Material and method for improving anti-permeability and anti-cracking performance of municipal road rainwater ditch concrete box culvert

Abstract

The application provides a material and method for improving the anti-permeability and anti-cracking performance of a municipal road rainwater ditch concrete box culvert, and belongs to the technical field of building materials. The concrete loaded with siliceous powder particle fillers comprises concrete, siliceous powder particle fillers and slag, and is mixed with cement, coarse aggregate and high-performance anti-cracking waterproof agent to form a concrete base surface. Polyurethane waterproof paint is selected as a waterproof layer on the concrete base surface. The construction method comprises the following steps: site cleaning; excavation and construction of drainage; optimization of the mixing proportion of concrete; enhanced vibration; reduction of concrete porosity; layered construction; overall chiseling treatment of the construction joint surface; ensuring the cleanliness and flatness of the concrete base surface; creating a suitable curing environment, strengthening the curing of the concrete; and optimization of the waterproof layer material. The material and method provided by the application can improve the anti-permeability of the concrete, and make it more suitable for the construction of box culverts.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, and in particular relates to a material and method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains. Background Technology

[0002] A box culvert is a large-scale hydraulic engineering structure, typically used in culverts and similar applications. It can be used in drainage systems to help drain surface water and prevent flooding, or as a passageway to facilitate the passage of people and vehicles. In some cases, box culverts can be used as bridges, such as when crossing ditches or rivers. A box culvert can also be considered a simple tunnel, helping travelers navigate through obstacles.

[0003] With the widespread use of concrete box culverts, some inherent problems have gradually emerged, the most obvious being cracking. Box culverts are particularly sensitive to cracks; their presence not only affects aesthetics but also threatens their safety. Cracks allow corrosive media to enter the structure, corroding the reinforcing steel and accelerating its corrosion, thus reducing the structure's service life. Once cracks appear in a concrete box culvert, leakage is likely to occur, adversely affecting urban road traffic and impacting driving safety.

[0004] Impermeability is an important aspect of concrete durability, primarily depending on the porosity, pore size, and pore characteristics within the concrete. There are generally two technical approaches to improving concrete impermeability: one is to use a third medium to prevent the permeating substance from contacting the concrete; the other is to improve the concrete's own density.

[0005] The presence of tiny pores in cement paste that cannot be completely sealed leads to a deterioration in the impermeability and frost resistance of concrete. Existing main measures to improve the impermeability and frost resistance of concrete have not been very effective. Therefore, there is an urgent need for a method that can improve the impermeability of concrete, making it more suitable for the construction of box culverts. Summary of the Invention

[0006] This invention provides a material and method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains, in order to solve the problems mentioned in the background art.

[0007] To solve the above problems, the present invention adopts the following technical solution: On one hand, the present invention provides a material for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road rainwater drainage ditches. The material uses concrete with silica powder particles as filler. The concrete with silica powder particles as filler includes concrete, silica powder particles as filler, and slag. The concrete with silica powder particles as filler is mixed with cement, coarse aggregate, and high-performance crack-resistant and waterproofing agent to form a concrete base surface. A polyurethane waterproof coating is used as a waterproof layer on the concrete base surface.

[0008] Furthermore, in the concrete, the ratio of cement: coarse aggregate: crack-resistant and waterproofing agent: modified manufactured sand: granular filler containing silica powder: slag is 50: 95~105: 1.15~1.25: 70~75: 7~10: 10~15.

[0009] On the other hand, the present invention also provides a method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains, specifically including the following steps: S1: Site clearing includes vegetation clearing and topsoil removal; S2: Excavation and drainage operations are carried out to remove seepage water, rainwater runoff, and construction wastewater from the trench. S3: Optimize the concrete mix proportion by incorporating particulate filler containing the silica powder, slag, and high-performance crack-resistant and waterproofing agent, and adjust the concrete mix design. S4: Combine with high-flow concrete, strengthen vibration and reduce concrete porosity; S5: Use a layered continuous pouring method, control the construction sequence of each layer, and control the construction height of each layer; S6: The construction joint surface is fully roughened to further enhance its seepage prevention ability; S7: Ensure the concrete base surface is clean, flat, free of stains and debris, and can adhere tightly to the waterproof layer; S8: Create a suitable curing environment and strengthen concrete curing; S9: Optimize waterproof layer materials.

