Self-sensing capabilities of cement-based sensor with layer-distributed conductive rubber fibres

Abstract

Piezoresistive-based cementitious composites have unique advantages compared with other sensors for structural health monitoring. A novel cement-based sensor incorporating conductive rubber was explored in this study, including its raw materials, manufacturing process, electrical conductivity, self-sensing efficiency, repeatability and compressive strength. Different water to binder (w/b) ratios of composites and loading stress magnitudes were also investigated. The results show that the conductive rubber fibres had capacity to improve the electrical conductivity of cementitious composite, with percolation threshold approximately from 60–100 rubber fibres (0.96–1.6 vol.% to specimen). The higher w/b ratio, the lower resistivity and the more inconspicuous percolation the composite was. Furthermore, the composites at w/b ratio of 0.38 were provided with best piezoresistivity, whose fractional changes of resistivity reached 25% under stress magnitude of 10 MPa when reinforced by 80 rubber fibres (1.28 vol.%). The sensitive coefficient proposed could describe piezoresistive sensitivity in different stress magnitudes, because of the non-linear resistivity changes with increased stress amplitude. As for the mechanical properties, satisfactory compressive strength of 36 MPa was obtained for the composite filled with 80 rubber fibres (1.28 vol.%) at w/b ratio of 0.38. Therefore, the conductive rubber embedded cementitious composites have great application potential as new cement-based sensors for concrete structural health and pavement traffic monitoring.