Impact of Unbound Layer Mineralogy on the Long-Term Performance and Cost-Effectiveness of Pavements

Abstract: A growing focus has recently been on strengthening pavement structures by incorporating advanced solutions such as geosynthetics and recycled materials. While these innovations enhance pavement performance, they also introduce challenges related to cost-effectiveness, sustainability, and practical application. As a result, it is crucial to enhance and optimize the evaluation and design of existing materials to gain a deeper understanding of their properties and potential applications. One such material is base aggregates, which come from various sources and exhibit diverse mineralogical compositions. This study investigates the impact of aggregate mineralogy on their mechanical performance in pavement structures. Mineralogical testing was conducted using X-ray fluorescence spectroscopy (XRF) to accurately determine the composition of the aggregates, followed by basic index property testing for classification purposes. The resilient modulus of the aggregates was then measured following the AASHTO T307 protocol to evaluate stiffness. The laboratory results were analyzed to assess the influence of aggregate mineralogy on the long-term performance of flexible pavements and the sensitivity of mechanistic-empirical pavement analysis to changes in the stiffness of unbound layers. Additionally, a performance-based cost analysis was performed for each type of aggregate mineralogy, providing cost-effective recommendations for enhancing road structure performance. This comprehensive approach offers insights into optimizing material selection for sustainable and durable pavement design.