Petrography and mineralogy of Roman mortars from buildings of the ancient city of Jerash, Jordan

Roman mortars (cementing materials) from the archaeological site of Jerash have been studied by means of petrography, mineralogy, microstructure and geochemical analysis. They are mainly composed of lime with differing in the type and proportion of aggregates used, including crushed carbonate rocks (limestone), gypsum, and siliceous sand. The samples were studied in order to identify their mineralogical composition using thin section, XRD and SEM and their chemical compositions were analysed using XRF. The results showed that two types of natural aggregate sources were used: the first was composed of calcite, gypsum and quartz while the second was composed of calcite gypsum, clay minerals and crushed pozzolan. One sample of the first type showed fine particles with micrite matrix and clay minerals. Petrographic analysis showed the strong binder cohesion and perfect binder bond of aggregate and high reactivity for of the lime, and these agree with soft burning of the raw limestone.