Comparison of soil index properties value for different pre-drying conditions on clayey soil

Abstract

Pre-test treatment prior to soil index properties testing particularly pre-drying plays an important role in order to obtain accurate and reliable results. According to British Standard, BS1377:1990-Part 1, soil sample shall be dried by either air drying or oven drying before testing. However, permanent alteration of soil physical properties will eventually influence the characteristic and behavior of the soil. Hence, effect of pre-drying conditions on the soil index properties is studied on three number of disturbed clayey soil samples pre-treated in five (5) different pre-drying conditions at different temperatures and drying duration. Soil specimens were tested based on index properties in accordance to BS1377:1990-Part 2. The results obtained revealed that increase of pre-drying temperature and duration has significant effect on the plasticity index of about 13%, shrinkage limit of about 4% and the classification of the clayey soils consisted higher percentage of fine particles. Conclusively, oven drying method should not be used in soil preparation for plasticity and shrinkage testing.