Development and Investigation of Repair Self-Sensing Composites Using S-CNT

This study analyzed the mechanical and electrical characteristics of repair self-sensing composites. In order to ensure homogeneous dispersion of carbon nanotubes (CNTs) in the repair mortar, porous powder was impregnated with the liquid MWCNT, dried, and then pulverized. This CNT powder was named S-CNT, and a repair self-sensing cement composite was fabricated using it with different dosages, by weight, of 3, 6, and 9%. Mechanical and electrical performances of the developed materials were investigated through flexural, compressive, and bonding strengths, dry shrinkage, porosity, and fractional change in resistance (FCR) tests. There was little difference in terms of strength, between the three different composites made with the different dosages of S-CNT. The strength of the composite with 9% of S-CNT was even higher than that of the plain specimen. As a result of measuring drying shrinkage, conducted to evaluate the effect of improving dispersion, the length change rate decreased as the amount of S-CNT increased. As a result of the porosity results of the specimens incorporating the same mass of CNT as S-CNT, it was confirmed that the dispersibility was clearly improved. In addition, as an electrical characteristic, when the S-CNT mixed specimen was repeatedly loaded with a bending load, FCR appeared, confirming the self-sensing performance.