Cement-based materials for self-sensing and structural damage advance warning alert by electrical resistivity

Abstract

Damage detection and advance warning method of steel fiber mortar are developed by using electrical resistivity. Unsized steel fiber is employed as sensors to generate flow paths of electrons. Four-probe method is used to measure electrical current and voltage. Specimens with different steel fiber ratios, namely 1.5% by weight of cement, 5% by weight of cement, 7.5% by weight of cement, 10% by weight of cement, 12.5% by weight of cement, and 15% by weight of cement, have been examined to explore their effects on the fractional resistance variation and advance warning alert duration. To evaluate the effect of distances between probes, two different mold sizes are employed. The feasibility of this method is the real time monitoring of mortar subjected to real-time monotonic compression loading. The fractional resistivity, which decreases by increasing compression stress up to failure. The results revealed that the higher the steel fiber content, the higher the sensitivity of fractional resistivity curve. Further advantage of real time monitoring of smart mortar is to determine the advance warning alert of complete failure of the smart concrete matrix. The effect of steel fiber ratios on the advance warning alert duration was also examined. The higher the steel fiber content, the longer the advance warning alert duration and the higher the accuracy of advance warning alert.