[0010] Furthermore, in S2, the drainage operation adopts the method of open ditch drainage to lower the groundwater level. A sump is set up near the inspection well, and water is pumped to a newly built three-stage sedimentation tank on the outside, and then discharged into the local sewage pipeline to prevent the ditch from being affected.

[0011] Furthermore, in S3, during actual construction, taking into account the climate and hydrological characteristics of the construction area, and with the goal of controlling the internal temperature stress of the concrete, the optimal mix design and construction scheme are proposed by adopting the theory and numerical analysis of grout film thickness and combining it with field tests.

[0012] Furthermore, in S4, ready-mixed concrete with characteristics of slow setting, early strength, and high fluidity is selected. The shrinkage compensation concrete method is adopted to compensate for the shrinkage stress caused by the early hydration heat of cement. An immersion tamping device is used to vibrate the concrete. In areas with dense reinforcement, a φ32 small tamping device is used, and a dedicated person is assigned to tamp the concrete to ensure the quality of concrete pouring.

[0013] Furthermore, in S5, the layer thickness shall not be less than 20cm and not more than 50cm. Concrete pouring shall be carried out continuously. If an interruption is necessary, the interruption time shall be shortened as much as possible, and the next layer of concrete shall be poured before the previous layer of concrete has initially set.

[0014] Furthermore, in S8, the concrete curing process involves spraying and installing spray pipes to identify areas with high temperature stress and accordingly install electronic thermometers for monitoring.

[0015] Furthermore, in S9, the waterproof layer material is selected as polyurethane waterproof coating. The polyurethane coating is a single-component environmentally friendly waterproof coating that is applied in a liquid state, with imported polyurethane prepolymer as the basic component.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes concrete filled with silica powder particles. These particles expand upon contact with water, filling the pores in the concrete and blocking seepage pathways, thus achieving an anti-seepage effect. Furthermore, the silica powder overflows into the concrete, filling the voids and making the material structure denser, further blocking potential seepage pathways. The addition of slag powder reduces the water-cement ratio of the concrete, decreasing bleeding and increasing its fluidity, workability, and pumpability. It also reduces calcium hydroxide in the concrete, making the structure denser and improving its durability. Finally, it improves the thermal conductivity of the concrete, reducing thermal expansion and contraction, thereby further reducing shrinkage cracks.

[0017] 2. This invention employs high-flowability concrete, strong vibration, and dynamic temperature control measures to ensure concrete construction quality, guaranteeing that the concrete is free of voids and dense; it creates a suitable curing environment, improves construction conditions, enhances project quality, and improves the seepage resistance of the box culvert.

[0018] 3. This invention uses polyurethane waterproof coating as the waterproof layer on concrete substrates. It can be directly applied to various substrates, whether damp or dry, and has strong adhesion to the substrate. It cures upon contact with moisture in the air, forming a strong, tough, seamless, integral waterproof membrane on the substrate surface. It can be directly applied to various substrates, whether damp or dry, and has strong adhesion to the substrate. The polymer substances in the coating can penetrate into the micro-cracks of the substrate, exhibiting strong conformability. It has good weather resistance, does not flow at high temperatures, and does not crack at low temperatures. It has excellent anti-aging properties, and is resistant to oil, abrasion, ozone, and acid and alkali corrosion. The membrane is dense, the waterproof layer is intact, without cracks, pinholes, or bubbles, and has a low water vapor permeability coefficient, providing both waterproof and air-barrier functions. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. The accompanying drawings described below are example diagrams of the novel radio frequency front-end receiving surface acoustic wave filter module described above. Obviously, the accompanying drawings described below are merely exemplary. For those skilled in the art, other embodiment drawings can be derived from the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of impermeable concrete; Figure 2 This is a schematic diagram of a polyurethane waterproof coating layer. Detailed Implementation

