Responses of composite beams with high-performance fiber-reinforced concrete

•Evaluating synergistic effect of the hybrid fiber system on direct tensile resistances of HPFRCs.•Developing a composite beam using normal concrete combined with high-performance fiber-reinforced.•concrete (HPFRC).•Proposing models and equations to estimate moment resistance of the composite beam with HPFRC. This investigation focuses on the moment resistance of a composite beam with high-performance synergized fiber-reinforced concrete (HPFRC) by performing analytical and experimental works. At first, the HPFRC containing 1.0 vol% long hooked steel fibers blended with 0.5 vol% short smooth steel fibers was explored to produce an important synergy in direct tension. The synergy coefficients according to tensile parameters of the HPFRC were ranked as follows: strain capacity