Morphology in Relation to free Calcium Hydroxide Determination in Saudi Portland Cement Pastes

F. M. Helmy*, G. N. Al-Twaher and D. A. Al-Hashimi

Faculty of Girls, Department of Chemistry Jeddah University, Jeddah (Saudi Arabia)

Quantitative X-ray diffraction analysis is used in determination of the free Ca(OH)2 released during the hydration of Saudi Commercial Portland Cement for the periods, 5 hour to 28 days. Four standard mixtures are prepared containing 10% Mg(OH)2, 5-35% Ca(OH)2 and four different diluents to get 100% matrix. The four diluents are Portland Cement clinker and commercial, hydrous and anhydrous. Four X-ray different calibration curves are obtained. The more available curve to determine the free Ca (OH)2 in the Portland cement pastes is given from the mixture containing Portland cement clinker (gypsum free). Four morphological groups of hexagonal crystalline Ca(OH)2 are detected during the hydration of the commercial Portland Cement. The relation between the two strongest X-ray lines of Ca(OH)2 at 4.91, 2.63

Morphology; X-ray Free Ca(OH)2; Hydration; Diluents; Solvent extraction