High tensile strength, FRP tensile strength is significantly higher than steel, and high-strength steel wire tensile strength is almost, generally steel bar twice times even up to 10 times times. However, the FRP material has almost no plastic deformation before reaching the tensile strength, and the stress and strain on the tensile line increase until brittle. Therefore, the FRP Composite in the process of interaction with the concrete structure, often not because of the FRP material was broken, but because the FRP concrete interface strength of the concrete structure of the interface is stripped, so, FRP concrete interface Bonding performance problem becomes a focus and difficulty in the future engineering application.
Coefficient of thermal expansion
The thermal expansion coefficient of FRP composites is similar to that of concrete, so that when the ambient temperature changes, the FRP works in coordination with the concrete, which will not produce large temperature stress.
Compared with steel, most of FRP products have small elastic modulus. About 25%~ 75% of ordinary steel bars. Therefore, the design of FRP structures is usually controlled by deformation.
The shear strength of FRP is low, its strength is only the $number of tensile strength, which makes the FRP components need to develop special anchors and fixtures during the connection process. This also makes the degree of the FRP component to be the research outstanding problem.
Corrosion resistance, fatigue resistance
FRP materials can be used in acid, alkali, chlorine salt and humid environment for a long time, so it can improve the service life of the structure, which is hard to compare with the structural materials. But at the same time, compared with the general concrete, the fire resistance of FRP composite materials, which also restricts the popularization and application of this kind of structural products, becomes one of the problems to be solved in the future.