Rut potential determination of marginal asphalt with low traffic volumes on a regional airport in Southern Africa

Asphalt production and paving in remote regions of Africa can be problematic in terms of logistics, material sourcing and production quality. Airport planning also tend to project high growth rates of aircraft movements which don’t always realize. A further complication is the tendency to use roads design and specifications on airports in such remote regions. A recent airport runway upgrade and asphalt overlay on the west coast of Africa taxed these realities. Dynamic creep modulus was specified as main criteria for rut resistance. The dynamic creep modulus gave variable results partly due to the proven inherent unreliability aspects of the test procedure. Therefore the asphalt had to be evaluated against fit-for-purpose criteria. Actual asphalt thicknesses were variable and in some instances significantly thicker than the specified 50mm. The thicker asphalt, in particular, raised questions about perceived rut propensity. The air traffic movements at this remote airport are low and in future will also be low, which potentially lowers the potential impact of excessive rut development. A number of additional tests including the Light Weight Falling Weight Deflectometer (LFWD) and Falling Weight Deflectometer (FWD) were done to determine and confirm the overall structural pavement strength. Asphalt rut propensity was evaluated with Model Mobile Load Simulator (MMLS) tests. MMLS tests were done on site and additional MMLS tests were done in South Africa on cores from site. Constant Height Repeated Simple Shear Tests (CH-RSSTs) were also done. The latter test allowed comparison of data obtained from Heavy Vehicle Simulator (HVS) tests and associated CH-RSST data base developed in California, USA. All these tests to determine rut potential have different quirks and positives. A comparative triangulation approach had to be followed to arrive at a weighted best evaluation of this asphalt surfacing. The net result was positive.

Language

  • English

Media Info

  • Pagination: 10p
  • Monograph Title: 11th Conference on Asphalt Pavements for Southern Africa: CAPSA15, 16-19 August 2015, Sun City, South Africa

Subject/Index Terms

Filing Info

  • Accession Number: 01597079
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Apr 22 2016 11:12AM