Carbon fiber reinforced concrete for smart structures capable of non-destructive flaw detection

Abstract

Electrically conducting concrete, as provided by the addition of a short carbon fibers (0.2-0.4 vol.%) to concrete, can function as smart structure material that allows non-destructive electrical probing for the monitoring of flaws. The electrical signal is related to an increase in the concrete's volume resistivity during crack generation or propagation and a decrease in the resistivity during crack closure. The linearity between the volume resistivity change and the compressive stress was good for mortar containing carbon fibers together with either methylcellulose or latex as dispersants. However, the linearity was poor for mortar containing carbon fibers together with both methylcellulose and silica fume, as this mortar required a minimum compressive stress for crack closure, whereas the other two mortars did not.