Durability assessment of coarse aggregates for HMA in Maine.

PDFTech Report43075Hot mix paving mixturesCoarse aggregatesDurabilityAbrasionAggregate gradationDegradation (Thermodynamics)Alternatives analysisMaineMaine. Dept. of TransportationNener-Plante, DerekMaine. Dept. of TransportationUS Transportation CollectionIn this study, Micro-Deval and L.A. Abrasion were used to evaluate the durability of 72 individualcoarse aggregates used for HMA in Maine. Aggregates used in hot-mix asphalt (HMA) must bedurable and resistant to abrasion and degradation. Material loss in HMA pavements has recentlybeen observed by MDOT and aggregate degradation has been hypothesized as a possible contributor.The Micro-Deval results showed no correlation with results from the L.A. Abrasion and the range invalues was quite large. Two alternative methods of analyzing Micro-Deval were employed tomeasure the change in gradation of aggregate samples. A relatively large portion of tested aggregatesources were found to degrade significantly in the Micro-Deval test while having acceptableAASHTO Micro-Deval loss values, this presumably due to fracturing instead of abrasion. Theweighted average method and area between curves method proved to be effective in measuring thechange in particle size distribution not captured with the Method 1 Micro-Deval loss value. Inaddition, a significant influence of initial grading size was found in all of the Micro-Deval data withfiner initial gradations producing higher loss values. The alternative analysis methods for Micro-Deval are recommended for use in detecting degradation not captured by the traditional Micro-Devalvalu