Mineralogical and microstructural study of the phases developed during the hydration process of industrial cement mixtures

The phases identified in two industrial cement mixtureswere qualitatively and quantitatively characterizedbefore and during their hydration process. The studywas carried out as a function of time, water/cement ratioand temperature; the characterization was performedusing XRPD (with the Rietveld method to obtainquantitative phase analysis, hereafter QPA), SEM/EDSand ESEM techniques. QPA revealed that the drymixtures have similar composition and that differ for thesource of calcium sulphates. The use of differentcalcium sulphates need different w/c ratios and givesrise to a different amounts of C6AS3H32, amorphousphase and to a different reaction rate. Results fromESEM technique agree with XRPD results and confirmthe different behaviour of the mixtures. Hightemperature reduces the difference in the reaction rate