Restoration of two-span RC beams with severely corroded reinforcement using C-FRCM composites

Abstract

The feasibility and viability of using carbon fabric-reinforced cementitious matrix (C-FRCM) composites for restoration of continuous reinforced concrete (RC) beams with severely corroded reinforcement were examined. Five large-scale dual-span RC beams were fabricated and tested. One beam was not corroded to serve as a control. Four beams were subjected to accelerated corrosion that corresponded to a tensile steel cross-sectional loss of 40% in either the sagging or the hogging region. Such a steel cross-sectional loss would cause a comparable reduction in the yield load of bare steel reinforcing bars. Two of the corroded beams were repaired with C-FRCM composites. An analytical model was formulated and utilized to design the number of C-FRCM layers required to fully restore the original load capacity. Experimental results verified the redistribution of moments between the sagging and hogging regions due to yielding of the tensile steel at critical sections. Both sagging and hogging sections contributed to the load-bearing capacity, and hence, the reduction in the load capacity caused by corrosion in one of the critical sections was smaller than the tension steel cross-sectional loss caused by corrosion. It was possible to predict the load capacity of the tested beams with reasonable accuracy considering the residual cross-sectional area of the corroded tension steel bars while keeping their yield strength and Young’s modulus unaltered in addition to implementing other conventional assumptions adopted by international codes and guidelines. As predicted analytically and verified experimentally, rehabilitation of corroded continuous beams with appropriate number of C-FRCM composite layers fully restored their original load capacity. Research findings would assist practitioners in conducting a proper analysis of continuous RC beams with corroded reinforcement before and after repair with C-FRCM composites.