The present invention screens the components of the slurry and aggregate in the concrete in advance, and combines the apparent density of these components, the average slurry thickness of the aggregate, the minimum slurry volume and other technical parameters to optimize the sand ratio of the aggregate and the replacement rate of the shield silt sand for the machine-made sand, and then determines the amount and proportion of each component in the concrete raw material. It is most appropriate to add 114-120kg / m³ of shield silt sand to the concrete. The C35 concrete prepared in this way not only has mechanical properties and working performance, but also other properties that meet the requirements of standard specifications, and also realizes efficient utilization of silt sand resources; 2. The present invention sequentially performs soaking modification and ball milling modification treatment on silty sand. First, during the soaking process, bis-PEG-18 methyl ether dimethyl silane is a water-soluble silicone wax, which is filled in the cracks and sharp surfaces of the silty sand through aluminum lactate and magnesia clay, which is beneficial to improving the surface morphology of the silty sand, and is supplemented with triethoxyoctylsilane to significantly improve the surface finish of the silty sand and the bonding strength between the machine-made sand particles, reduce the negative impact on the slurry and admixtures, and thus achieve the improvement of working performance. In the ball milling process, hydrated silica, talc and microcrystalline cellulose are used for ball milling dispersion, further optimizing the gradation of fine particles in the silty sand, and improving the cross-sectional adhesion between the silty sand and the slurry, which is conducive to improving the mechanical properties of concrete; 3. The shield silt sand used in the present invention is industrial waste generated during the shield construction process, which has the dual advantages of environmental protection and resource recycling. By using the shield silt sand as one of the components of concrete, it not only reduces the accumulation of waste and environmental pollution, but also reduces the production cost of concrete, achieving a win-win situation of economic benefits and environmental benefits; 4. The preparation method of the present invention has simple steps, does not require complicated equipment and other raw materials, and ensures the uniformity and stability of the concrete. During the mixing process, the addition of admixtures further improves the fluidity, cohesiveness and water retention of the concrete, so that the concrete has better working performance during the construction process. DETAILED DESCRIPTION

[0027] In order to make the technical means, creative features, objectives and functions achieved by the present invention clearer and easier to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0028] Embodiment 1: A method for preparing high-content shield silt sand concrete disclosed in the present invention comprises the following steps: S1 prepares the raw materials for concrete, which include 233kg / m³ cement, 78kg / m³ fly ash, 78kg / m³ mineral powder, 647kg / m³ machine-made sand, 114kg / m³ shield sand, 775kg / m³ 10~25mm crushed stone, 194kg / m³ 5~10mm crushed stone, 180kg / m³ water, and 6.3kg / m³ polycarboxylic acid admixture; among which, The cement is P.Ⅱ52.5 silicate cement, produced by Ningguo Cement Plant of Anhui Conch Cement Co., Ltd.; The fly ash is Class F, Grade I fly ash, produced in Haining; The slag powder is S95 grade slag powder, produced by Ningbo Henglong New Materials Co., Ltd., with a density of ≥2.8g / cm³, a specific surface area of ​​≥400㎡ / kg, a fluidity ratio of ≥95%, a loss on ignition of ≤1.0%, a 7-day activity index of ≥70%, and a 28-day activity index of ≥95%. The machine-made sand is medium sand of Class II in Zone 2, produced in Shaoxing; Shield silt sand is silty sand that has been processed after shield construction through silty sand strata. It is produced in Shaoxing. GBJ145-90 "Soil Classification Standard" stipulates that soil with a fine particle content between 15% and 50% and fine particles in the form of silt is called silty sand; The crushed stone is in two specifications: 5~10mm and 10~25mm. It is produced in Shaoxing, with mud content ≤0.5%, mud block content 0, needle-like content ≤5%, crushing value ≤10%, apparent density ≥2600kg / m³, void ratio ≤43%, and water absorption rate ≤1.0%; The admixture is polycarboxylic acid high-performance water-reducing agent, produced in Lanxi, with a pH value of 4.0~4.7, a density of 1.02~1.06g / cm³, cement paste fluidity ≥180mm, water reduction rate ≥25%, air content ≤6.0%, 1h slump loss over time ≤80mm, 7-day compressive strength ratio ≥150%, 28-day compressive strength ratio ≥140%; The water is tap water, produced in Shaoxing; S2 first adds gravel in the aggregate and stirs for 2 minutes, then adds sand in the aggregate and stirs for 2 minutes, then adds cement and admixtures into the mixer and stirs for 2 minutes, finally adds the remaining raw materials of concrete by the same mixing method, wet mixes for 2 minutes, until the mixture is evenly dispersed, and obtains C35 concrete.

