Compressive strength, water absorption, water sorptivity and surface radon exhalation rate of silica fume and fly ash based mortar

In this study, the effect of partial cement replacement with silica fume and fly ash on the compressive strength, water absorption, volume of permeable pore, water sorptivity, radon content and surface radon exhalation rate of mortar mixtures were investigated. It was observed that the compressive strength of mortar mixtures containing silica fume as partial cement replacement increased as the amount of silica fume content increased while the water absorption, volume of permeable pore, water sorptivity and radon exhalation rate of mortar mixtures decreased. The decrease in surface radon exhalation rate was ranged between 23% and 43% while that of mortar mixtures containing fly ash increased up to 15% of the rate of the control mortar mixture. Results showed that silica fume addition decreased the radon concentration and surface radon exhalation rate while fly ash showed a detrimental effect.