Effect of Method of Soil Drying on Atterberg Limits and Soil Classification

Abstract

One of the most significant factors that effects the soil classification is Atterberg limits, liquid limit and plastic limit. Atterberg limits were developed by a Swedish scientist at the early 1900's called Atterberg. These limits could express the consistency of fine-grained soils due to variety of water content. These limits divide the soil into four major states, solid, semi-solid, plastic, and liquid state. According to American Standard for Testing and Materials (ASTM), to check liquid limit and plastic limit tests for a soil, the soil should be dried before the test for preparation purpose. ASTM specified two ways to dry the soil specimens, oven dry and air weather dry and both should give same results. Most of engineers will go with dry oven method to speed up the specimen preparation process assuming there is no any difference between these two methods of drying. In this research, the effect of the drying method has been studied. The results showed that the drying method has a significant effect on the liquid and plastic limits and then on the classification of soils. The soil specimens of this research were brought from all over Iraq cities to ensure studying different soils that could exhibits different behaviors.