Behavior of RC columns incorporating with steel and recycled plastic fibers under eccentric load: An experimental work

There was a dearth of research into the behavior of eccentric RC columns reinforced with fibers, particularly recycled plastic fiber (RF) reinforced columns. The effect of employing end hooked steel fiber (EF) and RF on the performance of eccentric columns was explored in this experiment. Under compressive eccentric load, eight RC columns of 150 x 150 x 1000 mm with a 2% longitudinal reinforcement ratio were tested up to failure. The ratio of load eccentricity to column dimension was 15%. The fiber content (V-f) was variable. Both EF and RF had a V-f of 1%, 2%, and 3%. The applied load was recorded axial/lateral displacement and transverse/longitudinal reinforcement strain. The ultimate load (P-u), ultimate displacement, yield load, stiffness, and ductility index ( increment ) were all calculated to investigate column behavior. Results showed that adding fibers prevented the concrete cover separation hence prevented the sudden failure as it happened in the control column without fiber (P-0). 1% RF and 2% EF enhanced P-u by 10.4% and 34.8%, respectively, while fiber content 3% decreased P-u. Stiffness of columns containing 1% RF and 2% EF was 16.3% and 33.8% higher than that of P-0, respectively. The use of 1% and 2% EF delayed yield load, resulting in improved column performance. All fiber contents significantly improved ductility, with enhancement rates ranging from 4.2% with 3% RF to 146.2% with 3% EF. Also, use of 1% RF increased ductility by 70.6%.