Durability of self-cleaning cement-based materials

Abstract

The use of self-cleaning materials as building materials is gaining more and more interest, but their performance characterization over time has been poorly investigated. For this purpose, accelerated durability tests were carried out on different self-cleaning materials, either based on photocatalytic principles (i.e. containing TiO2) or on the lotus effect, which were subjected to UV radiation, rain, freeze-thaw and thermal cycles variations. The accelerated ageing tests program involved different commercial materials and was aimed at a second step of characterization of their photocatalytic activity and self-cleaning ability, in order to investigate their durability and the retention of such functionality over time. With this aim, rhodamine B (Rh-B) dye degradation tests were performed. The experimental campaign proved the actual self-cleaning behaviour of these materials in their freshly produced state, but it also demonstrated the detrimental effect of ageing on their performances. Moreover, issues related to the test method emerged with special reference to the evaluation of materials durability.