A new near-surface-mounted anchorage system of shape memory alloys for local strengthening

Shape memory alloys (SMAs) are increasingly used as local reinforcements to control deformation and crack development of reinforced concrete members. This paper presented a new near-surface-mounted strengthening approach, in which the bond performance between SMAs and cement mortar is concerned. To ensure a reliable anchorage of smooth SMA wires embedded in cement mortar, three types of anchors, i.e. the U-shaped stirrups (AU), the block anchors with the flat head bolts (AF), and the block anchor with the hex socket bolts (AH), were suggested. The tensile and recovery tests were firstly undertaken to verify the anchorage performance between smooth SMA wires and the anchors. Then the bond performance of anchored SMA wires embedded in cement mortar was studied by pull-out tests. The results showed that the proposed AH anchor could ensure a reliable anchorage between smooth SMA wires and cement mortar within a short embedded length.