Pull-out tests of ribbed steel reinforcing bars embedded in concrete with steel fibres

Abstract

This paper presents an experimental study on the behaviour of the bond stress of steel reinforcing bars embedded in steel-fibre-reinforced concrete. In total, 27 specimens were subjected to pull-out tests. The main variables included the volumetric fraction of the fibre, the diameter of the reinforcing bars and the anchorage length. The results showed that the introduction of steel fibres had a significant effect on improving the bond stress performance in terms of the failure load resistance, the tensile resistance of the concrete and the reduction in the anchorage length, resulting in a more ductile bonding behaviour of reinforcing bars with smaller tested diameters. An equation to estimate the ultimate bond stress was proposed based on the prescriptions of the Brazilian design code NBR 6118, which is more accurate and considers the observed effects of the fibre addition.