CHARCTERISTICS OF SULPHATE RESISTING CEMENT PASTES CONTAINING DIFFERENT RATIOS OF BELITE PHASE

H. El-Didamony[1a], A. Radwan[1b], I. Khattab[2], E.A. El-Alfi[3] , Mona S. Mohammed[4]
Page No. 52-62

The influence of tricalcium silicate (alite) content on the properties of the sulphate resisting cement
(SRC) was studied. Three types of SRC with various ratios of alite/belite were prepared. The water
of consistency, initial, and final setting time of these cements as well as the kinetics of hydration
and physico-mechanical properties of the cement pastes were determined. Some of the hydrated
cement pastes were investigated using DTA, TGA, XRD and IR techniques. The results show that
the increase of alite content enhance the rate of hydration, and hence the early strength
development, at the expense of the ultimate strength. One reason for this is that the microstructure
formed during the accelerated hydration is usually coarser and less favorable for strength
development. Contrary to this, slow hydration with increasing belite content cement paste allows
the formation of a microcrystalline or gel-like structure of large surface area, which results in an
ultimate good strength.
Keywords: Sulphate resistance cement, Belite phases, Hydration properties