[0021] Exemplary embodiments of the present patent will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present patent are shown in the drawings, it should be understood that the present patent can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present patent and to fully convey the scope of the present patent to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described in the present patent can be combined with each other. The present patent will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] like Figure 1-2As shown, this invention provides a material for improving the seepage resistance and crack prevention performance of concrete box culverts in municipal road storm drains. It utilizes concrete filled with silica powder particles, comprising concrete, silica powder particles, and slag. The particles expand upon contact with water, filling the pores in the concrete and blocking seepage pathways, thus achieving an anti-seepage effect. The silica powder overflows into the concrete, filling the voids and making the material structure denser, further blocking potential seepage pathways. The addition of slag powder reduces the water-cement ratio of the concrete, decreasing bleeding and increasing its fluidity, workability, and pumpability. It also reduces calcium hydroxide in the concrete, making the structure denser and improving its durability. Furthermore, it improves the thermal conductivity of the concrete, reducing thermal expansion and contraction, thereby further reducing shrinkage cracks.

[0023] Concrete containing silica powder particles is mixed with cement, coarse aggregate, and a high-performance crack-resistant and waterproofing agent to form a concrete base. Specifically, the ratio of cement:coarse aggregate:crack-resistant and waterproofing agent:modified manufactured sand:silica powder-containing particle filler:slag = 50:95~105:1.15~1.25:70~75:7~10:10~15. A polyurethane waterproof coating is used as a waterproof layer on the concrete base. Figure 2 As shown, polyurethane waterproof coating is used as a waterproof layer on concrete substrates. It can be directly applied to various substrates, whether damp or dry, and has strong adhesion to the substrate. After contact with moisture in the air, it cures, forming a strong, tough, seamless, integral waterproof membrane on the substrate surface.

[0024] This invention also provides a method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains, specifically including the following steps: S1: Site clearing includes vegetation clearing and topsoil removal; S2: Excavation and drainage operations are carried out to remove seepage water, rainwater runoff, and construction wastewater from the trench. S3: Optimize the concrete mix proportions by incorporating granular fillers containing silica powder, slag, and high-performance crack-resistant and waterproofing agents, and adjust the concrete mix design. S4: Combine with high-flow concrete, strengthen vibration and reduce concrete porosity; S5: Use a layered continuous pouring method, control the construction sequence of each layer, and control the construction height of each layer; S6: The construction joint surface is fully roughened to further enhance its seepage prevention ability; S7: Ensure the concrete base surface is clean, flat, free of stains and debris, and can adhere tightly to the waterproof layer; S8: Create a suitable curing environment and strengthen concrete curing; S9: Optimize waterproof layer materials.

[0025] The method will be described in detail below with reference to specific embodiments.

[0026] S1-S2: Site clearing mainly uses backhoe excavators to load dump trucks and transport the soil to the spoil disposal site. Tree roots, vegetation, etc. are cleared manually. The foundation is cleaned and leveled, and relevant units are organized to conduct foundation testing. If the geological conditions do not meet the design requirements, graded crushed stone should be used for replacement, with a replacement thickness of 50cm. The replacement range should extend at least 50cm beyond the outer edge of the structure. The bearing capacity of the foundation after replacement should not be less than 120kPa. If the bearing capacity of the foundation still does not meet the design requirements after replacement, the replacement thickness should be increased.

