Between 1960 and 1972 road smoothness measurements were made on 8,778 two-lane miles of PCC and bituminous concrete surfaced pavements in Illinois. The results were evaluated to determine the effects of certain design and construction variables on the as-constructed riding quality of new pavement surfaces. Annual weighted average Roughness Index (RI) values were determined for both types of pavement surfaces, and the RI trends are discussed relative to changes that occurred in construction specifications and in paving equipment and procedures. Relative to both types of surfaces, the results showed that, on the average, longer paving projects were smoother than short projects and that rural projects were smoother than urban jobs. In comparing standard jointed PCC pavement to continuously reinforced, no difference in as-constructed riding quality was found that could be attributed to pavement design. PCC pavements constructed by the slipform process were smoother than those constructed with side forms, and slipform pavers that depend upon the track line for grade control produced smoother pavements than those equipped with automatic grade control. Bituminous concrete pavement surfaces constructed in three separate layers were smoother than those constructed in two layers. Smoothness was not affected by the type of bituminous paver. The use of leveling and grade control devices during the placement of all courses improved riding quality. The length of grade reference device used with automatic control affected pavement smoothness; longer devices produced smoother pavements.

  • Supplemental Notes:
    • Conducted in cooperation with FHWA.
  • Corporate Authors:

    Illinois Department of Transportation

    126 East Ash Street
    Springfield, IL  United States  62706
  • Authors:
    • LaCroix, J E
  • Publication Date: 1975-10

Media Info

  • Pagination: 41 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00139799
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: Ill-PR-65 Intrm Rpt.
  • Files: TRIS, USDOT
  • Created Date: Oct 6 1976 12:00AM