Leaching Behavior of Concrete Containing Municipal Solid Waste Incineration Bottom Ash

The object of this study was to investigate the impacts of municipal solid waste incineration (MSWI) bottom ash (BA) regarding cement hydration and leaching when used cement-based materials. As a mean of cement hydration assessment, energy dispersive X-ray (EDS) and X-ray diffraction (XRD) analysis were conducted on MSWI BA ‘as is’, hydrated BA, and BA-combined cement paste. The results show that MSWI BA led to small amount of cement hydration. In addition, the leaching characteristics of major alkaline and trace elements from concrete containing varied amounts (10%-50%) of BA were investigated by synthetic precipitation leaching procedure (SPLP) batch testing. The results reveal that the release of highly alkaline elements increases with increasing the BA content. However, the release of selected alkaline and trace heavy metals is reduced when mixed with PCC properly due to the binding effect in cement mixtures and consuming from cement hydration. Results show that crushed PCC mixed with the MSWI BA demonstrated significant reduction of Al and Si. Moreover, Mg ranged from 475.9 μg/L for the 100% BA to 181.3 μg/L for the PCC with 50% BA and Cu ranged from 45.5 μg/L to 15.1 μg/L.