External chemical shrinkage of pastes containing Flue Gas Desulphurisation (FGD) Waste

The effect of including flue gas desulphurisation (FGD) waste on total chemical shrinkage of cement paste up to 7 days is reported. The FGD wastes were obtained from different plants located in different countries which vary in compositions. Also simulated FGD wastes were prepared in the laboratory which is a blend of fly ash and gypsum. Pastes were prepared with water to binder ratio of 0.5. The binder consists of cement and FGD. Cement was replaced with 25% (by weight) of different FGD materials. The results reported show varying trend depending upon chemical composition. Using calcium sulphate based FGD waste in cement paste, both the short and long-term total chemical shrinkage were reduced. For paste containing SiO2-Al2O3-CaSO4 based waste the total chemical shrinkage was reduced.