Analysis of ancient mortars and design of compatible repair mortars: The case study of Odeion of the archaeological site of Dion

Ten mortar samples (structural, plaster, floor substratum), taken from Roman Odeion of the archaeological site of Dion, were analyzed, regarding their physico-mechanical, microstructural and chemical properties. The evaluation of test results led to the definition of their structure and consistency, while proposals for repair materials were made. Compositions of repair mortars were tested (physico-mechanical properties, behavior in ageing) and results showed the suitable mixtures, meeting the requirements of resistance to the extreme environmental conditions of the site (humidity, salt accumulation), as well as of compatibility to old materials. Through the analysis, the criteria for the selection of suitable repair mortars are presented, aiming in the preservation of ancient structures and the maintenance of their integrity and authenticity.