Smart characteristics of cement-based materials containing carbon fibers

Cement-based materials is an inert material with high electrical resistivity, but its electrical conductivity can be obviously improved by the addition of short carbon fibers (0.2 - 1.2 vol%). In this paper, the relationships between inner microstructure and apparent electrical properties, change of electrical resistivity and external applied load of carbon fiber reinforced cement-based material were investigated. Test results indicated that carbon fiber reinforced cement-based material could function as a smart material for real time diagnosis of damage. The electrical signal is related to an increase in the material's volume resistivity during crack generation or propagation and a decrease in the resistivity during crack closure, The linearity between the electrical resistance change and the applied load was good for Wing the carbon fiber reinforced cement-based material. In contrast, cement-based material without carbon fibers showed no variation of the resistivity during the entire load process. The change of electrical characteristics reflects large numbers of information of inner damage of cement-based material, which can be used to detect potential damage and to prevent fatal failure.