Prediction of Asphalt Mixture Compactability from Mixture, Asphalt, and Aggregate Properties

The underlying purpose of any pavement is to provide a safe, smooth and reliable surface for the intended users. In the case of hot mix asphalt (HMA) pavements, this includes producing a surface that is resistant to the principal HMA distress types: permanent deformation (or rutting) and fatigue damage (or cracking). To protect better against these distress types, there have recently been changes in HMA mixture design practice. These changes have had the positive effect of producing more damage resistant mixtures but have also had the effect of producing mixtures that require more compaction effort to obtain required densities. It is important to understand what properties of an HMA mixture contribute to their compactability. This study presents analysis of the correlation between HMA mixture properties and laboratory compaction parameters for the purpose of predicting compactability. Mixture property data were measured for a variety of mixtures; these mixtures were compacted in the laboratory and compaction parameters were collected. A statistical analysis was implemented to correlate the mixture data to the compaction data for the purpose of predicting compactability. The resulting model performs well at predicting compactability for mixtures that are similar to the ones used to make the model, and it reveals some mixture properties that influence compaction. The analysis showed that the binder content in an HMA mixture and the slope of the aggregate gradation curve are important in determining the compactability of a mixture.