Abstract

This paper is the study of sulfate attack resistance of reactive powder concrete (RPC). RPC that is also known as ultra-high performance concrete is a special type of concrete material obtained when fine powders like silica fume (SF) are added into the concrete mortar along with very low waterto-binder ratio (w/b). SF is a pozzolanic material obtained as a by-product of silicon metal or ferrosilicon alloys production. In this study, total 6 different RPC mixtures with various w/b (0.18, 0.22 and 0.26) and various SF content were studied. SF was added into the concrete mixtures in the amount of 15%, 20% and 25% of cement by weight. The other testing parameter includes 3 different concentrations of sodium sulfate (Na2SO4) solutions (0.35 M, 0.7 M and 1.4 M concentrations). Broad laboratory investigations of behavior of the RPC mixtures were conducted in terms of compressive strength and mass gain of cubes (50×50×50 mm3) and expansion and mass change as in accordance with ASTM C1012. Test results had been analyzed and assessed by Taguchi method. The significance level of experimental parameters was determined by using Analysis of variance (ANOVA) method. According to statistical and analytical results it was observed that RPC has high sulfate attack resistance. Moreover, addition of optimal amount of SF into the RPC mixtures as well as decreasing w/b can significantly improve Na2SO4 resistance of RPC.