Evaluation Of New Innovations In Rubber Modified Asphalt Binders And Rubberized Asphalt Mixes For Nevada Dot

The objective of the proposed research project is to determine the feasibility of utilization of laboratory blended ground tire rubber (GTR), terminally-blended GTR following Nevada Department of Transportation's (NDOT’s) specifications, or other crumb-rubber-modified (CRM) products to meet the rheological and engineering properties of asphalt modified binders and mixtures. The test results will be compared to styrene butadiene styrene (SBS) modified binders used in Nevada. The specific objectives of the research project will include the following: (1) Determining initial recommendations for terminally-blended GTR mix design guidelines based on the literature review and basic laboratory test results; (2) Investigating the rheological characteristics of various crumb rubber types (e. g. -30, -40, and terminal blend) at high, intermediate, and low performance temperatures through the performance of American Association of State Highway and Transportation Officials (AASHTO) standards and any other NDOT’s specification requirements; (3) Investigating the effects of various rubber modifiers on NDOT’s mix design including the mix volumetric properties such as air voids, voids in mineral aggregate (VMA), and optimum asphalt binder ratio specifications from AASHTO and NDOT; (4) Determining the Hveem stability, moisture susceptibility, permanent deformation, dynamic modulus, flow number characteristics of various alternate modifiers with hydrated lime in terms of specifications from AASHTO and NDOT; and (5) Developing recommended specifications for Nevada DOT regarding the utilization of these materials.