Water filtration concrete suitable for seepage channel water intake structure of sediment-rich river and preparation method thereof

Abstract

The present invention discloses a water filtration concrete suitable for a water intake structure of a seepage channel in a river with a lot of sediment and a preparation method thereof. 3 The filter concrete comprises the following components: 350-450kg of cementitious material, 700-950kg of coarse aggregate, 600-800kg of fine aggregate, 95-135kg of water, 5-7kg of water-reducing agent, and 1-2kg of modified material, with a water-cement ratio of 0.26-0.32. The resulting filter concrete not only enables the infiltration channel intake structure to meet the filtration requirements of sediment-laden rivers, but also boasts high filtration capacity and a large water intake, meeting the water intake requirements of engineering projects. It also provides excellent anti-clogging properties, thereby increasing the service life of the infiltration channel intake system. Furthermore, using locally sourced aggregates to prepare the filter concrete not only addresses the shortage of natural aggregates in plain areas but also expands the resource utilization of sediment, contributing to the ecological protection and high-quality development of sediment-laden river basins.

Description

Technical Field

[0001] The invention belongs to the technical field of water conservancy projects, and in particular relates to a water filtration concrete suitable for a water intake structure of an infiltration channel in a silt-laden river and a preparation method thereof. Background Art

[0002] Construction water supply systems are one of the earliest components of a water conservancy project and a key technical challenge that constrains its cost and operation. Construction water supply systems impose strict regulations and restrictions on water quality, particularly sediment content. However, sediment-laden rivers often have high sediment content, fine particles, and a high concentration of impurities. Therefore, effective and long-term treatment of these sediment-laden rivers is crucial to the success of construction water extraction.

[0003] Currently, infiltration canal water extraction is a common water extraction method in water conservancy projects, and the permeability of the infiltration canal structure is crucial for water extraction. In engineering, concrete with a low permeability coefficient is often used as the filter layer of the infiltration canal structure to improve sediment filtration. However, on the one hand, the permeability coefficient of the concrete filter layer in the existing technology is low, resulting in poor water filtration efficiency and failure to meet the construction water intake requirements, which can easily lead to insufficient construction water supply. On the other hand, the concrete filter layer is susceptible to sedimentation, meaning that the pores are easily clogged by sediment, which significantly reduces the water filtration performance and service life of the infiltration canal filtration system.

[0004] Improving the water filtration performance of concrete filter layers and effectively reducing silt accumulation and blockage are key to the success of water extraction from infiltration channels along sediment-laden rivers. A new water-filtration concrete with a specific mix ratio has been proposed. Unlike conventional concrete, this concrete has a "skeleton-pore" structure, with a high proportion of coarse aggregate, typically single-size or discontinuously graded, and a low or no proportion of fine aggregate. Therefore, the coarse aggregate can be considered to form a skeleton structure bonded together by the slurry coating the surface, with the remaining space being a pore structure.

[0005] Currently, permeable concrete is primarily used in municipal engineering, road construction, underground construction, and various new sports venues. However, there are no precedents or research results for using permeable concrete for sediment filtration. Permeable concrete has large pore sizes, and its filtration diameter primarily targets particles larger than 0.05 mm, which cannot meet the requirements for filtering sediment below 0.05 mm in sediment-laden rivers. Data shows that approximately 80% of the sediment that needs to be filtered in sediment-laden rivers has a particle size of less than 0.05 mm. Existing permeable concrete cannot effectively filter sediment particles below 0.05 mm, limiting its application in infiltration channel water intake structures in sediment-laden rivers. Therefore, the key to achieving infiltration channel water intake in sediment-laden rivers lies in determining the concrete mix ratio that can effectively filter fine sediment particles, particularly those below 0.05 mm, in sediment-laden rivers. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a water-filtration concrete suitable for the seepage channel water intake structure of a river with a lot of sediment and a preparation method thereof. The prepared water-filtration concrete can not only enable the seepage channel water intake structure to meet the requirements of the filtration effect of a river with a lot of sediment, but also has a high filtration capacity and a large water intake, which can meet the requirements of water intake for engineering construction, but also enable the seepage channel water intake structure to have better anti-clogging performance, thereby increasing the service life of the seepage channel water intake system. In addition, the use of local materials to prepare aggregates for water-filtration concrete not only solves the problem of shortage of natural aggregates in plain areas, but also expands the resource utilization of sediment, which is conducive to the ecological protection and high-quality development of river basins with a lot of sediment.

[0007] The water filtration concrete of the present invention is suitable for the water intake structure of the seepage channel of the river with a lot of sediment, 1m 3 The drainage concrete includes the following components: 350-450 kg of cementitious material, 700-950 kg of coarse aggregate, 600-800 kg of fine aggregate, 95-135 kg of water, 5-7 kg of water reducing agent, 1-2 kg of modifying material, and water-cement ratio = 0.26-0.32.

