Mineralogical characterization of expansive clays for stabilization purposes

Abstract

The research carried out shows the results of experimental mineralogical exercises carried out to characterize expansive clays and evaluate their mineral predominance. The laboratory program consisted of tests to determine the mineralogical composition by means of X-ray Diffraction (XRD) tests, Differential Thermal Analysis and Scanning Electron Microscopy. The material object of analysis corresponded to variegated clay sediments of a primarily reddish color, microlaminated, with the presence of gypsum lenses and carbonaceous traces, belonging to the León Formation (Tol), a tertiary complex of Oligocene age. Superficially, such materials reveal different degrees of erodibility and weathering and are essentially acid soils, susceptible to undergoing volumetric changes due to changes in their moisture content, emerging in a very dry tropical forest climate environment. The tests highlight that the tested material presents characteristics of high plasticity, high compressibility and medium to high expansivity, with preferentially illitic and kaolinitic clay minerals and ductile stress-strain behavior.

Keywords

• expansive clays
• mineralogy
• geology
• x-ray diffraction
• thermo-differential analysis
• scanning electron microscopy