The analysis of the results of determination of the concentration
of fixed calcium hydroxide – Chapelle method – showed that
the best results are obtained with a calcination temperature
of 700 C for 30 min. However, this value is very close to the
one obtained with a calcination temperature of 600 C for 1 h,
which requires less energy. The resulting value is more than
twice the limit required to classify a material as having low pozzolanic
activity.