[0008] Optionally, the cementitious materials comprise, by mass percentage, 65%-75% cement, 20%-25% fly ash, and 5%-10% kaolin. The cement is ordinary Portland cement (PO42.5), the fly ash is Grade II fly ash, and the kaolin is 325-mesh coal-based metakaolin. At a microscopic level, the microaggregate effect of the fly ash and kaolin optimizes the particle size distribution of the cementitious material system. The pozzolanic effect of the fly ash and kaolin increases the secondary hydration products of the cementitious material system, refining the pore size of the concrete. The combined "superposition effect" of the two further optimizes the concrete's pore structure. At a macroscopic level, the addition of fly ash and kaolin improves the mechanical properties and impact and wear resistance of concrete. Furthermore, it effectively prevents segregation, sinking, and pore blockage in the concrete mix, improving the concrete's water filtration capacity and extending the service life of the infiltration channel water intake structure.

[0009] Optionally, the coarse aggregate and fine aggregate are artificially prepared sediment aggregates, the particle size of the coarse aggregate is 5mm-10mm, and the fine aggregate is composed of two particle sizes: 1.25mm-2.5mm and 2.5mm-5mm, and the mass ratio of 1.25mm-2.5mm to 2.5mm-5mm particle size aggregates is 3:2.

[0010] The coarse aggregate acts as a framework in the drainage concrete, ensuring high porosity and permeability while maintaining the concrete's mechanical properties. Unlike permeable concrete, the drainage concrete of this invention contains a significant amount of fine aggregate, accounting for 40%-50% of the total aggregate mass. This significantly reduces the number of macropores in the drainage concrete and refines the diameter of the micropores, enhancing its ability to filter sediment particles under 0.05mm in diameter and ensuring effective water extraction from the infiltration channel structure.

[0011] Optionally, 1m 3 The sediment aggregate includes: 200kg cement, 100kg slag powder, 200kg fly ash, 40kg fiber, 5.5kg water reducer, 200kg alkali activator, 125kg water, and 1350kg sediment.

[0012] The sediment aggregate is made of cement, slag powder and fly ash as binder, fiber as reinforcement, water reducer and alkali activator as regulator, and water is added to mix with the sediment and stirred evenly; it is formed by secondary short vibration to prepare 150mm cubic specimens, and subjected to standard curing in a curing box. After curing for 28 days, the mold is removed and crushed into aggregate with a particle size of 1.25mm-10mm on a crusher; after screening and shaping, it is formed into coarse aggregate and fine aggregate of corresponding grade.

[0013] The silt aggregate prepared by the mass-based components proposed in the present invention has better compressive strength and cylinder compressive strength, and can also effectively reduce interface problems, thereby improving the mechanical properties and durability of drainage concrete. The cement is ordinary Portland cement (PO42.5), and the fineness of the slag powder is 4000cm 2 / g, the fly ash is Class II fly ash, the fiber is alkali-resistant glass chopped fiber, the water reducer is a naphthalene-based high-efficiency water reducer, the alkali activator is water glass with a modulus of 1.5-4 and a solid content of 20%-40%, the median particle size (D50) of the sediment is not greater than 200μm, and the SiO2 content is not less than 60%.

[0014] Optionally, the water reducer is a naphthalene-based high-efficiency water reducer with a pH of 8±1, a water reduction rate of 15%-25%, and a water bleeding rate ratio of ≤40%. When added to a concrete system, the naphthalene-based high-efficiency water reducer is adsorbed on the surface of the cementitious material particles. After the water reducer molecules dissolve, some additional water reducer molecules are adsorbed on the resulting hydration products, slowing the transformation of the hydration products from an amorphous gel to a crystalline state. As hydration continues, the water reducer molecules cause the crystals to grow larger, thereby reducing the total porosity and the number of macropores in the concrete and improving the concrete's pore structure.

[0015] Optionally, the modified material is a composite admixture of a surfactant and a dispersant, wherein the modified material comprises, by mass percentage, 85%-90% of the surfactant and 10%-15% of the dispersant.

[0016] Optionally, the surfactant is composed of sodium lauryl sulfate and hexadecyl sulfobetaine in a mass ratio of 5:3 to 5:4; the dispersant is composed of a styrene-acrylic emulsion and modified talc particles in a mass ratio of 2:3 to 2:5. The components of these modified materials work synergistically to effectively prevent concrete from settling and pore clogging, optimize the concrete's pore structure, and enhance its ability to filter sediment. They also effectively prevent sediment from adhering to pores, improving the concrete's anti-clogging properties.

