Refinement of Current WisDOT HMA Mixture Application Guidelines Related to NMAS and Aggregate Characteristics.

摘要

Current Wisconsin Department of Transportation (WisDOT) Specifications limit nominal maximum aggregate size (NMAS) of hot-mix asphalt (HMA) to 12.5 mm in the surface layer and 19.0 mm in lower layers. This potentially places unnecessary limits on both construction practice and pavement design. The purpose of this research project was to evaluate the feasibility of expanding WisDOT specifications to include a wider range of aggregate NMAS and lift thicknesses in HMA pavements. In addition to a literature review, a variety of models and laboratory tests were used to determine the likely effects of varying NMAS and lift thickness on various aspects of pavement performance. Based upon this research, it is recommended that WisDOT allow use of 9.5 and 12.5 mm NMAS in HMA surface layers, and 12.5 mm and 19 mm NMAS in intermediate and base layers. Additional recommendations, including restrictions on lift thickness, are also given in the report.