Petrographical and geoengineering characteristics of evaporitic rocks (Abu Dhabi city vicinity, United Arab Emirates)

Abstract

The mineralogical composition and textural features of rocks are principal controls on rock engineering properties. A challenging rock material for engineers is represented by the evaporites, typically composed of gypsum, anhydrite and halite-rich sediments. In Abu Dhabi city vicinity, the bedrocks consist of evaporites and carbonate rocks that are partly covered by recent eolian sands and fluvial deposits. This contribution characterizes the petrographical and geoengineering properties of evaporitic rocks from Abu Dhabi city vicinity, United Arab Emirates since there are no published data available. Construction sectors in this city vicinity regularly face technical difficulties and foundation instabilities associated with evaporite bedrocks supporting foundations of buildings and infrastructures due to expansion and dissolution of evaporites. The data collected in this study includes (i) the mineralogical composition and textural features of the evaporites, and (ii) a list of geoengineering characteristics of evaporite rocks aimed to assist engineers and decision makers in resolving foundation problems at construction sites. Petrographic descriptions were obtained using polarized-light microscope, scanning electronic microscope (SEM), x-ray diffraction (XRD) and x-ray fluorescence (XRF) methods. Rock mechanical tests included Unconfined Compressive Strength (UCS), Point Load Index (PLI), Indirect Tensile Strength (ITS), Schmidt Hardness Value (SHVRB) and Slake Durability Index (SDI), performed according to the International Society of Rock Mechanics (ISRM) and the American Society for Testing and Materials (ASTM) standards. Varying degrees of correlation (weak to strong, positive to negative) exist between the geoengineering parameters, probably reflecting the influence of petrographical properties of evaporitic rocks on these parameters.