[0017] The hexadecyl sulfobetaine is a zwitterionic surfactant, and sodium lauryl sulfate is an anionic surfactant. Their combined system exhibits significant synergistic effects. The mechanism of this synergistic effect is due to electrostatic attraction between the positive charge of the hydrophilic group of hexadecyl sulfobetaine and the negative charge of the hydrophilic group of sodium lauryl sulfate. This electrostatic attraction primarily produces competitive adsorption at the interface, enhancing the surface activity of the combined system and promoting the formation of a tighter adsorption film at the gas-liquid interface.

[0018] The styrene-acrylic emulsion is prepared using a monomer drop polymerization method, with styrene and butyl acrylate as polymerizable monomers and a small-molecule organosilicon and vinyl macromolecular organosilicon prepolymer emulsion as grafted organosilicon. The talc-modified particles are surface-modified with a titanate coupling agent. This surface modification chemically bonds the alkoxy groups in the titanate coupling agent with the inorganic powder surface, forming an organic active monolayer at the interface between the inorganic and organic materials. The dispersant is a mixture of the styrene-acrylic emulsion and the talc-modified particles. The principle is that the styrene-acrylic emulsion primarily disperses the concrete slurry, while the talc-modified particles physically disperse and fill the concrete pores, preventing aggregation of the cementitious material particles. The combined action of the two ensures stable settlement and uniform dispersion of the concrete slurry, optimizing its pore structure.

[0019] The method for preparing the water filter concrete suitable for the water intake structure of the seepage channel of a river with a lot of sediment of the present invention is characterized by comprising the following steps:

[0020] Step (1): weighing the raw materials according to the mix ratio of the drainage concrete;

[0021] Step (2): Take 5%-10% water, add the water reducer into the water, and stir in a stirrer at a speed not exceeding 100 r / min for at least 30 seconds;

[0022] Step (3): taking 10%-20% water, adding sodium lauryl sulfate and hexadecyl sulfobetaine as surfactants to the water in sequence, and stirring in a stirrer at a speed not exceeding 200 r / min for at least 60 seconds;

[0023] Step (4): adding the styrene-acrylic emulsion and the talc modified particles in the dispersant to the surfactant solution of step (3) in sequence, and stirring in a stirrer at a speed not exceeding 150 r / min for at least 30 seconds;

[0024] Step (5): Add the cementitious material, coarse aggregate and fine aggregate into the forced mixer in sequence and mix for at least 60 seconds;

[0025] Step (6): Add the remaining water to the mixture of step (5) and stir for at least 120 seconds;

[0026] Step (7): The water-reducing agent solution of step (2) and the modified material solution of step (4) are sequentially added to the slurry of step (6), and stirred for at least 120 seconds until the mixture is uniformly mixed.

[0027] All of the above steps are performed under normal pressure. This preparation method can improve the uniformity of the drainage concrete paste at the aggregate interface and enhance the bond strength between the aggregate and the paste, thereby maximizing the mechanical properties and durability of the drainage concrete and thereby increasing the service life of the infiltration channel filtration system.

[0028] The beneficial effects of the present invention are:

[0029] (1) Compared with the permeable concrete technology in the prior art, the composition design of the permeable concrete material containing no or a small amount of fine aggregate is changed. The water-filtration concrete of the present invention contains a large amount of fine aggregate components, which reduces the number of macropores in the concrete, refines the pore diameter, enhances the ability to filter sediment with a particle size of less than 0.05 mm, and ensures the water filtering effect of the infiltration channel water intake structure.

[0030] (2) Compared with ordinary concrete technology, the water filtration concrete material of the present invention contains modified materials. The components in the modified materials cooperate with each other and work synergistically, which can effectively prevent the concrete from settling and clogging, optimize the pore structure of the concrete, and effectively prevent sediment from adhering to the pores, thereby improving the anti-clogging performance of the concrete pores and extending the service life of the seepage channel water intake structure.

[0031] (3) The drainage concrete of the present invention uses artificially prepared sediment aggregate to replace natural aggregate, and uses sediment from sediment-rich rivers to prepare aggregate, reducing the consumption of natural stone. This not only solves the problem of shortage of natural aggregate in plain areas, but also provides a new way to utilize sediment as a resource.

[0032] (4) The preparation method of the water-filtration concrete of the present invention can not only improve the mechanical properties and durability of the water-filtration concrete, and achieve the purpose of large-flow and long-term water extraction in sediment-rich rivers, but also the preparation process of the water-filtration concrete does not require changing the original equipment system or adding new equipment, and is simple and easy. DETAILED DESCRIPTION

[0033] The water filter concrete of the present invention, which is suitable for the water intake structure of the seepage channel of the river with a lot of sediment, is composed of the following components by mass: 350-450 kg / m 3 , coarse aggregate 700-950kg / m 3 , fine aggregate 600-800kg / m 3 , water 95-135kg / m 3 , water reducing agent 5-7kg / m 3 , modified material 1-2kg / m 3 , water-cement ratio = 0.26-0.32.

