Exploring the applications of medical waste ash as a sustainable construction material

Medical waste ash (MWA), a byproduct of the incineration of biomedical waste, poses environmental risks if not properly treated. As a potential supplementary cementitious material, MWA offers both environmental and engineering advantages by enabling waste valorization and reducing reliance on conventional cement. However, the differences in its physical, chemical, and microstructural properties, together with variations in pre-treatment and incorporation methods, have led to inconsistent performance across construction applications. This review systematically studies the recent research (2020–2024) in upcycling MWA in construction materials including asphalt mixtures, mortar, and concrete focusing on its effects on key performance indicators such as compressive strength, sorptivity, and heavy metal leaching. Optimal replacement levels, typically ranging from 5% to 15%, are summarized to achieve a best mechanical performance. Comparative results show that properly treated MWA can increase the 28-day compressive strength of concrete up to 65 MPa. This review aims to provide a strategic framework for the application of MWA in the construction industry to promote cleaner production and sustainable waste management solutions by incorporating MWA into construction materials.