EVALUATION OF COLORADO'S FLEXIBLE PAVEMENT BASE DESIGN METHODS-FINAL REPORT

TWENTY-SEVEN FLEXIBLE PAVEMENT PROJECTS 15 TO 16 YEARS OLD WERE INVESTIGATED TO CORRELATE PERFORMANCE WITH MOISTURE, TRAFFIC, SOIL, AND DESIGN CONDITIONS. THE FOLLOWING CONCLUSIONS ARE GIVEN: (1) USED BASE AND SUBBASE MATERIAL IN COLORADO IS REUSABLE. NO DEGRADATION OR ADULTERATION OF BASE AND SUBBASE AGGREGATES OCCURS AFTER 15 TO 20 YEARS USE UNDER A FLEXIBLE PAVEMENT IN THIS DRY CLIMATE. (2) LOSS OF SERVICEABILITY IS HARDENING AND CRACKING OF THE ASPHALT MAT. (3) IN-PLACE CALIFORNIA BEARING TEST VALUES ON SUBGRADE MATERIALS WERE ALMOST TWICE AS HIGH AS LABORATORY CBR TESTS PERFORMED ON SOAKED SAMPLES 15 TO 20 YEARS AGO. (4) TRAFFIC VOLUMES PREDICTED 15 TO 20 YEARS AGO WERE REASONABLY ACCURATE FOR 20 OUT OF 27 PROJECTS INVESTIGATED. (5) TWO-THIRDS OF THE DENSITIES TAKEN IN THE SUBGRADES WERE BETWEEN 95% AND 100% OF THE AASHO T-99 STANDARD. LOW DENSITY SUBGRADES ARE ASSOCIATED WITH WET CLAYEY SUBGRADES. (6) LONGITUDINAL CRACKING NEAR THE EDGES OF MATS IS ASSOCIATED WITH NARROW SHOULDERS AND STEEP EMBANKMENT SLOPES. BLOW-SANDS AND LOOSE ROCK FILLS SHOULD BE WIDENED TO PROVIDE BETTER LATERAL SUPPORT. (7) ALMOST ALL WEAK SPOTS OBSERVED WERE ASSOCIATED WITH POOR DRAINAGE AREAS. (8) DEFLECTION DATA MAY PROVIDE A FAIR GUIDE TO THE AMOUNT OF USEFUL LIFE REMAINING IN A ROADWAY, BUT IT DOES NOT CORRELATE WELL WITH PERFORMANCE OF LOW-TRAFFIC ROADWAYS IN COLORADO. /AUTHOR/

• Corporate Authors:

  Colorado Department of Highways

  4201 East Arkansas Avenue
  Denver, CO  United States  80222

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Publication Date: 1970-4

Subject/Index Terms

• TRT Terms: Base course (Pavements); Deflection; Density; Design; Flexible pavements; Longitudinal cracking; Moisture content; Pavement performance; Pavements; Service life; Serviceability; Soils; Subbase materials; Subgrade (Pavements); Traffic
• Uncontrolled Terms: Base; Data
• Old TRIS Terms: Conditions; Pavement life
• Subject Areas: Design; Geotechnology; Highways; Materials; Operations and Traffic Management; Pavements;

Filing Info

• Accession Number: 00206439
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Files: TRIS, USDOT, STATEDOT
• Created Date: Jun 1 2000 12:00AM