Archaeometry

Three different historical mortars, one from the 18th'“19th centuries and two from the 12th century, were crushed and sieved to give eight fractions between less than 0.063 mm and 4 mm for each sample. Each fraction was chemically analysed for the amount of calcium carbonate binder, using the reactions with HCl and EDTA and by means of atomic absorption spectroscopy. The samples were also characterized by X-ray diffraction (XRD) and by low-temperature nitrogen adsorption isotherms. The limitations and advantages of each of the various methodologies for the determination of the binder are discussed. Reactions with HCl and XRD were shown to be the methods that gave the more coherent results.