Design of Compatible Mortars for a Late Roman Tomb in Serbia

Abstract

Design of conservation mortars for architectural heritage is always an ambitious and inspiring task, asking for many diverse requirements to be success-fully harmonised. Principally, conservation mortars need to comply with demanding chemical, mineralogical, textural, and mechanical compatibility criteria. The main aim of this paper is to show the design and development of compatible mortars for conservation of a late Roman tomb in Serbia, situated around the former Danube Limes. It is only a fragment of the MoDeCo2000 project which deals with the research of mortars from the archaeological sites along the Limes, dated to the period from the first to the sixth centuries. Laboratory activities for the sampled mortars included visual observations, stereo-optical and digital microscopy, spec-trophotometry and colourimetry, mineralogical and petrographic analyses, physical– mechanical tests, thermal characterisation, mechanical and chemical separation of aggregates and binders, and characterisation of samples, binders, and aggregates using FTIR, Raman, XRF, and XRD. The obtained results enabled designing of conservation mortars mixtures based on local raw materials. Following laboratory preparation of mortar models and several cycles of mixtures optimisation, the newly developed mortars for the Roman tomb were artificially aged and compared with original samples. The models which successfully fulfilled requirements qualified for application on small test areas of the historical building, and their behaviour was closely monitored in situ. The promising research results directly led to production of compatible mortars for upcoming conservation actions on the Danube Limes in Serbia and contributed to the universal body of knowledge about Roman mortars and architecture.