Strain sensing properties of cement-based sensors embedded at various stress zones in a bending concrete beam

CBCC sensor, a kind of cement-based strain sensor, has been developed by utilizing the piezoresistivity of carbon black filled cement-based composite (CBCC1) and the strain sensing property of a free CBCC sensor has been explored. In this paper, CBCC sensors are embedded at three different stress zones in a bending beam, i.e. uniaxial compression, combined compression and shear, and uniaxial tension to investigate the strain sensing properties of embedded CBCC sensors under these stress states. The experimental results show that the precision of embedded CBCC sensors for measuring compressive strain is as good as that of a free CBCC sensor, no matter shear stress exists or not, indicating the precision of embedded CBCC sensors is nearly insensitive to shear stress. The adverse influence of shear stress is reducing the sensing range of embedded CBCC sensors because existing of shear stress will decrease the maximum compressive strain. Embedded CBCC sensors under uniaxial tension show good tensile strain sensing properties before they are crushed. (C) 2011 Elsevier B.V. All rights reserved.