Round 1 Type 2 Unbound Cohesive Subgrade Soil Proficiency Sample Program

摘要

SHRP Protocol 46, Resilient Modulus of Unbound Granular Base/Subbase Materialsand Subgrade Soils was the specified procedure for laboratories performing resilient modulus tests on research samples of unbound cohesive subgrade soil obtained from LTPP field sites. All laboratories conducting tests for the LTPP program were required to be accredited by the AASHTO Accreditation Program (AAP). AAP includes site inspections of equipment and procedures, and participation in applicable proficiency sample testing. A few critical LTPP tests, such as the triaxial resilient modulus test, were not addressed fully by the AAP, and LTPP decided to conduct supplemental testing. P46 requires a test system which includes a triaxial pressure cell component, a closed loop electro-hydraulic repeated load component, and certain load and specimen response control, measurement, and recording components. Worksheets, supporting data, analyses, final comments, conclusions are presented. A complete set of proficiency sample statements in AASHTO/ASTM format are provided.