New strategies in mortar characterization and radiocarbon dating

Radiocarbon dating was used on mortars exploiting the C uptake during the carbonation process, where the atmospheric CO2 signal is absorbed by reaction with lime putty, and then it is converted back into CaCO3-binder containing the signature of the construction time. The CaCO3-binder must be isolated from other carbonate sources and contaminants such as delayed hydraulic and secondary alteration products which could affect the dating process [1]–[3]. An appropriate mineralogical characterization of the mortar greatly enhances the understanding of the reaction history of the material allowing the preliminary assessment of the “dateability” of the binder, and afterwards, the choice of the needed pretreatments for a reliable radiocarbon dating. In this paper, our procedures in mortar characterization, binder isolation and innovative treatments of the fine binder fraction in order to obtain a suitable dateable material are shown.