Investigation on asphalt-screed interaction during pre-compaction: Improving paving effect via numerical simulation

Pavement pre-compaction is vital for asphalt pavement construction due to its influence on the quality and service life of asphalt pavement. Conventional methods of evaluating and researching the pavement pre-compaction are based on mixture density with empirical theories, which cannot provide an understanding of asphalt-screed interaction during pre-compaction. An innovative approach is developed in this paper to evaluate pavement pre-compaction through Discrete Element Model (DEM) simulation. The contact model and input parameters were discussed and defined separately based on the real condition of paving compaction. A field test about paving compaction was conducted as well for the model validation, in the test track, the operations of paving machine can be adjusted such as paving speed, paving angle, and paving thickness. In addition, the optimized working operation was recommended in this paper based on the results from DEM simulation as well as filed test. Finally, a method to evaluate the pre-compaction of bulk materials via the average aggregate angular velocity was proposed in this study and validated through the test track, and the index Compaction Increase Ratio (CIR) was defined to compare and describe the quality of pre-compaction.