This paper deals with the effects of silica fume content and polymer-binder ratio on the properties of ultrarapidhardening polymer-modified mortar using silica fume and ethylene-vinyl acetate redispersible polymer powder instead of styrenebutadiene rubber latex to shorten the hardening time. The ultrarapid-hardening polymer-modified mortar was prepared with various silica fume contents and polymer-binder ratios, and tested flexural strength, compressive strength, water absorption, carbonation depth and chloride ion penetration depth. As results, the flexural, compressive and adhesion strengths of the ultrarapid-hardening polymer-modified mortar tended to increase as increasing polymer-binder ratio, and reached the maximums at 4 % of silica fume content. The water absorption, carbonation and chloride ion penetration resistance were improved according to silica fume content and polymer-binder ratio.

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The effects of slag content and polymer–binder ratio on the strength properties of autoclaved and combined wet/dry-cured SBR-modified concretes using ground granulated blast-furnace slag (GGBS) and styrene-butadiene rubber (SBR) latex are examined. As a result, the compressive and tensile strengths of the autoclaved and combined wet/dry-cured SBR-modified concretes using GGBS reach maxima at a slag content of 40%, and increase with increasing polymer–binder ratio. In particular, the autoclaved and combined wet/dry-cured SBR-modified concretes with a slag content of 40% and a polymer–binder ratio of 20% provide about three and two times higher tensile strengths than the same-cured unmodified concretes without GGBS, respectively. Such a high strength development is attributed to the improved bonds between cement hydrates and aggregates because of the incorporation of SBR latex.

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