Experimental investigation on the performance of flexural displacement recovery using crimped shape memory alloy fibers

Damage to a structure generally accompanies flexural deformation, which is mainly related to the safety of the structure. Displacement recovery should precede the repair and retrofitting of damaged concrete structures. In this study, a discrete shape memory alloy (SMA) wire was used to prepare a cementitious material with the capacity for flexural displacement recovery. The applicability of the SMA fiber-reinforced cementitious material is limited because of the geometry of the SMA wire. The proposed method for recovering the flexural displacement of concrete structures involves a new shape of the crimped SMA wire that increases the resistance between the wire and cementitious matrix. Cementitious slab specimens were designed according to the SMA content. A bending test was performed to determine the cracking and post-cracking flexural resistances. Heat was then applied to activate the shape memory effect of discontinuous SMA wire randomly mixed with cementitious materials. The results demonstrated that the crimped SMA fiber-reinforced cementitious slab with a content of 0.5-1.5% recovered the flexural displacement of the slab specimen, in addition to the closure of the crack.