Design & Construction of Heavy-Duty Pavements, 2nd Edition

A revised and updated version of Design, Construction, and Performance of Heavy-Duty Mixes (QIP-123), originally published by the National Asphalt Pavement Association in 2002.Heavy duty mixes are needed in any pavement structure subjected to severe loading conditions as evidenced by the number and weight of heavy loads, heavy static loads, and/or high tire pressures. As pavements meeting these conditions increase, heavy-duty mixes designed to withstand these loads are being used more frequently. Integrating the pavement structural and mixture designs is essential to provide a long-lasting, durable pavement under severe traffic conditions. This publication provides a state-of-the-practice of the material selection, mixture design, structural design, and construction of asphalt mixtures and pavements used under heavy truck traffic or specialized loading conditions, including discussing the use of large-stone mixtures, polymers, and other additives commonly used to provide higher strengths for heavy-duty asphalt mixtures. Because the aggregate skeleton must carry much of the load, it is important that a good quality crushed aggregate is used and that the gradation meets the appropriate requirements. The gradation requirements typically require large nominal maximum size aggregate. Although segregation of the large stone can be a problem, using good production and construction practices can minimize this. Three principal problems that may arise when using large maximum size aggregate are segregation, aggregate fracture, and a slight increase in equipment wear. These problem areas are discussed with an emphasis on the causes of, and steps that can be taken to overcome, segregation.  This report is available from teh National Asphalt Pavement Association at http://www.asphaltpavement.org/PDFs/EngineeringPubs/QIP123_Heavy-Duty_Pavements_2e.pdf