22 Apr 2026

Laboratory Performance Evaluation of Coarse Aggregates for Asphalt Concrete Mixtures

Abstract: An extensive laboratory evaluation was conducted to investigate the performance of coarse aggregates under different test methods. Test methods including the Los Angeles abrasion (LAA), sulfate soundness, Micro-Deval abrasion, aggregate crushing value, aggregate impact value, aggregate durability index, and aggregate slake durability were chosen to determine the aggregates’ resistance to abrasion, impact, crushing, and soundness. A total of twenty-five aggregate sources were included in the laboratory experiments, including seven different aggregate types (crushed gravel, gabbro, greywacke, granite, limestone, monzonite, and sandstone). The mineral composition of the aggregate sources was determined using X-ray diffraction (XRD) analyses. According to this study, the LAA test results were reasonable in screening out an aggregate source perceived as marginally resistant to abrasion. The sulfate soundness test results were ineffective in quantifying the quality of the different aggregate sources. Most alternative test methods identified similarly unacceptable aggregate sources, consisting mainly of aggregate types composed of carbonate minerals. Strong statistical correlations were not found among the aggregate test parameters. Recommendations were given to further investigate existing test requirements for the selection of coarse aggregates, particularly when using the sulfate soundness test method.

22 Apr 2026

Validation of the Swift and Quiet Airfield Assessment Device (SQUAAD)

Abstract: The need to rapidly determine the subsurface strength required to support various aircraft loading during contingency operations is critical to the success of tactical missions. Current Air Force Special Operations teams are required to perform this task using the dynamic cone penetrometer (DCP), a destructive test method that requires up to three personnel to operate, is time-consuming and representative of only a small area, requiring multiple tests to evaluate terrain suitable for airfield landing. An alternative, nondestructive methodology to capture the subsurface strength is the Swift and Quiet Airfield Assessment Device (SQUAAD). The purpose of the study presented in this report was to validate the SQUAAD to provide military personnel confidence in the operation and accuracy of the unit with respect to the legacy DCP device. A series of nine full-scale test sections were constructed at the US Army Engineer Research and Development Center’s indoor pavement testing facility. The test results indicate that the SQUAAD requires further testing and evaluation before it can replace the DCP.