Determination and Modelling of Bond Properties of Synthetic Macro-Fibres in Concrete

Abstract

Bond behaviour of a synthetic macro-fibre in concrete is the object of this research. The bond strength and stiffness are the parameters characterising the bonding mechanism that determines the efficiency of the reinforcing material. However, there is no general methodology developed to evaluate fibre efficiency. There also exists neither a straightforward procedure to estimate the bond quality of a synthetic macro-fibre nor a reliable numerical model to simulate the bond behaviour of such fibres. In this work, the bond mechanisms of 40 mm long synthetic macro-fibres are investigated using pull-out tests: 16 concrete cubes were made for that purpose. One type of synthetic macro-fibre available at the market is considered. In each test sample, three fibres were inserted perpendicular to the top and two side surfaces; two bonding lengths (10 mm and 20 mm) were used. A gripping system was developed to protect the fibres from local damage. A physically non-linear finite element model of the pull-out sample was developed. A bond model was proposed to simulate deformation behaviour of the fibres.