Experimental study of mechanism properties of interfacial transition zones in steel fiber reinforced concrete

Abstract

To investigate the effects of steel fibers on the macroscopic mechanical properties, fracture properties and microstructure of the interfacial transition zones (ITZs) in concrete, composite spilt tensile and three-point bending specimens with three different volume fractions of steel fibers (0.5%, 1.0%, and 1.5%) and two types of rock aggregates (Limestone, Granite) were tested, and the fiber- cement paste and reinforced cement paste-aggregate interfacial transition zone microstructure by scanning electron microscopy (SEM). The results show that SF affects the mechanical properties of ITZ on different rock surfaces by different mechanisms, and the high volume content of steel fibers (≥ 1.5%) significantly reduces the tensile strength, fracture energy and fracture toughness in the transition zone.