Slaking behavior of evaporitic rocks from Abu Dhabi area, United Arab Emirates

Abstract

Slaking behavior of rocks is an essential indicator of their ability to resist degradation and is commonly assessed via the second cycle of slake durability index (I_d2, SDI) test. In Abu Dhabi area, the evaporitic rocks commonly extend from the near surface to several meters depth, so that they lie at the foundation level of buildings and other infrastructures. Evaporites pose significant challenges for the construction sectors due to the easily degradable nature of these rocks. This study presents new and definitive data for evaporites that provides essential information for the construction businesses, engineers, and decision makers. Eighty-six rock blocks from eleven locations were collected. A representative sample of each block was extracted for slake durability testing. Samples were prepared and tested according to ASTM standards. Before and after the slaking process, the mineralogical composition and characteristic textures of the samples were examined in petrographic thin section and via XRD (X-ray diffraction), XRF (X-ray fluorescence), and SEM (scanning electron microscopy) analyses. Based on multiple cycling, I_d1 to I_d4, the slake test data for evaporitic rocks from Abu Dhabi indicate high to very low values. The weight loss values from the first to the fourth cycle (I_d1–I_d4) of all samples lie in the range 40 to 93 wt%. This is attributed to chemical and mineralogical properties of the evaporites, which allow rapid development of hydration-dehydration effects. The evaluation of the slaking behavior of evaporitic rocks provides explanations for durability problems associated with these rocks in the study area and elsewhere.