Assessment of bond strengths of underwater polymer-modified concrete

Abstract

This research project aims to study the effect of styrene-butadiene rubber (SBR) latex admixture on washout loss of UWC and bond strength to existing concrete in case of repair applications. Three mixtures were prepared and tested, with 0.34, 0.44, 0.5 water to binder ratio that includes 0% to 15% SBR content. Initial casting was carried out in a 1.5-m long channel that was designed to simulate the UWC casting, where concrete falls from the outlet of a V-funnel apparatus and flows onto an inclined surface before dropping underwater and spreads in a 25x50-cm box. Results show that washout and aggregate segregation increases when casting underwater, hence decreasing pull-off strengths. The addition of SBR latex helped reducing washout loss and improved pull-off strengths with the damaged concrete.