Field and laboratory pavements were instrumented and load tested to evaluate the effect of widened lanes, concrete shoulders, and slab thickness on measured strains and deflections. Eight slabs were tested in the field and two in the laboratory. Pavement slabs were 203, 229, or 254 mm (8, 9, or 10 in.) thick. Other major design variables included the width of lane widening, the presence or absence of dowels or of a concrete shoulder, joint spacing, and the type of shoulder joint construction. Generally, there was good agreement between measured strains and values calculated by using Westergaard's theoretical equations. Concrete shoulders were effective in reducing the magnitude of measured strains and deflections. A chart is presented to show the allowable reduction in thickness of the outer lane of the main-line pavement when there is a tied concrete shoulder. Lane widening of about 406 mm (16 in.) was as structurally effective as a concrete shoulder in reducing edge strains and deflections. However, it should be remembered that a concrete shoulder provides the added advantage of draining runoff farther from the pavement edge. Because of the possibility of load encroachments on a widened lane, it is recommended that lanes be widened by a minimum of 0.46 m (1.5 ft) plus any additional width required to avoid encroachment. Under the conditions considered, tied-butt, tied and keyed, and keyed-joint constructions were equally effective in reducing load-induced pavement strains and deflections. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 39-45
  • Monograph Title: Pavement surface properties, evaluation, and shoulders
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00189508
  • Record Type: Publication
  • ISBN: 0309028051
  • Files: TRIS, TRB
  • Created Date: Apr 12 1979 12:00AM