This past summer, Infrasense surveyed 10 miles of interstate pavement and 23 bridge decks with ground penetrating radar. The objectives of the GPR survey included:
- Locating the lateral and longitudinal extents of the underlying PCC pavement and full-depth asphalt pavements
- Providing thicknesses of asphalt and PCC pavement layers
- Locating and quantifying deterioration in the underlying PCC pavement
- Locating and evaluating the condition of joints in the underlying PCC pavement
- Locating and quantifying subsurface anomalies, including patches, air voids, and moisture at the PCC/base, AC/PCC, and AC/base interfaces
- Providing thickness and depth of cover over reinforcing steel for each bridge deck
- Evaluating bridge deck conditions
Multifaceted survey to quantify and map subsurface conditions
The equipment setup use for this survey was a dual 1-GHz horn antenna system manufactured by GSSI of Nashua, NH. The antennas, along with a distance measuring instrument and a GPS unit, were integrated into the SIR-30 GPR control system. At a collection rate of 6 scans per foot, data was collected at offsets paced 3-feet transversely within each mainline lane and shoulder, and along all intersecting ramps and select bridge decks.