Bound water content measurement in cement pastes by stoichiometric and gravimetric analyses

The cement hydration is one of the most complex processes creating the cement matrix. The degree of hydration is a quantity of Portland clinker with gypsum, that as a whole react with water. For purposes of this analysis it was found to be directly proportional to the bound water in the cement paste specimens. Using the gravimetric method the bound water content was determined in samples by calculating the quantitative loss of the dry specimens weight after igniting to 1000°C and keeping the temperature for 5h. Obtained results were collated with theoretical stoichiometric analysis based on the Bogue and Taylor equations and XRD testing for Portland cement, CEM I 42.5. Obtained outcome has confirmed the relationship between the degree of hydration and the bound water content in cement paste. The influence of the w/c ratio and cement oxide components on bound water quantity were also noticed.