UHPC and carbon fiber grating net reinforced concrete column structure

Abstract

The invention discloses a UHPC (Ultra High Performance Concrete) and carbon fiber grating net reinforced concrete column structure, which relates to the technical field of bridge reinforcement and comprises a concrete matrix, a steel structure, a UHPC bonding layer, a carbon fiber grating net and a UHPC reinforcing layer. The invention provides a structure for reinforcing a concrete column by using UHPC (Ultra High Performance Concrete) and a carbon fiber grating net, which is used for overcoming the defects of an existing concrete column reinforcing method in the aspects of aging resistance, high temperature resistance, moisture resistance and the like, and effectively avoiding the consequence of collapse caused by overlarge stress.

Description

Technical Field

[0001] The present invention relates to the technical field of reinforced concrete column reinforcement, and in particular to a UHPC and carbon fiber grid reinforced concrete column structure. Background Art

[0002] Concrete columns are made of concrete materials and are the most basic load-bearing components in various engineering structures such as houses, bridges, and hydraulic structures. When the column is subjected to excessive loads, the concrete column will collapse, which can easily cause accidents and endanger people's life and property safety. At present, the main reinforcement methods for concrete columns include increasing the cross-section method, external steel plate method, composite material method, replacement reinforcement method, etc. Traditional reinforcement methods all have their own shortcomings. For example, the increasing cross-section method requires the construction of pouring holes, which may damage the original structure; the external steel plate method and the external steel reinforcement method have poor fire resistance, and the external steel needs to be welded. Fiber reinforcement and deformation resistance, the fiber grid made of it has good application prospects in construction. Ultra-high performance concrete, referred to as UHPC (Ultra-High Performance Concrete), is the most innovative cement-based engineering material in the past three decades, achieving a big leap in the performance of engineering materials. The innovative use of UHPC and carbon fiber grid combined with steel bars can give full play to their respective excellent properties and reinforce concrete columns, which has good application prospects. Summary of the invention

[0003] The present invention discloses a UHPC and carbon fiber grid reinforced concrete column structure, which is used to solve the shortcomings of traditional reinforcement methods such as increasing the cross-section method, external steel plate method, composite material method, replacement reinforcement method, etc. For example, the increasing the cross-section method requires opening a casting hole for construction, which may damage the original structure; the external steel plate method and the external steel reinforcement method have poor fire resistance, and the external steel needs to be welded.

[0004] The present invention provides a UHPC and carbon fiber grid mesh reinforced concrete column structure, comprising: a concrete matrix, a steel structure, a UHPC bonding layer, a carbon fiber grid mesh and a UHPC reinforcement layer.

[0005] The steel structure is a cross-layered steel structure that penetrates the concrete matrix; the UHPC bonding layer wraps the concrete matrix; the carbon fiber grid mesh wraps the UHPC bonding layer; and the UHPC reinforcement layer wraps the entire outer circle of the structure.

[0006] The steel structure has multiple layers of cross-shaped steel structures, which are connected by a longitudinal reinforcement. The longitudinal reinforcement passes through the intersection of the cross-shaped steel structures and runs through the entire matrix. The cross-shaped steel structure is symmetrical about the center of the intersection. The intersection is the centroid of the cross section of the longitudinal reinforcement, and is also the centroid of the cross section of the concrete matrix.

[0007] Preferably, the steel structures are uniformly distributed in the longitudinal direction, that is, the inserted cross-shaped steel structures are spaced at a uniform distance within a range of 100 to 200 mm.

[0008] Preferably, the UHPC bonding layer is coated on the outer layer of the concrete column base to increase the bonding performance with the carbon fiber grid mesh and improve the bearing capacity.

[0009] Preferably, the fiber grid is a bidirectional carbon fiber grid or a unidirectional carbon fiber grid, the grid size is 15-25 mm, and the number of fiber grid layers is 1-3. This fiber woven mesh can be treated with sand on the surface before use to better exert its effective restraint ability.

