Anti-cracking self-healing concrete structure

Abstract

The utility model discloses an anti-cracking self-healing concrete structure which comprises a concrete base layer, and the upper surface of the concrete base layer is sequentially coated with a polypropylene fiber layer, a nanometer silicon powder layer, a polyurethane coating, a hydrogel layer and a reinforced concrete layer. The thickness of the polypropylene fiber layer is 1-2mm; the thickness of the nano silicon powder layer is 0.5-1 mm; the thickness of the nano polyurethane coating is 1 to 1.5 mm; and the thickness of the hydrogel layer is 1.5 to 2.5 mm. The problems that in the prior art, concrete is prone to cracking and damage in the long-term service process, and durability and safety are seriously affected are solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of building materials relates to a kind of anti-cracking self-healing concrete structure. BACKGROUND

[0002] With the continuous development of construction industry, as the main structural material, the improvement of its performance has become a hot research topic. However, the traditional concrete is prone to cracks and damage in long-term service, which seriously affects its durability and safety. In order to solve this problem, the development of concrete material with self-repairing ability has become a new research direction.

[0003] In the current research, concrete cracks are a common phenomenon in concrete structures, and one of the most difficult problems to solve. The appearance of cracks can affect the service life of the house, and even endanger the structural safety of the building. Especially during the rain, the component is poured and exposed to the air environment. Not only will the surface appear cracks of different depths, but also it may lead to a decrease in concrete strength. In addition, the formation of early cracks and insufficient concrete strength will exacerbate the penetration of erosion medium, leading to the loss of protective layer and corrosion of steel bars, ultimately reducing the carrying capacity and service life of the structure. Therefore, it is necessary to develop an anti-cracking self-healing concrete structure to effectively improve the long-term service performance of concrete. SUMMARY

[0004] In order to achieve the above purpose, the utility model provides an anti-cracking self-healing concrete structure, which solves the problem of cracks and damage in long-term service of concrete in the prior art, which seriously affects the durability and safety.

[0005] The technical scheme adopted by the utility model is,

[0006] An anti-cracking self-healing concrete structure, comprising: a concrete base layer, the upper surface of the concrete base layer is coated with a polypropylene fiber layer, a nano silicon powder layer, a polyurethane coating layer, a hydrogel layer and a reinforced concrete layer in sequence; the thickness of the polypropylene fiber layer is 1-2mm; the thickness of the nano silicon powder layer is 0.5-1mm; the thickness of the polyurethane coating layer is 1-1.5mm; the thickness of the hydrogel layer is 1.5-2.5mm.

[0007] Further, the polypropylene fiber layer is woven by mixing polypropylene fiber and glass fiber.

[0008] Further, the nano silicon powder layer is composed of SiO2 nanoparticles and superplasticizer.

[0009] Further, the polyurethane coating layer is composed of polyurethane resin base material and curing agent.

[0010] Further, the hydrogel layer is composed of sodium polyacrylate.

[0011] Further, the polypropylene fiber layer has a thickness of 1.3-1.5mm.

[0012] Further, the nano-silicon powder layer has a thickness of 0.7-0.9mm.

[0013] Further, the nano-polyurethane coating layer has a thickness of 1.2-1.5mm.

[0014] Further, the hydrogel layer has a thickness of 1.8-2.0mm.

[0015] The present application has the following advantages:

[0016] 1. The cold construction process is adopted, and no heating or adhesive is needed, so that the safety hidden danger in the construction process is reduced, the environmental protection requirement is met, and the negative influence on the environment is reduced.

[0017] 2. The hydrogel layer can actively absorb water when the micro-crack is formed, promote the hydration reaction of the cement, realize self-healing, and has high adhesive force between the layers, so that various extreme climates can be adapted, and obvious advantages are obtained in the rainy season construction, and the construction period can be effectively shortened.

[0018] 3. The nano-silicon powder layer and the polyurethane coating layer are combined, so that the waterproofness and the anti-permeability of the concrete are significantly improved.

[0019] 4. The polypropylene fiber layer enhances the toughness of the concrete, disperses the external stress, and reduces the risk of stress concentration.

[0020] 5. The composite application of the multiple layers simplifies the construction process, reduces the requirement for the foundation layer, i.e. the concrete base layer, and can adapt to different construction conditions. DRAWINGS

[0021] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Fig. 1 is a sectional view of the anti-cracking self-healing concrete structure.

