Development of surface friction guidelines for LADOTD.

Details

• Creators:
  Wu, Zhong ; King, Bill
• Corporate Creators:
  Louisiana Transportation Research Center
• Corporate Contributors:
  Louisiana. Dept. of Transportation and Development ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Friction course
  • Surface course (Pavements)
  • Friction tests
  • Rolling friction
  • Rolling resistance
  • Aggregates
  • Aggregate mixtures
  • Physical properties
  • Texture
  • Polishing (Aggregates)
  More +
• Publication/ Report Number:
  FHWA/LA.11/485
• Resource Type:
  Tech Report
• Geographical Coverage:
  Louisiana
• Edition:
  Final report; July 2009-June 2011.
• Corporate Publisher:
  Louisiana Transportation Research Center
• Abstract:
  The main objective of this study was to develop a Louisiana pavement surface friction guideline that considers polished stone value (PSV) and mixture ; type alike in terms of both micro- and macro- surface textures. The polishing and texture properties of aggregates were characterized using the British ; Pendulum, Micro-Deval and Aggregate Imaging System (AIMS). Asphalt mixture slabs were fabricated with different combinations of two aggregate ; sources (sandstone and limestone) and four mixture types and polished by a three-wheel accelerated polishing device developed by the National Center for ; Asphalt Technology (NCAT). The surface frictional characteristics of each slab were measured by Dynamic Fiction tester (DFT) and Circular Texture ; Meter (CTM) at various pre-determined polishing cycles. In addition, an inventory dataset of field friction number (FN) measurements was obtained from ; the LADOTD’s Materials Laboratory and analyzed in this study to determine the effects of traffic loading, aggregate and mixture types on the measured ; FN values. ; The laboratory results indicated that the accelerated polishing device used in this study performed just as the expectation; i.e., as the polishing cycle ; increases, the measured frictional property of testing slab surface decreases. It was found that the DFT measurements were fairly sensitive to the coarse ; aggregate types (related to micro-texture) used in mix design, but were not very sensitive to different mix types or aggregate gradations (related to macrotexture). ; The analysis of CTM measured Mean Profile Depth (MPD) results confirmed a strong relationship between MPD and mixture type, indicating ; MPD does reflect well of surface macro-texture. Because friction resistance of an asphalt mixture should account for both micro- and macro-texture, the ; International Friction Index (IFI) friction numbers, the F(60), were determined based on an IFI model using measured DF20 (the DFT measurement at a ; friction speed of 20 mi/hr) and MPD values for each slab tested. Further analysis of F(60) results generally indicated that an open-graded friction coarse ; (OGFC) mix type considered in this study had the highest friction resistance due to its largest surface macro-texture (or MPD values), followed by the ; stone matrix asphalt (SMA) mix type, and then by the two Superpave mix types considered (a 19-mm Superpave Level-II mix, a 12.5-mm Superpave ; Level-II mix). The F(60) results also indicated that a selected sandstone type (AB13) with a high polishing resistance (PSV>37) performed significantly ; better in terms of mixture friction resistance than a selected limestone (AA50) with an PSV of 31. Mixtures using an aggregate blend of 30 percent of ; selected sandstone and 70 percent of the limestone tended to have a better surface friction resistance than those with 100 percent of the limestone. This ; observation demonstrates that blending of low and high friction aggregates together can possibly produce an asphalt mixture with an adequate field friction ; resistance. ; The analysis has led to the development of a set of prediction models of mixture frictional properties, and a laboratory mix design procedure that ; addresses the surface friction resistance of an asphalt mixture in terms of both micro- and macro- surface textures. The developed frictional mix design ; procedure allows estimating a friction-demand based, design SN value for an asphalt mixture during the mix design stage.
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• Format:
  PDF
• Funding:
  LTRC Project number: 09-2B ; SIO number: 30000119
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/24727/dot_24727_DS1.pdf
• File Type:
  [PDF - 1.54 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:31bdbcba7e5453b169f91a52049178e1e26afd4b7bdf97eeaa112102c41b3f82