Diana was born in South Africa, then moved to Scotland before eventually studying physics at the University of Bristol. After graduating she remained at Bristol as a PhD student. Her main research interests include the conservation of historic buildings and works of art. In 2006 Diana entered into collaboration with Italian universities to investigate the mosaics of the Basilica di San Marco, Venice, to aid restoration work. Her presentation is based on this work.

Investigation of Lime Mortar/Tesserae Adhesion in Medieval Mosaics from the Basilica di San Marco, Venice

The Basilica di San Marco contains many beautiful mosaics. Unfortunately, salt water has caused deterioration of mosaic mortar which now requires restoration. To ensure the most appropriate materials are used, the original mortar has been analysed and modern day materials selected to work in sympathy with the original mortar and tested to determine their adhesion with glass tesserae.

The chemistry and structure of the original mortar was investigated using surface analysis techniques. It contains magnesium as well as two distinct phases, one inorganic, possibly calcium carbonate, and an unidentified organic phase.

A shear strength testing rig was specially designed to investigate the lime/tesserae bond of ‘simulated mosaics’ prepared by placing glass trial sections on various lime mortar mixes. Lime containing magnesium produced the strongest bond, indicating that it may be the most appropriate choice for restoration.

Back to list of 2008 finalists