Toward Sustainable Concrete: Experimental Investigation Using Municipal Solid Waste Incineration Bottom Ash

This study explores the feasibility of using municipal solid waste incineration bottom ashes (MSWIBAs) as a partial replacement for cement in concrete with respect to the fresh and hardened properties of concrete. MSWIBA samples from five Swedish incineration plants (BA1–BA5) were collected and analyzed for their mineral composition and particle size distribution (PSD). The samples (BA3 and BA5), exhibiting better pozzolanic behavior and particle sizes closer to those of conventional cement, were selected for further detailed study. Mechanical activation was performed on the BA3 and BA5 samples. Concrete mixes were prepared with 10% and 20% (by mass) cement replacements utilizing raw and activated BA3 and BA5 samples. The resulting concrete specimens were evaluated through slump, density, and compressive strength tests at 7, 28, and 56 days. The results showed that activated MSWIBAs improved the workability of the concrete specimens compared with the control concrete mix, and the density of the concrete decreased with increasing the MSWIBA content. The compressive strength of the concrete mixes generally decreased as the replacement level of MSWIBAs increased. At 56 days, the concrete mix with 10% raw BA5 reached about 77% of the compressive strength of the control concrete mix, whereas mixes with 20% raw or activated MSWIBAs reached about 58%. The concrete mix with BA3 performed better than the mix with BA5 at 7 days, while the concrete mix with BA5 showed higher later-age compressive strength. In addition, mechanical activation of MSWIBAs did not significantly improve compressive strength of concrete mixes. Despite the reduction in compressive strength when using MSWIBAs, this sustainable concrete contributes to the development of climate-friendly concrete and offers potential environmental benefits.