Performance Evaluation of Asphalt Pavement with Fly Ash Stabilized FDR Base: A Case Study

With the demands for environmental-benign technology for highway construction, recycling in-place pavement materials for reconstruction or rehabilitation has become an important re-construction alternative. For asphalt pavement reconstruction/rehabilitation, full-depth reclaimed (FDR) asphalt pavement materials is a viable option, which pulverizes the existing asphalt layer and/or base materials as a new base. In some occasions, to increase the support of base consisting of recycled pavement materials, additives, such as cement, emulsion, or self-cementing Class C fly ash, are added as a binder. Self cementing Class C fly ash is both economical and an environmentally-friendly approach which makes beneficial use of a coal combustion by-product. This paper addresses the performance evaluation of an asphalt pavement with Class C fly ash stabilized FDR asphalt pavement materials as the base. The performance was evaluated using distress survey, falling weight deflectometer (FWD), and mechanistic-empirical (M-E) design program, as a case study. It was found that within the three year after the construction, the modulus of Class C fly ash stabilized FDR base has continuously increased, as a result of continuing pozzolanic reactions. However, it was also found that in the sixth year after the construction, the modulus of base began to decline when compared to the third year results. It is believed that freeze-thaw effects may have reduced the strength of the stabilized base course. A visual distress survey found that top-down cracking from the asphalt surface began to occur three years after the construction as the predominant distress, followed by thermal cracking and rutting. The verification of performance using M-E design program found that the M-E design program underpredicted the amount of top-down cracking and thermal cracking and did reasonably well for prediction of the rutting. It is believed that the stiff base could be a reason for the top-down cracking and that friction between the HMA layer and base contributed to the thermal cracking.

Language

  • English

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 423-433
  • Monograph Title: Airfield and Highway Pavements. Efficient Pavements Supporting Transportation's Future

Subject/Index Terms

Filing Info

  • Accession Number: 01144298
  • Record Type: Publication
  • ISBN: 9780784410059
  • Files: TRIS
  • Created Date: Nov 13 2009 2:40PM