Radiocarbon dating potential of lime binders used in Prague in Medieval Period

0495100 - ÚTAM 2019 FR eng A - Abstract
Válek, Jan - Kozlovcev, Petr - Skružná, Olga - Bruthans, J.
Radiocarbon dating potential of lime binders used in Prague in Medieval Period.
MoDIM 2018. Mortar dating international meeting. Bordeaux: Université Bordeaux Montaigne, 2018. s. 24-24. ISBN N.
[MoDIM 2018. Mortar dating international meeting. 25.10.2018-27.10.2018, Bordeaux]
R&D Projects: GA MK(CZ) DG16P02H012
Keywords : lime * mortar binders * Prague castle * radiocarbon dating
OECD category: Materials engineering

The beginning of the use of lime as a mortar binder for masonry structures at Prague castle area is in general dated to the end of the 9th century when the church of Our Lady was erected. Mortars from various buildings dating up to the 15th century have been characterised by means of optical microscopy, SEM EDS, thermal analysis, XRF, XRD and ratio determination by acid dissolution during the last 15 years. This characterisation has been also accompanied by experiments replicating historic lime technologies, mapping of local historic geological resources and by studying written sources in archives. This approach brought a relatively comprehensive understanding of the mortar materials used in that period in Prague. Overall, the mortars were all rich in binder and showed a certain chemical and mineralogical similarities. They were composed mostly from feebly to moderately hydraulic lime and a siliceous sand of fluvial nature. The origin of the raw material is in the southwest vicinity of Prague of Devonian age. Aim of this recent study was to utilise the relatively detailed understanding of the materials used at Prague castle area including the technological processes of binder production and processing and to evaluate them in terms of their potential for the use carbon dating. It specifically focused on characterisation of course binder related particles present in the historic mortars and the predominant hydraulic nature of these binders. For this purpose, three archaeological mortar samples representing different construction periods and buildings were dated by AMS using three separated CO2 fractions. The obtained data are discussed in depth with regard to estimate the potential of a future use of the radiocarbon dating method for the site. It also offers an overview regarding the understanding of the use of natural hydraulic lime in Mediaeval Period and its hardening processes.
Permanent Link: http://hdl.handle.net/11104/0288653