Preparation and piezoresistivity of carbon nanotube-coated sand reinforced cement mortar
Song Gao, Jianlin Luo, Jigang Zhang, Teng Fei, Chao Liu, Chao Feng, Qian Yuan
Abstract
Abstract Water and sand were used as the medium of multiwall carbon nanotube (MCNT) and prepared MCNT aqueous suspension and MCNT suspension-coated sand, respectively; afterwards, they were introduced into cement mortar (MNT/CM, MNTSM), respectively. Next, mechanical strengths and piezoresistive properties (DC resistivities ( ρ v ), AC impedances ( Z r )) under cyclic loadings ( σ c ) of two types of MNT/CM and MNTSM nanocomposites were investigated to explore the intrinsic and self-sensing behaviors. Results reveal that MCNT can be evenly and well-coated on sand, which favors to achieve its intrinsic self-sensing property. Although the fraction changes in ρ v and Z r under the same σ c of MNTSM are both lower than those of MNT/CM, the stress sensitivity of MNTSM is only −1.16%/MPa (DC resistivity), −1.55%/MPa (AC impedance); its sensing linearity and stability (2.53, 2.45%; 2.73, 2.67%) are superior to those of MNT/CM (4.94, 2.57%; 3.78, 2.96%). Piezoresistivity using AC impedance technique is helpful to acquire balanced sensing sensitivity and stability while applied as intrinsic sensors in infrastructure.