Development of an IDEAL-Low Temperature (IDEAL-LT) Test for Balanced Mix Design and Acceptance in Cold Regions
State departments of transportation (DOTs) in cold regions are increasingly encountering premature pavement failures, including low-temperature transverse and block cracking, despite adherence to existing design standards, construction methods, and material specifications. These cracks form when thermal stress exceeds the asphalt mixture’s strength during severe temperature drops. Thermal stress accumulation is driven by thermally induced strain, which depends on the mixture’s coefficient of thermal contraction (CTC) and relaxation modulus. However, current mix design practices primarily rely on asphalt binder properties such as stiffness and m-value (a parameter indicating the rate at which asphalt binder stiffness changes over time under stress) from the Bending Beam Rheometer while neglecting CTC and mixture strength at low temperatures. This limits the reliability of evaluation of a mixture’s resistance to thermal cracking and its integration into the Balanced Mix Design (BMD) for cold regions. If this failure mechanism is not properly addressed in BMD, premature thermally induced surface cracking can occur even when the mixtures comply with existing standards. Although the Thermal Stress Restrained Specimen Test (TSRST) and the Disk-Shaped Compact Tension [DC(T)] Test could account for mixture resistance to thermal cracking, they involve complex procedures and labor-intensive sample preparation, discouraging their routine use. For NCHRP 20-30/IDEA 266, the research team will develop a simple, reliable alternative, the IDEAL-LT test, for evaluating asphalt mixture resistance to thermal cracking that could then be integrated into a comprehensive BMD framework for cold regions. The test will streamline testing by eliminating the need for specimen cutting, coring, notching, and gluing while enabling simultaneous testing of three replicates and improving correlation with field ranking and with established thermal cracking tests, such as the TSRST and ABCD tests. The research will involve building and refining a system unit, validating its field performance, and comparing the results with traditional low-temperature cracking tests. The test frame will be modified to test three replicates simultaneously, improving efficiency and reducing variability. The procedure will be standardized for integration into the BMD. Validation will involve selecting relevant field sections in cold regions with varying levels of thermally induced surface distresses and correlating IDEAL-LT test results with observed field performance. Additionally, the IDEA-LT results will be compared with TSRST/DC(T) and binder ABCD test results to confirm its reliability. Minnesota and Ohio DOTs will collaborate in field evaluations.
Language
- English
Project
- Status: Active
- Funding: $140,000.00
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Contract Numbers:
Project 20-30, IDEA 266
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Sponsor Organizations:
National Cooperative Highway Research Program
Transportation Research Board
500 Fifth Street, NW
Washington, DC United States 20001American Association of State Highway and Transportation Officials (AASHTO)
444 North Capitol Street, NW
Washington, DC United States 20001Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC United States 20590 -
Project Managers:
Jawed, Inam
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Performing Organizations:
Florida State University
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Principal Investigators:
Elwardany, Michael
- Start Date: 20250101
- Expected Completion Date: 0
- Actual Completion Date: 0
Subject/Index Terms
- TRT Terms: Frigid regions; Low temperature tests; Mix design; Pavement cracking; Pavement design; Thermal stresses
- Subject Areas: Design; Highways; Pavements;
Filing Info
- Accession Number: 01993215
- Record Type: Research project
- Source Agency: Transportation Research Board
- Contract Numbers: Project 20-30, IDEA 266
- Files: TRB, RIP
- Created Date: Jun 23 2026 1:33PM