Title:
Ultra-Sensitive Cement Sensor with In-Situ Growth CNTs
Author(s):
Mimi Zhan
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/17/2021
Abstract:
Carbon nanotube cement-based sensors have gathered many interests in the structural health monitoring (SHM) area as they not only perfectly solve the incompatibility of conventional sensors but also possess an outstanding sensitivity that conventional sensors cannot compare. However, the sensitivity to strain (gauge factor) of such materials are limited by the difficulty in dispersing carbon nanotubes (CNTs). Here we synthesized CNTs in situ on the surface of fly ash (FA) to significantly improve the CNT dispersibility and enabled the cement mortar to exhibit an outstanding strain-sensing capability. The mortar with CNT-coated FA (CNT@FA) at 2.0 wt% CNT concentration exhibited a gauge factor of 6544, about one order of magnitude higher than that of mortar with commercial CNTs under the same condition. Its fractional change in electrical resistivity also reached as high as 70% upon compressive loading. This outstanding piezoresistivity was explained by the great dispersion of CNT@FA observed by optical microscopy measurements and indicates the great potential applications of CNT@FA cement sensor in assessing the conditions of civil engineering structures.