| บทคัดย่อ(English) |
The objective of this study is to investigate a comparison of asphaltconcrete mixtures designed by two different methods; respectively Marshalland Superpave('TM) Level I mix design. The comparison is made by looking atthe volumetric properties and perfonnance properties for mixes at optimumasphalt content achieved by the different mix design methods. In this study, asphalt cement AC60/70 and three gradations oflimestone were utilized. Three different gradation, respectively placed onthe upper, passing through and below the Restricted Zone in Superpave('TM),were selected in the investigation. The first step was to determine theoptimum asphalt content for asphalt concrete mixtures designed by Marshalland Superpave('TM) level I methods. This was done by looking at the optimumasphalt content, voids in the mineral aggregate(VMA) and the voids filledwith asphalt(VFA). A comparison was made of density variation of thesamples from each compaction methods. The last step was to compareresilient modulus and values from fatigue test of the samples from eachoptimum asphalt content from each design methods. The Superpave('TM) LevelI mix design shows a lower optimum values of needed asphalt cement, VMA andVFA for all gradations. At the same time the variation in density of thesamples from Gyratory Compactor is smaller and both the resilient modulusand defomation resistance are higher. In conclusion that, for asphalt cement AC60/70 and limestoneaggregate, the utilization of Superpave('TM) Level I mix design tend togive the low cost asphalt concrete mixtures due to less asphalt cement thanthat of Marshall method. At the same time, it will be possible to gethigher durability and quality road surface resulting from higher resilientmodulus and better deformation resistance. |
