Experimental Study on Autogenous Healing of Cracked SHCC Under Sustained Bending Loading

Abstract

SHCCs have been widely reported for their distinct autogenous healing property of the multiple fine cracks because of fiber bridging effect and remarkable precipitation of secondary products in cracks. However, most of previous studies performed autogenous healing tests of SHCC without simultaneous loading, i.e., applying healing environment to specimens after removing the pre-cracking load. Experiment studies on autogenous healing of cracked SHCC under sustained loading, which is closed to serving conditions of real structures, are still limited. In this study, the authors performed autogenous healing experiment of SHCC specimens under sustained bending loading. Small SHCC beams with steel rebar reinforcement at tensile side were prepared. A setup that can offer sustained load was used to apply four-point bending to the beam. Then, the tensile side of the beam, where multiple bending cracks took place, were immersed in water for autogenous healing in more than one month during when the bending load was sustained. For the control group, the same healing operation was applied but the load was unloaded before that. The crack widths were observed using microscopy periodically to study the healing degree. The results indicated that, although all of the specimens exhibited crack healing in certain degrees, the specimens with sustained load showed slower healing process than those unloaded, leading to higher water absorption after the healing operation.