Impact properties of steel fibre reinforced concrete in bending

Abstract

The effects of strain rate of loading including impact on the bending properties of steel fibre reinforced mortar are studied using an instrumented drop-weight impact machine. Particular emphasis is put on clarifying the influence of the fibre reinforcing parameters and matrix strength. The parameters investigated in the experimental programme include three volume fractions of fibres (1%, 2% and 3%), three fibre aspect ratios (47, 62 and 100, two mortar mixes and four strain rates of loading ranging from 0.5 x 10-5 to 1.2 strains per second. It is found that depending on the fibre reinforcing parameters the energy absorbed by the composite at static loading rates can be one to two orders of magnitude higher than that of the unreinforced matrix. Moreover, up to a three-fold increase is observed in the modulus of rupture and the energy absorbed by the composite when the strain rate increases from 0.5 x 10-5 to 1.2 strain per second.