Reactivity of fine particles in incineration bottom ash for supplementary cementitious materials

The high-value exploitation of municipal solid waste incineration bottom ash can be achieved by reducing its particle size to serve as a substitute for cement. This study uncovers the reactivity of fine bottom ash recycled micro-powder (FBA-RMP). In addition, the application of FBA-RMP as a cement substitute in mortar is studied. The results suggest that a certain quantity of active constituents exist in FBA-RMP, wherein SiO2, CaO, Al2O3 and Fe2O3 together make up around 85.3 wt.%. Although C-S-H gel and AFt are found in the paste with 30% FBA-RMP replacing cement, there are significant pores, among which the content of large pores is about 19.27%. As a result, the 28-day compressive strength of the mortar is 55.0% lower than that of the reference mortar. However, decreasing the proportion of FBA-RMP or extending the curing days can remarkably enhance the mortar strength.