RATE EFFECT ON INTERFACIAL RESPONSE BETWEEN FIBERS AND MATRIX

A study on steel fibres pulled out from a cementitious matrix at diffe rent slip rates was conducted. A measurement system, which allows one to use two independent methods to evaluate pull-out load, was develope d for the Charpy pendulum. Two series of specimens, with 16 and 8 fibr es, respectively, were tested. Effects of the rate of slip and of numb ers of fibres on interfacial behaviour have been examined. A theoretic al model to predict the slip-rate effect on fibre pull-out has been pr oposed based on fracture mechanics. Based on the peak fibre pull-out l end of a reference specimen with a static slip-rate, the proposed mode l can predict peak pull-our loads and corresponding slips at faster sl ip-rates.