Evaluation of physicochemical and hydromechanical properties of MSWI bottom ash for road construction

Municipal Solid Waste Incinerator (MSWI) Bottom Ash has been used as a substitute for traditional aggregates in road construction; however, this material is little understood. The work presented in this paper pursues the study on the mechanical performance of bottom ash, proven by Le et al. (2017). Using a coupling technique for the first time, the physicochemical aspects and hydromechanical resistance of bottom ash were evaluated and analyzed. Physicochemical tests were first carried out, followed by oedometer tests under a wetting path. This coupled evaluation underlined the role of principal mineralogical components of the studied bottom ash as well as the link with its hydromechanical properties. Tests results showed that the principal constituent of bottom ash is SiO₂, which thus affects the characteristics of bottom ash. Given the physical stability of SiO₂ which generated a compacted material being less sensitive to water and chemical reactions, and bottom ash's other characteristics, this demonstrates why bottom ash could be a viable material in roadworks.