The influence of waste crumb rubber in reducing the alkali–silica reaction in mortar bars

Abstract

The objective of this experimental work was to study the effect of crumb rubber on decreasing the expansion caused by Alkali–Silica Reaction (ASR) in mortar specimens prepared with highly reactive aggregate.In this regards, mortar bars containing 0%, 16% and 24% crumb rubber by volume as fine aggregate replacement were prepared for the accelerated mortar bar test (AMBT).Results from this study indicated that the use of 16% and 24% crumbed rubber as fine aggregate replacement decreased the ASR expansion in mortar bars by 43% and 39%, respectively. However, the compressive strength of the mortar cubes containing 16% and 24% crumb rubber reduced by 20% and 47% at 28 days, respectively. While Thermo-Gravimetric Analysis (TGA) showed no reaction between rubber particles and pore solution of concrete, the Scanning Electron Microscopy analysis from mortar bar sections containing crumb rubber confirmed the positive impact of physical damping of crumb rubber particles on reducing the ASR in the mortar specimens.