Chip seal coats are used extensively by most state highway departments as a maintenance tool. Although use in the past has been restricted to low traffic volume facilities, more agencies are investigating use of chip seals on other parts of networks including high traffic pavements. This use has prompted more interest in higher quality chip seal materials and practices not only for high traffic facilities, but low volume pavements as well. Polymer modified asphalt emulsions and cements have become very popular in many states for chip seal construction. Benefits of these binders prompt high use because of apparent good initial chip retention. Although many agencies believe these modified binders are performing as well or better than conventional binders, no data has been collected to assess the cost-effectiveness of these more expensive binders. In addition, it is desired to determine whether use of these modified binders on all types of pavements is justified. The purpose of this study was to construct a full-scale test pavement using binders consisting of two sources of polymer modified high-float asphalt emulsion and one control high-float emulsion. Aggregates used varied from clean, high quality materials to marginally dirty materials. All materials were placed at rates appropriate for the existing pavement surface conditions and aggregate properties. Emulsions were applied from two pressure distributors equipped with standard and variable rate nozzles such that effect of lower emulsion application rates in the wheel paths could be observed. Field and laboratory Vialit tests were conducted during the experiment and suggestions are presented for imprvoement to the recommended procedure for obtaining repeatable test results.

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 84 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00493591
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-HPR-NM-87-02, NMERI OC 89/122
  • Contract Numbers: 87-02
  • Created Date: Apr 30 1990 12:00AM