Geotechnical properties and microanalyses of marble dust-bentonite as an alternative geomaterial of sand-bentonite mixes

ABSTRACT The present works have been aimed to investigate the potential of marble dust (i.e. a waste material obtained as a by-product from the marble industry) as a replacement of sand to achieve the desired geotechnical properties for its possible use as a geomaterial. Hence, marble dust (MD) is amended with a wide range of Bentonite (B) content (up to 95%) to examine the geotechnical properties [i.e. Atterberg’s limits, free swell indexes, compaction characteristics, California Bearing Ratio (CBR), Unconfined Compressive Strength (UCS), and shear strength]. The efficacy and potential of MD-B mixes are confirmed by validating the geotechnical properties of sand (S)-bentonite (B) mixes. Results revealed that the geotechnical properties of MD-B mixes are observed to be comparable with S-B mixes. However, the amendment of MD and S with 60% B has been observed to be most beneficial in terms of achieving the ultimate CBR, UCS, and shear strength values. Thus, it is concluded that MD can be used as an alternative geomaterial to the sand with bentonite. Further, microanalyses [X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDAX), Fourier Transform Infrared Spectroscopy (FTIR) and Thermal Analysis (TA)] and physicochemical are performed to elucidate the results.