Effect of fiber content on flexural fracture parameters of high-performance steel fiber-reinforced concrete

This study deals with the effect of fiber content on fracture parameters of high-performance steel-fiber-reinforced concretes through a bending test program. All the high-performance steel-fiber-reinforced concretes flexural specimens were tested under configuration of three-point loading. The fracture parameters were hardening energy, softening energy and length of cohesive crack. Two steel fiber types were employed in the studied high-performance steel-fiber-reinforced concretes, including 35 mm long hooked fiber and 13 mm short smooth fiber. The high-performance steel-fiber-reinforced concretes were produced from the same matrix but added different fiber contents as follows: 0.0 vol.%, 0.5 vol.%, 1.0 vol.%, and 1.5 vol.%. The experimental resultsdemonstrated that two parameters, including the hardening energy and softening energy, were observed to increase with increasing of fiber content, regardless of fiber type. The hardening energy was lower than thesoftening energy at any fiber content. The short smooth fibers generally produced the higher fracture energyparameters than the long hooked fibers. The highest total fracture energies of the high-performance steel-fiber-reinforced concretes were observed at 1.0 vol.% as follows: 58.25 kJ/m2 for using short smooth and 59.16 kJ/m2 for using long hooked fibers. Besides, the addition of reinforcing fibers considerably improved the length of the cohesive crack of the high-performance steel-fiber-reinforced concretes: from 0.58 mm using no fiber to 519.85 mm using short smooth fibers 0.5 vol.%.