The impact of MSWI bottom ash as aggregate on concrete mechanical performance

Abstract

This research investigates if bottom ash produced by incinerating municipal solid waste after recovery of metals and aging (weathering) can be used as a substitute for natural aggregates in the manufacture of concrete without additional treatment, rather than being disposed of in landfill. In this research, the performance of eight concrete mixtures that contained different amounts (0–100%) of MSWI bottom ash was analysed. Mixtures were produced by fully replacing coarse aggregate, fine aggregate, and then both of them with MSWI bottom ash and mixing with two amounts (340 and 300 kg/m3) of cement (CEM I 42.5 R). Reference mixtures were produced as well. The influence of MSWI bottom ash as aggregate on concrete performance was evaluated in terms of density, compressive strength and flexural strength. The effect of cement content was investigated as well. In addition, the changes in density and compressive strength after 2 days, 7 days and 28 days were analysed. The research showed that concrete with a compressive strength class of C20/25 and bending strength of 3.4– 4.3 MPa can be produced by fully replacing coarse or fine aggregate. To achieve this, at least 340 kg/ m3 of cement is required.