Etude de la dégradation des mosaïques romaines de Volubilis (Maroc)

Roman mosaics in Volubilis are opus tessellatum type. They show different deterioration features represented by the lacunae formation (lack of tesserae) and break down of mosaic pavements by fracturing. The deterioration of the tessellatum and the formation of cracks are related to the swelling of soil supporting these mosaics. Furthermore, the tessellatum is also damaged by chemical dissolution of the fine grained-mortar between (lime and quartz fine grain) and under tesserae, giving an important porosity and making the tessellatum very easy to collapse. A part from limestone tesserae, which show formation of vesicles by chemical dissolution, other ones such as marble and glass tesserae appear to be resistant to the weathering action.