Study on Mechanical Properties of Flue Gas Desulphurization Gypsum-titanium Slag Powder Composite Cementitious Material

Flue gas desulphurization gypsum-titanium slag powder（abbreviation:FGD-TS） composite cementitious material was prepared from flue gas desulphurization gypsum and titanium slag powder which are the industrial solid waste.The effect of addition amount of titanium slag powder on the phase composition and microstructure of FGD-TS composite cementitious material was investigated by XRD and SEM.The results show that with increase of the amount of titanium slag powder,the amount of dihydrate gypsum crystals per unit volume of FGD-TS composite cementitious material decreases,and both of the 2-hour bending strength and compressive strength of FGD-TS composite cementitious material decrease.The suitable amount of titanium slag powder is 10%～20%,and the titanium slag powder is embedded in the dihydrate gypsum crystals,which plays a role of skeleton and makes the dry compressive strength of FGD-TS composite cementitious material increased by 10%～27% with comparison with that of single flue gas desulphurization gypsum.It increases the long-term strength of FGD-TS composite cementitious material and meets the requirements of 3.0 grade of Building Gypsum（GB/T 9776—2008）.