Influence of Aggregate Gradation and Particle Shape/Texture on Permanent Deformation of Hot Mix Asphalt Pavements.

摘要

In recent years, the incidence of premature rutting in hot mix asphalt (HMA) pavements has increased. This deformation usually develops in the wheelpaths under channelized traffic in the top 3 to 4 in. of the HMA pavement. The primary cause of this premature rutting has been higher traffic volumes, increased loads and tire pressures, and lower quality HMA mixtures. This investigation focused on permanent deformation produced by plastic flow and densification of the HMA layers. Approximately 85 percent of the total volume of HMA mixtures is aggregate, and the performance of HMA mixtures is greatly influenced by aggregate properties. This study was conducted to evaluate the influence of these properties on permanent deformation characteristics of HMA mixtures. The analysis consisted of correlating aggregate properties with HMA mixture properties and the rutting potential of HMA pavements. The research study consisted of a literature review, laboratory evaluation, and field evaluation. The laboratory evaluation consisted of aggregate characterization tests and HMA mixture tests. The aggregate characterization tests included Particle Index, National Aggregate Association (NAA), and Modified NAA particle shape and texture, unit weight and voids in aggregates, and direct shear tests. The HMA mixtures were evaluated with Marshall properties, Gyratory Testing Machine, indirect tensile tests, direct shear tests, and confined repeated load deformation tests. The field evaluation included construction of 10 test items, trafficking with a load cart simulating aircraft loads and tire pressures, and evaluating performance with rut depth measurements. (MM).