Influence of the mineral paragenesis, porosity and structural defects In the alterability of historical clay brick

The aim of this study is to determine the durability of historical brick in relation to mineralogy, porosity and estructural defects. To this aim, the mineralogy of the raw clay used to make the brick was analysed. The mineralogy of the raw clay fired at different temperatures was also determined. The temperature at which the brick was fired was deduced by comparing the mineral paragenesis of the brick at the building with those of the fired samples. The porosity of the brick was measured by mercury po'osimetry. The resistance of the brick to weather was tested by performing durability tests in the laboratory. Durability tests included freeze-thaw, thermal-moisture and salt crystallization cycles.' The results of a// the above tests and analytical techniques showed that the main factors which determine the weathering of the ceramic ware are both structural defects and mineralog