Incinerator residual ash – Metakaolin blended cements: Effect on cement hydration and properties

Abstract

Abstract In this study two types of residual ash (with and without amorphous phase) derived from multi-fuel industrial incinerators were used for cement replacement in conjunction with metakaolin (MK). X-ray diffraction-Rietveld analysis and thermogravimetry were used to evaluate the impact of incinerator residual ash and MK on hydration of binary and ternary cement formulations, while compressive strength and water absorption changes were also assessed. Results showed that hydration of ternary systems depends on the type of residual ash. Ternary compositions with cement substituted by MK in conjunction with ash containing amorphous phase showed higher hydration rate, bigger content of monocarboaluminate with lower amount of portlandite in respect to the ternary paste with the ash free of amorphous phase. With regard to water absorption and compressive strength, better performance showed ternary cement formulations with residual ash containing amorphous phase, while strength similar to the reference paste was gained at later age.