Hydration Study of Ordinary Portland Cement in the Presence of Lead(II) Oxide

The aim of this work was to investigate the effect of the addition of lead(II) oxide on hydration heat and specific conductivity of a CEM I Portland cement. The heat released during hydration was determined by differential microcalorimetry up to 48 hours of hydration and the specific conductivity by a digital conductometer. Thermogravimetric analysis was employed in the characterization of the cement structure. The hydration heat results show that the addition of lead(II) oxide affects the cement hydration kinetics. Kinetic curves show that higher content of lead(II) oxide slows down the hydration processes and the heat values are lower. Addition of lead(II) oxide significantly delays the time to the appearance of maximum conductivity. Setting time is prescribed by standard for a particular type of cement and can be determined based on the appearance of specific conductivity maximum, which occurs at the setting time. It wasfound that the acceptable amount of lead (II) oxide in cement system was w = 0.25 wt. %