LAUSR

In this paper, we analyze the state of conservation of ceramic building materials (clay masonry units) containing a large share of waste materials in the form of ash and slag from coal combustion and sawdust from wood processing, operated for several decades in facing walls of religious buildings, in external environment conditions. For the purpose of this analysis, comparative tests were carried out on the samples of ceramic materials cut out from facing walls and samples extracted from the same ceramic materials; they were stored in laboratory conditions for the entire time. The following were investigated: initial water absorption, capillary rise, and porosity structure determined with mercury intrusion porosimetry (MIP). The research has shown, among other things, that the ceramic materials exploited in the external environment are characterized by an almost twofold increase in the initial rate of water absorption and by a different size of dominant pores and a pore size distribution in comparison with ceramic materials stored in laboratory conditions. The results, obtained for ceramic building materials (clay masonry units) containing the above-mentioned waste materials in their composition, constitute a novelty. They fill a gap in the literature by establishing how decades-long operation in natural conditions affected the capillary properties and the porosity structure of the ceramics under investigation. Based on the obtained research results, conclusions of cognitive and practical significance have been formulated that relate to the possibility of the exploitation of facing walls made of investigated ceramic materials.