Development of a mix design methodology for asphalt mixtures with analytically formulated aggregate structures
Doctor of Philosophy (PhD)
Civil and Environmental Engineering
This research documents an extensive study on the design and characterization of asphalt mixtures for use as road pavement material. Several aspects of asphalt mixtures were addressed using the state of the art laboratory test equipment and technical literature from different information sources. The research was divided into two phases. Phase one included the design and detailed analysis of compaction and performance characteristics of asphalt concrete mixtures with aggregate structures that were designed using an analytical method of aggregate blending. Three aggregate types were considered in this study: limestone, sandstone, and granite. All the aggregates were crushed aggregates. Three different aggregate structures were designed for each aggregate type using the Bailey method of aggregate gradation evaluation. The Bailey method is a comprehensive gradation. Sandstone and Granite mixtures had a nominal maximum aggregate size (NMAS) of 12.5mm and were designed for high traffic level, while two types of Limestone mixtures were designed (25.4 mm and 12.5 mm NMAS) for two traffic levels (high and low traffic volumes). For the heavy traffic mixtures the binder type selected was PG 76-22M while PG70-22 was used for low volume mixtures. The outcome of this research suggests that suitable mixes can be developed with dense aggregate structures using the Bailey method of aggregate gradation that provides good resistance to permanent deformation while still maintaining adequate levels of durability. A systematic, simplified design approach was recommended in which asphalt mixtures are designed based on the locking point concept, analytical aggregate gradation method and fundamental mechanistic properties that describe the behavior of asphalt mixtures based on sound engineering principles.
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Alshamsi, Khalid Salim, "Development of a mix design methodology for asphalt mixtures with analytically formulated aggregate structures" (2006). LSU Doctoral Dissertations. 3811.
Louay N. Mohammad