Experimental and theoretical investigations on flexural performance of hybrid fiber reinforced ECC-NC composite beams

This study aims to clarify the mechanical behavior of hybrid fiber reinforced Engineered Cementitious Composite (ECC)-normal concrete (NC) composite beams. A comprehensive analysis was conducted to study the effects of the fiber type, reinforcement ratio, and steel fiber dosage on the flexural performance of the composite beams. The results showed that, compared with the NC beam, the stiffness of the composite beams with a 1.7% volume fraction of polyvinyl alcohol (PVA) fibers increased by 14.7%. Furthermore, those with a 1.7% volume fraction of polyethylene (PE) fibers increased by 26.1%. Steel fibers with volume fractions of 0.6% and 1.0% improved the flexural capacity of the PVA fibers composite beams by at least 8.1%. In addition, considering the fiber bridging effect, a calculation model for the flexural capacity of the composite beams was developed. Meanwhile, calculation methods for the average crack spacing and maximum crack width were proposed, which could provide a reference for further research and engineering applications.