The performance of fiber reinforcement in concretes exposed at high temperatures

The benefits derived from the ability of the fibers to control crack propagation have been recognized for many years. In addition, the development of high-performance concretes has enhanced this situation as the increases in strength lead to a more brittle behavior of the material. The introduction of steel-fiber reinforcement in these concretes is probably the best way to improve the performance of concrete when higher tenacity is required. This paper shows the contribution of fiber reinforcement in both conventional and high-strength concretes exposed to temperatures up to 500degreesC. Concretes with different types and content of fibers are analyzed, mainly regarding the failure mechanism and tenacity. The post-peak behavior under conpressive and flexural loads is studied using a close loop system. NDT was also used to evaluate the damage. The residual mechanical properties of fiber-reinforced concretes are affected in a similar way than those corresponding to plain concrete. Nevertheless, it can be seen that the residual parameters tend to increase as the strength increases when high carbon-steel fibers instead of low carbon-steel fibers are used, and when fiber reinforcement is introduced.