Stabilisation of medical waste ash in mortar mixtures

Abstract

This study investigates the stabilisation of medical waste ash (MWA) in mortar mixtures. Three MWA dosages were considered in the study: 5%, 10% and 15%. The other experimental parameters investigated in the study were: aggregate type and curing regime. The properties explored in the study include: setting time, workability, compressive and flexural strength and leaching of heavy metals. The mortar mixture proportions were 1∶3∶0·7 by weight for cement, sand and water, respectively. The results of the study have shown that MWA can be stabilised in mortar mixtures without significant leaching of heavy metals. The setting time of cement paste decreased with the increase in MWA content. The workability of mortar increased when the MWA level was increased. The compressive strength of mortar increased with the increase in the MWA content as a partial replacement of silica sand under moist and autoclaving curing conditions. However, the flexural strength of mortar decreased as the content of MWA increased as a partial replacement of silica sand under moist and autoclaving curing. The amount of heavy metals leached from mortar specimens after 28 days’ immersion in water were very small and insignificant (maximum percentage 0·58%) compared with the original heavy metals present in the MWA powder.