This report represents the culmination of more than seven years of careful planning, construction,and objective data analysis. The results should be of value to federal, state and local agencies concerned not only with the restoration of existing roadways but also with new highway construction. The recommendations contained herein refer to overlays--in particular, thin overlays of 102 mm (4 in) or less placed over existing badly cracked, rutted, or otherwise distorted bituminous pavements. Overlaying can also immprove skid resistance or rideability. However, no one treatment is a cure-all for all roadway conditions. Rather, the recommended crack-preventing treatments should be integrated into a total overlay design that is carefully tailored to the nature of the distress. Five treatments have significantly reduced reflective cracking: (a) asphalt-rubber membrane seal coat under asphalt concrete finishing course (ACFC), (b) asbestos plus 3 percent asphalt, (c) heater as scarification with reclamite (surface recycling), (d) asphalt-rubber membrane flushed into asphaltic concrete overlay, and (e) 200/300 penetration asphalt. Application considerations are as follows: (a) one of the preceding treatments should be used in conjunction with a thin overlay of 102 mm (4 in) or less of asphalt concrete (AC), (b) application of an asphalt-rubber membrane seal coat under the AC or ACFC should be used with chips to provide direct transfer of vertical loads, (c) heater scarification should be to a depth of 19 mm (0.75 in) or more, and (d) the lowest possible viscosity AC asphalt with the slowest aging characteristics should be used. Findings from this project led to the use of thin overlays with special treatments. The thickness of these thin overlyas varies from 19 mm (0.75 in) to 90 mm (3.5 in). If significant cracking appears on the existing highway before overlay, a special treatment is used. Treatments include either asphalt-rubber or heater scarification.

Media Info

  • Media Type: Print
  • Features: References; Tables;
  • Pagination: pp 29-32
  • Monograph Title: Concrete Pavements and Pavement Overlays
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00325978
  • Record Type: Publication
  • ISBN: 0309030706
  • Files: TRIS, TRB
  • Created Date: May 21 1981 12:00AM