Cyclic Behaviour of Thin-Walled Pre-cracked HPFRC in Bending

Applications of High-Performance Fibre-Reinforced Concrete (HPFRC) are gaining popularity both thanks to its enhanced mechanical performance and its capability of guaranteeing pleasant finishing that makes this type of materials a good solution for thin elements like façade panels. These kinds of elements are often subjected to cyclic loads throughout their service life. The impact of cyclic loads on material properties is significant and can potentially lead to fatigue failures, particularly in situations in which the elements have experienced cracks during their service life. The research presented here is oriented to studying the cyclic bending behaviour of thin-walled elements made of one specific HPFRC material, also considering different level of pre-cracking that refers both to serviceability limit state and to ultimate limit state condition. A set of four-point bending tests were performed on 35 mm thick samples applying a pulsating load with a cycle frequency of 1.3 Hz and considering different load range typical of the serviceability limit state. The pre-crack levels considered correspond to 0.5, 1.5 and 2.5 mm of global crack opening measured astride the constant bending moment region. The crack evolution has been measured during the proceeding of the cycles and, in the cases in which the samples did not experience failure before 100.000 cycles, a monotonic test was performed in order to compare the structural performance after cycles with that in pristine condition.