Carbon Fiber Reinforced Concrete
Writer： admin Time：2023-11-01 16:07 Browse：
Carbon fiber reinforced concrete (CFRC) is a kind of composite material with multiple functions and structural properties, which is referred to as CFRC. It is mainly composed of ordinary concrete with a small amount of certain shape carbon fiber and ultra-fine additives (dispersant, defoamer, early strength agent, etc.). Compared with ordinary concrete, it not only has better mechanical properties, but also has many excellent properties. Very high strength, high flame retardant, high temperature resistance, with very high tensile modulus.
Carbon fiber reinforced concrete has been widely used in the following aspects:
(1) Adding appropriate amount of short carbon fiber into concrete can improve the tensile strength, bending strength and impact resistance of concrete, reduce dry shrinkage, improve wear resistance, improve the shock absorption capacity of concrete, improve the bond strength between new and old concrete, and improve the bond strength between brick and mortar. Therefore, it has considerable potential in practical construction. Short carbon fiber reinforced concrete can be made into various kinds of roof, internal and external walls, floor and ceiling plates, etc. one of the development trends in the future is to use long carbon fiber reinforced concrete as load-bearing components.
(2) Carbon fiber can prevent the spread of cracks in concrete components, but the crack problem of high strength concrete in China is more prominent. Therefore, it is necessary to study and try to use carbon fiber to improve the performance of high strength concrete.
(3) Therefore, carbon fiber reinforced concrete can play an important role in industrial anti-static, grounding engineering and cathodic protection of reinforcement.
(4) Adding short carbon fiber into ordinary concrete can significantly enhance the electromagnetic shielding performance of concrete. Therefore, carbon fiber shielding concrete can be applied in military and commercial fields, such as preventing electromagnetic damage caused by nuclear explosion, interference and conventional electromagnetic weapons, electromagnetic shielding protection, protection of electromagnetic signal secrets, etc., and can also be applied to civil buildings to prevent electromagnetic pollution.
(5) The electro mechanical effect of carbon fiber reinforced concrete is closely related to the mechanical behavior of concrete, so its electrothermal effect can be used for snow melting and ice melting of bridge pavement.
(6) The mechanical and electrical effects of carbon fiber reinforced concrete can provide a new method for nondestructive testing of concrete strength.
(7) In recent years, the technology of repairing and strengthening concrete structures with carbon fiber reinforced materials has been improved and developed rapidly. For example, many industrial plants (such as hyperbolic thin shell), bridges and residential buildings (concrete frames) in Italy are strengthened by sticking carbon fiber reinforced plastic (CFRP) strips, and the effect is obvious, reaching the performance requirements of original strength and stiffness; there are also successful examples of carbon fiber reinforced plastic bars used in bridge, bridge deck and tunnel engineering in Japan; Continuous fiber reinforced plastic (FRP) reinforcement technology is becoming more and more mature, and the corresponding specifications have been formulated in the world. In 2003, China promulgated CECS 146:2003 "technical specification for strengthening and repairing concrete structures with carbon fiber sheet".
(8) Carbon fiber reinforced concrete (CFRC) has temperature sensitivity, that is, the resistance change caused by temperature change (temperature resistance) and the temperature difference inside the carbon fiber concrete will produce thermoelectric property of potential difference (Seebeck effect). Therefore, it can be used for real-time monitoring of changes in the internal and surrounding environment of buildings; it can also realize the temperature self-monitoring of mass concrete, as well as used for thermal elements and fire alarm; It is expected to be used in intelligent concrete structures with temperature control and fire warning requirements.
(9) By using the mechanical sensitivity of carbon fiber reinforced concrete, the stress-strain state of carbon fiber reinforced concrete structure can be mastered by monitoring the resistance change rate of carbon fiber reinforced concrete, so as to realize the location of structure damage and the evaluation of damage degree. It can be used for dams, bridges and important building structures to realize real-time on-line monitoring of structures.
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