Performance Evaluation of Wearing Course Asphalt Mixes Based on Resilient Modulus, Indirect Tensile Strength and Marshall Stability

The roadway industry in Pakistan is flourishing with one belt one road project. In near future, the roads of the country will help to accommodate the trade of billions of dollars from south Asia to the entire world. This project have increased the importance of flexible pavements in view of its widespread use in the local roadway industry due to low construction and maintenance costs. In Pakistan, local highway authorities rely on Marshal mix design method to design wearing course asphalt mixes. This method is empirical in nature and fails in accurately determining the behavior of flexible pavements due to variable environmental and traffic load conditions, and material properties. Considering these limitations, this study is an initial attempt in Pakistan to evaluate and compare asphalt mixes prepared based on both modern mix design method referred to as superior performing asphalt pavements (SUPERPAVE) and already adopted conventional mix design method using locally available material queries and considering local environmental and loading conditions. Using most common pavement conditions, comparative research was carried out to judge the performance of wearing course asphaltic mixtures prepared based on both Marshall and SUPERPAVE techniques. The matrix of the experimental plan involves one locally available aggregate source, two different aggregate gradations, and one locally available binder type. For mix evaluation, two sets of samples were prepared at optimum asphalt binder content and selected aggregate gradations for the two mix design methods under study. Performance of each mix type was then evaluated by mechanical properties including marshall stability, loss of marshall stability, indirect tensile strength, loss of indirect tensile strength, and modulus of resilience.