## 1 Introduction  
Shape memory alloy (SMA) is a special alloy with characteristics (Shape Memory Effect (SME)) that can be recovered to its original shape through an activation process consisting of heating and cooling processes even when plastic deformation occurs in it [1]. In 1951, SME was first discovered in Au-Cd single crystal alloy, and many types of SMA have been developed since then [2; 3; 4; 5]. In particular, after SME was discovered in Ni-Ti alloy (Nitinol), which was being developed to secure corrosion resistance in 1963, SMA began to be used in various fields such as aircraft, ships, and satellite antennas [6; 7; 8; 9]. Recently, many researchers have conducted various studies to use SMA as a construction material [10; 11; 12; 13; 14; 15]. SMA with superelasticity can improve the seismic performance of the structure by damping the vibration applied to the structure [16; 17; 18; 19; 20]. In addition, SMA enables new attempts that were difficult to implement with conventional construction materials, such as the ability to apply stress to a structure in a desired direction through SMA's SME [21; 22]. In particular, a method to introduce prestress using the recovery stress of SMA can resolve several disadvantages of conventional prestressed concrete. When the deformation of the pre-tensioned SMA is constrained and then activated, the SMA tries to return to its original shape, but because the SMA is constrained, a compressive force called recovery stress occurs inside it. As in this principle, when the pre-tensioned SMAembedded in concrete is activated by induction heating or electrical resistance heating, SME is generated in the SMA and it tries to shrink to its original state. However, since the deformation of the SMA is constrained by the bonding force between the SMA and concrete, recovery stress is generated inside the SMA, and this recovery stress acts as a compressive force on the concrete like prestress force of conventional prestressed concrete. Concrete members to which prestress are introduced in this method have great mechanical performance because concrete and the SMA work integrally as in the bonded prestressed concrete. In addition, in the method of introducing prestress using SMA, it is possible to simply introduce prestress to the concrete member only by heating SMA without an anchoring device and jacking device, unlike the conventional prestress method. Moreover, unlike conventional bonded prestressed concrete, concrete members to which prestress is introduced through SMA can recover the initial recovery stress through simple reactivation even if recovery stress is lost due to various causes such as drying shrinkage and creep of concrete, and SMA relaxation [23]. The most widely used SMA in the industrial field is Nitinol. However, Nitinol has a relatively narrow temperature history [24]. Moreover, it is practically impossible to use Nitinol, which contains expensive Ni and Ti in large proportions, as a construction material. On the other hand, Fe-based shape memory alloy (Fe-SMA) has a lower manufacturing cost compared to Nitinol because relatively inexpensive iron is used as the main material. Therefore, studies for introducing a prestress force into a structure using Fe-SMA have been studied by many researchers. [PERSON] et al. [25] conducted an experimental study to evaluate the flexural performance of mortar specimens reinforced with Fe-SMA bars. They reported that the initial cracking load and ultimate load of mortar specimens reinforced with Fe-SMA bars were larger than those of mortar specimens reinforced with stainless steel bars. They explained that the cause was the introduction of a prestressing force into the specimen due to the activation of Fe-SMA. [PERSON] et al. [26] performed an experimental study to confirm the prestressing effect of the Fe-SMA wires in mortar beams. They conducted a bending test of the mortar beams reinforced with Fe-SMA wire.