Project Details
18-683, TR-769
12/15/18
04/30/25
Iowa Department of Transportation
Iowa Highway Research Board
Researchers
Franciszek Hasiuk
Bora Cetin
About the research
The goal of this project was to characterize the relative performance and changes in microstructural and engineering properties for various types of coarse aggregates subjected to weathering as well as real and simulated traffic loads typical of granular surfaces and shoulders of Iowa roads. Through an extensive program of geotechnical laboratory tests, image analysis, geological laboratory tests, and analysis of data from prior projects, the deterioration of both fresh quarry samples and field test section samples was analyzed and compared.
Of the five main quarry materials tested, the Class A materials from the Pedersen, Crescent, and Moore Quarries produced the lowest values of total breakage during gyratory compaction testing, with the Pedersen aggregates exhibiting the smallest changes in morphology. Clean aggregates from the Alden and Gehrke Quarries had the highest breakage values and among the largest changes in morphology during gyratory compaction tests.
Among the three materials tested and analyzed from the TR-704 project’s field test sections, the Bethany Falls Limestone (BFL) had the highest total breakage while the Oneota Formation Dolomite (OFD) had the lowest breakage, and the Lime Creek Formation (LCF) materials had only slightly greater breakage than the OFD. Overall, the BFL materials yielded the greatest changes in morphological parameters over time, whereas LCF exhibited slight changes and OFD exhibited the smallest changes.
For the materials tested from 12 different test sections of the TR-721 project, the materials from the Optimized Gradation with Clay Slurry (OGCS) test sections had the best overall performance in terms of the smallest relative decreases in gravel fraction, smallest increases in sand and fines fractions, smallest cumulative total breakage values, and lowest changes in particle morphological parameters. The performance of the OGCS materials were followed by the surfacing materials of the Aggregate Columns test sections, which had intermediate performance, and finally those of the Control sections, which had the poorest performance.