Restoration Synthesis of Crushed Brick Mortars Simulating Byzantine Lime and Material Technologies in Crete

Abstract

The original mortars, which have been deteriorated by natural weathering, salt decay and the corrosive action of polluted atmospheres, have to be replaced. However, the uncontrolled and rather extensive use of cement and polymer-based mortars, give very unsatisfactory results, due to the high content of soluble salts and the limited compatibility with the original components of the masonry. Hence, restoration mortars compatible with the traditional building materials, though more resistant than the original ones, should be searched out. In the present work an attempt is made to evaluate whether the traditional materials and technologies, reproduced by the monks of the Toplou Monastery in Crete, do provide ameliorated restoration mortars. Physical, chemical and mineralogical investigations on Byzantine and post - Byzantine mortars and plasters of crushed brick and lime from Rhodes, Crete and Hagia Sophia, by Optical Microscopy, X-Ray Diffraction Analysis, Thermogravimetric Analysis, Hg- Porosimetry and Infra Red Spectroscopy, seem to provide reliable evaluation criteria. This comparative study leads to the conclusion that the proper mixture ratio, the appropriate lime technology and raw materials, the crushed brick granulometry and texture, as well as the proper application techniques are necessary to achieve an optimized approach to the traditional mortars.