Evaluation of Rut Resistant Asphalt Mixtures for Intersection

ABSTRACT The Nevada Department of Transportation (NDOT) sponsored a two-phase research study to develop specific requirements to be used for HMA mixes at intersection. The phase i of the study evaluated the impact of different aggregate gradations on the mixtures' resistance to rutting. The rutting resistance of a HMA mix was found to be highly dependent upon the aggregate gradation. The phase II consisted of a laboratory evaluation of the mixes with the most promising gradations identified in phase i for fatigue cracking resistance. Additionally, a full mechanistic analysis is conducted to effectively evaluate the relative fatigue and rutting performances of the evaluated HMA mixes under heavy braking 18-wheel truck. Based on the data generated in this study a new aggregate specification limit was recommended for asphalt mixtures at intersections. The recommended gradation is intended to improve the asphalt mixture's resistance to rutting without jeopardizing its resistance to fatigue cracking.