Assessment of clay soil fabric using scanning electron microscope (SEM)

This paper introduces the way of assessing the soil fabric using outlines given by Collins and McGown (1983).The physical and mechanical properties of soils depends particularly on their fabric. At micro levels, the fabric of a soil sample consists of different elemental particles as well as it does at visible range of view. The arrangements of elementary particles and their sizes and shapes predict its mechanical behavior and characteristics. One of the best ways to recognize the fabric of a soil sample is to utilize scanning electron microscope. In this paper first the fundamental alphabets of scanning electron microscopes are explained then the soil fabric classification system given by Collins and McGown is fully described. Three clay soil sample were selected. Six specimens were prepared for swelling test, three of them without any treating agents and remains were treated with apolymeric agent. After applying swelling test according to ASTM D-4546 the samples were scanned using scanning electron microscope (SEM) and 18 micrographs were taken. For clarifying the terms used in the classification system, all micrographs were fully interpreted.