摘要: |
All laboratories conducting tests for the Long-Term Pavement Performance (LTPP) program were required to be accredited by the American Association of State Highway and Transportation Officials (AASHTO) Accreditation Program (AAP). AAP includes site inspections of equipment and procedures, and participation in applicable proficiency sample testing. A few critical LTPP tests were not addressed fully by the AAP, and the LTPP decided to conduct supplemental testing. The asphalt concrete synthetic reference sample program and the asphalt concrete core proficiency sample program were among the supplemental programs approved for implementation. In the first of these two programs, a set of four specimens was circulated to all participating laboratories for testing in accordance with specified parameters. In the second program, two sets of cores (five per set) were shipped to the laboratories. Twenty-four laboratories participated in either one or both programs. Worksheets, supporting data, analyses, final comments, and conclusions are presented. A complete set of proficiency sample statements are provided. |