Effect of axial cyclic loading on frcm confined concrete

This study presents the results of an experimental campaign aimed at testing the behavior of fiber-reinforced cementitious matrix (FRCM) confined concrete subjected to axial cyclic and monotonic loading. Several parameters were investigated in the campaign, including fiber material (glass and carbon), number of layers applied (1-4 layers) and loading protocol. The results of 22 cylindrical specimens, between control and confined ones, were tested while carefully monitoring axial stress and strain developments. Lateral strain development was also monitored, through electrical strain gauges (eSGs), directly on the fibers of each confinement layer applied to better understand fiber exploitation during cyclic loading. Test results show that even though concrete strength was enhanced in all confined specimens, ductility is the one that is most improved. Both strength and ductility enhancements strongly depend on fiber properties and have a linear proportional enhancement with an increase in the FRCM layers applied. Additionally, no significant difference was observed between the envelope stress-strain curve from cyclic tests with respect to the monotonic ones.