Measurements of Asphalt Pavement Density Using Ground Penetrating Radar and Its Relationship to Performance

The Ground Penetrating Radar (GPR) has been used for many years to determine the thicknesses of asphalt pavement layers. This study explores expanding the use of GPR as a non-destructive quality control (QC) tool to assess the density (air void distribution) of asphalt layers. In addition, it quantifies the effect of density on mechanical properties of asphalt mixtures measured using various methods under dry and wet conditions. The compactability and mechanical properties of warm mix asphalt (WMA) were also compared to hot mix asphalt (HMA). There was excellent correlation between maps of air void distributions produced based on GPR data and percent air voids of field cores. In addition, the results of the mechanical tests provided valuable information on the effect of density on performance; such information is needed to support the development of QC limits for density. The WMA used in this study was easier to compact than the HMA; however, the results showed that the WMA was more susceptible to moisture damage compared to HMA.