Comparison of the field measurements of asphalt concrete densities obtained by ground-penetrating radar, pavement quality indicator and the borehole coring methods

Density is an important parameter of asphalt mixtures used to control the quality of pavement construction. Enough air voids of asphalt mixture prevent bleeding and/or infiltration of air or water into the mixture. Hence, accurate measurement of density is essential for quality control, quality assurance and prediction of pavement performance. Coring and measuring density in the lab is the most prevalent method but it is a destructive method. To decrease the damages of using destructive methods, non-destructive methods such as nuclear and non-nuclear gages, pavement quality indicator (PQI) and ground-penetrating radar (GPR) were suggested. In this research study, the accuracy of the PQI and the GPR methods in measuring density of mixtures were evaluated and compared. To evaluate the accuracy of each method field measurement results were compared with coring results. Then, an economic comparison was performed by considering effective parameters of using each method. Findings indicated that the GPR method provides more accurate results than the PQI, but the PQI is the more economical device based on the analysis of effective parameters.