Testing the volcanic material burying Pompeii as pozzolanic component for compatible conservation mortars

The aim of this work is to evaluate the potential use of ashes and lapilli that buried Pompeii as pozzolanic material for the formulation of conservation mortars. XRD analyses proved that the mineralogical composition of these volcanic products is consistent with the original pozzolanic mortars preserved at the archaeological site. A first set of pozzolanic mortars were prepared by using silica sand as aggregate. After curing the lapilli-based mortars, the measured compressive and flexural strengths proved to be higher than those of the control samples made of commercial pozzolan. A second set of samples, prepared by replacing silica sand with similar size coarse ash and lapilli, proved that volcanic aggregates further enhanced the mechanical properties by the formation of interfacial transition zones. The result of this research demonstrates that the volcanic material burying the archaeological site of Pompeii could be used as raw material in the formulation of compatible conservation mortars. As volcanic pozzolan is increasingly investigated as potential Supplementary Cementitious Material (SCM) for the production of sustainable concretes, preliminary considerations about the impact of the present work to this field of research are also provided.