The effects of solar UV radiation on the gloss values of polished stone surfaces

Natural stones, each featuring different physical, mechanical, chemical, mineralogical and petrographic properties, play an important role in construction because they are often used as cladding or paving/flooring materials. The physical and mechanical properties of the materials used as for cladding and/or flooring open areas are affected by both the environment and people. In construction projects, gloss value is one of the most essential physical features of natural stones that is used as a reference for cladding or flooring materials. Solar exposition, often in combination with other environmental factors, has a considerable importance in the aging of natural stones, particularly at lower latitudes. In order to determine the stone behaviour in the areas exposed to sunlight, gloss value was investigated using a thermostatic chamber. In this study, the effect of UV irradiation cycles on the surface brightness of polished natural stones and the relationship between gloss values and some physical, mechanical properties and calcite grain size of natural carbonatic stone samples were elucidated. As a result, it appears that marble samples have less gloss variation if compared with limestones.