Electrical Resistance Tomography for non­destructive evaluation of concrete structures

Aku Seppänen1, Kimmo Karhunen1, Anssi Lehikoinen1, Joshua Blunt2, Jari P. Kaipio1,3 and Paulo J.M. Monteiro2

1 Department of Physics and Mathematics, University of Eastern Finland, FI­70211, Kuopio, Finland, Aku.Seppanen@uef.fi

2 Department of Civil and Environmental Engineering, University of California, Berkeley, USA

3 Department of Mathematics, University of Auckland, New Zealand

ABSTRACT

In this paper we apply Electrical Resistance Tomography (ERT) for imaging of concrete. ERT is an imaging modality in which the internal three­dimensional conductivity distribution is reconstructed on the basis of electrical measurements acquired from the surface of the target. In reinforced concrete, metallic phases (reinforcing bars and fibers), cracks and air voids, moisture gradients, and chloride distributions carry contrast with respect to conductivity. Hence, ERT might be a potential tool for non­ destructive evaluation of concrete structures. We carried out experiments in which a set of concrete specimens was imaged using ERT. Cylindrical specimens and beams were tested. The results show that ERT is capable for detecting reinforcing bars and cracks in concrete.

Keywords Concrete, non­destructive evaluation, electrical resistance tomography (ERT), crack detection