Understanding the Effect of Rebar Presence And/or Multilayered Concrete Resistivity on the Apparent Surface Resistivity Measured via the Four-Point Wenner Method

Results from laboratory specimens and finite element modeling are being used to better understand the apparent surface resistivity values obtained from field measurements. Concrete specimens were prepared with no rebar and also specimens with two different rebar arrangements. Most of the specimens were moist cured for 60 days, and then transferred to lab environment for the following 60 days; thereafter, exposure was outdoor cyclic ponding with sea water. The last two exposures are expected to produce multi-layered concrete resistivity close to the surface. An analytical method was used to study multi-layered resistivity close to concrete surface. Finite element methods were used to assess rebar presence, multi-layered resistivity close to the surface, and the combined effect of these two parameters. It was found that the finite geometry also affects the resistivity measurements.