Asphalt Pavement Compaction Assessment Using Ground Penetrating Radar-Arrays: Fid-Bau Portal

Asphalt Pavement Compaction Assessment Using Ground Penetrating Radar-Arrays

Hoegh, Kyle / Dai, Shongtao

Air void content is a crucial parameter affecting long term pavement performance. Ground penetrating radar (GPR) offers a nondestructive method of determining relative asphalt air void content cheaply, quickly, and over an entire project. Previous implementations of GPR for the determination of air void content, including demonstrations as part of a recent SHRP2 study, were mostly positive, but suggested the need for a testing protocol. To explore various survey methodologies, a large-scale case study was conducted on U.S. HWY 52 in Minnesota using the rolling density meter (RDM), a commercially available device developed specifically for air void analysis in asphalt pavements. The lessons learned from the SHRP2 studies and initial Minnesota pilot projects were used on a full coverage trial implementation. The full coverage trial allowed for determination of the potential of the technology for improved QA/QC and resulted in development of best practice recommendations. This paper illustrates information provided by the full coverage data and outlines recommendations related to survey coverage, data file standardization and organization, verification of location and GPR measurements, and a rigid core collection procedure. The application of these recommendations allow an RDM crew to collect valuable relative compaction data for real time feedback without interfering with paving operations or traffic closures. Additionally, core calibration can be performed after surveying to convert data to air void content and project data analysis can be used to determine the construction practices most crucial to achieving sufficient compaction.