Experimental Detection of Embedded Rebar Corrosion in Concrete with Ground Penetrating Radar

Abstract Reinforced concrete structures have been extensively investigated using Ground Penetrating Radar (GPR) for qualitatively analyzing corrosion-induced degradation. However, no reliable quantitative model exists for the corrosion evaluation of the embedded steel rebars. Such corrosion may significantly impact the strength, serviceability and long-term durability of concrete structures. This study involved an experimental work to determine the relationship between the rebar corrosion quantity and the maximum amplitude as well as the two-way travel time (TWTT) of the GPR electromagnetic wave. A direct current was impressed into embedded steel rebars in concrete beams immersed in a 5% saltwater solution to induce accelerated corrosion. GRP data were collected before saline submersion and at 10-day intervals. A multivariate regression equation with high reliability was developed to estimate corrosion-indued rebar mass loss with independent variables, including concrete cover, rebar diameter, age of the reinforced concrete, concrete strength and GPR scanning parameters.