Mechanical performance and energy absorption capacity of concrete reinforced with hybrid fiber systems

Abstract

Fiber-reinforced concrete (FRC) can improve the post-cracking behavior of conventional concrete, but local experimental data on toughness and energy absorption remain limited in Ecuador. This study evaluates steel and polypropylene fiber systems for applications in slabs, industrial floors, and pavements. Eight concrete mixtures (M0–M7) were evaluated using EFNARC panel tests to obtain load-deflection curves, absorbed energy up to 25 mm (E25), and residual load at 25 mm (R25). Compressive strength, slump, and material cost per cubic meter were also assessed to compare single-fiber and steel-polypropylene hybrid systems. M7 achieved E25 = 653.63 N⋅m, R25 = 21.70 kN, a peak load of 33.89 kN, f’c = 257.98 kg/cm 2 , and a slump of 18.33 cm. Compared with M0, M7 increased absorbed energy by approximately 18 times and residual load by more than 100 times. M6 achieved a slightly higher E25 of 656.86 N·m but had lower slump and R25 and a cost 13.9% higher than M7. M7 provided the most favorable balance among post-cracking performance, compressive strength, workability, and material cost. The contribution of this study is to establish a local, replicable, and performance-oriented experimental basis that enables the selection of hybrid fiber-reinforced concretes based on mechanical and economic criteria.