Abstract

This paper summarizes the impact of rubber modified binders on the laboratory performance of hot mix asphalt mixtures (HMA). The purpose of this study is to compare the laboratory performance of the mixtures manufactured with the PG64-28TR and PG76- 22TR rubber modified binders to the performance of mixtures manufactured with the Nevada Department of Transportation (NDOT) currently used PG64-28NV and PG76-22NV polymer modified binders, respectively. The PG64-28TR and the PG76-22TR are terminal blend binders modified with 10% ground tire rubber. The mixtures were evaluated in terms of their resistance to rutting, fatigue cracking, thermal cracking, dynamic modulus, and moisture sensitivity. The PG64-28TR mix showed lower rutting resistance than the PG64-28NV mix and lower laboratory fatigue resistance than the PG64-28NV mix at a strain level higher than 500 microns. On the other hand, the PG76-22TR mix showed higher rutting resistance than the PG76-22NV mix and lower laboratory fatigue resistance than the PG76-22NV mix at all strain levels. The PG64-28TR mix and the PG64-28NV mix showed good resistance to thermal cracking, and approximately similar dynamic modulus at 21.1℃. On the other hand, the PG76-22TR mix showed higher dynamic modulus than the PG76-22NV mix at 21.1℃. All mixtures exhibited good resistance to moisture damage.

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