The carbon fiber strengthening is to use a bonding resin to stick the carbon fiber to the dry-mixed surface, which plays the role of structural reinforcement and earthquake resistance. It is widely used in the reinforcement of building beams, columns and walls, as shown in the figure. It can also be used to reinforce bridges, tunnels and other civil engineering.

Compared with the traditional reinforcement and repair methods and the steel, epoxy resin mortar, and shotcrete reinforcement technologies, CFRP reinforced and repaired concrete structures have obvious technical advantages.

(1) High strength and high efficiency

In the reinforcement and repair of the concrete structure, the characteristics of high strength and high elastic modulus can be fully utilized to improve the bearing capacity and ductility of the concrete structure and components, improve the mechanical performance, and achieve the purpose of efficient reinforcement and repair. This is especially important for seismic reinforcement.

(2)Convenient construction

The construction efficiency is high, there is no wet operation, no on-site fixed facilities are needed, and less space is occupied during construction. The reinforced and repaired CF of the finished product is a unidirectional or bidirectional fabric, the width of which can be 200mm, 300mm, 500mm, 1000mm, and the length is 50-100m/roll. On-site use can be arbitrarily cut with scissors or blades as required. Unlike steel plates, special steel cutting tools are required. According to relevant statistics, the same method is used to paste reinforcement, and the CFRP method is 4-8 times more efficient than the steel plate construction.

(3) Has excellent corrosion resistance and durability

The CF reinforced and repaired concrete structure has good corrosion resistance and durability, and can resist the corrosion of various acids, alkalis and salts that the building often encounters to the structure. After using this kind of reinforcement and repair method to treat the structure, it not only does not require the regular anti-rust maintenance as required by the steel bonding method, but also saves a lot of maintenance costs. Moreover, it can play a role in protecting the internal concrete structure and achieve the purpose of double reinforcement and repair.

(4) Wide application

CFRP reinforced and repaired concrete structure can be widely applied to various structural types (such as buildings, structures, bridges, tunnels, culverts, etc.), various structural shapes (such as rectangular, circular, curved surface structures, etc.), various structural parts (such Beams, slabs, columns, arches, shells, etc.). It does not change the shape of the structure and does not affect the appearance of the structure, which is unmatched by any current method of structural reinforcement. Especially important is that for some large civil engineering structures, such as bridge piers, bridge slabs, tunnels, large-scale simplified and shells, the old reinforcement methods can hardly be implemented, and the use of this reinforcement technology can be smoothly solve.

(5) Construction quality should be guaranteed

Since CFPR is soft before curing, even if the surface of the reinforced structure is not very flat, it can basically guarantee an effective adhesion rate of nearly 100%. In addition, even if bubbles are found on the surface after the paste is cured, it is very easy to repair. As long as the resin is injected to drive the air out of the bubbles, it is difficult to achieve a 100% effective veneer with the paste steel plate.

(6) After reinforcement and repair, the weight of the original structure is basically not increased

The CFRP prepreg is light and thin, with a mass of less than 1.0 kg/m (including resin), and the thickness of a single layer is only about 1.0 mm. Therefore, after reinforcement and repair, the original mass and geometric size will not be increased.

(7) The technology of CFRP repair and reinforcement of concrete structure belongs to the intersection of materials and civil engineering in a certain sense. Its technical characteristics are reflected in two aspects of materials and technology, representing the trend of repairing and strengthening civil engineering.

It can be seen that the advantages of CF reinforced and repaired concrete technology are very obvious, which just meets the requirements of repair and reinforcement, and is a reinforcement method with broad development prospects.