A detailed breakdown of the IRI statistic: the LTPP GPS3 profile case study

This paper presents a generic statistical method for parameterization of any single-value road profile index (IRI in this case) as a function of any number of "pavement surface geometry" type components. This general method can be used to break down any profile index for any type of road using any relevant surface geometry statistics. Many pavement engineers have been slow to accept IRI as a useful pavement condition index because it is a single value and cannot show what explicitly is causing roughness (IRI). This case study shows directly how slab warping and joint faulting affect the overall International Roughness Index (IRI) values for the FHWA LTPP GPS3 JPCP. A non-linear regression for back-predicting IRI from the nine JPCP profile geometry components, and the relevant correlation statistics and scatter plots are provided. It is shown that an IRI value for a JPCP is mostly related to the size and number of faults per unit length of road. Based on this research, relations between loss of initial IRI (and AASHTO PSI), to locked-in slab curvature are also presented.


  • English

Media Info

  • Pagination: 195-207
  • Monograph Title: Proceedings of the International Conference on Highway Pavement Data, Analysis and Mechanistic Design Applications, September 7-10 2003, Columbus, Ohio: volume 2

Subject/Index Terms

Filing Info

  • Accession Number: 01390910
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Aug 23 2012 5:08AM