2011 Participants
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NAME: John Cuchta

PROJECT TITLE: Determining Engineering and Geochemical Properties of Paleosols

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The research I am conducting deals with examining the engineering and geochemical properties of paleosols (fossilized soils) and finding correlations between them. Engineering properties being tested are: Slake Durability, which is a rock’s resistance to weatherability; Atterburg Limits, which are various moisture content at which a soil stops acting as a brittle substance and begins acting like a plastic (Plastic Limit), and the moisture content at which a soil stops acting as a plastic substance and begins behaving as a liquid; the presence of microfractures via the Scanning Electron Microscope; and Unconfined Compressability, which uses a core sample of a rock and adds pressure until the sample fails. The geochemical aspect that is being examined is the clay mineralogy using X-Ray Diffractometry.

The majority of paleosols have a clay fraction and silica fraction. The clay fraction is subdivided in to the four main groups of clay minerals (Kaolins, Smectites, Illites, and Chlorites), which have different crystallographic properties. Vertisols (soils comprised mostly of smectites) are a problem for geotechnical engineers due to the smectites ability to shrink and swell greatly (Smectites can easily have >100% moisture vs. dry weight). We hope to be able to link a rock’s engineering properties to composition, clay fraction, and clay type.