[0010] Preferably, the UHPC reinforcement layer is cast in the outermost layer of the overall structure, and the UHPC is a coarse aggregate low shrinkage UHPC, does not require steam curing, and has a compressive strength of more than 100 MPa. The curing conditions of UHPC are natural curing, and the curing time is 7 days. In terms of mass fractions, the raw materials include: 780-850 parts of silicate cement, 190-250 parts of silica ash, 25-35 parts of calcium carbonate, 520-580 parts of silica sand, 450-480 parts of bauxite, 121-192 parts of steel fiber, 15-45 parts of water reducer, and 170-200 parts of water. The particle size of silica sand is 1-3 mm, the particle size of bauxite is 1-3 mm, and the particle size of bauxite is 3-5 mm.

[0011] The UHPC and carbon fiber grid reinforced concrete column structure provided by the present invention has the following advantages: Including: The UHPC used as the matrix in the present invention to fill the concrete column has many significant advantages compared with ordinary concrete: With ultra-high strength and durability, UHPC's compressive strength far exceeds that of ordinary concrete, usually reaching more than 200MPa. It can also resist erosion from harsh environments such as chemical corrosion and freeze-thaw cycles, thereby extending the service life of the structure; The fiber-reinforced materials in UHPC can effectively inhibit the generation and development of cracks, improve the integrity and stability of the structure, and show higher crack resistance when subjected to complex stresses such as bending and shearing; UHPC has good construction performance, can be quickly poured and formed on site, hardens quickly, and can reach sufficient strength in a shorter time, thereby shortening the construction period and improving construction efficiency.

[0012] The carbon fiber grid mesh used in the present invention is a composite material composed of carbon fiber and epoxy resin. Compared with traditional reinforced concrete, it has the following excellent properties: The yield strength of carbon fiber grid is about 2000MPa, which is much higher than the yield strength of reinforced concrete. It can greatly reduce the weight of the structure while improving the mechanical properties of the structure. Carbon fiber grid mesh has corrosion resistance and can better withstand chemical corrosion and electrochemical corrosion; the density of carbon fiber grid mesh is only 1 / 4~1 / 5 of reinforced concrete, making the overall structure lighter, construction easier and work more efficient; Carbon fiber grid mesh has good durability and anti-aging properties, which can extend the service life of concrete columns to a certain extent.

[0013] The present invention adopts a cross-intersecting multi-layer steel structure, so that when the concrete column is subjected to vertical stress, the stress is concentrated on the steel structure, thereby reducing the damage to the concrete to a certain extent.

[0014] The UHPC uses low shrinkage UHPC with a compressive strength of more than 120MPa, containing coarse aggregate and not requiring steam curing. When pouring UHPC, due to the coarse aggregate contained in it, the fluidity is good, the construction is simpler, and the application efficiency is higher. Compared with the existing technology, the combined application of UHPC, carbon fiber grid, and cross-cross steel structure is more efficient and has stronger mechanical properties, which can avoid the damage of concrete columns and accidents to a certain extent, while reducing the difficulty of construction and saving time and effort. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the description of the invention or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 A schematic diagram of a UHPC and carbon fiber grid reinforced concrete column structure provided in the present invention; Figure 2 A schematic diagram of a cross-intersecting multi-layer steel structure provided in the present invention; Figure 3 This is a schematic diagram of the carbon fiber grid structure provided in the present invention; Figure 4 This is a schematic diagram of the structure of a carbon fiber grid wrapped concrete matrix provided in the present invention; Figure 5 It is a schematic diagram of the structure of the UHPC reinforcement layer provided in the present invention; Figure 6 It is a schematic cross-sectional view of a UHPC and carbon fiber grid reinforced concrete column structure provided in the present invention; In the figure: 1. Concrete matrix; 2. Cross-layered steel structure; 3. UHPC bonding layer; 4. Carbon fiber grid; 5. UHPC reinforcement layer. DETAILED DESCRIPTION

[0017] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] It should be noted that the directions or positional relationships indicated by terms such as “center”, “up”, “down”, “left”, “right”, “vertical”, “horizontal”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the embodiments of the present invention.

[0019] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0020] In the description of the present invention, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0021] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0022] The embodiment of the present invention discloses a UHPC and carbon fiber grid reinforced concrete column structure, which is used to solve the shortcomings of traditional reinforcement methods such as increasing the cross-section method, external steel plate method, composite material method, replacement reinforcement method, etc. For example: the increasing the cross-section method requires opening casting holes for construction, which may damage the original structure; the external steel plate method and the external steel reinforcement method have poor fire resistance, and the external steel needs to be welded.

