Effect of fiber volume content on electromechanical behavior of strain-hardening steel-fiber-reinforced cementitious composites

This research investigated the effect of fiber volume content on the electromechanical behavior of strain-hardening steel-fiber-reinforced cementitious composites under direct tension. There is strong correlation between the change of electrical resistivity and the tensile response of strain-hardening steel-fiber-reinforced cementitious composites: the electrical resistivity of strain-hardening steel-fiber-reinforced cementitious composites clearly decreased during strain hardening as the tensile strain of them increased. The electrical conductivity, tensile resistance, and damage-sensing capacity of strain-hardening steel-fiber-reinforced cementitious composites were generally increased as the volume content of twisted steel fibers added in a mortar matrix increased from 0.0 to 2.0%. The strain-hardening steel-fiber-reinforced cementitious composites with fiber content more than 1% by volume produced high damage-sensing capacity with high nominal gauge factor: absolute value over 150. Besides, the addition of carbon black or ground granulated blast furnace slag in mortar matrices significantly reduced the electrical resistivity but slightly enhanced the damage-sensing capability of strain-hardening steel-fiber-reinforced cementitious composites.