The Effect of Mix Constituents in the Permanent Deformation Resistance of Asphalt Mixtures

Abstract

This study evaluated 28 asphalt mixtures with respect to the relationship between the results of their uniaxial repeated load test and tests of their corresponding binders: Multiple Stress Creep and Recovery (MSCR), G*/sinδ, softening point, and Brookfield viscosity at 135 °C. The following parameters were considered: binder content, aggregate mineralogical origin, Nominal Maximum Aggregate Size, and type of filler. It was found a low relationship between the binder Performance Grade (PG) and the mixture Flow Number (FN). Non-recoverable compliance (J_nr) at 3.2 kPa⁻¹ and 64 °C, G*/sinδ at 70 °C, and softening point were found to be better indicators of mixture resistance to rutting. The relation J_nr × FN was better expressed by a potential curve, which calls attention for linear regressions commonly used in the literature. Based on the results, the binder parameters were insufficient to predict the behavior of the corresponding mixture with respect to its resistance to rutting. This work also suggests that FN values are better governed by the characteristics of the binders when they are modified. When pure binders are used, the responsibility becomes greater for parameters such as skeletal stone structure and mix volumetrics. Finally, additional evaluation is suggested including other properties related to permanent deformation, such as aggregate interlocking and morphology.