The mechanical property and frost resistance of roller compacted concrete by mixing silica fume and limestone powder: Experimental study

Abstract

This study aims at the effects of different cementitious materials (i.e. limestone powder, silica fume and fly ash) on the mechanical performance and frost resistance of roller compacted concrete (RCC) for dam engineering. The compressive strength, split tensile strength and elastic modulus of RCC with admixtures (i.e. 20% limestone powder +20% fly ash (LF), 5% silica fume +35% fly ash (SF), 20% limestone powder +5% silica fume +15% fly ash (LSF)) were determined from 7d up to 90d. Furthermore, the crack resistance and frost resistance of RCC with different mixtures were also investigated. The results show that LSF had the optimal mechanical performance at 7d and 28d, while the best mechanical performance at 90d was SF. The anti-cracking performance of SF at 90d was much better than that of LF due to the pozzolanic reaction of silica fume. However, high addition of silica fume had no advantage of improving the frost resistance, which have been verified by carrying out mercury porosimeter analysis. Furthermore, micro-structural analysis and thermogravimetric analysis were performed to evaluate the micro mechanism, which can provide the theoretical basis for the macro mechanical performance of RCC with new admixtures for application of dam engineering at a microscopic level.