Influence of municipal solid waste incineration bottom ash on the hydration and carbonation behavior of reactive magnesia cement

Abstract

This study investigates the effects of Municipal solid waste incineration bottom ash (MSWIBA) on the hydration and carbonation behavior of reactive magnesia cement (RMC). The results indicate that the incorporation of MSWIBA accelerates the early hydration rate of RMC due to its dilution and nucleation effects. However, excessive MSWIBA content formed layered double hydroxides (LDH) inhibiting the hydration of magnesium oxide cement. Furthermore, while a 5% addition of MSWIBA enhances the compressive strength of RMC after carbonation, higher contents lead to a reduction in post-carbonation strength and long-term durability due to the formation of microcracks from hydrogen gas generation and the expansion from carbonation products. Additionally, the carbonation process is affected by LDH, which hinders the crystallization of hydromagnesite and favors the formation of more amorphous phases. The findings suggest that while MSWIBA can be beneficial at low dosages, its excessive use may compromise the long-term performance of RMC.