With the introduction of Superpave designed mixtures and the increase use of polymer modified binders; compaction has become a bigger issue. Overall, Superpave designed mixes have been cited as more difficult to compact than Marshall/Hveem mixes and greater compactive efforts have been needed to achieve similar density levels. In this study, the Accumulated Compaction Pressure (ACP) is used to quantify the total applied compactive effort to the HMA mat. The total accumulated compaction pressures applied on each mixture were analyzed using several factors that affect field compaction such as gradation type, aggregate size (NMAS), lift thickness and/or t/NMAS, mix temperature and asphalt grade. Several analysis techniques were used for explaining the variability observed in ACP. The result of this study is the development of a simple measure of field compactability that may be related with mix characteristics. The results suggested the total compactive energy was mainly affected by lift thickness, temperature of the mix and the desired density level.
Abstract