Characterization of historic lime mortars

Historic lime mortars are an amalgam of natural and man-made materials. Thus, the study of lime mortars inherently requires interdisciplinary approaches. In an effort to evaluate the applicability of select analytical techniques typically utilized by geoscientists, fourteen samples of historic lime mortars are examined with transmitted polarized light microscopy, scanning electron microscopy (SEM), backscattered-electron imaging (BSE), and energy-dispersive X-ray analysis (EDS). The imaging and analysis tools prove very effective in determining mineralogical characteristics of the aggregate and binder materials, the binder-to-aggregate ratio, the pore structure, possible secondary cements, and the presence of hydraulic and/or pozzolanic constituents. This research highlights the many benefits gained from application of traditional geological analysis techniques to the field of conservation science. In addition, the research points towards areas of future research for integrating these techniques into a standardized analysis methodology for the characterization of historic lime mortars