Experimental Study on Structural Behavior of UHPFRC Members under Different Strain Rates

Reinforced concrete structure has suffered severe degradation due to the combined effects of aggressive environments and significantly increased live load. Furthermore, many concrete civil infrastructures such as buildings and bridges are not designed to resist highly impulsive load such as blast or impact. As a result, the structures will progressively fail when subjected to high strain rates loading such as impact or explosion. In the uncertain times facing us these days such infrastructures need to be less susceptible by using a material with high energy absorption capacity, such as Ultra-high performance reinforced concrete (UHPFRC). UHPFRC is a new class of cement composite and is characterized by highly dense microstructure and very high compressive strength more than 150 MPa. Therefore, the aim of this research is to investigate the strain rate effects on flexural strength of UHPFRC and to develop a better understanding about the behavior of UHPFRC under different loading rates. The response of UHPFRC was determined from 3-point bending test which applied three different loading rates which are 0.1 kN/s, 0.5 kN/s, and 1.0 kN/s. Besides, the behavior of UHPFRC under different loading rates is also discussed as the volume ratio of steel fibers, Vf is varies from 0% to 3%. From this study, higher fiber volume ratio results in higher flexural strength and the flexural strength of UHPFRC is increasing as higher loading rates are applied. Based on the excellence performance of UHPFRC, its behavior appears to make it an ideal material for resisting high strain rates effects.