DTA method was used to follow the hydration process of cement admixtures containing fluidized bed combustion by-product, formed
on joined combustion and desulphurisation in some installations with fluidized bed. Based on endothermic peaks attributed
to the dehydration of phases formed on hydration, the conditions leading to the formation of so-called ‘delayed’ ettringite
were found. This calcium alumino-sulphate hydrate is responsible for lower durability of fluidized bed ash containing material.
DTA method is also beneficial in the studies of fluidized bed combustion by-product itself, giving information about the un-burnt
carbon content and pozzolanic properties.