Abstract: The standard soil moisture retention content is one of the important indices for determining properties of the expansive soil samples. The relationship between the standard soil moisture retention content and the time was laboratory investigated and the quadratic polynomial relationship with time was established. The completion time in the standard soil moisture absorption test is observed mainly related to the soil type, the initial moisture content, the mineral composition in soil particles and the particle size. Throughout the analysis of these factors, the tests discussed in this paper provide guidelines for the practical testing of the standard soil moisture absorption tests also provides a theoretical basis for a better understanding of the physical meaning of the standard moisture absorption.

Key words: standard soil moisture retention content, time, relation functions