[0023] See also Figure 1-4 , an embodiment of the present invention provides a UHPC and carbon fiber grid reinforced concrete column structure, comprising: a concrete matrix 1, a cross-multilayer steel structure 2, a UHPC bonding layer 3, a carbon fiber grid 4 and a UHPC reinforcement layer 5; The cross-multilayer steel structure 2 penetrates the concrete matrix 1, the UHPC bonding layer 3 wraps the concrete matrix 1, the carbon fiber grid 4 wraps the UHPC bonding layer 3, and the UHPC reinforcement layer 5 wraps the entire outer circle of the structure; The cross steel structure has multiple layers and is connected by a longitudinal reinforcement. The longitudinal reinforcement passes through the intersection of the cross steel structure and runs through the entire matrix 3. The cross steel structure 2 is symmetrical with respect to the center of the intersection. The intersection is the centroid of the cross section of the longitudinal reinforcement and is also the centroid of the cross section of the concrete matrix 3. It should be noted that in this embodiment, the cross-layered steel structure 2 is evenly distributed in the longitudinal direction, that is, the distance between the inserted steel structures is uniform and within the range of 100-200 mm; in this embodiment, the UHPC bonding layer 3 is coated on the outer layer of the concrete column base 1 to increase the bonding performance with the carbon fiber grid mesh 4 and improve the bearing capacity; in this embodiment, the fiber grid type is a bidirectional carbon fiber grid or a unidirectional carbon fiber grid, and its grid size is 15-25 mm, and the number of layers of the fiber grid layer 4 is 1-3 layers. This fiber woven mesh 4 can be used after the surface is treated with sand to better exert its effective restraint ability; from Figure 4 It can be seen that the carbon fiber grid 4 in the present invention is connected to the concrete matrix 1 through the UHPC bonding layer 3, giving full play to the bonding performance of UHPC.

[0024] In addition, the carbon fiber grid mesh 4 used in the present invention is a composite material composed of carbon fiber and epoxy resin, with a yield strength of about 2000MPa or more, which is much higher than the yield strength of reinforced concrete. It can greatly reduce the weight of the structure while improving the mechanical properties of the structure; at the same time, the carbon fiber grid mesh 4 has corrosion resistance and can better withstand chemical corrosion and electrochemical corrosion; the density of the carbon fiber grid mesh 4 is only 1 / 4 to 1 / 5 of that of reinforced concrete, making the overall structure lighter, the construction difficulty lower, and the work efficiency higher; the carbon fiber grid mesh 4 has good durability and anti-aging properties, and can extend the service life of the concrete column to a certain extent; from Figure 1 It can be seen that the UHPC reinforcement layer 5 is cast in the outermost layer of the overall structure, which improves the corrosion resistance and durability of the entire structure; and, Figure 5The UHPC used in the middle UHPC reinforcement layer 5 is a coarse aggregate low shrinkage UHPC, which does not require steam curing and has a compressive strength of more than 100 MPa. The curing conditions are natural curing, and the curing time is 7 days. Calculated by mass, the raw materials include: 780~850 parts of silicate cement, 190~250 parts of silica fume, 25~35 parts of calcium carbonate, 520~580 parts of silica sand, 450~480 parts of bauxite, 121~192 parts of steel fiber, 15~45 parts of water reducer, and 170~200 parts of water. The particle size of silica sand is 1~3mm, the particle size of bauxite is 1~3mm, and the particle size of bauxite is 3~5mm; from Figure 1 , Figure 2 , Figure 6 It can be seen that the present invention adopts a cross-layered steel structure 2, so that when the concrete column is subjected to vertical stress, the stress is concentrated on the steel structure 2, thereby reducing the damage to the concrete to a certain extent.

[0025] In the present invention, the UHPC adopts low shrinkage UHPC with a compressive strength of more than 120MPa, containing coarse aggregate and not requiring steam curing. In the UHPC reinforcement layer 5, when UHPC is poured, due to the coarse aggregate contained therein, the fluidity is good, the construction is simpler, and the application efficiency is higher. Compared with the prior art, the cross steel structure 2, the UHPC bonding layer 3, the carbon fiber grid 4, and the UHPC bonding layer 5 are combined and applied. The efficiency is higher and the mechanical properties are stronger. To a certain extent, the concrete column is prevented from being damaged and accidents occur, while reducing the construction difficulty and saving time and effort.

