Analysis of durability (frost resistance) of MSWI fly ash modified cement composites

The research focused on effective utilisation of fly ash (FA) from municipal waste incineration plants. FA was found to have an effect on rheological characteristics (viscosity) of cement pastes, to suppress cement hydration processes. Evidence was obtained that up to 10% of FA in hardened cement paste and mortars does no impair compressive strength characteristics. XRD analysis and SEM tests revealed that FA modified cement composites contain Friedel salt compounds, which have an effect on frost durability of cement composites. Tests of heavy metal leakage from hardened cement paste showed that the amount of heavy metals leached from specimens containing 5–10% FA did not exceed the limit values of inert waste specified in Directive 2003/33/EC. Frost durability tests showed that FA can be utilised in the manufacturing of cement composites with improved durability properties.