It indicates the toughness index of soil.ģ. The value of the plastic limit is used to classify the fine-grained soils and evaluating the activities of clayey soil.Ģ. The main importance of the plastic limit test of soil can be summarized as follows:ġ. In this regard, the soil is considered non-plastic if the soil thread cannot be rolled down to 3.2 mm at any possible moisture conditions.Ģ. In other words, the plastic limit may be defined as the moisture content where the thread of soil breaks apart at a diameter of 3.2 mm (about 1/8 inch). The plastic limit of soil can be defined as the water content at which the soil begins to crumble when rolled into threads of the specified size. One such test of soil is the plastic limit test. Thus, to ensure the quality of the soil, various tests are conducted. Soil should have an acceptable quality to ensure adequate structural strength and safety.
In this regard, soil can be considered as the foundation of all types of surface construction. Soil can be regarded as the structural basis of any type of construction as the majority of the structures are erected on the soil itself.