[0027] S3: By incorporating granular fillers carrying silica powder and slag, the use of cement is reduced; the adverse effects of the concrete's own hydration temperature rise on the concrete structure are mitigated, reducing the occurrence of undesirable temperature cracks; the concrete mix design is adjusted; and the cement content per unit volume and concrete strength are controlled by adjusting the slurry film thickness. The ratio of cement:coarse aggregate:crack-resistant and waterproofing agent:modified manufactured sand:granular fillers carrying silica powder:slag = 50:95~105:1.15~1.25:70~75:7~10:10~15, ensuring concrete strength. In actual construction, considering the climate and hydrological characteristics of the construction area, and aiming to control the internal temperature stress of the concrete, the optimal mix design and construction scheme are proposed by using slurry film thickness theory and numerical analysis combined with field tests.

[0028] S4: Taking into account the characteristics of high-flowability concrete, an immersion tamping device is used to vibrate the concrete, especially in areas with dense reinforcement. φ 32 small tamping devices are used, with dedicated personnel for tamping to ensure the quality of concrete pouring. The concrete below the waterstop at the construction joint of the slab is tamped using a lifting and pressing method to ensure the density of the concrete below the waterstop. During concrete vibration, attention should be paid to constantly checking the stress on the formwork and the position of the reinforcing bars to prevent displacement of the formwork and reinforcing bars.

[0029] S5: The concrete shall be poured in layers continuously, with each layer being no less than 20cm and no more than 50cm thick. The pouring of concrete shall be continuous. If an interruption is necessary, the interval shall be minimized, and the next layer of concrete shall be poured before the previous layer has initially set.

[0030] S6: The construction joint surfaces of each layer are fully roughened to further enhance the seepage prevention capability.

[0031] S7: The concrete base surface needs to be carefully inspected by a specialist to ensure it is clean and flat, and to remove oil and dirt so that it can easily adhere tightly to the waterproof layer and reduce gaps.

[0032] S8: Create a suitable curing environment and strengthen concrete curing.

[0033] In this embodiment, spraying and the installation of spray pipes are employed to create a suitable curing environment, thus providing optimal construction conditions for concrete pouring at approximately 22°C and humidity above 70%. Box culvert pouring is not carried out during periods of sustained temperature below 0°C or above 30°C to reduce potential quality issues. Areas with significant temperature stress are identified, and electronic thermometers are strategically placed within the concrete for monitoring. The concrete's initial pouring temperature is strictly controlled (<30°C) to prevent excessive temperature differences between the concrete center and surface. The internal and external temperature differences are monitored and controlled to be no greater than 18°C ​​to avoid harmful surface cracks. Based on the measured actual temperature, boundary conditions, and climatic conditions, temperature warning standards and corresponding countermeasures are proposed. When the temperature exceeds the warning value, rapid temperature control measures are implemented. Concrete curing is dynamically adjusted according to changes in ambient temperature and internal / external temperature differences at the construction site to address cracking issues caused by temperature variations.

[0034] The specific temperature control measures are as follows: In dry, hot climates, after the formwork is removed, cover it with plastic film for curing. Do not spray water if water droplets remain inside the plastic film; once the film is dry, use a method of alternating spraying by groups of four to keep the concrete surface moist. During winter construction, have a designated person measure the temperature before pouring the concrete, ensuring it is above 10℃, and minimize pouring time while maintaining quality. The formwork can only be removed after the concrete reaches the required frost resistance and demolding strength. For heat-cured structures, the formwork and insulation layer can only be removed when the temperature reaches above 50℃. The removed concrete surface should be covered to allow for slow cooling. After concrete pouring, immediately cover the surface for insulation, first with a layer of plastic film, then with one or two layers of straw mats. Straw mats should be directly attached to the outer walls of the side formwork. If necessary, add 5cm thick polystyrene boards between the formwork sections.

[0035] S9: Optimize the waterproof layer material and select polyurethane waterproof coating, which is a single-component environmentally friendly waterproof coating with liquid construction and imported polyurethane prepolymer as the basic component.

[0036] In this embodiment, the concrete mix design was adjusted and polyurethane waterproof coating was selected as the waterproof layer. A 3-4 cm thick polyurethane waterproof coating layer was applied to both the inner and outer sides of the bottom slab, side walls and top slab of the box culvert to improve its impermeability.

