Electrical properties of smart ultra-high performance concrete under various temperatures, humidities, and age of concrete

This study investigates the effects of temperature, relative humidity, and storage age on the electrical properties of smart ultra-high performance concretes (UHPCs) with different functional fillers (FFs) and free water content (FWC) for the practical application purpose by measuring impedance spectroscopy. As the temperature increased from 0 to 40 degrees C, the electrical resistivity of smart UHPCs clearly decreased (approximately 2.27% per oC). However, the FWC effect on the temperature sensitivity was limited. The smart UHPCs with fiber type FFs (steel fibers) produced slightly higher temperature sensitive than that with particle type FFs (fine steel slag aggregates). The effect of change in relative humidity (20-80%) on the change in electrical resistivity of smart UHPCs was little owing to high density of matrices. The electrical resistivity of smart UHPCs clearly decreased until 21 days and then little changed until 180 days owing to change of FWC in matrices.