Experimental analysis on reinforced concrete beams enlarged with ferrocement retrofit system

This paper reports the experimental results obtained from the first phase of the study involving the loading tests for reinforced concrete (RC) beams retrofitted with the jacketing ferrocement system. Five beams, in which one is the control beam, and the other four beams are enlarged with ferrocement jacket, are prepared for the four-point bending tests. The obtained results indicate that the retrofit of the RC beams with ferrocement jacket alone induces the adverse influence on the member performance in terms of the load-carrying capacity, stiffness, safety, and ductility. In contrast, the strengthening with the ferrocement jacket incorporating addition of the steel tension bars noticeably improves the flexural efficiency of the RC beams. In such circumstance, besides the amelioration in the capacity, stiffness, and ductility, the strengthened beams exhibit numerous flexural cracks with narrow spacing and small width following the yielding of longitudinal reinforcement and the crushing of concrete at loading area. In addition, the continuity for the stress transfer at the ferrocement–concrete bonded interface remarkably governs the failure mechanism and ductility of the retrofitted beams. The discontinuity of the adherence between ferrocement and concrete by shear connector with anchored bars coupling the addition of the tensile reinforcement positively impacts the performance of the ferrocement-retrofitted beams. Sectional analysis cannot predict the flexural strength of the beams retrofitted with only ferrocement, while it can accurately assess the maximum capacity of the control beam and the beams with both ferrocement jacket and additional steels.