[0037] It should be noted that the content and exemplary embodiments herein are only used to illustrate the technical solution of this patent, but the implementation of this patent is not limited to the above content. Any changes, modifications, substitutions, combinations, etc., made without departing from the innovative essence and principle of this patent are included within the protection scope of this patent. Those skilled in the art can understand the specific meaning of the above terms in the patent according to the specific circumstances.

Claims

1. A material for improving the seepage resistance and crack prevention performance of concrete box culverts in municipal road storm drains, characterized in that: The concrete is made of siliceous powder particles, which includes concrete, siliceous powder particles and slag. The concrete is mixed with cement, coarse aggregate and high-performance crack-resistant and waterproofing agent to form a concrete base. A polyurethane waterproof coating is used as a waterproof layer on the concrete base.

2. The material for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains according to claim 1, characterized in that: The concrete mix proportions in the concrete base are: cement: coarse aggregate: crack-resistant and waterproofing agent: modified manufactured sand: granular filler containing silica powder: slag = 50: 95~105: 1.15~1.25: 70~75: 7~10: 10~15.

3. A method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains, characterized in that: Specifically, the steps include the following: S1: Site clearing includes vegetation clearing and topsoil removal; S2: Excavation and drainage operations are carried out to remove seepage water, rainwater runoff, and construction wastewater from the trench. S3: Optimize the concrete mix proportion by incorporating particulate filler containing the silica powder, slag, and high-performance crack-resistant and waterproofing agent, and adjust the concrete mix design. S4: Combine with high-flow concrete, strengthen vibration and reduce concrete porosity; S5: Use a layered continuous pouring method, control the construction sequence of each layer, and control the construction height of each layer; S6: The construction joint surface is fully roughened to further enhance its seepage prevention ability; S7: Ensure the concrete base surface is clean, flat, free of stains and debris, and can adhere tightly to the waterproof layer; S8: Create a suitable curing environment and strengthen concrete curing; S9: Optimize waterproof layer materials.

4. The method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains according to claim 3, characterized in that: In S2, the drainage operation adopts the method of open ditch drainage to lower the groundwater level. A sump is set up near the inspection well, and the water is pumped to a newly built three-stage sedimentation tank on the outside, and then discharged into the local sewage pipeline to prevent the ditch from being affected.

5. A method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains according to claim 3, characterized in that: In S3, during actual construction, taking into account the climate and hydrological characteristics of the construction area, and with the goal of controlling the internal temperature stress of the concrete, the optimal mix design and construction scheme are proposed by adopting the theory and numerical analysis of grout film thickness and combining it with field tests.

6. A method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains according to claim 3, characterized in that: In S4, ready-mixed concrete with slow setting, early strength and high fluidity is selected. The shrinkage compensation concrete method is adopted to compensate for the shrinkage stress caused by the early hydration heat of cement. An immersion tamping device is used to vibrate the concrete. In areas with dense reinforcement, a φ32 small tamping device is used and a dedicated person is assigned to tamp the concrete to ensure the quality of concrete pouring.

7. A method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains according to claim 3, characterized in that: In S5, the thickness of each layer shall not be less than 20cm and not more than 50cm. Concrete pouring shall be carried out continuously. If an interruption is necessary, the interruption time shall be shortened as much as possible, and the next layer of concrete shall be poured before the previous layer of concrete has initially set.

8. A method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains according to claim 3, characterized in that: In S8, the concrete curing process involves spraying and installing spray pipes to identify areas with high temperature stress and to install electronic thermometers for monitoring.

9. A method for improving the seepage resistance and crack prevention performance of concrete box culverts for municipal road storm drains according to claim 3, characterized in that: In S9, the waterproof layer material is selected as polyurethane waterproof coating, which is a single-component environmentally friendly waterproof coating applied in liquid form.

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