3D-Move Mechanistic Analysis and Cost Effectiveness of Asphalt Rubber Pavement Under Various Axle Loading Conditions

Description

3D-Move Mechanistic Analysis and Cost Effectiveness of Asphalt Rubber Pavement Under Various Axle Loading Conditions

Logan Proffer, Mena I. Souliman

ABSTRACT. A variety of axle loading conditions can lead to different tensile strains in asphalt pavements. Over time, these tensile strains can greatly affect the overall lifespan for these given asphalt pavements. One way to increase resistance to these tensile strains is to add materials such as crumb rubber to the pavement mixture. This crumb rubber additive can lead to better fatigue performance in a given asphalt pavement. Using two asphalt pavement design mixtures, a 3D-Move mechanistic analysis was performed to determine the fatigue life of the two mixtures: an unmodified reference pavement along with an asphalt rubber pavement mixture. In the mechanistic analysis, these mixtures were tested under a variety of axle loading conditions, including single, double, and triple axles. These axle configurations were tested at various speeds and under two different loads for both the unmodified reference mixture and the asphalt rubber mixture. The resulting fatigue life lengths for each mixture were then used to determine the fatigue ratios for the asphalt rubber mixture in reference to the unmodified mixture for each of the selected loading conditions. The results of this analysis were then combined with a cost analysis which showed that despite the increase in cost, the asphalt rubber design mixture was the most cost-effective ahead of the unmodified reference mixture. With an average fatigue ratio of 5.92 when compared to the unmodified reference mixture, the asphalt rubber mixture greatly outperformed the unmodified mixture under the various loading conditions. When taking into account the increased cost of the asphalt rubber mixture, the mixture still had a fatigue life-cost ratio of 4.59. Despite the fact that the asphalt rubber mixture is more expensive to produce, it still greatly outperforms the cheaper unmodified reference mixture under multiple different loading conditions. These results show that in areas where fatigue issues with pavement are common, an asphalt rubber mixture could be a better alternative than a standard unmodified asphalt mixture.

KEYWORDS: crumb rubber, tensile strain, fatigue, mechanistic analysis, 3D-Move, cost analysis, axle configuration.