Influence of steel fiber on dynamic compressive behavior of hybrid fiber ultra high toughness cementitious composites at different strain rates

This paper describes an investigation of the influence of steel fiber (abbreviated as SF) on the dynamic compressive behavior of hybrid fiber ultra high toughness cementitious composites (UHTCC) at different strain rates. The volume content of SF was varied from 0.0% to 1.5%, whereas the volume content of polyvinyl alcohol (abbreviated as PVA) fiber remained constant at 2.0%. The cylindrical specimens were prepared and tested at strain rates ranging from 113.8 to 192.1 s(-1) by using an 80 mm diameter split Hopkinson pressure bar (SHPB). The dynamic behavior of hybrid fiber UHTCC was evaluated in terms of failure patterns, dynamic compressive strength, dynamic increase factor (DIF), and energy absorption ability. Moreover, the visco-elastic model was employed to describe the viscoelastic behavior of hybrid fiber UHTCC. The experimental results show that the addition of SF improves the dynamic behavior of UHTCC significantly. In contrast to the previous studies, the rate sensitivity of dynamic strength in hybrid fiber UHTCC depends upon the fiber volume fraction. It was found that specimens with higher SF volume fractions exhibit lower rate sensitivity in dynamic strength than specimens with lower fiber volume fractions. In contrast, decreased strength sensitivity to SF content was observed with an increase of strain rate. (C) 2016 Elsevier Ltd. All rights reserved.