Experimental Investigation on Self-Rehabilitation of Intelligent Concrete Beams Reinforced with Superelastic Shape Memory Alloys

This paper investigates the self-rehabilitation properties of Intelligent Reinforced Concrete Structures (IRCS) with superelastic Shape Memory Alloys (SMAs). The concrete structure reinforced with superelastic shape memory alloys is intelligent in the sense that the structure possesses the self-rehabilitation capacity, which refers to that the structure can significantly reduces the width of its cracks induced by earthquakes or other disastrous events by taking advantage of the superelastic property of SMA reinforcements. In this study, SMA strands/cables, made of SMA wires, were developed for reinforcing concrete structures via post-tensioning. For comparison purposes, three reinforced concrete beam specimens were cast: an ordinary concrete beam containing only steel reinforcements and two concrete beams containing both superelastic SMA and steel reinforcements with different configurations. The post-tensioning method was used to reinforce the concrete beam using SMA strands and the three-point bending tests were conducted on these beams to induce severe cracks. The test results show that with a proper arrangement of steel and superelastic SMA reinforcements the specimen exhibits the self-rehabilitating capacity in the sense that the induced cracks can be closed by the superelastic SMA reinforcements upon removing of the load.