Research On Properties Of Silicate And Sulpho-Aluminate Composite Cement Blending With Fly Ash

This paper studied from the physical performances of the composite cement system composed of four contents: sulphoaluminate cement clinker, Portland cement clinker, fly-ash and gypsum. XRD and SEM are used to determine hydrated production of composite cement system, through which hydrated mechanism is discussed in detail. The mineral matching of composite cement system is discussed by calculated mineralogical composition and hydrated production.In the paper, the mixing proportion of each component is ensured. Study showed that, when gypsum addition is 10% and CSA clinker is about 5%, achieved better performance index of the composite system. In the research small amount sulphoaluminate cement clinker is mixed into Portland cement clinker and with moderate gypsum addition, which can enhance the early-age strength of the composite system, expressive strength is enhanced by 5Mpa on the average and the same-age fracture strength is increased. Furthermore, the cement setting time is shortened after compounding of two clinkers. Fly ash can improve the setting procession fasten. Compared with black sample, the early setting time is extended from 27 minutes to 54 minutes. The final hydrated production is AFt, AFm, AH and C-S-H. The quantity of hydrated production is different when the ratio of composite cement is different. The hydrated processing of composite cement is studied based on existed cement hydrated mechanism, and calculate the probable hydrated production.