Barrett, The Honors College Thesis/Creative Project Collection
Barrett, The Honors College at Arizona State University proudly showcases the work of undergraduate honors students by sharing this collection exclusively with the ASU community.
Barrett accepts high performing, academically engaged undergraduate students and works with them in collaboration with all of the other academic units at Arizona State University. All Barrett students complete a thesis or creative project which is an opportunity to explore an intellectual interest and produce an original piece of scholarly research. The thesis or creative project is supervised and defended in front of a faculty committee. Students are able to engage with professors who are nationally recognized in their fields and committed to working with honors students. Completing a Barrett thesis or creative project is an opportunity for undergraduate honors students to contribute to the ASU academic community in a meaningful way.
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Expansive soils in the United States cause extensive damage to roadways, buildings, and various structures. There are several treatment or methods of mitigation for these expansive soils. These treatments can be physical or chemical treatments that serve to provide more suitable building qualities for foundations and roadways alike. The main issue with expansive soils, is the volumetric variations, which are known as swelling and consolidation. These behaviors of the soil are usually stabilized through the use of lime solution, Portland Cement Concrete, and a newer technology in chemical treatments, sodium silicate solutions. Although the various chemical treatments show benefits in certain areas, the most beneficial method for stabilization comes from the combination of the chemical treatments. Lime and Portland cement concrete are the most effective in terms of increasing compressive strength and reduction of swell potential. However, with the introduction of silicate into either treatment, the efficacy of the treatments increases by a large amount lending itself more as an additive for the former processes. Sodium silicate solution does not lend itself to effectively increase the compressive strength of expansive soils. The sodium silicate solution treatment needs extensive research and development to further improve the process. A proposed experiment plan has been recommended to develop trends of pH and temperature and its influence on the effectiveness of the treatment. Nonetheless, due to the high energy consumption of the other processes, sodium silicate solution may be a proper step in decreases the carbon footprint, that is currently being created by the synthesis of Portland Cement Concrete and lime.
ContributorsMeza, Magdaleno (Author) / Zapata, Claudia (Thesis director) / Kavazanjian, Edward (Committee member) / Civil, Environmental and Sustainable Eng Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
This thesis is part of a larger research project, conducted by Elizabeth Stallings Young, which aims to improve understanding about the factors controlling the process of MIDP and the interaction between the biochemical reactions and the hydrological properties of soils treated with MIDP. Microbially Induced Desaturation and Precipitation (MIDP) is a bio-geotechnical process by which biogenic gas production and calcite mineral bio-cementation are induced in the pore space between the soil particles, which can mitigate earthquake induced liquefaction (Kavazanjian et al. 2015). In this process substrates are injected which stimulate indigenous nitrate reducing bacteria to produce nitrogen and carbon dioxide gas, while precipitating calcium carbonate minerals. The biogenic gas production has been shown to dampen pore pressure build up under dynamic loading conditions and significantly increase liquefaction resistance (Okamura and Soga 2006), while the precipitation of calcium carbonate minerals cements adjacent granular particles together. The objective of this thesis was to analyze the recorded pore pressure development as a result of biogenic gas formation and migration, over the entire two-dimensional flow field, by generating dynamic pressure contour plots, using MATLAB and ImageJ software. The experiment was run in a mesoscale tank that was approximately 114 cm tall, 114 cm wide and 5.25 cm thick. Substrate was flushed through the soil body and the denitrifying reaction occurred, producing gas and correspondingly, pressure. The pressure across the tank was recorded with pore pressure sensors and was loaded into a datalogger. This time sensitive data file was loaded into a MATLAB script, MIDPCountourGen.m, to create pressure contours for the tank. The results from this thesis include the creation of MIDPContourGen.m and a corresponding How-To Guide and pore pressure contours for the F60 tank. This thesis concluded that the MIDP reaction takes a relatively short amount of time and that the residual pressure in the tank after the water flush on day 17 offers a proof of effect of the MIDP reaction.
ContributorsCoppinger, Kristina Marie (Author) / van Paassen, Leon (Thesis director) / Kavazanjian, Edward (Committee member) / Stallings-Young, Elizabeth (Committee member) / Civil, Environmental and Sustainable Eng Program (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05