Crack self-healing effect on performance of reinforced concrete members subjected to water supply and cyclic loading

Self-healing concrete (SHC) can heal itself from cracks and other minor imperfections and thus prolong the life of the material itself and structure. In plain and reinforced concrete structures, fatigue is one of the major causes of both material and structural failures. Under the moving load due to traffic, it is not only the relatively simple opening and closing action in the transverse direction to the crack plane but also the severe reversed shear displacement along the crack plane. This accelerates the deterioration on the shear transfer mechanism at the crack surface. Although the shear transfer between two cracks accelarates the rupture of crack surface, a lot of crushed powders and fragments are produced in the crack. Even in this severe situation it is expected for self-healing concrete that crushed powders and fragments would bring the healing effect to cracks and then water leakage through cracks would reduce. When cracks form, the release of effective components from the SHA (Selfhealing additives) would be promoted. Under cyclic loading, not only opening-closing action,but also reversed shear transfer are repeated and then the release of effective components from SHA would be accelerated. To verify this interesting scenario several SHA were applied to specimens of structural reinforced members subjected to cyclic loading in a series of tests. In this study, flexural fatigue tests were conducted for three different types of Self-healing concrete (SHC) and the effect of self-healing at fracture process zone (FPZ) and cracks area on structural performance is examined. The experimental results indicate that one of SHC shows remarkable effect not only on water sealing in water pass tests but also prolongation of fatigue life in flexural tests