Styrene-butadiene rubber modified cementitious grouts for embedding anchors in humid environment

Abstract

The effect of styrene-butadiene rubber (SBR) polymers on bond properties of cementitious grouts used for embedding anchors in presence of water is not understood. Different grouts containing 5–15% SBR and proportioned for fixed or varying water-to-cementitious materials ratio are investigated; testing was made under both dry and submerged water conditions. Test results have shown that SBR inclusion remarkably improves resistance to bleeding and washout loss, given the water-soluble latexes that coalesce in the cementitious matrix to increase stickiness and viscosity of the interstitial liquid phase. Such additions were particularly beneficial to attenuate the drop in mechanical properties when casting takes place in humid environments. Series of regression models and predictive charts are proposed to evaluate the effect of SBR on washout loss and residual compressive, flexural, and pullout bond strengths.