Relationship among the firing temperature, wetting properties and colonization of fungi on clay roofing tile surfaces

The wettability of clay roofing tiles as a surface phenomenon plays a key role considering their deterioration process during exploitation. The experimental investigations in this paper were performed combining the data of the material-relevant parameters and the surface wetting properties in order to assess clay roofing tiles biodurability. The fungus Aspergillusniger was used as a model microorganism whose colonization and growth, during a period of 28 days on the tiles fired at two temperatures (900 and 1020ºC), was analyzed. The paper confirms that the colonization of the tiles with the fungus goes through two stages: up to the 18th day, based on the surface characteristics, and after the 18th day when the textural characteristics (values of water absorption) are the dominant parameters