Balanced Mixture Design Framework for Asphalt Mixtures Based on Index- and Performance-Volumetrics Relationships

Asphalt mixture design methods range from approaches that rely on the volumetric properties of the mix to those that are based on the pavement performance. More advanced mixture analysis procedures allow a comprehensive evaluation that attempts to predict pavement distress based on factors such as traffic, climate, and mixture properties. Among them, balanced mix design (BMD) has been a frequently used approach; its purpose is to achieve an optimum balance between stability and durability. The objective of this work is to bridge the gap between the volumetric properties and performance of asphalt mixtures with respect to pavement fatigue cracking and rutting. In the study, an asphalt mixture was initially designed and then variations in voids in mineral aggregate (VMA) and voids filled with asphalt (VFA) were evaluated based on specified volumetric limits to create a broad volumetric space. Then, dynamic modulus, cyclic fatigue, and stress sweep rutting (SSR) tests were performed at each volumetric condition. Index-volumetrics and performance-volumetrics relationships were calibrated and the optimum mixture design was identified. In addition, a BMD framework was developed, which allows the mixture performance evaluation at multiple volumetric conditions and the selection of an optimized mixture based on the predicted pavement performance and on indexes for all possible combinations of the given set of component materials.