Development of Performance-based Specifications for Louisiana Asphalt Mixtures

Quality control and quality assurance (QC/QA) specifications typically define the asphalt mixtures by how close the as-built mixture meets the requirements of the as-designed mix. A common QC/QA specification for asphalt pavement construction is based on controlling the volumetric properties of compacted asphalt mixtures such as air voids, asphalt content, and aggregate gradation. However, there is no fundamental correlation to ensure that these volumetric properties are sufficient to provide satisfactory long term performance of the asphalt pavements. In order to address the issue in the current QC/QA specification, it is needed to develop a performance-based specification (PBS), which measures the mechanical and/or engineering properties of asphalt mixture as performance predictors of finished pavements. Such a PBS must be verified to actual field performance data. The objective of this study is to develop a framework for the implementation of PBS for Louisiana. To achieve this objective, nine asphalt paving projects were selected across the state. A total of 14 pavement sections that includes 21 asphalt mixtures were selected. A suite of laboratory tests using the Hamburg type loaded-wheel tester (LWT) and the semi-circular bending (SCB) device were performed to evaluate the rutting (in terms of rut depth, RD) and cracking resistance (in terms of critical strain energy release rate, Jc), respectively. In addition, indirect tensile dynamic modulus tests (IDT |E*|) were conducted to evaluate the viscoelastic properties of the asphalt mixtures. The dynamic modulus from IDT |E*| can be used as a material input in the Mechanistic-Empirical Pavement Design Guide (MEPDG) software to predict the 20-year projected distresses. The field distress data were obtained from Louisiana pavement management system (LA-PMS) for the selected projects and used to calibrate the 20-year projected rutting by the MEPDG simulations. From the comparison analyses, it was observed that the LWT measured rut depths of 6 mm or less and 10 mm or less can be the tentative quality limits for the Level 2 and Level 1 Louisiana asphalt pavements, respectively. Similarly, the minimum SCB Jc values of 0.6 and 0.5 kJ/m² for Level 2 and Level 1 asphalt pavements, respectively, seemed to serve well as the tentative criteria to avoid crack related problems. Along with the tentative rutting and cracking performance criteria, a draft sampling and testing plan of the PBS was proposed. A continued effort to collect more field and laboratory performance data in accordance with the proposed PBS is desired to validate the tentative performance criteria and to address unknown challenges for the Louisiana Department of Transportation and Development (DOTD) and contractors in implementing the proposed PBS.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Maps; Photos; References; Tables;
  • Pagination: 149p

Subject/Index Terms

Filing Info

  • Accession Number: 01598807
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/LA.14/558
  • Contract Numbers: April 2011-September 2014
  • Files: NTL, TRIS, ATRI, USDOT, STATEDOT
  • Created Date: Apr 26 2016 11:31AM