[0026] See also Figure 1-6 The present embodiment provides a construction step of a UHPC and carbon fiber grid reinforced concrete column structure, including: Step 1: Use a steel bar detector to detect the original steel bar position of the concrete matrix 1, measure the depth from the internal steel bar to the outer wall of the concrete column, and mark it; Step 2: Punch holes in the concrete matrix 1, and insert the cross steel structure 2 from the side and top respectively (this step can also be applied to the concrete matrix before pouring, first weld the cross multi-layer steel structure 2, and then pour concrete on it to form a concrete column matrix combining the concrete matrix 1 and the cross multi-layer steel structure 2), and clean the debris on the surface of the pores; Step 3: Apply UHPC evenly on the outer layer of the concrete substrate 1 as the UHPC bonding layer 3; Step 4: Before the UHPC solidifies, quickly wrap a layer of carbon fiber grid 4 outside the UHPC bonding layer 3; Step 5: Repeat step 3 and step 4 1-2 times, so that the carbon fiber grid 4 has 1-3 layers in the final structure; Step 6: After steps 1 to 5, the overall structure is Figure 4 As shown, Figure 4 The outer layer of the structure is poured with UHPC to form a UHPC reinforcement layer 5, thereby forming a complete concrete column reinforcement layer structure.

[0027] The number and positions of the holes are determined according to the height and diameter of the concrete substrate 1 .

[0028] The connection method between different plates in the UHPC and carbon fiber grid reinforced concrete column structure of the present invention is simple and quick, and each component is prefabricated in a factory and quickly installed on site, thereby shortening the construction period.

[0029] The above is a detailed introduction to a UHPC and carbon fiber grid reinforced concrete column structure provided by the present invention. For those skilled in the art, according to the ideas of the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A UHPC and carbon fiber grid reinforced concrete column structure, characterized in that: include: Concrete matrix, steel structure, UHPC bonding layer, carbon fiber grid mesh and UHPC reinforcement layer. The steel structure is a multi-layer cross steel structure and penetrates the concrete matrix; The UHPC bonding layer wraps the concrete matrix; the carbon fiber grid mesh wraps the UHPC bonding layer; and the UHPC reinforcement layer wraps the entire outer circle of the structure.

2. The steel structure according to claim 1, characterized in that: The cross steel structures in the steel structure have multiple layers and are connected by a longitudinal reinforcement. The longitudinal reinforcement passes through the intersection of the cross steel structures and runs through the entire matrix. The cross steel structure is symmetrical about the center of the intersection. The intersection is the centroid of the longitudinal reinforcement cross section, and is also the centroid of the concrete matrix cross section.

3. The steel structure according to claim 2, characterized in that: The cross-shaped steel structures are evenly distributed in the longitudinal direction, that is, the inserted steel structures are spaced at uniform distances within a range of 100 to 200 mm.

4. According to claim 1, a UHPC and carbon fiber grid reinforced concrete column structure is characterized in that: The UHPC bonding layer is coated on the outer layer of the concrete column base to increase the bonding performance with the carbon fiber grid mesh and improve the bearing capacity.

5. According to claim 1, a UHPC and carbon fiber grid reinforced concrete column structure is characterized in that: The raw material used for the UHPC bonding layer is the mortar material used for the UHPC reinforcement layer.

6. The UHPC and carbon fiber grid reinforced concrete column structure according to claim 1, characterized in that: The fiber grid type is a bidirectional carbon fiber grid or a unidirectional carbon fiber grid, and its grid size is 15-25 mm. The bidirectional carbon fiber grid or the unidirectional carbon fiber grid can be treated with sand on the surface before use to better exert its effective restraint ability.

7. The carbon fiber grid net according to claim 6, characterized in that: The number of fiber grid layers is 1 to 3.

8. The UHPC and carbon fiber grid reinforced concrete column structure according to claim 1, characterized in that: The UHPC reinforcement layer is cast on the outer layer of the carbon fiber grid, and the UHPC is a coarse aggregate low shrinkage UHPC, does not require steam curing, and has a compressive strength of more than 120 MPa.

9. The UHPC reinforcement layer according to claim 8, characterized in that: The raw material water-cement ratio of UHPC is 0.18, the sand rate is 39% to 42%, the machine-made sand content is 15% to 30%, the fly ash content is 20%, and the curing conditions are natural curing for 7 days.

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