Advanced engineered cementitious composites with combined self-sensing and self-healing functionalities

This study focused on enhancing the self-sensing ability of engineered cementitious composites (ECC) to accurately monitor their cracking behavior and healing performance. The ultimate goal was to develop an advanced smart material that combines self-sensing and self-healing capacities, while preserving the high mechanical and ductility properties of standard ECC. To achieve those features, carbon fibers (CF) and carbon nanotubes (CNT) were added to ECC mixtures in different concentrations. Compressive and flexural strength and mid-span beam deflection capacity testing of sound specimens were performed as part of the mechanical characterization. Recovery rates of flexural properties were assessed on pre-cracked specimens at different healing ages. The combined self-sensing and self-healing capabilities of sound and pre-cracked specimens were evaluated based on electrical resistivity (ER) measurements completed at different moisture states and healing ages. Microstructural analysis was used to investigate outer and inner regions of healed crack lines. Test results showed that mechanical properties, self-healing ability and conductivity of ECC can be improved by incorporating CNFs or CNTs. However, accurate combined self-sensing and self-healing efficiency can only be reached with CNT-based ECCs.