Abstract
Stone matrix asphalt (SMA) is a specialized asphalt mixture designed to improve pavement performance by combining a coarse aggregate skeleton with a high-binder content mortar. This innovative design, adopted by the Indiana Department of Transportation (INDOT) in the late 1990s, offers distinct advantages over conventional hot mix asphalt (HMA). Currently, INDOT SMA-surfaced pavements are undergoing a second round of rehabilitation, which presents a valuable opportunity to assess their performance and return on investment (ROI). In Indiana, steel slag is used as the primary SMA coarse aggregate because of its toughness and durability. However, it may be possible to use other, more locally available coarse aggregates in SMA without loss of mixture performance. Field performance evaluations highlight the superior performance of SMA over HMA on U.S. Highways. The significant percentage differences in roughness and cracking demonstrate SMA's enhanced durability and ability to resist deformation and cracking. The LCCA results demonstrate that, despite higher initial construction costs, SMA overlays exhibit superior long-term cost performance relative to HMA. The ROI analysis reveals that SMA overlays yielded a 69.3% ROI over the 29-year analysis period. Exploring steel slag alternative aggregates for Indiana provides important insights into coarse aggregate selection for SMA in Indiana. With strict coarse aggregate requirements, steel slag and dolomite have been the main choices for Indiana SMA mixtures. However, the study results indicate that crushed gravel can perform similarly to steel slag in laboratory testing, possibly expanding options for aggregate selection. Although increasing dolomite content to replace steel slag is possible, it would require careful consideration of the aggregate toughness requirements.
Keywords
SMA, field performance, LCCA, ROI, steel slag
Report Number
FHWA/IN/JTRP-2025/09
SPR Number
4728
Sponsoring Organization
Indiana Department of Transportation
Performing Organization
Joint Transportation Research Program
Publisher Place
West Lafayette, Indiana
Date of Version
2025
DOI
10.5703/1288284317853
Recommended Citation
Lee, J., Jeon, J., Al Mamun, A., Khajehvand, M., & Haddock, J. E. (2025). Stone matrix asphalt (SMA) overlay performance evaluation (Joint Transportation Research Program Publication No. FHWA/IN/JTRP-2025/09). West Lafayette, IN: Purdue University. https://doi.org/10.5703/1288284317853
SPR-4728 Technical Summary