Introduction of prestressed carbon fiber reinforcement

The technology of prestressed carbon fiber plate reinforcement structure is a new type of reinforcement technology that has been studied since the end of the 20th century. It has made a major breakthrough in the traditional reinforcement technology of pasting carbon fiber plate. It can make full use of the high tensile strength of carbon fiber composite materials and avoid the phenomenon of premature stripping of carbon fiber. Effectively improve the strength and rigidity of the structure, achieve the effect of reducing the original crack width of the structure and limiting the formation and development of cracks, and significantly improve the working performance of the structure. The principle is similar to that of steel plate reinforcement, which is to paste tensile materials on the tensile side of the structure to share the force with the structure and strengthen the reinforcement.

Comparison of prestressed and non-prestressed carbon fiber plate reinforcement

Through a number of domestic and foreign research and practical results, it can be seen that applying prestress to the carbon fiber plate significantly increases the cracking and yielding moments of the structure, and reduces the deformation and section strain. But it has little effect on bearing capacity. The ultimate deformation of prestressed carbon fiber reinforced specimens is significantly smaller than that of non-prestressed reinforced specimens. The carbon fiber anchor effectively prevents the peeling of the carbon fiber, so that the damage of the component is changed from the tearing and peeling damage of the surface concrete to the breaking of the carbon fiber composite material. It can also be seen that the failure mode of the non-prestressed carbon fiber reinforcement is the peeling failure of the carbon fiber, and the failure mode of the prestressed reinforcement is the tensile fracture of the carbon fiber plate. The prestressed carbon fiber plate can reduce the overall deformation of the component, make the carbon fiber play a greater efficiency, and also bear more load than the non-prestressed carbon fiber.

Advantages of prestressed carbon fiber

The non-prestressed carbon fiber reinforcement technology is to paste the carbon fiber plate with adhesive in the tensile area of the structure, so that it can bear the tensile stress together with the component concrete and internal steel bars. The efficiency of this process is very low. Because the modulus of elasticity of carbon fiber plate is low, generally only 160-165GPa, and the tensile strength is high, up to about 2600MPa. The elastic modulus of steel bars is generally about 205 GPa, and the yield strength is only about 305 MPa. The yield strength of the steel bar needs a tensile deformation of 0.0014, and the carbon fiber plate needs a tensile deformation of 0.017 to achieve the tensile strength, which is more than 11 times higher than the yield deformation of the steel bar. It can be explained that the carbon fiber plate works with the internal reinforcement of the component. Regardless of the original initial strain of the reinforcement, the strength that the carbon fiber can exert when the reinforcement yields is only 8.8% of the tensile strength. And under the strain of 0.017 required for the full strength of the carbon fiber, the concrete structure will produce large deformation and obvious cracks. Reinforced with non-prestressed carbon fiber plate, the tensile strength provided by carbon fiber plate is extremely low. Therefore, it is necessary to apply prestress to the carbon fiber plate so that it can exert a certain strength in advance in order to effectively exert its high-strength performance.

Therefore, in the field exposure environment, the prestressed carbon fiber plate reinforcement structure has more advantages.

Prestressed carbon fiber plate reinforcement is a bonded prestressed reinforcement, which also has significant performance in reducing cracks and improving the flexural bearing capacity of components. It can be shown that the prestressed carbon fiber plate reinforcement technology has the advantages that the traditional non-prestressed carbon fiber reinforcement technology can not match, and has greater engineering practical value.

Reinforcement effect of prestressed carbon fiber plate

Between the reinforced structure and the prestressed carbon fiber plate that has been tensioned and anchored, structural glue can be used for reinforcement, even if the carbon fiber plate and the component are bonded together. Let the anchor and structural glue fix the carbon fiber plate to the solid surface. With the passage of time and the aging of the colloid, it gradually transforms into an unbonded form, which only allows the anchor to provide tensile force to the carbon fiber plate. This is the reinforcement technology of variable bonding prestressed carbon fiber plate. This technology is easy to operate, variable bonding prestress, so that the later unbonded and the early bonded have the same crack spacing and width, which is beneficial to the anti-corrosion and durability of the structure. It is suitable for the reinforcement measures of existing structural parts, and can have the advantages of bonded prestress and unbonded prestress at the same time.