Study of ancient mortars from Sagalassos (Turkey) in view of their conservation

Since 1990, regular archeological excavations are done in the Roman city of Sagalassos (southwestern Turkey) by the Catholic University of Leuven (Belgium). The mineralogy and petrography of the lime mortars at Sagalassos have been studied in detail as part of an investigation of the provenance of mineral raw materials present in the territory of Sagalassos. The samples were analysed with optical microscopy on thin sections followed by XRD analyses to design a suitable repair mortar. The lime used as binder was burnt from local Triassic limestones and prepared by dry slaking. Three main types of aggregates have been identified: limestone from local Mesozoic limestones, crushed ceramics from locally produced coarse wares and volcanic tuff from a nearby volcanic region. To preserve the excavated remains in very harsh climatic winter conditions, experimental mixtures of restoration mortar have been tested for strength and frost resistance using similar raw materials as in ancient times. The proposed mortar for further on-site conservation and restoration consists of a mix of lime with crushed volcanic rock from the region of Isparta. This composition is very similar to the original Roman material and shows a high frost resistance in freeze-thaw testing. (C) 2002 Elsevier Science Ltd. All rights reserved.