Performance of cements with calcined clays as main constituent

Pozzolanic properties of calcined clays of various mineral composition mixed with four different CEM I Portland cements were examined. It was found that the firing temperature has a great influence on the specific surface area of clay and, as a consequence, the water demand of pozzolana cement. Calcined clay with a high content of active Al and Si contributes to the high strength of cement. Cement with 20% by wt. of calcined clay can reach the strength class 52,5 N in accordance with EN 197-1 without further improvements. For cements with 40% by wt. of calcined clay the strength class 42,5 N can be achieved.

Author: S.E. Schulze, J. Rickert

Section: Science and production

Keywords: pozzolanic cement, pozzolanic material, calcined clay, hydration