Mineralogical Compositions of Some Indian Expansive Soils and Their Influence on Swelling Properties

Mineralogical characteristics of nine Indian expansive soils were examined using the X-ray diffraction (XRD) technique. Interpretation of diffraction patterns confirmed the presence of major non-clay minerals (quartz and calcite) and clay minerals (kaolinite, illite, and montmorillonite/smectite) in these expansive soils. In addition, the values of montmorillonite content (MC) in these soils have been collected from the literature and correlated with swelling properties such as swelling potential (S) and swelling pressure (Sp). A critical examination of the X-ray diffraction patterns that have been established on different specimens clearly shows the natural variability in their mineralogical compositions, indicating that the swelling properties of an expansive soil get strongly affected by the type of clay mineral and its content. The relationship between swelling parameters (i.e., S, Sp) and MC was found to be linear in nature. Interestingly, the greater influence of MC is noticed on the swelling pressure than on the swelling potential. © 2017, Springer International Publishing Switzerland.