A GPR-based Sensor to Measure Asphalt Pavement Density

Density is one of the most important parameters in construction of asphalt mixtures and pavement engineering. When a mixture is properly designed and compacted, it will contain enough air voids to prevent plastic deformation but will have low enough air voids to prevent water ingress and moisture damage. The ability to map asphalt pavement density has been identified as a key variable that predicts the future life and performance of asphalt pavement. We describe a new instrument, the Pavement Density Profiler (PDP) that has evolved from many years of making measurements of road properties. This instrument measures the electromagnetic (EM) wave impedance to infer the asphalt pavement density (or degree of compaction), locally and over profiles.