[0034] The mass percentages of the components of the cementitious material are: cement 65%-75%, fly ash 20%-25%, and kaolin 5%-10%.

[0035] Coarse aggregate and fine aggregate are artificially prepared silt aggregate. The particle size of coarse aggregate is 5mm-10mm. The fine aggregate is composed of two particle sizes, 1.25mm-2.5mm and 2.5mm-5mm. The mass ratio of 1.25mm-2.5mm to 2.5mm-5mm particle size aggregate is 3:2.

[0036] The sediment aggregate is composed of the following components by mass: cement 200kg / m 3 , slag powder 100kg / m 3 , fly ash 200kg / m 3 , fiber 40kg / m 3 , water reducing agent 5.5kg / m 3 , alkali activator 200kg / m 3 , water 125kg / m 3 , sediment 1350kg / m 3 .

[0037] The water reducer is a naphthalene-based high-efficiency water reducer with a pH value of 8±1, a water reduction rate of 15%-25%, and a water bleeding rate ratio of ≤40%.

[0038] The modified material comprises 85%-90% of a surfactant and 10%-15% of a dispersant in terms of mass percentage.

[0039] The surfactant is composed of sodium lauryl sulfate and hexadecyl sulfobetaine in a mass ratio of 5:3 to 5:4; the dispersant is composed of styrene-acrylic emulsion and talc modified particles in a mass ratio of 2:3 to 2:5.

[0040] Four examples and four comparative examples are used to compare and test the performance of the water-filtration concrete of the present application. The raw materials used for the water-filtration concrete of Examples 1-4 and the concrete of Comparative Examples 1-4 are as follows:

[0041] Cement: P·O42.5 cement produced by Zhengzhou Tianrui Cement Co., Ltd.

[0042] Fly ash: Grade II fly ash produced by Jiaozuo Danyang Mineral Powder Co., Ltd.

[0043] Kaolin: coal-bearing metakaolin produced by Shanxi Jufeng Kaolin Co., Ltd.;

[0044] Water reducer: FDN-C type naphthalene series high efficiency water reducer produced by Shandong Wanshan Chemical Co., Ltd.

[0045] Sodium dodecyl sulfate: SDS (analytical grade) produced by Sinopharm Chemical Reagent Co., Ltd.

[0046] Hexadecyl sulfobetaine: HDPS (purity > 99%) produced by J&K Chemical Reagent Co., Ltd.

[0047] Styrene acrylic emulsion: SAE produced by Mengtai Weiye Building Materials Co., Ltd.

[0048] Talc modified particles: SH-G100 talc produced by Hubei Xinsihai Chemical Co., Ltd.

[0049] Water: The test water is tap water, and its performance index test results are in line with the requirements of the "Specifications for Hydraulic Concrete Construction" (SL677-2014).

[0050] The sediment aggregate is made of cement, slag powder and fly ash as binder, fiber as reinforcement, water reducer and alkali activator as regulator, and water is added to mix with the sediment and stirred evenly; it is formed by secondary short vibration to prepare 150mm cubic specimens, and subjected to standard curing in a curing box. After curing for 28 days, the mold is removed and crushed into aggregate with a particle size of 1.25mm-10mm on a crusher; after screening and shaping, it is formed into coarse aggregate and fine aggregate of corresponding grade.

[0051] Example 1:

[0052] The water filter concrete of this embodiment, which is suitable for the water intake structure of the infiltration channel of a river with a lot of sediment, is composed of the following raw materials by mass: cement 230kg / m 3 , fly ash 90kg / m3 , kaolin 30kg / m 3 , coarse aggregate 750kg / m 3 , fine aggregate 700kg / m 3 , water 105kg / m 3 , water reducing agent 5kg / m 3 , modified material 1.6kg / m 3 Among them, the fine aggregate with a particle size of 1.25mm-2.5mm is 420kg / m 3 , 2.5mm-5mm particle size fine aggregate 280kg / m 3 .

[0053] The modified material is prepared by mixing the following raw materials in percentage by mass: 56.2% of sodium lauryl sulfate, 33.9% of hexadecyl sulfobetaine, 2.9% of styrene acrylic emulsion, and 7.0% of talc modified particles.