[0029] Embodiment 2: A method for preparing high-content shield silt sand concrete disclosed in the present invention, which is different from Embodiment 1 in that it comprises the following steps: S1 prepares the raw materials for concrete, which include 203kg / m³ cement, 88kg / m³ fly ash, 78kg / m³ slag powder, 639kg / m³ machine-made sand, 120kg / m³ shield sand, 755kg / m³ 10~25mm crushed stone, 252kg / m³ 5~10mm crushed stone, 165kg / m³ water, and 5.5kg / m³ admixture; S2 first adds gravel in the aggregate and stirs for 2 minutes, then adds sand in the aggregate and stirs for 2 minutes, then adds cement and admixtures into the mixer and stirs for 2 minutes, finally adds the remaining raw materials of concrete by the same mixing method, wet mixes for 2 minutes, until the mixture is evenly dispersed, and obtains C35 concrete.

[0030] Example 3: A method for preparing high-content shield silt sand concrete disclosed in the present invention, which is different from Example 1 in that, in S1, the shield silt sand is processed in advance as follows: S11 is configured with modifiers, additives, and abrasives; wherein, The modifier is composed of the following raw materials in parts by weight: 10 parts of bis-PEG-18 methyl ether dimethyl silane, 5 parts of aluminum lactate, 4 parts of attapulgite, 5 parts of triethoxycaprylylsilane, and water is added to 100 parts; The auxiliary agent is composed of the following raw materials in parts by weight: 20 parts of sodium carboxymethyl cellulose, 30 parts of hydroxyethyl urea, and water is added to 100 parts; The abrasive material is composed of the following raw materials in parts by weight: 38 parts of hydrated silica, 30 parts of talc, and 20 parts of microcrystalline cellulose; S12: soaking silty sand with mud content ≤30% and water content ≤18% in the modifier obtained in S11 until saturated with water, stirring continuously during the soaking and dropping the additive obtained in S11, controlling the volume ratio of silty sand, modifier and additive to be 1:5:0.5, the height difference between the additive dropping port and the liquid level of the modifier to be 0.3m, and the soaking time to be 5h; S13 mixes the silty sand obtained in S12 and the abrasive obtained in S11, uses ceramic balls as ball milling media, and adds water for wet grinding. The mass ratio of the silty sand, abrasive, ball milling media and water obtained by soaking is controlled to be 1:0.08:0.5:0.5, the ball milling speed is 10r / min, and the ball milling time is 3h. After the ball milling screening is completed, shield silt sand is obtained.

[0031] Example 4: A method for preparing high-content shield silt sand concrete disclosed in the present invention, which is different from Example 1 in that, in S1, the shield silt sand is processed in advance as follows: S11 is configured with modifiers, additives, and abrasives; wherein, The modifier is composed of the following raw materials in parts by weight: 12 parts of bis-PEG-18 methyl ether dimethyl silane, 6 parts of aluminum lactate, 2 parts of attapulgite, 8 parts of triethoxyoctylsilane, and water is added to 100 parts; The auxiliary agent is composed of the following raw materials in parts by weight: 24 parts of sodium carboxymethyl cellulose, 36 parts of hydroxyethyl urea, and water is added to 100 parts; The abrasive material is composed of the following raw materials in parts by weight: 42 parts of hydrated silica, 33 parts of talc, and 25 parts of microcrystalline cellulose; S12: soaking silty sand with mud content ≤30% and water content ≤18% in the modifier obtained in S11 until saturated with water, stirring continuously during the soaking and dropping the additive obtained in S11, controlling the volume ratio of silty sand, modifier and additive to be 1:10:1.2, the height difference between the additive dropping port and the liquid level of the modifier to be 0.3m, and the soaking time to be 5h; S13 mixes the silty sand obtained in S12 and the abrasive obtained in S11, uses ceramic balls as ball milling media, and adds water for wet grinding. The mass ratio of the silty sand, abrasive, ball milling media and water obtained by soaking is controlled to be 1:0.10:1.3:0.8, the ball milling speed is 10r / min, and the ball milling time is 3h. After the ball milling screening is completed, shield silt sand is obtained.

