Tensile behaviour of high performance fibre-reinforced cementitious composites at high strain rates

摘要

The promise of fibre-reinforced cementitious composites for dynamic loading application stems from their observed good response under static loading. An experimental research aimed at contributing to the understanding of the behaviour of advanced fibre-reinforced cementitious composites subjected to low and high strain rates was carried out. The material behaviour was investigated at four strain rates (0.1, 1, 150 and 300 s -1) and the tests results were compared with their static behaviour. Tests at intermediate strain rates (0.1-1 s -1) were carried out by means of a hydro-pneumatic machine (HPM). High strain rates (150-300 s -1) were investigated by exploiting a Modified Hopkinson bar (MHB). Comparison between static and dynamic tests highlighted several relevant aspects. First, with the change in the strain rate, the Dynamic Increase Factor (DIF) of the material appears well predicted by some models proposed in the literature up to a value of 0.1 s -1, while at higher strain rates it increases less than expected from models. Moreover, the post-peak behaviour showed a stress plateau influenced by the fibres and dependent on the strain rate.