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Soft and semisolid states of fine-grained soils and clay minerals (FGS-CMs) are frequently dealt with during execution of infrastructure projects located in the coastal areas, analysis of natural hazards, and mineral processing. In most of these cases, the FGS-CMs flow like a slurry, and hence determination of their rheological characteristics becomes essential. However, test methods and approaches available for determining the rheological behavior of the FGS-CMs when they transform from the solid to the liquid state are yet to evolve. This study uses a parallel-plate rheometer, which is widely used for rheological characterization of complex fluids (i.e., fluids which exhibit yield stress), to determine the rheological parameters (i.e.,yield stress, T-y, and strains) of the FGS-CMs with a consistency near the liquid limit. A critical analysis of the existing protocols that are used to determine T-y and their applicability to FGS-CMs is conducted. The constant shear-rate (CSR) test, when conducted at low shear-rate, yields the most accurate T-y of FGS-CMs. Subsequently, the results are used to develop a generalized relationship which explains the variation of the T-y of the FGS-CM with the consistency represented as water content normalized with respect to the liquid limit. Furthermore, to understand the nature of strains that develop during the preyielding regime of FGS-CMs, creep-relaxation (CR) tests are conducted by imposing stress equivalent to different fractions of T-y. The results from CR tests were utilized in the development of a novel methodology to determine the elastic component of the shear modulus, G(E), of FGS-CMs. This study reveals that FGS-CMs behave as a linear elastoplastic material in the preyield stage, contrary to the much expected purely elastic response, providing a new insight in the realm of contemporary geomechanics. (C) 2018 American Society of Civil Engineers.

The dependence of the rate of relaxation of semolina pasta on moisture content and temperature and how it affects shrinkage during drying has not yet been determined. The purpose of this research was to develop an equation that relates moisture content and temperature in order to obtain a master curve for creep of the product. When found, this equation could help to optimize the drying process and increase the quality of the final pasta product. Semolina flour mixed with water and propionic acid to create a 35% wet basis product was extruded on a C.W. Brabender 2523 to obtain a flat, thin pasta. This product was dried in desiccators calibrated at different relative humidities (53.2%, 82.3%, 96.4%) and temperatures (40OC, 80OC) and then run through creep testing with a DMA and Texture Analyzer. Creep testing related the rate of relaxation to the relative humidity, moisture content, and temperature. The pasta that was tested at higher stresses tended to strain more. Also, higher moisture content pastas and pastas dried at higher temperatures tended to strain more. These results will be used in ongoing research relating the creep of semolina pasta to the rate of shrinkage of the product. Eventually, data such as this for other bio products will be collected and analyzed which can lead to better quality products and higher efficiency processes.