Capturing the strain hardening and softening responses of cementitious composites subjected to impact loading

Ultra-high performance fiber reinforced concrete (UHP-FRC) is a type of cementitious composite that has extended hardening and softening responses when subjected to tension. The length of the tensile loading regime complicates the development of test setups that can capture the full tensile response at high strain rates. To address this challenge, analytical and finite element modeling are used to propose modifications to an existing test set up to enable it to conduct accurate and practical testing of UHP-FRC specimens in direct tension, under high strain rate. The test device employs suddenly released strain energy to generate an impact pulse and a sufficiently long transmitter bar to channel the signal and measure it. Tests conducted on UHP-FRC specimens at strain rates of 90-145 1/s show that, under increasing strain rates, the material maintains its strain capacity and has highly enhanced strain dissipation capacity, making it particularly well suited for blast and impact applications.