Effect of bottom ash as partial fine aggregate replacement on fresh properties of self-compacting mortar

Abstract

This paper presents the effects of partial fine aggregate replacement by bottom ash on flowability and viscosity of self-compacting mortar with cement paste to mortar volumetric ratio of 50% and 55% and water to cement ratio of 35%, 40% and 45%. Bottom ash replacement ratio were 0%, 15% and 30% by volume. The results show that the increase of wet surface dry bottom ash did not significantly reduced flowability of mortar because free water was not absorbed by bottom ash. Viscosity of mortar tended to decrease with 15% wet surface dry bottom ash replacement. On the other hand, it slightly increased with 30% replacement due to internal friction increment by rough surface. However, viscosity was not noticeably changed in mortar with W/C of 45% due to its high water content which was sufficient for deducting the increase in internal friction by bottom ash volumetric replacement of 30%. Bottom ash replacement up 30% did not significantly affect fresh properties of mortar. Therefore, this could be applied to concrete industry. Moreover, rate of change in flowability of mortar at 30 minutes after mixing decreased with the increase of bottom ash replacement. Flow diameter changed in range of ±20 mm. Rate of change in viscosity decreased in mortar with cement to mortar ratio of 55%. V-funnel time changed in range of ±2 seconds but the change was up to 5-6 seconds in mortar with cement to mortar ratio of 50% and W/C of 35%.