APPLICATION OF CALORIMETRY IN STUDIES OF THE IMMOBILIZATION OF HEAVY-METALS IN CEMENTITIOUS MATERIALS

Cementitious systems based on blends of normal portland cement with di fferent materials are used for the treatment and conditioning of toxic and hazardous wastes. The addition of waste material may interfere wi th the hydration reaction in the cement matrix and consequently with t he setting and with hardening process. Some of the waste materials acc elerate the hydration process, others act as set retarders, The progre ss of hydration can be monitored by heat evolution measurements and th e calorimetric results are considered as indicators of the degree of h ydration. In this study microcalorimetry was used to evaluate the heat output during the hydration of cement and of blends of cement and bla st furnace slag treated with solutions of heavy metals.