Effect of compaction temperature and procedure on the design of asphalt mixtures using Marshall and gyratory compactors

The use of the Superpave Gyratory Compactor (SGC) for asphalt mixtures design is increasingly common in many countries. Although in Spain the Marshall compactor is still used, the possibility of adopting the gyratory compactor is currently being evaluated. This is the reason why this study is focused on evaluating the influence of these compaction procedures in volumetric and mechanical properties of asphalt mixtures. Two representative mixtures of the most used in Spain have been selected. Specimens of continuous (AC16S) and gap-graded (BBTM11B) mixtures with 50/70 penetration bitumen were produced. Three combinations of vertical pressure and angles of gyration, and five compaction temperatures, were used and the influence of these variables on the shear stress, density, air-void content and stiffness modulus was analyzed. The stiffness modulus and densities obtained in samples produced with SGC and Marshall hammer at different temperatures were also compared. For the studied mixtures it was shown that the variation of the temperature slightly affects the volumetric properties of the mixtures and introduces a significant change in the stiffness modulus.