Abstract

Stainless steel wires (SSWs) with micro diameter and stainless steel fiber (SFs) with millimeter diameter were incorporated together to develop multifunctional ultra-high performance concrete (UHPC) in this study. The addition of 0.2 vol.% of SSWs can already improve interface between matrix and SFs, reduce the microcracks in UHPC caused by shrinkage and initial load, increase SFs’ distribution and orientation with their high flexibility, thus enhancing the flexural toughness and resulting in the occurrence of multiple cracking flexural failure mode of UHPC with less than 2.0 vol.% SFs. The hybrid SWs and SFs reinforced UHPC possesses low electrical resistivity and can sense its initial cracking, residual flexural loading and cracking development by the measured fractional change in electrical resistivity. This is mainly coming from the inhibition effect of SWs on microcracks and the extensively conductive pathway formed by both SWs and SFs. The multiple cracking failure mode under flexural load and the self-sensing capacity to monitor crack initiation and propagation of UHPC with low content hybrid wires and fibers is important to develop multifunctional UHPC, thus providing a new approach for maintaining sustainable development of infrastructures.