Strengthening and impact performance of reinforced concrete (RC) beams using various high-performance fiber-reinforced cementitious composites (HPFRCCs)

This study investigates the strengthening effect of various high-performance fiber-reinforced cementitious composites (HPFRCCs) on the impact resistance of reinforced concrete (RC) beams. Four different HPFRCCs—ultra-high-performance concrete (UHPC), high-performance strain-hardening cementitious composite (HPSHCC), engineered cementitious composite (ECC), and ultra-rapid-hardening strain-hardening cementitious composite (URSHCC)—were evaluated alongside a normal-strength concrete (NSC) as a control. The results showed that RC beams strengthened with UHPC and HPSHCC achieved the highest flexural load capacities, approximately 8 % greater than the plain RC beam. While UHPC reduced flexural ductility due to its lower tensile strain capacity, HPSHCC enhanced ductility. Strengthening with HPFRCCs also led to a reduction in maximum deflection under impact, with the S-UHPC beam showing the lowest deflection. Despite impact damage, RC beams retained residual flexural strength similar to undamaged beams but exhibited reduced flexural stiffness and ultimate deflection. However, UHPC and URSHCC experienced decreased load capacity after impact due to deformation beyond their tensile strain limits. These findings highlight the effectiveness of HPFRCCs, particularly HPSHCC, in improving the impact resistance and post-damage performance of RC beams. • RC beams strengthened with UHPC and HPSHCC exhibit the highest flexural load capacities. • S-HPSHCC beam demonstrates improved ductility compared to the plain RC beam. • Use of HPSHCC and URSHCC is effective in enhancing the flexural performance of RC beam than ECC. • Strengthening with HPFRCCs slightly reduces maximum deflection of RC beam subjected to impact. • RC beams strengthened with UHPC and URSHCC show a decrease in load capacity after impact damage.