[0054] The preparation method of the water-filtration concrete of this embodiment comprises the following steps:

[0055] Step (1): weighing the raw materials according to the mix ratio of the drainage concrete;

[0056] Step (2): Take 5% of stirring water, add the water reducer into the water, and stir in a stirrer at a speed of 80 r / min for 40 s;

[0057] Step (3): taking 15% of stirring water, adding sodium lauryl sulfate and hexadecyl sulfobetaine in the surfactant into the water in sequence, and stirring in a stirrer at a speed of 150 r / min for 60 s;

[0058] Step (4): adding the styrene-acrylic emulsion and the talc modified particles in the dispersant to the surfactant solution of step (3) in sequence, and stirring in a stirrer at a speed of 100 r / min for 40 s;

[0059] Step (5): Add the cementitious material, coarse aggregate and fine aggregate into the forced mixer in sequence and stir for 60 seconds;

[0060] Step (6): add the remaining 80% of the stirring water to the mixture of step (5) and stir for 120 seconds;

[0061] Step (7): The water-reducing agent solution of step (2) and the modified material solution of step (4) are sequentially added to the slurry of step (6), and stirred for 120 seconds until the mixture is uniformly mixed.

[0062] All the above steps are performed under normal pressure.

[0063] Example 2:

[0064] The water filter concrete of this embodiment, which is suitable for the water intake structure of the infiltration channel of a river with a lot of sediment, is composed of the following raw materials by mass: cement 310kg / m 3 , fly ash 85kg / m 3 , kaolin 25kg / m 3 , coarse aggregate 750kg / m 3 , fine aggregate 650kg / m 3 , water 125kg / m 3 , water reducing agent 5.6kg / m 3 , modified material 1.9kg / m 3 Among them, the fine aggregate with a particle size of 1.25mm-2.5mm is 390kg / m 3 , 2.5mm-5mm particle size fine aggregate 260kg / m 3 .

[0065] The modified material is prepared by mixing the following raw materials in percentage by mass: 50.8% of sodium lauryl sulfate, 35.4% of hexadecyl sulfobetaine, 4.7% of styrene acrylic emulsion, and 9.1% of talc modified particles.

[0066] The preparation method of the drainage concrete described in Example 2 is the same as that in Example 1.

[0067] Example 3:

[0068] The water filter concrete of this embodiment, which is suitable for the water intake structure of the infiltration channel of a river with a lot of sediment, is composed of the following raw materials by mass: cement 300kg / m 3 , fly ash 80kg / m 3 , kaolin 20kg / m 3 , coarse aggregate 770kg / m 3 , fine aggregate 630kg / m 3 , water 120kg / m 3 , water reducing agent 5.5kg / m 3 , modified material 1.8kg / m 3 Among them, the fine aggregate with a particle size of 1.25mm-2.5mm is 378kg / m 3 , 2.5mm-5mm particle size fine aggregate 252kg / m 3 .

[0069] The modified material is prepared by mixing the following raw materials in percentage by mass: 53.8% of sodium lauryl sulfate, 32.5% of hexadecyl sulfobetaine, 4.1% of styrene acrylic emulsion, and 9.6% of talc modified particles.

[0070] The preparation method of the drainage concrete described in Example 3 is the same as that in Example 1.

[0071] Example 4:

[0072] The water filter concrete of this embodiment, which is suitable for the water intake structure of the infiltration channel of a river with a lot of sediment, is composed of the following raw materials by mass: cement 315kg / m 3 , fly ash 95kg / m 3 , kaolin 40kg / m 3 , coarse aggregate 900kg / m 3 , fine aggregate 670kg / m 3 , water 135kg / m 3 , water reducing agent 5.8kg / m 3 , modified material 2kg / m 3 Among them, the fine aggregate with a particle size of 1.25mm-2.5mm is 402kg / m 3 , 2.5mm-5mm particle size fine aggregate 268kg / m 3 .

[0073] The modified material is prepared by mixing the following raw materials in percentage by mass: 49.8% of sodium lauryl sulfate, 39.1% of hexadecyl sulfobetaine, 3.7% of styrene acrylic emulsion, and 7.4% of talc modified particles.

[0074] The preparation method of the drainage concrete described in Example 4 is the same as that in Example 1.

[0075] Comparative Example 1:

[0076] Compared with Example 1, the fine aggregate in Example 1 is replaced by coarse aggregate in this comparative example, that is, the permeable concrete technology is adopted in this comparative example, and the mass of the coarse aggregate is 1450 kg / m 3 , other compositions are the same as those in Example 1.

[0077] The preparation method of the concrete described in Comparative Example 1 is the same as that in Example 1.

[0078] Comparative Example 2:

[0079] Compared with Example 1, the modified material component in Example 1 is removed in this comparative example, that is, this comparative example adopts ordinary concrete technology, and the other components are the same as those in Example 1.

