Influence of nanoparticles additions on the bond between steel fibres and the binding paste

In the last decades, steel fibres have been widely used to reinforce the binding paste of concrete, mainly aiming at preventing/controlling cracking, by significantly increasing the (low) tensile strength and deformation capacity of current concretes. In this scope, the bond between steel fibres and the binding paste is of paramount importance. Following the More recent development of nailoparticles, several studies have been conducted to assess how they can enhance the properties of concrete mixtures. An experimental program was defined and conducted to analyze the influence of nanoparticles additions in the fibre-to-paste bond strength. A new pull-out test for monitor the fibres' slip versus the applied load was specifically designed in this scope, using current equipment, and thirty-six specimens were tested up to failure. It was concluded that it is more effective to add nanoparticles to the binding paste than to add these as fibres' coating and the fibres' anchorage, namely the hooks at both ends of the fibres, plays a much more significant role on the fibres-to-paste bond strength than the nanoparticles addition. (C) 2017 Elsevier Ltd. All rights reserved.