In recent years, with the development of science and technology, many new materials and methods are gradually applied to the field of bridge reinforcement. The new technology and method are different from the conventional reinforcement measures. They are mainly some special reinforcement measures formed through the innovation of materials and construction methods. The main reinforcement measures are composite reinforcement technology (FRP).

FRP composite strengthening

In the reinforcing technology of composites, the application of carbon fiber reinforced composites is the main one. Carbon fiber reinforced composites are mainly composed of carbon fibers and polymer matrix. These composites usually immerse CFRP sheets in resin-based adhesives and adhere to the surface of the tension zone of concrete members, so that they and the concrete matrix become a whole, deformation and force together, so as to achieve the purpose of improving the bearing capacity of the structure. The main materials used for strengthening and repairing are carbon fiber sheet and binder.

Carbon fibre sheets have excellent mechanical properties. The carbon fibre bundles are evenly distributed and processed into sheets, which play a role of uniform force on the whole. Carbon Fibre Sheets for structural reinforcement usually contain preprepreg resin, which plays a role in making the mutual restraint and bonding between fibers into a common force. Carbon fibre reinforced concrete structure is completed by repeated infiltration of carbon fibre sheets coated with epoxy resin and coated with epoxy resin. Binder is a kind of bonding material which combines continuous fibrous carbon fibers to give full play to its tensile strength and to bond with concrete surface.

The high performance fiber conforming material represented by carbon fiber material is a kind of high quality structural material. Its performance mainly has the advantages of light weight, high strength, good corrosion, easy construction, convenient construction and little influence on the structure, especially in improving the bearing capacity and ductility of the structure or component, so it has been widely used in structural reinforcement, repair and transformation.

In addition, carbon fiber materials have the following properties:

High strength and high efficiency. Due to its high strength, elastic modulus, small elongation and light weight, carbon fibers can make full use of the mechanical properties of friendship to improve the bearing capacity, ductility and crack resistance of concrete structures, so as to achieve the purpose of strengthening and repairing concrete structures with high strength and high efficiency.

The construction is gradual and the reinforcing construction period is short. Carbon fibre composites are light in weight and are generally manually operated without large construction tools. The construction space restriction is small and the construction interference is small. In some cases, on-line construction can be realized (reinforcing construction can be carried out in years of continuous wiping sweat). The reinforcing construction period is short. The surface of CFRP structural members is solidified by cementing to meet the strength requirement. It takes only 3 to 5 days for the members to be put into use.

Construction quality is easily guaranteed. The standard of construction quality of CFRP reinforced members is mainly reflected in the degree of loss of CFRP bonding. Because CFRP is flexible, it is easy to stick on the surface of the structure. It is lost in the bonding between CFRP and concrete. Generally, it can ensure the effective bonding of CFRP.

The bonding area is not less than 95%, which meets the quality requirements of CFRP reinforced structures.

Super waterproof and anti-corrosion effect. Epoxy resin is attached to the surface of concrete structure, which has good waterproof effect and can prevent steel corrosion. Carbon fiber materials have excellent corrosion resistance, which can avoid building being corroded by various acids, alkalis and salts.

In view of the excellent properties of carbon fiber reinforced composites, they are widely used in engineering reinforcement. They are widely used in industrial, civil buildings, water conservancy, power, bridges and other engineering structures and components in different hands. But its construction process is basically the same. Its specific process is as follows: construction unloading, surface treatment, coating primer, repairing ash leveling, dipping coating, plastering fiber cloth, dipping coating, plastering fiber cloth, maintenance and so on.

Bridge reinforcement is not only related to the safety of vehicles and people's lives and property, but also a microcosm of the rapid development of science and technology. Only by making full use of science and technology, materials and construction methods, can we make a better contribution to the economic development.