FLUIDITY AND UNCONFINED COMPRESSIVE STRENGTH OF CEMENT-FLY ASH-DESULFURIZATION GYPSUM COMPOSITE CEMENTITIOUS MATERIAL

A new type of composite cementitious material was developed from cement, fly ash and desulfurization gypsum(CFG).The influence of the amount of each component in CFG on the fluidity and un-confined compressive strength (UCS) of CFG were studied by the flow test and the UCS test based on the orthogonal test method. The results showed that composite with a higher cement content achieved a higher fluidity, but composite with a higher the ratio of desulphurization gypsum to fly ash achieved a lower fluidity with the constant cement content. The effect of cement content on the UCS of the material was highly significant at the age of 3d, and the maximum reduction of average strength was 50.1% when cement content decreased by 20%.The effect of cement content on the UCS of the material was significant at the age of 28d,and the maximum reduction of average strength was 23.1% when cement content decreased by 20%.The ratio of desulphurization gypsum to fly ash had a certain effect on the UCS of the material at the age of 28d. and the growth rate of UCS of composite was more affected by the cement content at the ages of 3d-14d while the ratio of desulfurized gypsum to fly ash had a greater influence at the ages of 14d-28d.