Nowadays, strengthening interventions and protective treatments on heritage masonry structures require compatibility of the new material for improving effectiveness and avoiding future damage. Knowledge of the physical, chemical, and mineralogical properties of the mortars represents an invaluable tool for deepening this aspect. This study focuses on three types of samples of lime-based mortars that come from different historical periods: a medieval lime mortar (14th century), a lime mortar from the turn of the 18th/19th century, and, for comparison, a modern cement-lime mortar of M7 class. Samples of historical mortars have been collected from historic buildings located in southern Poland. These materials have been characterized experimentally using destructive and non-destructive techniques, such as X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and petrographic microscopy in order to obtain mineralogical and chemical information on the samples. These analyses also provide information on the physical properties in the reference periods analyzed. Our results evidenced differences in the use of feldspars among the different historic periods but similar composition of quartz and calcite. Furthermore, evaluation of the internal structure of the samples using X-ray micro-computed tomography (micro-CT) and double punch compressive tests on historic mortar joints and mortar plates of the materials have been performed, highlighting the influence of the micro-scale properties on the compressive strength.

PDF (Download Full text)

| Download Citation (XML)