Quantitative Assessment of Workability for Hot Mix Asphalt: Inclusive Study on Mix Variables

Abstract

The workability of Hot Mix Asphalt (HMA) plays an integral role in the successful construction of flexible pavement. Workability not only refers to the ease of handling and paving of the mixture but also to the superior compaction characteristics. In practice, an optimum compaction effort ensures that the laid mixtures attain the desired set of mix variables post-construction. As the HMA exemplifies temperature-dependent viscoelastic properties, several mix variables in HMA offer a complex interaction that in effect contributes to the ease of compaction of HMA. With this background, this study will investigate the workability of HMA and quantify the impact of mix variables on workability of HMA. The scope of this study will include a comprehensive characterization of aggregate gradations, rheological investigation of asphalt binders, an experimental investigation on the compaction behaviour of HMA, and quantitative assessment of variables that potentially contribute to the compaction energy of HMA. In this study, Superpave Mix Design method will be adopted to measure the compaction mechanism of HMA that comprises mix variables such as types of asphalt binders, viscosity at compaction temperatures, the activation energy of HMA, aggregate structures, etc. Furthermore, a predictive model will be developed using the fundamental mix variables which will help predict the optimum compaction energy in terms of gyrations. It is envisaged that the research findings will provide important insights to the compaction mechanism of HMA, and thus advancing the state-of-the-art pertinent to the superior quality of construction for flexible pavements.