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.

An Overview of Characterisation, Utilisation, and Leachate Analysis of Clinical Waste Incineration Ash

“…The compressive strength of the mortar, however, decreased as the CWA content increased. After 28 days of immersion in water, the number of heavy metals leached from mortar specimens was very small and negligible (maximum percentage of 0.58%) compared to the original heavy metals present in the CWA powder (Al-Akhras et al 2011 ).…”

“…Table 2 shows the Physical Properties of CWIFA. However, compared to CWIBA, CWIBA was dark black or black (Al-Akhras et al 2011 ; Anastasiadou et al 2012 ) . The specific gravity of CWIFA is 1.82 (Ali Jawaid and Kaushik 2012 ).…”

“…Portland cement systems can be an option for the disposal of these kinds of ashes, and mortars are prepared to contain up to 50% of cement (Genazzini et al 2003 ). In the study, Al-Akhras ( 2011 ) investigates the stabilisation of CWA in mortar mixtures by three CWA dosages: 5%, 10%, and 15%. The proportions of the mortar mixture are 1:3:0.7 for cement, sand, and water by weight.…”

“…With the rise in CWA content, the setting time of cement paste declined. When the CWA level was raised, mortar workability improved (Al-Akhras et al 2011 ). The compressive strength of the mortar, however, decreased as the CWA content increased.…”

“…The amount of heavy metals leached is negligible compared to the total amount of heavy metals present in CWA powder. However, in practice, the mortar will remain wet for a shorter period but more frequently during rainy occurrences (Al-Akhras et al 2011 ).…”