VAA Virginia Asphalt Fall/Winter 2020

VAASPHALT.ORG 31 Table 1 - Perpetual Pavement Thickness Sensitivity Analysis (Tran et al., 2015) Subgrade Mr(ksi) Base Mr(ksi) Calculated AC Thickness (in.) Range of Maximum Thickness (in.) Minneapolis (PG 64–34) Phoenix (PG 70–22) Baltimore (PG 64–22) Average 5 30 12.5 15.5 14 14.0 12.5–15.5 5 50 12 15 14 13.7 12–15 5 100 12 14 13.5 13.2 12–14 10 30 10.5 14 12 12.2 10.5–14 10 50 10.5 13 12 11.8 10.5–13 10 100 10 12 11 11.0 10–12 20 30 9 12.5 10 10.5 9–12.5 20 50 8.5 12.5 9.5 10.2 8.5–12.5 20 100 8 12 9 9.7 8–12 PERPETUAL PAVEMENTS THE NEXT EVOLUTIONARY STEP but more than 150 pavement sections around the U.S. have demonstrated that asphalt pavements can be designed and built to prevent deep structural distresses. Many of these sections resulted from over design in earlier design systems. More modern approaches, such as that imple- mented in PerRoad and PAVEXpress, allow for an optimized perpetual pavement cross-section typically ranging from 8 to 15 inches, depending on the design conditions which are practical and economically feasible. For More Information The National Asphalt Pavement Associa- tion has just published a new document (Quality Improvement Publication 130), “Perpetual Pavements: A Manual of Practice” for those interested in much more detail on the design, materials selection, and construction of perpetual pavements. More modern approaches to perpetual pavement design have aimed to optimize the pavement section. https://member.asphaltpavement.org/ Shop/Product-Catalog/Product- Details?productid={C45DA814-BF- CD-EA11-A812-000D3A4DF1CD} References Castro, A., N. Tran, F. Gu, D.H. Timm and C. Wagner, “Limit- ing Strain Distribution Criteria for Perpetual Pavement Design Using AASHTOWare Pavement ME Design,” Journal of the Association of Asphalt Paving Technologists, Volume 87, 2018, pp. 275–304. Newcomb, D.E., M. Buncher, and I.J. Huddleston, “Concepts of Perpetual Pavements,” Transportation Research Circular No. 503. Perpetual Bituminous Pavements. Transportation Research Board. Washington, D.C., 2001, pp. 4–11. Tran. N., M.M. Robbins, D.H. Timm, J.R. Willis and C. Rodezno, “Refined Limiting Strain Criteria and Approximate Ranges of Maximum Thicknesses for Designing Long-Life Asphalt Pavements,” Report No. 15-05, National Center for Asphalt Technology, Auburn University, 2015.