Effect of high strain rate loading on compressive behaviour of fibre-reinforced high-strength concrete

This paper presents a laboratory experimental study on the effect of high strain rate loading on compressive behaviour of plain and fibre-reinforced high-strength concrete with similar strength of 80–90 MPa. Steel fibres, polyethylene fibres and a combination of these were used in the fibre-reinforced high-strength concrete. Split-Hopkinson pressure bar equipment and a hydraulic test machine were used to determine the concrete behaviour at strain rates from about 10 to 300/s and from about 10⁻⁴ to 10⁻¹/s, respectively. Dynamic increase factor and fracture patterns of the specimens, concrete matrix and fibres are discussed. The CEB–FIP equation is found to be applicable to the high-strength concrete, but overestimated the dynamic increase factor of fibre-reinforced high-strength concrete at strain rates beyond a transition strain rate of 30/s. A modified dynamic increase factor equation is proposed for plain high-strength concrete and fibre-reinforced high-strength concrete.