[0032] Example 5: A method for preparing high-content shield silt sand concrete disclosed in the present invention, which is different from Example 1 in that, in S1, the shield silt sand is processed in advance as follows: S11 is configured with modifiers, additives, and abrasives; wherein, The modifier is composed of the following raw materials in parts by weight: 15 parts of bis-PEG-18 methyl ether dimethyl silane, 8 parts of aluminum lactate, 6 parts of attapulgite, 10 parts of triethoxycaprylylsilane, and water is added to 100 parts; The auxiliary agent is composed of the following raw materials in parts by weight: 30 parts of sodium carboxymethyl cellulose, 40 parts of hydroxyethyl urea, and water is added to 100 parts; The abrasive material is composed of the following raw materials in parts by weight: 45 parts of hydrated silica, 35 parts of talc, and 32 parts of microcrystalline cellulose; S12: soaking silty sand with mud content ≤30% and water content ≤18% in the modifier obtained in S11 until saturated with water, stirring continuously during the soaking and dropping the additive obtained in S11, controlling the volume ratio of silty sand, modifier and additive to be 1:15:1.5, the height difference between the additive dropping port and the liquid level of the modifier to be 0.3m, and the soaking time to be 5h; S13 mixes the silty sand obtained in S12 and the abrasive obtained in S11, uses ceramic balls as ball milling media, and adds water for wet grinding. The mass ratio of the silty sand, abrasive, ball milling media and water obtained by soaking is controlled to be 1:0.12:1.5:1.0, the ball milling speed is 10r / min, and the ball milling time is 3h. After the ball milling screening is completed, shield silt sand is obtained.

[0033] Comparative Example 1 is a method for preparing high-content shield silt sand concrete disclosed in the present invention. The difference from Example 3 is that the replacement rate of shield silt sand for machine-made sand is 0%.

[0034] Comparative Example 2 is a method for preparing high-content shield silt sand concrete disclosed in the present invention. The difference from Example 3 is that the replacement rate of shield silt sand for machine-made sand is 5%.

[0035] Comparative Example 3 is a method for preparing high-content shield silt sand concrete disclosed in the present invention. The difference from Example 3 is that the replacement rate of shield silt sand for machine-made sand is 10%.

[0036] Comparative Example 4 is a method for preparing high-dosage shield silt sand concrete disclosed in the present invention, which is different from Example 3 in that no modifier is used.

[0037] Comparative Example 5 is a method for preparing high-dosage shield silt sand concrete disclosed in the present invention, which is different from Example 3 in that no additive is used.

[0038] Comparative Example 6: A method for preparing high-dosage shield silt sand concrete disclosed in the present invention, which is different from Example 3 in that no abrasive is used.

[0039] Test example 1: First, the C35 concrete of Examples 3 to 5 and Comparative Examples 1 to 6 was added to the test mold in layers and portions, vibrated for 1.5 to 2.5 minutes, demolded after 12 to 24 hours of vibration molding, and cured to obtain a concrete specimen. The specimen was intact and had no defects in appearance. Then, the performance of the concrete specimen was tested according to the slump method and GB / T50081-2019, and the test results are shown in Table 1.

[0040] Table 1 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Slump / mm 221 230 210 121 151 138 128 180 142 Expansion / mm 580 590 560 455 465 470 460 510 480 Liquidity good good good Difference good good Difference good good Cohesiveness good good good good good good Difference good Difference Water retention good good good Difference good good good good good Density / kg / m³ 2296.0 / / 2303.4 2301.6 2302.6 / / / 28d compressive strength 41.4±2.1 41.2±1.5 43.5±2.3 22.4±2.0 30.6±3.3 30.9±2.5 32.8±2.8 36.4±2.7 25.6±2.5 From Table 1, we can see that 1. The present invention screens the components of the slurry and aggregate in the concrete in advance, and combines the apparent density of these components, the average slurry thickness of the aggregate, the minimum slurry volume and other technical parameters to optimize the sand ratio of the aggregate and the replacement rate of the shield silt sand for the machine-made sand, and then determines the amount and proportion of each component in the concrete raw material. It is most appropriate to add 114-120kg / m³ of shield silt sand to the concrete. The C35 concrete prepared in this way not only has mechanical properties and working performance, but also other properties that meet the requirements of standard specifications, and also realizes efficient utilization of silt sand resources; 2. The present invention sequentially performs soaking modification and ball milling modification treatment on silty sand. First, during the soaking process, bis-PEG-18 methyl ether dimethyl silane is a water-soluble silicone wax, which is filled in the cracks and sharp surfaces of the silty sand through aluminum lactate and magnesia clay, which is beneficial to improving the surface morphology of the silty sand, and is supplemented with triethoxyoctylsilane to significantly improve the surface finish of the silty sand and the bonding strength between the machine-made sand particles, reduce the negative impact on the slurry and admixtures, and thus achieve the improvement of working performance. In the ball milling process, hydrated silica, talc and microcrystalline cellulose are used for ball milling dispersion, further optimizing the gradation of fine particles in the silty sand, and improving the cross-sectional adhesion between the silty sand and the slurry, which is conducive to improving the mechanical properties of concrete; 3. The shield silt sand used in the present invention is industrial waste generated during the shield construction process, which has the dual advantages of environmental protection and resource recycling. By using the shield silt sand as one of the components of concrete, it not only reduces the accumulation of waste and environmental pollution, but also reduces the production cost of concrete, achieving a win-win situation of economic benefits and environmental benefits; 4. The preparation method of the present invention has simple steps, does not require complicated equipment and other raw materials, and ensures the uniformity and stability of the concrete. During the mixing process, the addition of admixtures further improves the fluidity, cohesiveness and water retention of the concrete, so that the concrete has better working performance during the construction process.

