This research aimed to develop accurate earthwork expansion and conversion factors for various geomaterials, thereby enhancing the accuracy of earthwork calculations for Wisconsin’s roadway construction. Survey results from 26 state Departments of Transportation (DOTs) were obtained to understand existing practices of earthwork calculations and show that only about 31% of the DOTs surveyed provide specific expansion factor equations for commonly used soils. Less than half of the DOTs consistently align their design expansion factors with post-construction data. For aggregates, the survey results were less conclusive, with only about 23% of DOTs providing conversion factors, and a notable lack of consistent data alignment between design factors and post-construction results. These findings reveal that practice for applying earthwork factors substantially relies on personnel experience and a wide variety of methodologies, thus highlighting the need for a more systematic approach. To address this, comprehensive field and laboratory testing was conducted on 29 aggregates and 14 natural soil types collected across Wisconsin. Test results were used to develop a suite of expansion and conversion factors for natural soils and aggregates in various states of compaction (bank, loose, compacted). Expansion factors for natural soils from the compacted to bank state show considerable variation, with factors for sands ranging from 1% to 15%, silts at 12%, and clays between (-5)% to 9%. Results for aggregates show a range of conversion and expansion factors between 1.50 to 1.98 and 27% to 60%, respectively. There are notable variations in factors across different material types, in particular with overconsolidated clays. An Excel-based decision-making tool was developed that utilizes the index properties of materials to accurately estimate expansion and conversion factors. The findings of this study are crucial for practitioners in the field of geotechnical engineering and provide a comprehensive framework for precise earthwork calculations. These insights offer a thorough understanding of the behavior of geomaterials under different conditions, which is essential for improving the accuracy and reliability of construction projects. The methodologies and tools developed through this research can be effectively applied in similar geotechnical contexts, offering significant benefits for roadway construction and related earthwork applications.
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