COMPARISON OF LABORATORY AND FIELD DENSITY OF ASPHALT MIXTURES

Abstract

The objective of this paper is to investigate the relationships between the measured density of the mixture obtained in the mix design, during quality control of the mixture (laboratory compaction of field produced mix), after initial compaction (cores obtained after construction and before traffic), the final or ultimate density obtained from pavement cores after densification by traffic and the density of recompacted samples. Primary concern is the relationship between density after traffic, mix design density and density of laboratory compacted samples during construction. Eighteen different pavements were sampled from six states. Thirteen of the pavements were experiencing premature rutting and five of the pavements were performing satisfactorily. Construction history including mix design data, quality control and/or quality assurance data, traffic data and laboratory data of the physical properties of the pavement cores were analyzed from each site. The results show that in-place air void contents below 3% greatly increase the probability of premature rutting and the in-place unit weights of the pavements after traffic usually exceed the mix design unit weight resulting in low air voids and hence premature rutting.