Enhancing Pavement Performance through Balanced Mix Design: A Comprehensive Field Study in Oklahoma

The Oklahoma Department of Transportation (ODOT) embarked on a phased implementation of balanced mix design (BMD) starting in 2018. This involved initial shadow projects (Phase I) and a proof of concept stage (Phase 2) with pilot projects, followed by long-term evaluation and implementation in Phase 3 and Phase 4, respectively. The goal of this study is to evaluate the field performance of BMD mixes used in Oklahoma. Cutting-edge 3D laser imaging technology was used to collect pavement condition data from various BMD sites, including metrics such as percentage cracking, international roughness index (IRI), rut depth, and mean profile depth. Firstly, a comparative analysis directly compared traditional Superpave mixes to BMD mixes using hypothesis testing. Secondly, among BMD mixes, the study analyzed performance variations resulting from different mix constituents. Lastly, statistical regression analysis and machine learning techniques (gradient boosting algorithm and random forest models) were used to pinpoint the most influential factors affecting field performance. The findings are expected to offer insights into the successful application of BMD while contributing to a deeper understanding of pavement design and performance on a broader scale.