Investigations on the short and long-term behavior of a post-tensioning system with basalt fiber-reinforced polymeric tendons

This study examines the short- and long-term behavior of a post-tensioning system that employs basalt fiber-reinforced polymeric (BFRP) tendons and a hybrid anchorage unit. The research framework, which builds on preliminary investigations into the uniaxial load-bearing behavior of the system, addresses both time-independent and time-dependent tension force losses. Time-independent losses were characterized by anchorage slip and friction. For the investigated post-tensioning system, an anchorage slip of approximately 3.2 mm resulted in a force reduction of about 3 kN, while friction losses were strongly dependent on the materiality of the contact surface. Time-dependent effects were investigated through relaxation tests on three samples over a duration of 1000 h, yielding an average loss in tension force of approximately 6 %. These investigations give new relevant information about post-tensioning systems with BFRP tendons and provide the basis for further investigations in the future. • Holistic research approach accounting for the short and long-term behavior of BFRPs. • Losses due to wedge slip are not severe, since Young’s modulus of BFRP is low. • Friction losses are strongly dependent on the materiality of the contact surface. • Relaxation losses for BFRPs are about 10 % after one million hours.