[0041] 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, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing high-volume shield silt sand concrete, characterized in that: The following steps are included: S1 preparing the raw materials of the concrete, the raw materials of the concrete including 203-233 kg / m³ cement, 156-166 kg / m³ admixture, 1730-1766 kg / m³ aggregate, 165-180 kg / m³ water, and 5.5-6.3 kg / m³ admixture, the sand ratio of the aggregate is 42-45%, and the replacement rate of shield silt sand in the aggregate to machine-made sand is 14-17%; S2 first adds gravel in the aggregate and stirs for 1-2 minutes, then adds sand in the aggregate and stirs for 1-2 minutes, then adds cement and admixtures into the mixer and stirs for 1-2 minutes, finally adds the remaining raw materials of the concrete by the same mixing method, wet mixes for 2-3 minutes, until the mixture is evenly dispersed, to obtain C35 concrete.

2. The method for preparing high-content shield silt sand concrete according to claim 1, characterized in that: In the S1, the aggregate includes 639-647 kg / m³ machine-made sand, 114-120 kg / m³ shield silt sand, 755-775 kg / m³ 10-25 mm crushed stone, and 194-252 kg / m³ 5-10 mm crushed stone.

3. The method for preparing high-content shield silt sand concrete according to claim 1, characterized in that: In the S1, the admixture includes 78-88 kg / m³ fly ash and 75-80 kg / m³ slag powder.

4. The method for preparing high-content shield silt sand concrete according to claim 1, characterized in that: In the S1, silty sand with a mud content of ≤30% and a water content of ≤18% is soaked in a modifier until it is saturated with water, and stirring is continued during the soaking period and an auxiliary agent is added dropwise. After the soaking is completed, the sand is filtered and dried, and then mixed with abrasive, ball milled and sieved to obtain the shield silt sand; wherein the modifier is composed of the following raw materials in parts by weight: 10 to 15 parts of bis-PEG-18 methyl ether dimethyl silane, 5 to 8 parts of aluminum lactate, 4 to 6 parts of attapulgite, 5 to 10 parts of triethoxyoctylsilane, and water is added to 100 parts.

5. The method for preparing high-content shield silt sand concrete according to claim 4, characterized in that: During the soaking process, the auxiliary agent is composed of the following raw materials in parts by weight: 20-30 parts of sodium carboxymethyl cellulose, 30-40 parts of hydroxyethyl urea, and water is added to 100 parts.

6. The method for preparing high-content shield silt sand concrete according to claim 5, characterized in that: During the soaking process, the volume ratio of silty sand, modifier and additive is controlled to be 1:5-15:0.5-1.

5.

7. The method for preparing high-content shield silt sand concrete according to claim 6, characterized in that: During the soaking process, the soaking time is controlled to be 4-6 hours and the stirring speed is controlled to be 1000-1250 r / min.

8. The method for preparing high-content shield silt sand concrete according to claim 4, characterized in that: During the ball milling process, the abrasive is composed of the following raw materials in parts by weight: 38-45 parts of hydrated silica, 30-35 parts of talc, and 20-32 parts of microcrystalline cellulose.

9. The method for preparing high-content shield silt sand concrete according to claim 8, characterized in that: In the ball milling process, ceramic balls are used as ball milling media, and water is added for wet milling, and the mass ratio of silty sand, abrasive, ball milling media and water obtained by soaking is controlled to be 1:0.08~0.12:0.5~1.5:0.5~1.

0.

10. The method for preparing high-content shield silt sand concrete according to claim 9, characterized in that: During the ball milling process, the ball milling speed is controlled to be 10-15 r / min, and the ball milling time is 2-3 h.