Determination of Pozzolanic Activity of Thermally Activated Brick Loam

Abstract

Supplementary cementing materials (SCM) present of one of possible ways how to reduce the energy consumption and related CO2 emissions from Portland cement production. There is number of more or less stablished SCM. These may be by-products of another production technologies (blast furnace slag, coal fly ash), natural materials (certain volcanic rocks) or produced materials (calcined clays).Metakaolin (MK) – thermally activated kaolin – belongs to the widely studied SCM. Its main drawback is relatively high price, caused partially by the rather “exclusive” raw material – kaolin. The research on thermal activation of more abundant clay raw materials to SCM may raise the application potential of clay-based SCM. This paper deals with thermal activation of a brick loam. The loam under study contains all principle clay minerals (kaolinite, illite, montmorillonite) accompanied by quartz and feldspars. The loam was characterized by thermogravimetry and XRD. Then it was activated at three temperature levels (500, 550 and 600 °C) and the pozzolanic activity was determined by Saturated Lime Test. It was found that all three materials are fixing considerable amount of Ca 2+ ions, but probably not only by pozzolanic reaction, but also adsorption on clay minerals plays a role.