DEFLECTION STUDY AND DESIGN OF CRACK AND SEAT PAVEMENT REHABILITATION

A study of the deflection performance of cracked and seated and rubblized portland cement concrete pavements was conducted in response to failure of one crack and seat project during construction. Deflection testing was conducted using one or more Dynatest falling weight deflectometers and a 4,086-kg (9,000-lb) target load. Six of the eight crack and seat or rubblized projects built in North Carolina since 1990 were tested on one or more occasions. The projects included guillotine-induced crack spacings of 152, 457, 610, 762, and 1,219 mm (6, 18, 24, 30, and 48 in.), along with a rubblization project. The goal of the study was to determine under what conditions crack and seat rehabilitation is likely to perform successfully. Results indicated that uniform backcalculated subgrade moduli of 103,350 kPa (15,000 psi) or higher are one indicator. The importance of design details to the success of the projects was also clear, especially in the area of bridges. The areas of most severe distress noted on the oldest North Carolina project were associated with tapering under a bridge structure and the area of pavement just before the bridge approach slab. Proper location and use of stress relief cuts before crack and seat were also demonstrated on a project tested during construction. Backcalculation was performed on most of the projects to determine the modulus for portland cement concrete (Epcc), the subgrade modulus and the modulus of the asphaltic concrete layers. The results generally confirmed that decreasing the crack spacing decreases the Epcc of the broken slabs, and that rubblization produces an Epcc that is significantly lower than that from crack and seat. Rubblization also produced less deflection variation based on the one project tested.

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 47-53
  • Monograph Title: Flexible pavement construction
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00715644
  • Record Type: Publication
  • ISBN: 0309061733
  • Files: TRIS, TRB, ATRI
  • Created Date: Jan 24 1996 12:00AM