NCHRP Web-Only Document 163: Precision Estimates of Organic Content in Soils by Loss on Ignition

摘要

This report presents the results of an interlaboratory study (ILS) to prepare precision estimates for the AASHTO T267 test method used for the determination of organic content in soils by loss of ignition. The materials for the ILS included sand, silt, and clay each blended with 2%, 5%, and 8% finely ground walnut shells as the organic material. A total of 27 laboratories provided results of percent organic content of three replicates of each soil-organic blend. The results indicated that the repeatability and reproducibility precisions are the same for different levels of organic content of each soil-organic blend, but significantly different for different soil types. A precision statement for AASHTO T267 is proposed based on the precision estimates computed in this study.