Feasibility of using Fe-SMA rebar as cracking resistance spiral stirrup in the anchorage zone of post-tensioned prestressed concrete

To alleviate the problem of cracking in the anchorage zone of post-tensioned prestressed concrete. The novel iron-based shape memory alloy (Fe-SMA) spiral stirrups with self-prestressing properties were used in this study, which can provide active circumferential confinement to the anchorage zone. The compressive behavior of the anchorage zone was experimentally tested in terms of the damage modes, crack patterns, and load–displacement curves. Additionally, piezoelectric ceramics (PZT)-based smart aggregate (SA) was utilized to monitor the development of internal damages in the anchorage zone. The test results showed that the crack resistance of the anchorage zone was improved by Fe-SMA spiral stirrups. Since higher heating temperature and longer heating time resulted in temperature diffusion which aggravated the initial damage in the anchorage zone, the activation temperature and time needed to be limited. And numerical simulations were carried out based on the experimental results. Overall, the use of Fe-SMA spiral stirrups is found to be helpful in retarding the internal cracking damage of anchorage concrete at a reasonable activation temperature and time.