Assessment of accuracy in determining Atterberg limits for four Iraqi local soil laboratories

Abstract

The determination of Atterberg limits has large benefits in term of the classification of soil. Thus, it is necessary to obtain high accuracy in determination of these Atterberg limits, and the Atterberg limits test is considered an essential soil test. This study is focused on evaluation of results from four local laboratories, here labelled A, B, C and D based on sending two different type of soil to each laboratory. It was concluded from this study there may be large differences in determining Atterberg limits of as much as 17% for the same sample in the same laboratory. The accuracy of different laboratories in terms of measuring Atterberg limits differed widely. In general, laboratory B was the best followed by C, D then A. The percent of relative error in plasticity index value depend on the relative error product when determining Atterberg limits.