Identifying Concrete Deterioration using Ground Penetrating Radar Technology

摘要

Ground penetrating radar (GPR) is a widely utilized method for investigating the internal structure of materials. A few of the common GPR applications include locating buried objects in soil, locating structural reinforcement (this would include rebar, tension cables, etc...) in concrete, and determining the thickness of asphalt on roadways. The fact that rebar can readily be imaged using GPR led to an investigation of the feasibility of using GPR for locating areas of concrete deterioration in concrete bridge decks. During the spring and summer of 1999 the New Hampshire Department of Transportation (NHDOT) organized a comparison study of three deterioration-mapping methods on six asphalt overlaid bridge decks. GPR data were collected on four of these bridge decks. Corrosion potential and chloride concentration data were collected on each of the six bridge decks. Comparison of the processed GPR data with the corrosion potential data reveals very good correlation between areas of low rebar reflection amplitudes in the GPR data and the portions of the upper bridge deck possessing high corrosion potential or high chloride concentration.