Thermal deterioration of marbles: Gloss, color changes

This study assesses changes to surface aesthetic properties of some marble samples due to heat. For this purpose thermal ageing and thermal shock cycles were inflicted on six types of marble samples of differing colors. Marble samples of shiny surfaces were prepared. In thermal shock cycles, samples were heated up to 105 °C for 18 h then placed for 6 h in distilled water. In thermal ageing cycles, the samples were placed in an oven for 18 h then allowed to cool for 6 h at room temperature. At the end of cycles 4, 8, 12, 16 and 20, gloss measurements were recorded; at the end of the last cycles color changes were evaluated. The relationships between gloss and color parameters were also investigated. Thermal shock has more important effects on marble surface properties than the thermal ageing cycle. L∗ and b∗ parameters constituted an important effect on glossiness and these parameters were strong indicators for predicting gloss loss.