[0080] The method for preparing the concrete described in this comparative example comprises the following steps:

[0081] Step (1): weighing the raw materials according to the concrete mix ratio design;

[0082] Step (2): Take 5% of stirring water, add the water reducer into the water, and stir in a stirrer at a speed of 80 r / min for 40 s;

[0083] Step (3): Add cementitious materials (cement, fly ash and kaolin), coarse aggregate and fine aggregate into a forced mixer in sequence and mix for 60 seconds;

[0084] Step (4): add the remaining 95% of the stirring water to the mixture of step (3) and stir for 120 seconds;

[0085] Step (5): Add the water-reducing agent solution of step (2) to the slurry of step (4) and stir for 120 seconds until the mixture is uniform.

[0086] All the above steps are performed under normal pressure.

[0087] Comparative Example 3:

[0088] Compared with Example 1, this comparative example removes the surfactant sodium lauryl sulfate in the modified material of Example 1, and the other compositions are the same as those of Example 1.

[0089] The preparation method of the concrete described in Comparative Example 3 is the same as that in Example 1.

[0090] Comparative Example 4:

[0091] Compared with Example 1, the styrene acrylic emulsion as the dispersant in the modified material of Example 1 is removed in this comparative example, and the other compositions are the same as those of Example 1.

[0092] The preparation method of the concrete described in Comparative Example 4 is the same as that in Example 1.

[0093] The concrete described in Examples 1-4 and Comparative Examples 1-4 were tested for performance indicators according to the following standards or test methods:

[0094] (1) Mechanical properties: The compressive strength and flexural strength of concrete were tested in accordance with the Standard for Test Methods of Mechanical Properties of Ordinary Concrete (GB / T 50081);

[0095] (2) Porosity: The porosity of concrete is tested using the gravimetric method and the calculation formula is as follows;

[0096]

[0097] Where: P is the porosity of the concrete specimen, %; m1 is the mass of the specimen after saturation with water, g; m2 is the mass of the specimen after the air surface is dry, g; V is the volume of the specimen, mm 3 .

[0098] (3) Permeability coefficient: Referring to the test method in "Permeable Pavement Bricks and Permeable Pavement Slabs" (GB / T 25993), the permeability coefficient of concrete is tested using the constant water head method. The calculation formula is as follows;

[0099]

[0100] Where: K is the water permeability coefficient of concrete, mm / s; Q is the amount of water overflowed per unit time, mm 3 / s; A is the cross-sectional area of ​​concrete, mm 2 ; L is the thickness of concrete, mm; H is the head difference, mm.

[0101] (4) Wear resistance test: The wear resistance of concrete is characterized by the length of the wear pit, and the test is carried out according to the wear pit length method in the "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" (GB / T 50081).

[0102] (5) Water filtration test: The test was conducted using a self-developed concrete water filtration test device. A cylindrical specimen with a size of Φ100mm×100mm was placed in the test device, and the side walls between the specimen and the test device were sealed with wax. The average annual sediment content of the Yellow River water is 35kg per cubic meter, which is equivalent to 35g of Yellow River sand per 1000mL of water. 70g of Yellow River sand and 2000mL of water were weighed and mixed evenly as test filtration water. 1500mL of filtration water was added to the surface of the specimen, and then allowed to stand until no more water dripped downwards. The filtered water was poured into a mortar and dried in an electric oven at a constant temperature (105℃±2). The mass of the dried sediment was weighed on a balance. The sediment mass was used as the standard for judging the water filtration performance of concrete.

[0103] (6) Anti-clogging performance: Refer to the concrete anti-clogging performance test method in the patent application number CN 109437775 A, and evaluate the anti-clogging performance of concrete by permeability coefficient ratio = permeability coefficient after clogging / initial permeability coefficient.

[0104] The performance test results of concrete are shown in Table 1:

[0105] Table 1 Test results of concrete performance test

[0106]

[0107] From the performance test results of Examples 1-4, it can be seen that the mechanical properties, porosity, water permeability coefficient, and grinding pit length of the water filter concrete of the present invention, which is suitable for the seepage channel water intake structure of a silt-laden river, are controllable. When ensuring that the strength grade of the water filter concrete reaches C15 or above, its porosity is between 18.5% and 31.3%, and the grinding pit length is between 16.5mm and 20.6mm, that is, the water filter concrete of the present invention has excellent mechanical properties, permeability, and wear resistance. The water permeability coefficient of the water filter concrete is between 3.2mm / s and 4.7mm / s. From the perspective of engineering practice, the water permeability coefficient of the concrete is between 3.1mm / s and 7.2mm / s, which can meet the water consumption requirements of engineering construction. The filtration capacity of the water filter concrete of the present invention can meet the water consumption requirements of the seepage channel water intake structure for engineering construction.

