Strengthening of Reinforced Normal and Self-Compacted Concrete Beams: Comparative Experimental Investigation

Carbon fiber reinforced polymer (CFRP) is a sustainable and long-lasting material that can improve concrete strength in many different structural contexts. This work shows how well near-surface mounted (NSM) CFRP improves the flexural behavior of both self-compacted and normal-strength reinforced concrete beams. Six sets of reinforced concrete beams were cast in three groups with normal-strength concrete and three groups with self-compacted concrete. Four groups were externally strengthened using NSM-CFRP bars, and the remaining two groups acted as control beams without CFRP reinforcement. Two NSM groups had CFRP bars placed at the sides of the beams, whereas in the other NSM two groups, the bars were buried at the bottom. For normal-strength concrete and self-compacted concrete, the experimental findings showed that side-mounted NSM-CFRP bars increased the flexural strength by 32% and 44%, respectively. The flexural strength increases were 25% and 38% when mounted at the bottom. The novelty of this work lies in its comparative evaluation of two CFRP installation procedures across two concrete types under consistent structural and testing conditions, a feature not thoroughly investigated in previous work. This dual-variable approach provides a useful understanding of how to maximize CFRP retrofitting strategies depending on the concrete type and application situation.