The influences of matrix and steel fibre tensile strengths on the fracture energy of high-strength concrete

This research discusses the effects of both steel fibre and matrix strengths on fracture energy of high-strength concrete. The variables of experimental study were water/cement ratio, steel fibre strength and steel fibre volume fraction. The water/cement ratios of 0.35, 0.45 and 0.55, and steel fibres with a tensile strengths of 1100 and 2000 MPa were used and volume fractions of steel fibre were 0.33%, 0.67% and 1%. Mechanical properties, fracture energy and characteristic length of concretes were investigated.Significant influences of matrix and fibre tensile strengths on the fracture energy and the characteristic length are noted.

Research highlights
► We investigate effects of steel fibre and matrix strengths on concretes.
► Matrix and fibre strengths must be compatible to obtain maximum fracture energy.
► Tensile strength of steel fibre is important in mix design of fibre reinforced concrete.
► Optimisation is required for a good performance of steel fibre reinforced concrete.