Embedment Proves Chip Seal Quality
BY Applied Research Associates Inc.
The Illinois Center for Transportation (ICT) released its research report number FHWA-ICT 23-022 showing results of its findings of ICT Project R27-221 “Chip Seal Quality Assurance Using Percent Embedment.” The report was prepared by authors Ahmad Alhasan, Brian Moon, Doug Steele, Hung Lee and Abu Ahmed Sufian. The project was performed for the Illinois Department of Transportation (IDOT) Bureau of Research in cooperation with the U.S. Department of Transportation Federal Highway Administration to investigate the use of macrotexture as a quality assurance tool for chip seals.
Researchers tested the use of macrotexture as an indicator of the percent embedment (PE) of aggregate in a chip seal on 24 chip seal sections in the state of Illinois. They acquired surface texture measurements using two devices—a high-speed texture profiler in both right and left wheel paths and a stationary laser texture device measuring at 50, 250 and 450 feet (15, 76 and 137 meters) from the beginning of the test sections—in two testing phases during 2021 and 2022. They also procured cores “for the handheld scanning locations in the right wheel path for additional texture scans, cross section image acquisition, and overhead image analysis.”
“The field-testing program in 2021 included 10 in-service chip seal sections in Illinois. In 2022, a construction project on a road segment along Illinois Route 116 near Roseville included nine unique test sections with varying materials and construction methods. In addition to the construction project sections, five in-service sections were tested to further validate the test procedures. Combining the sites tested in 2021 and 2022, the study included 24 test sections. The test sites covered a wide range of treatment ages and locations to capture different traffic volumes, materials used in these locations, and construction practices such as binder and chip application rates.”
The report stated: “The analysis showed that stationary texture measurements were more consistent and reliable for estimating PE and characterizing chip seals in the field. Moreover, the ground truth PE values were estimated using an image analysis algorithm implemented on side-view images of cores extracted in the field.”
Read the full 64-page report with detailed construction and research analysis at https://apps.ict.illinois.edu/projects/getfile.asp?id=10789.
The technical review panel (TRP) members:
- John Senger, TRP Chair, Illinois Department of Transportation
- Chad Arkenberg, Illinois Department of Transportation
- Dennis Bachman, Federal Highway Administration
- Derek Parish, Illinois Department of Transportation
- David Peshkin, Applied Pavement Technology
- Tim Peters, Illinois Department of Transportation
- Duane Ratermann, Knox County
- LaDonna Rowden, Illinois Department of Transportation
- Clay Snyder, Illinois Department of Transportation
- William Snyder, Illinois Department of Transportation
- Sean Stutler, Illinois Department of Transportation
- Rick Walker, Mercer Engineering