Physical and transfer properties of mortar containing coal bottom ash aggregates from Tefereyre (Niger)

Abstract

This study is focused on the use of coal bottom ash from Tefereyre (Niger) power plant coal-fuelled, as a fine aggregate in cementitious mortar. Various volume fractions of natural sand (0%, 10%, 20%, 30%, 40%, 50%, 75%, and 100%) were replaced by the same volume of fine aggregates of coal bottom ash. In order to determine the effect of coal bottom ash incorporation on the composites obtained, fresh and dry density water absorption, porosity, thermal conductivity, ultrasonic pulse velocity, gas permeability and microstructure analyses were investigated.The results show that incorporating coal bottom ash in mortar causes an increase in the apparent porosity and that leads to an increase of the water absorption and the apparent permeability of the samples at 28days curing age. The densification of bottom ash mortar during the curing age contributed to significantly reduce the increase in the porosity and the apparent permeability. This densification was confirmed by SEM analysis and ultrasonic velocity measurement. However, the use of coal bottom ash reduces the specific weight and the thermal conductivity of cementitious materials. Overall, the mortars containing coal bottom ash offer an opportunity to recycle (by-product) wastes.