Instrumentation for multi-channel vertical electrical impedance scanning of concrete bridge decks

Abstract

This paper documents a new design for a vertical electrical impedance (VEI) scanner that has increased VEI scanning speeds by an order of magnitude. Specifically, a new impedance analyzer was designed with improved circuitry and signal processing; this analyzer is accurate over a large range of impedance magnitudes, has a high sampling rate, is inexpensive, has low power consumption, and has a small form factor. Additionally, the physical moving platform, the localization equipment, and the large-area electrodes (LAEs) of the VEI scanner were all significantly improved. The improved VEI scanner was used to scan a concrete bridge deck in a field demonstration. The VEI scanner was able to collect data at sufficiently high speeds to scan the bridge deck without stationary traffic control, and the resulting data were highly self-consistent and correlated well with both delamination and surface cracking data that were measured separately.