Evaluation of Superpave Mixtures Containing Hydrated Lime

Download or read book Evaluation of Superpave Mixtures Containing Hydrated Lime written by Louay N. Mohammad and published by . This book was released on 2013 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of hydrated lime in Hot-Mix Asphalt (HMA) mixtures can reduce permanent deformation, long-term aging, and moisture susceptibility of mixtures. In addition, hydrated lime increases the stiffness and fatigue resistance of mixtures. This study evaluated (1) the fundamental engineering properties of HMA mixtures containing hydrated lime as compared to conventional mixtures designed to meet the current Louisiana Superpave specifications and (2) the influence of the method of addition of hydrated lime on the mechanical properties of HMA mixtures. A Louisiana Superpave 19.0 mm Level II HMA mixture design was utilized. Siliceous limestone aggregates and three asphalt binders, a neat PG 64-22 and two Styrene-Butadiene (SB) polymer modified binders meeting Louisiana specifications for PG 70-22M and PG 76-22M were included. Based on the same mixture design, three conventional and six hydrated lime treated HMA mixtures were developed. The conventional mixtures contained no hydrated lime and the three aforementioned asphalt binders respectively. The lime treated mixtures were produced by incorporating hydrated lime into the HMA mixture in two ways: "slurry" or "paste" method when hydrated lime was mixed with the aggregate as slurry and "dry" or "no-paste" method when dry hydrated lime was blended with the asphalt binders. For each lime treatment method, three HMA mixtures were produced using the three identical asphalt cements (PG 64-22, PG 70-22M, and PG 76-22M) utilized in the three conventional mixtures. The overall results from mechanistic tests on HMA mixtures and rheological tests on asphalt binders indicated that the addition of hydrated lime improved the permanent deformation characteristics of the HMA mixtures. This improvement was substantial particularly at higher testing temperatures for mixtures containing polymer modified asphalt binders.