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

Optimizing the Strain-Sensing Property of Cement-Based Composite Based on a Piezoresisitivity Model

“…When the addition of conductive filler reaches the "threshold percolation", an effective conductive filler will be formed, i.e. the distance between each two adjacent conductive fillers is short enough that the electron can jump through this barrier based on tunnelling effect [3]. Considering each two adjacent conductive fillers as a tunnelling resistor t R , the current density in this tunnelling resistor at a low voltage region can be depicted by the tunneling effect equation [3] The characteristic of conductive network is dependent on the distribution of conductive fillers.…”

“…The electrical properties of composites filled with conductive fillers have been studied over the last decades due to their widely applications [1].Composites filled with conductive fillers in threshold content can serve as sensing materials due to the change of electrical resistivity upon strain, which is so called piezoresistivity [2][3]. Great achievements have been obtained on the piezoresistivity of conductive composites [4][5][6][7][8].…”

“…From the reported experimental results, it can be observed that the piezoresistivity of the conductive composites was associated with the strain state and conductive network formed by the conductive filler. For the aim of optimizing and predicting the strain sensing properties of piezoresistivity-based strain sensor under various loading and environmental states, piezoresistivity models have been proposed in the past decades based on percolation theory [3]. With the development of magnetic or electrical field induced CNTs, Nickel fibre or particle alignment method, Compared with the case of conductive filler randomly distributed, it is possible to take advantage of the alignment of the conductive filler to optimize the piezoresistivity of the composite.…”

Applications of Self-Sensing Concrete

“…The concrete columns embedded with carbon black-based self-sensing concrete detected the strain (as shown in Figures 7.27 and 7.28)[25]. Xiao et al also embedded concrete with carbon black into three different stress zones (i.e., uniaxial compression, combined compression and shear, and uniaxial tension zones) of bending reinforced concrete beams (as shown inFigure 7.29) and investigated the strain sensing properties of the concrete beams under four-point bending[26]. All sensors embedded under the three different stress zones exhibited reasonable sensing results (as shown inFigures 7.30-7.32)[26].…”

“…32 Strain sensing property of CBCC sensor-3 (a) under cyclic loading with an amplitude of 20 kN, (b) under cyclic loading with an amplitude of 40 kN, (c) under monotonic loading until the reinforcing bar yielded followed by unloading[26]. CBCC, carbon black with concrete column.…”