X-Ray Diffraction Assessment of Expanding Minerals in a Semi-Arid Environment

In semi-arid areas, light buildings, highways, and pavements are frequently damaged by the subsurface swelling or shrinkage of expansive soils during both wetting and drying cycles. The goal of this research is to explore the X-ray diffraction of natural clay with bentonite additives in order to determine the amount of expanding minerals in the clay based on changes in the diffractometer profile and diffraction intensity. Mineralogical studies are crucial for determining the geotechnical behavior of these soils. Five semi-arid areas were chosen to explore the key minerals that influence geotechnical behavior. The various geological backgrounds were reflected in differing expansivities, and X-ray diffraction revealed considerable mineralogy differences between the five zones under consideration. Non-sharp peaks rose above background intensities in zones containing smectite clay minerals. Significant expanding minerals produced distinct peaks in the clays. Adding 10, 20, 30, and 40% commercial bentonite changed the peak size and area beneath the peak. Overlapping intensities in clay minerals can affect the intensity of peaks in lower 2θ ranges. This was discovered to influence the method of quantification and can be improved by the usage of heating or glycolation processes. The diffraction profile for each examined area is supplied, along with an identification of expansion minerals. The methodology is provided for estimating clay minerals in areas with similar geological origins. Qatif clays were discovered to be the most expansive with estimated expanded mineral concentrations ranging from 23.9 to 34.7%. The remaining four clays had mineral concentrations ranging from 4.4 to 20%. Two proposed semi-quantitative methods are investigated. The peak intensity method produced better results than the area under the peak method.