[0108] The test results for the filtrate sediment content in Examples 1-4 indicate that the filtrate sediment content of the present invention after filtration ranges from 0.93 g to 1.81 g (i.e., 0.79 g / L to 1.54 g / L). This meets the requirements for mixing water for hydraulic concrete as specified in Table 5.6.2 of the "Specifications for Hydraulic Concrete Construction" (SL677), which stipulates that the insoluble matter content (sediment mass) in mixing water for reinforced concrete should be ≤ 2 g / L. The filtration performance of the present invention's filtrate concrete meets the water quality requirements for mixing water used in infiltration channel intake structures.

[0109] The permeability ratio test results for Examples 1-4 show that the permeability ratios of the water filter concrete of the present invention after filtration ranged from 82.1% to 89.2%. This indicates that the water filter concrete can reduce the adhesion of fine sediment particles in pores, thereby reducing pore blockage. In other words, the water filter concrete has excellent anti-silt clogging properties. Its application in infiltration channel intake structures in sediment-laden rivers can significantly extend the service life of these structures.

[0110] Comparative Example 1 utilizes permeable concrete technology. Compared to Example 1, the material composition design replaces fine aggregate with coarse aggregate, i.e., the material composition does not contain fine aggregate, while the other components remain the same. Performance test results for Example 1 and Comparative Example 1 indicate that the 28-day compressive strength of Comparative Example 1 is 28.5% lower than that of Example 1, reaching only 10.8 MPa, failing to meet the mechanical performance requirements for filtration concrete. The concrete material components of Comparative Example 1 do not contain fine aggregate, and the filtered water contains 5.96 g (4.19 g / L) of sediment, far exceeding the requirement of ≤2 g / L for insoluble matter in reinforced concrete mixing water in the "Specifications for Hydraulic Concrete Construction." This indicates that the filtration effect of Comparative Example 1 fails to meet the water quality requirements for construction mixing water in infiltration channel water intake structures.

[0111] Comparative Example 2 uses conventional concrete technology. Compared to Example 1, the modified material component is eliminated from the material composition design, while the other components remain the same. Performance test results for Example 1 and Comparative Example 2 show that the 28-day compressive strength of Comparative Example 2 is 36.4% lower than that of Example 1, reaching only 9.6 MPa, and the 28-day flexural strength is 34.5% lower than that of Example 1, reaching only 1.9 MPa. Both examples fail to meet the mechanical performance requirements for water filtration. The water permeability coefficient of Comparative Example 2 is 2.3 mm / s, which falls outside the range of 3.1 mm / s to 7.2 mm / s required for construction water use. This indicates that the filtration capacity of Comparative Example 2 cannot meet the construction water intake requirements of the infiltration channel water intake structure. The water permeability ratio of Comparative Example 2 is 44.3%, a significant decrease compared to Example 1. This indicates that Comparative Example 2 has poor anti-clogging performance. When treating sediment-laden river water, its water permeability coefficient will further decrease, failing to meet the designed filtration capacity and service life of the infiltration channel water intake structure.

[0112] Compared to Example 1, Comparative Example 3 modified the surfactant composition in the modified material formulation of the present invention, while maintaining the same other components. Performance test results for Example 1 and Comparative Example 3 indicate that the porosity of Comparative Example 3 is lower than that of Example 1, reaching 23.9%. Correspondingly, the water permeability coefficient is 31.9% lower than that of Example 1, reaching 3.2 mm / s. The water permeability coefficient ratio of Comparative Example 3 is only 55.4%, significantly lower than that of Example 1. During the treatment of sediment-laden river water, the water permeability coefficient will further decrease, and the infiltration channel water intake structure will not achieve its designed filtration capacity and service life.

[0113] Compared to Example 1, Comparative Example 4 modified the dispersant composition in the modified material ratio described in the present invention, while maintaining the same other components. Performance test results for Example 1 and Comparative Example 4 indicate that the porosity of Comparative Example 4 is lower than that of Example 1, reaching 22.4%. The water permeability coefficient of Comparative Example 4 is 2.9 mm / s, which falls outside the range of 3.1 mm / s to 7.2 mm / s required for construction water use. This indicates that the filtration capacity of Comparative Example 4 cannot meet the construction water intake requirements of the infiltration channel water intake structure. The water permeability coefficient ratio of Comparative Example 4 is only 59.9%, significantly lowering its anti-clogging performance compared to Example 1. During treatment of sediment-laden river water, the water permeability coefficient further decreased, and the infiltration channel water intake structure failed to achieve its designed filtration capacity and service life.

[0114] Analysis of the performance test results of Example 1 and Comparative Examples 1-4 indicates that altering the composition of the water-filtration concrete materials described herein, such as replacing fine aggregate with coarse aggregate, removing modified materials, or changing the mix ratio of modified materials, significantly reduces the mechanical and wear-resistant properties of the water-filtration concrete, increases the sediment content in the filtered water, and significantly reduces the concrete's anti-clogging performance. Specifically, after treating sediment-laden river water, its permeability coefficient and permeability coefficient ratio significantly decrease, and the permeability coefficient of the blocked concrete cannot meet the construction water intake requirements of the infiltration channel water intake structure. In particular, in Comparative Example 2, the removal of modified materials from the concrete's material composition significantly weakens its overall performance.

