Fabrication and performance analysis of sustainable municipal solid waste incineration fly ash alkali-activated acoustic barriers

The recycling of hazardous municipal solid waste incineration fly ash (MSWIFA) is drawing more attention, in which the alkali-activation technique may provide great potential to make full use of it as sustainable acoustic materials. The present work evaluated the applicability of alkali-activated MSWIFA-based materials (AAFMs) as porous acoustic barriers. The chemical composition and microtomography of the as-prepared AAFMs were characterized by X-ray diffraction. Fourier-transform infrared spectroscopy, and scanning electron microscopy. With the incorporation of MSWIFA and foaming agents, the dry bulk density and porosity of AAFMs were subsequently examined. Moreover, the compressibility and leachability of AAFMs were also investigated to evaluate their mechanical performance and environmental safety as construction materials. A sound absorption test was eventually conducted to explore the sound absorption performance of AAFMs, considering the main factors such as aluminum addition, MSWIFA dosage, and sample thickness. The results verified the good chemical stability, leachability, and sound absorption performance of porous AAFMs. Specifically, it indicated that the aforementioned factors have a boosting effect on forming highly porous structures that improve sound absorption performance, namely sound absorption coefficient and noise reduction coefficient.