Monitoring Electrical Resistivity of Strain Hardening Fiber-Reinforced Cementitious Composite Exposed to Cyclic Wetting and Drying

Abstract

Strain hardening fiber-reinforced cementitious composite (SHFRCC) is a new generation of cement-based material that exhibits high tensile strength, high ductility, and multiple microcracking behavior under direct tensile test. SHFRCC is expected to be a promising material for marine structural applications. This paper intends to evaluate durability of SHFRCC exposed to chloride environment by measuring electrical resistivity. Two types of steel fiber, hook and twisted fiber, were used in producing SHFRCC with a volume of 2%. The uncracked and precracked SHFRCC specimens were subjected to wet–dry cycling in 3.5% sodium chloride solution. The electric resistivity was measured at 0, 7, 14, 21, 49, 70, and 98 cycles. The results showed that the electrical resistivity reduced significantly as the number of chloride cycles increased. The electrical resistivity of SHFRCC was strongly dependent on the fiber type and the width of microcracks. SHFRCC with twisted fibers produced lower electrical resistivity at all measured cycles than those with hooked fibers. The precracked specimens exhibited much lower electrical resistivity than uncracked specimens. Furthermore, the measurement of electrical resistivity could deliver valuable information with respect to chloride and moisture penetration into uncracked and precracked SHFRCC.KeywordsFiber-reinforced cementititous compositeSteel fiberElectrical resistivityWet–dry cyclesChloride penetration