NCHRP Web-only Document 168: Precision Estimates to AASHTO T180: Moisture-Density Relations of Soils Using a 4.54-kg (10-lb) Rammer and a 457-mm (18-inches) Drop

摘要

Under the National Cooperative Highway Research Program (NCHRP) Project 09-26A, the AASHTO Materials Reference Laboratory (AMRL) is conducting a multiphase research project to determine or update estimates of precision of selected AASHTO test methods. The AASHTO T180 standard test method, Moisture-Density Relations of Soils Using a 4.54-kg (10-lb) Rammer and a 457-mm (18-inches) Drop is among the test methods that lack precision estimates. The test method is used to determine the required degree of compaction and a method to obtain the required compaction of soil-aggregate mixtures. An interlaboratory study (ILS) was designed to develop the precision estimates for AASHTO T180. The precision statistics from analysis of AMRL soil proficiency sample data were also incorporated in the development of the AASHTO T180 precision statement provided in this report.