Evaluation of methodologies for aging simulation of asphaltic mastics in laboratory

Abstract

The aging in laboratory of asphalt mastics, which have mineral fillers, should be analyzed differently from existing procedures for asphalt binders. For samples with filler, it is suspected that the decantation of the mineral particles takes place in the pressurized vessel (PAV), 100 °C for 20 hours, with aging of the asphaltic binder only and not in the binder-filler matrix. This study evaluates a modified aging procedure, reducing the temperature to 60 °C and increasing the time to 100 hours, with the shaking of the sample every 20 hours. Three different filers were evaluated: hydrated lime, Portland cement and limestone powder; two asphalt binders: one CAP 50/70 and one 85/100, and the tests were carried out on the Beam Flexural Rheometer and the Energy of Fracture in the two conditions of aging. The rigidity results show that the modified aging produces higher values than the conventional one, causing a greater stiffening of the binder and asphalt mastic. The relaxation rate results show that the type of aging is an influential factor. In the fracture energy data, the same behavior of the stiffness was noticed, so the samples subjected to conventional PAV can lead to overestimate fatigue strengths.