Estimation of swelling characteristics of expansive soils with influence of clay mineralogy

In the present study, characterisation and quantitative microanalysis were identified for six expansive soils of which one is natural soil, i.e. black cotton (BC) soil and remaining soils were prepared by mixing of BC soil with different percentage of bentonite. The BC soil and prepared soil samples were characterised by the X-ray diffraction (XRD) and scanning electron microscope (SEM). The regular or irregular mixed layers of soils justified by SEM images. There are superstructures whose spacing can simply be described as the ratio of BC soil and prepared soil. d-Spacing was calculated by Bragg’s formula (XRD) which was observed by joint committee on powder diffraction standards card and calculated by Bragg’s equation for h-k-l plane for expansive soils and it was observed that d-spacing decreased with increasing prepared soil combination. Moisture content was taken below optimum moisture content, i.e. 15%, 17% and 20% to determine swelling and swelling pressure and found that montmorillonite mineral affects the swelling characteristics of expansive soils.