Damage-sensitive lime mortars with carbon nanotubes and carbon microfibers for earthquake monitoring of historic masonry

This study presents an experimental investigation into the multifunctional properties of lime-based mortars enhanced with carbon nanotubes (CNTs) and chopped carbon microfibers (CCMFs), aiming to develop self-sensing materials for the structural rehabilitation of culturally and historically valuable buildings. The research focuses on the electrical and electromechanical behavior of mortars with varying conductive filler types to evaluate their self-monitoring capabilities. Mechanical loading tests, supported by Digital Image Correlation (DIC) technology, were conducted to assess the materials ability to detect crack initiation and propagation through changes in electrical resistivity. The fibers not only confer conductivity-based strain sensing capabilities to the otherwise non-conductive lime matrix, but their overpercolation decreases strain sensitivity and facilitates crack or damage detection. The ultimate goal is to create a restoration material that not only strengthens masonry structures but also enables continuous health monitoring, particularly valuable during seismic events. This approach contributes to more resilient and informed conservation practices by embedding smart sensing capabilities directly into repair materials.