Preliminary study of thermal activation of brick clays used as supplementary cementitious materials.

This paper deals with the thermal activation of brick clays. The main aim was to assess the possibility of their activation and afterwards also the applicability of such clays as supplementary cementitious materials. Three different brick clays were examined, varied in origin localities, and mainly in chemical and mineralogical composition. Their thermal activation was done at two different temperatures, namely exposure to 550 °C and 600 °C were investigated. The impact of temperatures was found to be of great importance. Clays exposed to 600 °C showed extremely higher specific surface area, and somewhat lower bulk density compared to those treated at 500 °C. Afterwards, blended cement pastes containing 10% of particular thermal activated clays were produced, and at the age of 28 days bulk density, bending strength and compressive strength were measured. The impact of temperature was indisputable. The exposure to 600 °C led to the blended cement pastes which showed better performance than the one treated at the lower temperature. However, the studied properties showed suitable values, and thus this study confirmed, that the thermal activation of brick clays is possible. [ABSTRACT FROM AUTHOR]