Enhanced concrete crack closure with hybrid shape memory polymer tendons

The paper presents a new healing system that uses pre-tensioned hybrid tendons to close cracks in cementitious structural elements. comprise an inner core, formed from aramid fibre ropes, and outer sleeve made shape memory PET. During the manufacturing process, core of tendon is put into tension compression, such equilibrium. A set are then cast element heat activated once cracking occurs. This triggers shrinkage potential PET sleeve, which turn releases stored strain energy core. tensile force thereby released applies compressive element, embedded, acts any have perpendicular axis tendons. Details component materials used form given along with process. experiments reported explore performance three different configurations prismatic mortar beams. results these show can completely 0.3mm beams act as effective reinforcement both before after activation. nonlinear hinge-based numerical model also described, shown be able reproduce experimental behaviour reasonable accuracy. help interpret and, particular, effects slip at anchorages amount prestress remains It that, two tested, over 75% crack closure.