Assessing the Micro-Deval Test for Compacted Dense-Graded Asphalt

Abstract

In recent years, the asphalt industry has been increasingly evaluating mixture testing for a variety of purposes. This article assesses the Micro-Deval (MD) test for its ability to evaluate compacted dense-graded asphalt mixtures. Historically, the MD test has been used to evaluate durability characteristics of loose aggregates, so this investigation deviates from the equipment’s intended purpose. MD testing was performed in traditional manners (i.e., submerged in water), as well as absent water. The investigation benchmarked MD testing against Cantabro mass loss and the Illinois Flexibility Index Test with an emphasis on use of the protocols during mixture production. Four evaluation criteria were used for assessment (level of rationality of test results, equipment cost, noise during testing, and time to achieve test results). Results of this investigation were that the MD testing protocol was not optimally suited for assessing compacted dense-graded asphalt. Wet MD tests (traditional test manner) were highly variable and provided no appealing test outputs. Operationally, the MD test was one of the noisier tests evaluated; it required an intermediate amount of time to conduct a test but had the lowest equipment cost. With all factors considered, the other tests considered are believed to be more promising than the MD for assessing dense-graded asphalt.

Data Mining Statewide Department of Transportation Volumetrically Designed Asphalt Mixture Records

“…Given the realities illustrated by Figures 1 and 2, these issues will likely continue to be difficult to address exclusively with volumetrics. Mechanical tests are badly needed, and many practitioners and agencies are already working to this end with tests such as the Illinois Flexibility Index Test (I-FIT) ( 23 , 24 ), Disc-Shaped Compact Tension (DCT) ( 30 ), Cantabro Mass Loss (CML) ( 22 , 54 – 57 ), and others as described in Howard et al ( 16 ).…”