Evaluation of the laboratory compaction method on the air voids and the mechanical behavior of hot mix asphalt

Marshall and Superpave mixture designs are based mainly on volumetric parameters. Despite this similarity, the definition of the optimum asphalt binder content is highly influenced by the laboratory compaction method. The main objective of this study is to evaluate the effect of the compaction method on the air void content and the mechanical properties of compacted asphalt mixtures. The experimental procedure included the Marshall and Superpave mixture design methods (the second one uses SGC - Superpave Gyratory Compactor, with two mold sizes), the French gyratory shear compactor (PCG), and also the LCPC French roller compactor. The effect of the compaction method, mold size and the number of gyrations on the air void content (and, consequently, on the optimum asphalt binder content), mechanical properties, permanent deformation, and fatigue behavior were evaluated. The main contribution of this study is the recommendation of the Superpave Gyratory Compactor with mold size of 100 mm diameter (Nominal Maximum Aggregate Size NMS <= 12.5 mm) for medium and high traffic. The use of 150 mm molds in the SGC is recommended only if the number of gyrations is smaller than the one used in this study (100 gyrations). (C) 2017 Elsevier Ltd. All rights reserved.