Mathematical modeling for quantitative estimation of geometric effects of nearby rebar in electrical resistivity measurement

Concrete resistivity in reinforced concrete structures is used as an indicator of durability related to the corrosion risk. This study aims to develop a quantitative analysis method of geometric effects of nearby reinforcement in the electrical resistivity measurement. The A-REM proposed in this study is a mathematical model to enable analysis of not only concrete (or mortar) and reinforcement resistivity, but also of geometric effects such as rebar diameter, cover depth, electrode interval, and the spatial relationship between the rebar and electrodes. The effect of nearby reinforcement on the electrical resistivity measurement was presented to be obtained from the apparent resistivity rate (AR rate) calculated by the A-REM. The A-REM for the estimation of the nearby reinforcement effects was verified by comparing the apparent resistivity values obtained from mortar specimens having different reinforcement diameters and cover depths. The result shows that the calculated values of the A-REM are correlated with the experimental values of apparent resistivity.