Development of MARBle 1.0: A Tool for Virgin Aggregate Proportioning in Reclaimed-Asphalt-Pavement-Incorporated Asphalt Mixtures

With the surge in use of reclaimed asphalt pavement (RAP) in asphalt mixtures, the need for efficient mix design optimization has become more critical. One of the fundamental aspects of mix design is the aggregate gradation, which plays a key role in the mixture’s performance, stability, durability, and workability. While several tools and spreadsheets exist for optimizing aggregate gradation in conventional virgin asphalt mixtures, there is limited development of tools for asphalt mixtures incorporating RAP. Addressing this gap, the objective of this study is to develop and present the Module for Aggregate and RAP Blending (MARBle), an Excel-based optimization framework designed to determine the optimal proportions of virgin aggregates required to meet a specified target gradation in RAP-incorporated asphalt mixtures. The scope of this study includes: 1) the formulation of a gradation-based optimization framework using Microsoft ^® Excel Solver, 2) the development of the MARBle tool for practical implementation in RAP mix design, and 3) demonstration of the tool’s performance through case studies with varying RAP contents. The results demonstrate that MARBle efficiently optimizes virgin aggregate proportions based on user-defined RAP contents and constraints, yielding blended gradations that closely match the target specifications. The tool supports researchers, practitioners, and transportation agencies in implementing RAP-incorporated asphalt mixtures, thereby promoting sustainable and resource-efficient pavement construction.