Remote Detection of Cement in Heritage Mortars Using Multispectral Imaging

This study proposes an experiment to detect and quantify the ratio of lime to cement in mortar compositions on heritage facades using multispectral imaging. Cement-based mortars, often incompatible with historic masonry, pose risks such as reduced breathability, thermal rigidity, and loss of heritage integrity. Identifying the precise amount of cement in mortars remotely could enhance non-invasive inspections, especially in culturally significant buildings. The proposed experiment will create a database of mortars with lime-cement ratios in 10% intervals, using visually distinct materials: white and grey cement and white and beige natural hydraulic lime. Spectrometers will capture full reflectance spectra, while multispectral cameras simulate realistic, field-relevant detection conditions. This remote sensing approach could support drone-based assessments of building facades, revealing material composition in otherwise hard-to-access areas. By providing restauration architects with more accurate data on building materials, this study aims to support restoration efforts, allowing more sensitive and informed restoration of cultural heritage structures.