Rutting represents one of the most common forms of distress in flexible pavements throughout the world. In order to rationally design pavements, in terms of economics, safety, serviceability to the user, and structural damage, it is necessary to be able to predict the actual magnitude of rutting under any given set of conditions. This paper describes a method of predicting rut depths in flexible pavements. It is based on the evaluation of permanent deformation characteristics of asphalt concrete and unbound base course materials. Statistically designed laboratory experiments provided information about the behaviour of these materials under simulated field conditions. From these laboratory results, mathematical models were developed to predict rutting. Verification was conducted through correlations with actual field test measurements of rut depths. Asphalt concrete was initially investigated and predictive models were developed in terms of load applications, stress state, temperature, air voids and asphalt penetration as variables. These models were verified using actual measured rut depths from full depth sections at the Brampton Test Road in Ontario. A high degree of correlation was achieved. The next phase of the study examined unbound base materials. Similar predictive models were developed, in terms of density, stress state and load application as variables. These laboratory based models were applied to the conventional flexible pavement sections at Brampton, again with a good degree of reliability. Finally, after a sensitivity analysis of variables expected to be significant in affecting rutting, a simplified regression equation incorporating only the important variables was developed. Granular and asphalt equivalencies were used and good agreement between predicted and measured values were found for sections at The Brampton Test Road, Ste. Anne Test Road and San Diego Test Road. /Author/

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 519-528

Subject/Index Terms

Filing Info

  • Accession Number: 00170235
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Mar 14 1978 12:00AM