In order to facilitate rehabilitation planning of an asphalt overlaid bridge deck carrying I-87 over Pascack Road, ground penetrating radar (GPR) was used to quantify and map concrete deterioration.
The GPR data was carried out at driving speeds using a vehicle-based system, so no lane closures were required. In addition to being deployed at driving speeds, GPR has the ability to penetrate and detect deterioration through the full thickness of the deck, regardless of the presence of an overlay. The GPR equipment used for this survey was a dual 2-GHz air-coupled horn antenna system manufactured by GSSI, Inc. of Nashua, NH.
This bridge deck analysis was carried out according to ASTM D6087-08 using Infrasense’s proprietary software, winDECAR® and was surveyed with 40 lines of GPR data, each representing a longitudinal cross-section through the deck. The cross-section shows the different structural layers of the bridge deck including the bottom of the asphalt overlay, top reinforcing steel, and bottom of the deck. The amplitude of these layers is calculated and then quantities and maps of concrete deterioration, asphalt overlay thickness, and concrete cover are produced. The resulting maps are provided in both PDF and CADD compatible formats.