Optimizing laboratory mixture design as it relates to field compaction to improve asphalt mixture durability.

Details

• Creators:
  Hekmatfar, Ali ; McDaniel, Rebecca S. ; Shah, Ayesha ; Haddock, John E.
• Corporate Creators:
  Purdue University. Joint Transportation Research Program
• Corporate Contributors:
  Indiana Department of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Air voids
  • Asphalt mixtures
  • Compaction
  • Deformation
  • Durability
  • Field tests
  • Laboratory tests
  • Mix design
  • Optimization
  • Superpave Hot-mix asphalt
  More +
• Publication/ Report Number:
  FHWA/IN/JTRP-2015/25
• DOI:
  http://dx.doi.org/10.5703/1288284316010
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  Final report
• Corporate Publisher:
  Purdue University
• Abstract:
  Most departments of transportation, including Indiana, currently use the Superpave mixture design method to design asphalt mixtures. ; This method specifies that the optimum asphalt content for a given gradation be selected at 4 percent air voids. During construction, ; these mixtures are typically compacted to 7‐8 percent air voids. If mixtures were designed to be more compactable in the field they ; could be compacted to the same density as the laboratory mixture design, which would increase pavement durability by decreasing the ; in‐place air voids. The objective of this research was to optimize the asphalt mixture design in order to increase in‐place asphalt ; pavement durability without sacrificing the permanent deformation characteristics of the mixture. ; Three asphalt mixtures were designed using the standard Superpave design method at 100 gyrations of the Superpave Gyratory ; Compactor, suitable for traffic levels of 3 to 30 million Equivalent Single Axle Loads. Each mixture was then used as a starting point to ; design three additional mixtures using 70, 50, and 30 gyrations, with optimum binder content chosen at 5 percent air voids, rather than ; the currently specified 4 percent. The effective asphalt content was held constant for the original and redesigned mixtures. Permanent ; deformation characteristics of the sets of four mixtures were determined by measuring the dynamic modulus and flow number. The ; results suggest that the mixture designs produced using 70, 50, and 30 gyrations had permanent deformation characteristics equal to or ; better than the original 100‐gyration mixtures. ; Based on the laboratory test results, two field trials were placed evaluate the design method, ease of construction and to compare the ; construction results of the re‐designed and original mixtures. Samples from both projects were collected during construction, test ; specimens compacted, and additional physical testing completed. The field trial results suggest that it is possible to place a mixture at 5 ; percent air voids and that mixtures designed at 5 percent air voids should have equivalent performance to those designed at the ; conventional 4 percent air voids.
  More +
• Format:
  PDF
• Funding:
  SPR-3624
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31055/dot_31055_DS1.pdf
• File Type:
  [PDF - 8.87 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:a499ea82ab720eae3b94455478f3a2902212613197e0927e2b28a892ba68cb5c6da9100c0316fd66d0c5db5a3e292e991dc3fdf59e31c94ee1bf368c1af0f35c