Nano-tailored multi-functional cementitious composites

Abstract

This paper explores the effects of single and binary use of nano-additions on the self-sensing and self-healing efficiencies of cementitious composites in achieving a material that combines high mechanical and multifunctional performances. The researchers studied three nano-tailored cementitious compositions incorporating nano-silica (NS), multi-walled carbon nanotubes (CNT) and binary NS/CNT, as well as control composites prepared without nano-additions. The study included compressive strength testing on sound specimens and an evaluation of combined self-sensing/self-healing capabilities with electrical resistivity (ER) measurements conducted before and after preloading and during the self-healing recovery stage. Recovery rates were also evaluated via crack width measurements recorded by video microscope and compared to ER testing results. To account for different self-healing products, microstructural characterization was performed on healed cracks using scanning electron microscopy coupled with EDX (SEM/EDX) and thermo-gravimetric (TG/DTG) analyses. Results show that while the single use of CNT can promote self-sensing and self-healing properties, using binary NS/CNT can significantly enhance these performances. The density and amounts of C-S-H and CaCO3 in healed cracks increased with the addition of nano-materials, especially for the binary NS/CNT.