Abstract
Current quality control and quality assurance practices for asphalt pavements rely heavily on density (%Gmm) measurements, which are directly linked to pay adjustments. However, these practices can inadvertently encourage over-compaction, leading to issues such as aggregate segregation, crushing, and reduced pavement quality, especially under poor subgrade conditions. This study examines the relationship between the density of newly laid asphalt layers and the conditions of underlying sublayers in Hot Mix Asphalt pavements. This study analyzed INDOT's historical compaction data and conducted gyratory compaction testing. The analysis result revealed a weak negative correlation between subgrade conditions and surface density. Similarly, the gyratory compaction testing demonstrated that poor sublayer conditions resulted in lower surface density values, while stable subgrades lead to higher densities. Based on these findings, this study proposes a probabilistic approach for pay factor adjustments using subgrade deflection as a key parameter. These findings offer a pathway to refine pay factor criteria, enhancing pavement consistency and durability while promoting equitable pay adjustments for both INDOT and contractors.
Keywords
asphalt compaction quality, subgrade deflection analysis, pay factor adjustment, hot mix asphalt (HMA) pavements, probabilistic approach in pavement specification
Report Number
FHWA/IN/JTRP-2024/37
SPR Number
4716
Sponsoring Organization
Indiana Department of Transportation
Performing Organization
Joint Transportation Research Program
Publisher Place
West Lafayette, Indiana
Date of Version
2024
DOI
10.5703/1288284317815
Recommended Citation
Kang, K., Lee, J., Park, H., & Lee, J. (2024). Lessening density requirement and adjusting density pay factors for asphalt pavements in poor sublayer conditions (Joint Transportation Research Program Publication No. FHWA/IN/JTRP-2024/37). West Lafayette, IN: Purdue University. https://doi.org/10.5703/1288284317815
Technical Summary