Effect of cracking on serviceability of fibrous concrete

In many types of concrete structure loss the serviceability due to wide cracking or large deflection, and it should be repair it as early as possible. As very important structures, such as the tunnel of super express railway, which has a drop of concrete fragment, was a lead to severe social accident. The fiber is expected to be useful in order to improve the serviceability and to prevent a drop of concrete fragment. The performance of concrete with fibers is judged by the flexural toughness obtained by load-deflection curves. The flexural toughness of concrete is different by the different types of fiber and it can express well the toughness of RC members at failure. Sometimes, it is difficult to use the flexural toughness in order to judge the behavior of concrete structures under service load. From the result of cracking on concrete beam cyclic applied load, the necessity of adequate method to judge the performance of concrete with different types of fiber is discussed.