Effect of the Conservation Treatment of Historical Ceramic Tiles on the Tensile Adhesion Strength

Abstract

The present work describes some preliminary results of a first attempt to study the effect of a conservation treatment on the adhesion strength of ancient ceramic tiles. Several tiles from the 16th through 20th centuries were submitted to a conservation treatment. The treatment involves the impregnation with Paraloid B-72 using a protocol widely used in most museum restoration departments. Treated and untreated tiles were attached to a brick surface with a bonding mortar. After 3 months, pull-off tests were performed in treated and untreated samples and the tensile adhesion strength was determined. Although a small number of samples was analyzed, the adhesion strength was found to increase for treated tiles in comparison with the pull-off strength of untreated samples.

Keywords:

• historical tiles
• adhesion strength
• conservation treatment
• bonding
• mortar

ACKNOWLEDGMENTS

The authors thank the ‘Museu Nacional do Azulejo’ of Lisbon, and extend thanks in particular to Dr. Paulo Henriques (former Director), Dra. Maria Antónia Matos (actual Director) and Dra. Lurdes Esteves (Conservator) for the samples and technical information. The authors also thank the technician, Bento Sabala (LNEC), for his assistance in pull-off tests.