Replacement of natural sand with MSW gasification slag as an alternative fine aggregate in greener concrete...

High temperature slagging gasification process converts municipal solid waste (MSW) to energy and at the same time it is generating gasification slag as a final by-product. This study investigates the effects of varying particle size and morphology of MSW gasification slag by adding as received, sieved and ground slag at different replacement ratios to the mortar and concrete mix. Replacement of up to 100 % natural sand with MSW slag is achieved with desirable compressive strength of 61.0 ± 1.6 MPa and 62.2 ± 3.4 MPa at 28 and 60 days curing of mortar cubes, respectively. MSW slag mortar demonstrates low slump but high flowability as compared to typical sand mortar owing to its lower water absorption capacity (0.18 ± 0.06 %). The leaching performance of MSW slag as fine aggregate in the mortar, evaluated based on batch leaching test (EN 12457-1), are within the relevant regulatory limits for waste-derived materials. The water penetration, water absorption and RCPT test were also conducted on 50 % and 100 % MSW slag concrete, and the results were satisfactory to regulatory standards (<30 mm for water penetration, <5% water absorption and low to moderate chloride resistance ∼ 2000 C). These findings suggest practical potential for utilizing MSW slag in light-duty pavement and non-structural concrete where durability and lower carbon footprints are key priorities.