STUDY OF THE EFFECTS OF GYMPSUM, POZZOLANIC ADDITIVE MIXTURES AND THEIR FINENESS ON THE STRENGTH OF PCB50 FICO CEMENT

In the study, raw materials including clinker, gypsum, pozzolan were separately milled on a ball mill (the ball mill size: φ500 mm × L500 mm, productivity: 5 kg / grinding time) to achieve the desired blaine fineness. A mixture is mixed at the calculated ratio includes of 90 % fineness clinker, 5 % fineness gypsum and 5 % fineness pozzolan (In it, pozzolanic additive is mixed at different fineness levels). The effects of the mixture of gypsum and fineness pozzolanic additive as well as the fineness of pozzolanic additive to strength of PCB50 Fico cement were investigated. The study shows that, pozzolanic additive have reduced the strength of cement. But, when pozzolanic additive is mixed with gypsum, this additive mixture has increased the strength of the cement at the late time (at the age of 28 days). The fineness of pozzolan has little effected on the early strength of cement.