Dynamic enhancement of blast-resistant ultra high performance fibre-reinforced concrete under flexural and shear loading

Two independent projects are described in which drop-hammer techniques are used to investigate the dynamic increase factor (DIF) under both flexural and shear high-speed loading of a new ultra high performance fibre reinforced blast-resistant concrete. The results from both studies correlate well. The results show that a DIF of the flexural tensile strength rising from 1.0 at 1 s -1 on a slope of 1/3 on a log (strain rate) versus log (DIF) plot can be used for design purposes. The results also show that no DIF should be used to increase the shear strength at high loading rates.