Aggregates used in the construction of roads must be durable, abrasion resistant, and freeze-thaw resistant in order to perform well in pavement or as base course. The objective of this study was to investigate whether the Micro-Deval test will provide better, timelier, and more repeatable information about the quality of an aggregate than other durability tests based on laboratory test data. This objective was realized by conducting: 1) a thorough analysis of aggregate durability data from around the U.S.; 2) a survey of the state-of-the-practice of state Departments of Transportation within the U.S.; 3) laboratory tests including Micro-Deval, L.A. Abrasion, and Sodium Sulfate; and 4) an extensive literature review. Test results were normalized to facilitate direct comparisons between Micro-Deval, L.A. Abrasion, Sodium Sulfate and Magnesium Sulfate tests. Linear regression of the data points and corresponding confidence intervals were plotted to qualitatively assess agreement or disagreement between test methods. Results of this study indicate that the Micro-Deval test is a suitable replacement for the Sodium Sulfate test as the primary method for evaluating aggregate durability, with limitations. Due to some inconsistent durability determinations between test methodologies, the authors recommend that the Micro-Deval test results be further supported by a second aggregate durability test whenever the Micro-Deval results fall within a certain range (i.e., between 18 and 27 percent loss). It was also concluded that the most conservative test is the Micro-Deval followed by Magnesium Sulfate, L.A. Abrasion and Sodium Sulfate tests, respectively.
Abstract