About the research
The use of nondestructive evaluation (NDE) to evaluate the structural worthiness of civil structures was continued in this Phase II research project. This aim of the project was to validate the use of two NDE methodologies, ground penetrating radar (GPR) and magnetic flux leakage (MFL), to detect material loss in reinforcing steel of a barrier rail on a bridge located in central Iowa. Controlled samples were used in laboratory experimental work to look at factors that might affect a response from reinforcing steel on the measurements collected with GPR and a MFL system. The GPR work involved measurements taken both in the air and with a “phantom concrete,” which mimicked the response expected from concrete. Data collected from the field were compared to data collected five years previously. Laboratory data collections were also performed with MFL with positive results. Due to the nature of the MFL system, no usable data were collected from field work. Data were collected from sections of reinforcing steel taken from a barrier rail on the bridge, but complications prohibited the comparison of these data to actual inspected sections of the barrier rail. Ultimately, the research provided positive insights into the use of NDE methodologies in a non-traditional manner for the detection of corrosion in reinforcing steel.