Dielectric and Spectroscopic Studies of A Fly Ash Blended Cement Paste

The dielectric constant ( epsilon ') of Sulfate Resisting Portland Cement (SRPC) blended with 30% of fly ash by addition is measured using microwave bench at 9.54 GHz, for initial 30 hours of hydration. The heat of hydration for the same blend using heat of solution calorimetry is also measured. It is observed that contrary to the usual trend of retarding of fly ashes, it shows an accelerating trend with increasing strength as times passes. SEM micrographs and XRD patterns are also recorded and observed that C sub( 4)Al sub( 2)SO sub( 16) (C sub( 4)A sub( 3)S super( -)) is found to be responsible for the accelerating trend of the mix. The hydration process in the early period is studied and it is suggested that suitable retarder should be adopted for the effective utilization. Cement chemistry notations: C=CaO, A=Al sub( 2)O sub( 3), S super( -)=SO sub( 3), H=H sub( 2)O, F=Fe sub( 2)O sub( 3), S=SiO sub( 2).