, Professor, Civil, Environmental and Geo-Engineering
Manik Barman, Assistant Professor, UMD-Civil Engineering
Kimberly Hill, Associate Professor, Civil, Environmental and Geo-Engineering
Jialiang Le, Associate Professor, Civil, Environmental and Geo-Engineering
Recent studies have shown that the air void ratio of hot mix asphalt (HMA) has a significant effect on the durability and long-term performance of asphalt pavements. Minnesota Department of Transportation (MnDOT) HMA pavements are typically constructed with air voids close to 7 percent in the mat and often exceeding 10 percent over the longitudinal construction joints. Recent efforts in Indiana have shown that a new mix design method, called Superpave 5, can be used to design mixtures at 5 percent air voids and to successfully compact them in the field at the same 5 percent air voids--a significant decrease compared to current practice.
The objective of this study is to build upon the preliminary results of the recently proposed Superpave 5 method and to investigate the compaction process of HMA through a combined experimental and computational approach. The computational model is anchored by a fluid dynamics-discrete element model, which is capable of capturing the motion of aggregates in the viscous binder. The model is calibrated and validated by a series of experiments, which include rheological test of the binder and compaction test of the mixture. The experiments involve typical Superpave mix designs in Minnesota and modified mix designs that follow the Superpave 5 approach. The mixtures also include a recently developed graphite nano-platelet (GNP)-reinforced asphalt mixture. The research will advance our understanding of how the viscous properties of the binder and the gradation of aggregates affect the compaction process of HMA.