Tests for Plastic Fines in Aggregates Related to Stripping in Asphalt Paving Mixtures

摘要

This study was undertaken for determining the best aggregate test method that indicates the presence of detrimental plastic fines in the fine aggregate, which may induce stripping in hot mix asphalt (HMA) mixtures. Ten fine aggregates representing a wide range of mineralogical compositions and plasticity characteristics were used. Their plasticity characteristics were evaluated by three test methods: (a) sand equivalent value, (b) plasticity index, and (c) methylene blue value. Ten HMA mixtures were made using a common limestone coarse aggregate but these different fine aggregates. Superpave volumetric mix design was used to establish the optimum asphalt contents. Two mix validation tests: (a) AASHTO T283 and (b) the Hamburg wheel-tracking device were used to evaluate the stripping potential of the ten HMA mixtures. Statistical analysis of the aggregate test data and the mix validation test data shows that the methylene blue test is best related to stripping in asphalt paving mixtures.