New Generation Of Performance-Engineered Asphalt Mixtures Based On Balanced Mix Design Concept

Asphalt mixtures must ideally exhibit long-lasting durability and stability to perform wellin the field. However, improving the stability and durability of asphalt mixtures has become a major concern. Given that available design approaches rely mainly on stringent volumetric criteria for asphalt mixtures, design approaches and specifications that incorporate performance tests are needed to follow a performance-engineered mix design (PEMD) process, especially with the introduction of the balanced mix design (BMD) concept This Dissertation study presents a comprehensive investigation of a feasible designapproach that can be implemented to develop PEMD specifications and produce BMD mixtures. An experimental evaluation of different mix design approaches was carried out to produce BMD mixtures with locally available pavement materials. The current volumetric-based design method was enhanced with a performance-based analysis that specifies parameters from the overlay tester (OT) and Hamburg wheel tracking (HWT) tests. Four typical mix designs (TMDs) produced following the Superpave method were selected from different asphalt plants for this evaluation. The volumetric based design with performance verification approach coupled with the selection of an alternative aggregate gradation was implemented to produce BMD mixtures. A performance-related quality control process was formulated with a brittleness parameter from a simple performance test. The influence of essential design variables such as binder sources, PGs of binder, recycled material types and contents, rejuvenators, and long-term aging was also documented. Finally, a preliminary verification of the PEMD specifications was carried out with experiments at an accelerated loading pavement facility. The PEMD specifications consisting of a volumetric based design with a performance verification approach can be satisfactorily implemented to produce durable and stable BMD mixtures