Laboratory Evaluation of Hot Mix Asphalt (HMA) in Delaware

Pavement design approach is slowly moving towards the mechanistic design approach from the traditional pavement design. One of the drawbacks of traditional pavement design is that it does not take into consideration the effect of changing load types in the design. Hence the mechanistic design approach has an edge over the traditional pavement design in this aspect. The mechanistic design approach also helps in improved characterization and utilization of available materials, better prediction of performance, and improved definition of existing pavement layer properties as well as the accommodation of environmental and aging effects. The success of the mechanistic design approach is dependent on understanding the behavior of the material properties. Of all the material properties, resilient modulus is the most important of all because it helps in better characterization of the stress-strain relationship of the material. The advantages of resilient modulus is that it is: (1) used to define fundamental material properties,(2) used in constitutive models, (3) used to predict stress, strain, and displacement, (4) used to develop performance models, (5) used in current American Association of State Highway and Transportation Officials (AASHTO) pavement design guide and (6) used in the mechanistic design approach. The focus of this research is to evaluate the resilient modulus of several mixtures from the Delaware Department of Transportation (DelDOT). Hence the goal is to develop quantitative models of Resilient Modulus of Delaware Hot Mix Asphalt (HMA). This research will help to increase the understanding of the behavior of construction materials that are used in Delaware and also provide a database of resilient moduli for further analysis and refinement of pavement design and evaluation. The resilient modulus test carried out in this research uses aspects of AASHTO and American Society for Testing and Materials (ASTM) test methods for determining the resilient modulus of bituminous mixtures by indirect tension.