[0023] Fig. 2 is a schematic view of the upper surface of the anti-cracking self-healing concrete structure.

[0024] In the figure, 1. Concrete base layer, 2. Polypropylene fiber layer, 3. Nano silicon powder layer, 4. Nano polyurethane coating layer, 5. Hydrogel layer, 6. Reinforced concrete layer. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0026] Referring to Figs. 1-2 A kind of anti-cracking self-healing concrete structure, including concrete base layer 1, concrete base layer 1 is the concrete floor base material well known to those skilled in the art, is obtained by mixing coarse and fine aggregate such as gravel, sand, Portland cement and water in proportion, cement concrete, mainly to provide bearing capacity and rigidity, is the main load-bearing part of the whole structure. Thickness can be formulated according to different engineering needs, and the thickness is 80mm to 100mm in the embodiment.

[0027] Polypropylene fiber layer 2 is coated on the surface of concrete base layer 1, and polypropylene fiber layer 2 is woven by mixing high-strength polypropylene fibers with a small amount of glass fibers, and polypropylene fiber layer 2 is obtained by coating polypropylene fibers on the surface of concrete base layer 1. The thickness of polypropylene fiber layer 2 is 1-2mm, and the thickness is too large to weaken the bonding strength between polypropylene fiber layer 2 and concrete base layer 1, resulting in interlayer separation or void problem; the thickness is too small to reduce stress dispersion, inhibit crack effect, and difficult to fully play the role of tensile and shear resistance.

[0028] Different thicknesses of polypropylene fiber layer 2 are selected for testing in the laboratory to evaluate their tensile strength, crack resistance and adhesion, and the thickness of the preferred polypropylene fiber layer 2 is 1.3-1.5mm. Polypropylene fiber layer 2 has high tensile strength and strong toughness, can form a network structure on the surface of concrete base layer 1, helps to buffer and disperse external stress, inhibits the expansion of microcracks, thereby enhancing the tensile and shear resistance of the structure, can effectively reduce stress concentration and inhibit the generation and expansion of cracks.

[0029] The upper surface of the polypropylene fiber layer 2 is coated with a nano-silica powder layer 3, which is composed of SiO2 nanoparticles and a superplasticizer. The nano-silica powder particles can undergo a secondary hydration reaction with water at the crack site, generating calcium silicate gel to fill the cracks, enhance the compactness of the concrete, and reduce porosity, thereby further improving the waterproofness and impermeability. The nano-silica powder layer 3 is arranged between the polypropylene fiber layer 2 and the polyurethane coating 4 to reduce porosity and enhance overall impermeability, which helps to form a sealing barrier at this location and further enhances waterproofness and corrosion resistance, thereby improving the durability and long-term stability of the structure.

[0030] The thickness of the nano-silica powder layer 3 is 0.5-1 mm. If the thickness is too large, it will cause a large difference in shrinkage between the inner and outer layers of the nano-silica powder layer 3 during the curing process, thereby causing cracking problems. If the thickness is too small, it cannot provide sufficient impermeability and corrosion protection. The sealing and chemical resistance performance will be weakened, affecting the long-term durability of the structure.

[0031] The finite element analysis software is used to simulate the behavior of nano-silica powder layers 3 of different thicknesses under stress, temperature changes, and other conditions, to observe stress distribution, deformation, and coating stability, and to determine the preferred thickness value. The preferred thickness of the nano-silica powder layer 3 is 0.7-0.9 mm.

[0032] The nano-silica powder layer 3 is roughened and cleaned, and then a polyurethane coating 4 is applied to the upper surface of the nano-silica powder layer 3, which can improve the adhesion of the polyurethane. The polyurethane coating 4 is a two-component polyurethane coating, including a polyurethane resin base and a curing agent. Polyurethane can form a high-elasticity, flexible coating that can adapt to the subtle deformation of the structure, prevent the penetration of corrosive substances such as water and chloride ions into the layers below the polyurethane coating 4, and provide additional protection for the concrete structure. The thickness of the polyurethane coating 4 is 1-1.5 mm. If the thickness is too large, it will cause uneven curing, with the surface layer curing quickly and the inner layer curing slowly, thereby affecting the final performance. If the thickness is too small, it cannot provide sufficient protection, reducing the resistance to external environmental factors such as chemical corrosion, wear, and moisture.