[0115] In summary, the filter concrete proposed in the present invention, suitable for use in seepage channel water intake structures in sediment-laden rivers, exhibits excellent overall performance. The synergistic effect of its components not only improves the concrete's compressive strength, flexural strength, and wear resistance, but also prevents pore clogging caused by slurry segregation and sinking during the concrete mixture molding process. This results in more uniform internal pores in the filter concrete, improving its ability to filter sediment with a particle size of 0.05 mm or less. Furthermore, the filter concrete described in the present invention prevents internal pores from being clogged by impurities such as sediment, thereby extending the service life of the seepage channel water intake structure. Only by formulating filter concrete within the material components and proportions specified in the present invention can its overall performance be significantly improved, meeting the filtering capacity and effectiveness of the seepage channel water intake structure and ensuring that the seepage channel water intake structure reaches its designed service life.

[0116] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A water filtration concrete suitable for the water intake structure of a seepage channel in a silt-rich river, characterized in that: 1m 3 Drainage concrete includes the following components: 350-450kg of cementitious material, 700-950kg of coarse aggregate, 600-800kg of fine aggregate, 95-135kg of water, 5-7kg of water reducer and 1-2kg of modified material, water-cement ratio = 0.26-0.32; The coarse aggregate and fine aggregate are artificially prepared sediment aggregates, the particle size of the coarse aggregate is 5mm-10mm, and the fine aggregate is composed of two particle sizes: 1.25mm-2.5mm and 2.5mm-5mm, and the mass ratio of 1.25mm-2.5mm to 2.5mm-5mm particle size aggregates is 3:2; The modified material comprises, by mass percentage, 85%-90% of a surfactant and 10%-15% of a dispersant; the surfactant is composed of sodium lauryl sulfate and hexadecyl sulfobetaine in a mass ratio of 5:3-5:4; the dispersant is composed of styrene-acrylic emulsion and talc modified particles in a mass ratio of 2:3-2:5; The sediment aggregate is made of cement, slag powder and fly ash as binder, fiber as reinforcement, water reducer and alkali activator as regulator, and water is added to mix with the sediment and stirred evenly; it is formed by secondary short vibration to prepare 150mm cubic specimens, and subjected to standard curing in a curing box. After curing for 28 days, the mold is removed and crushed into aggregate with a particle size of 1.25mm-10mm on a crusher; after screening and shaping, it is formed into coarse aggregate and fine aggregate of corresponding grade.

2. The water filtration concrete suitable for the water intake structure of the seepage channel of a silt-rich river according to claim 1, characterized in that: The gelling material comprises, by mass percentage, 65%-75% of cement, 20%-25% of fly ash and 5%-10% of kaolin.

3. The water filtration concrete suitable for the water intake structure of the seepage channel of a river with a lot of sediment according to claim 1 is characterized in that: 1m 3 The sediment aggregate includes: 200kg cement, 100kg slag powder, 200kg fly ash, 40kg fiber, 5.5kg water reducer, 200kg alkali activator, 125kg water and 1350kg sediment.

4. The water filtration concrete suitable for the water intake structure of the seepage channel of a river with a lot of sediment according to claim 1 is characterized in that: The water reducer is a naphthalene-based high-efficiency water reducer with a pH value of 8±1, a water reduction rate of 15%-25%, and a water bleeding rate ratio of ≤40%.

5. A method for preparing water-filtration concrete suitable for a water intake structure of a seepage channel in a silt-laden river according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step (1): weighing the raw materials according to the mix ratio of the drainage concrete; Step (2): Take 5%-10% water, add the water reducer into the water, and stir in a stirrer at a speed not exceeding 100 r / min for at least 30 seconds; Step (3): taking 10%-20% water, adding sodium lauryl sulfate and hexadecyl sulfobetaine as surfactants to the water in sequence, and stirring in a stirrer at a speed not exceeding 200 r / min for at least 60 seconds; Step (4): adding the styrene-acrylic emulsion and the talc modified particles in the dispersant to the surfactant solution of step (3) in sequence, and stirring in a stirrer at a speed not exceeding 150 r / min for at least 30 seconds; Step (5): Add the cementitious material, coarse aggregate and fine aggregate into the forced mixer in sequence and mix for at least 60 seconds; Step (6): Add the remaining water to the mixture of step (5) and stir for at least 120 seconds; Step (7): The water-reducing agent solution of step (2) and the modified material solution of step (4) are sequentially added to the slurry of step (6), and stirred for at least 120 seconds until the mixture is uniformly mixed.

Images