[0033] The finite element analysis software is used to numerically simulate polyurethane coatings 4 of different thicknesses to evaluate their stress distribution and deformation under different loads and environmental conditions, thereby determining the preferred value. The preferred thickness of the polyurethane coating 4 is 1.2-1.5 mm.

[0034] The upper surface of the polyurethane coating layer 4 is coated with a hydrogel layer 5, which is a sodium polyacrylate water-absorbing material. When the hydrogel layer generates microcracks in the reinforced concrete layer 6, it can absorb water and expand and gradually release water, keeping the surrounding area moist, thereby promoting the cement hydration reaction in the self-healing process, repairing microcracks and enhancing the long-term durability of the structure. The thickness of the hydrogel layer 5 is 1.5-2.5mm. If the thickness is too large, it will lead to uneven internal curing, increase the drying time, and even cause the phenomenon of internal water being trapped, leading to drying and cracking of the upper structure reinforced concrete layer 6. If the thickness is too small, it will not be able to effectively maintain and manage the moisture, leading to excessive moisture in the reinforced concrete layer 6, affecting its strength and durability.

[0035] By conducting water permeability tests on hydrogel samples of different thicknesses, the maximum water absorption of hydrogel of different thicknesses is evaluated, and then tests such as tensile, compression and shear resistance after water absorption are tested to determine the preferred value. The preferred thickness of the hydrogel layer 5 is 1.8-2.0mm. Further, steel bars can be directly tied on the upper surface of the hydrogel layer 5 for pouring the reinforced concrete layer 6, which not only improves the adhesion between the steel bars and the reinforced concrete layer 6, but also enhances the stability of the overall structure.

[0036] The reinforced concrete layer 6 refers to concrete, which means that coarse and fine aggregates such as gravel, sand, Portland cement and water are mixed in proportion, the proportion is consistent with layer 1, and steel bars are added to provide overall load-bearing capacity of the structure and prevent deformation and damage. In this embodiment, the thickness of the reinforced concrete layer 6 is 60-80mm. In special environmental conditions, the thickness needs to be further increased to ensure the stability and long-term durability of the structure.

[0037] After the hydrogel layer 5 is cured, in order to ensure good adhesion, a bonding agent is first applied to the upper surface of the hydrogel layer 5, and then the reinforced concrete layer 6 is poured on the upper surface of the hydrogel layer 5, so that the reinforced concrete layer 6 and the hydrogel layer 5 achieve interfacial bonding.

[0038] Each embodiment in the specification is described in a related manner, and the same or similar parts between each embodiment can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0039] The above only describes the preferred embodiments of the present application, and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application is included in the protection scope of the present application.

Claims

1. A crack resistant self-healing concrete structure comprising: The concrete base (1) is characterized in that the upper surface of the concrete base (1) is coated with a polypropylene fiber layer (2), a nano silicon powder layer (3), a polyurethane coating layer (4), a hydrogel layer (5), and a reinforced concrete layer (6) in sequence; the thickness of the polypropylene fiber layer (2) is 1-2 mm; the thickness of the nano silicon powder layer (3) is 0.5-1 mm; the thickness of the polyurethane coating layer (4) is 1-1.5 mm; and the thickness of the hydrogel layer (5) is 1.5-2.5 mm.

2. A non-cracking self-healing concrete structure according to claim 1, characterized in that, The polypropylene fiber layer (2) is woven by mixing polypropylene fibers and glass fibers.

3. A non-cracking self-healing concrete structure according to claim 1, characterized in that, The hydrogel layer (5) is composed of sodium polyacrylate.

4. A non-cracking self-healing concrete structure according to claim 1, characterized in that, The thickness of the polypropylene fiber layer (2) is 1.3-1.5 mm.

5. A non-cracking self-healing concrete structure according to claim 1, characterized in that, The thickness of the nano silicon powder layer (3) is 0.7-0.9 mm.

6. A non-cracking self-healing concrete structure according to claim 1, characterized in that, The thickness of the polyurethane coating layer (4) is 1.2-1.5 mm.

7. A non-cracking self-healing concrete structure according to claim 1, characterized in that, The thickness of the hydrogel layer (5) is 1.8-2.0 mm.

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