ETDs

This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.

In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.

Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.

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Laboratory and Field Testing in Support of Field Studies of Enzyme Induced Carbonate Precipitation (EICP) for Fugitive Dust Control

Description
Enzyme-Induced Carbonate Precipitation (EICP) has emerged as a promising biogeotechnical solution for mitigating fugitive dust emissions. EICP mitigates fugitive dust emissions by inducing carbonate precipitation to bind soil particles together and enhance soil strength. Traditional dust mitigation approaches, such as applying water and chemical treatments, are limited by concerns surrounding…

Enzyme-Induced Carbonate Precipitation (EICP) has emerged as a promising biogeotechnical solution for mitigating fugitive dust emissions. EICP mitigates fugitive dust emissions by inducing carbonate precipitation to bind soil particles together and enhance soil strength. Traditional dust mitigation approaches, such as applying water and chemical treatments, are limited by concerns surrounding cost, safety, and sustainability. In contrast, EICP treatment may offer a more eco-friendly and sustainable strategy for controlling fugitive dust emissions. Nevertheless, the lack of field-scale implementation has impeded the adoption of EICP treatment. This study is part of a larger effort to demonstrate the efficacy of EICP treatment at the field-scale by performing bench-scale and field-scale testing on three distinct soil types obtained from different field sites. The three soil types included a silty sand from fallow farmland in Pinal County, Arizona, clayey sand from an interim soil cover at a landfill site in Maricopa County, Arizona, and mine tailings from an abandoned mine site in Yavapai County, Arizona. Testing conducted for this research included evaluating wind erosion resistance using the Portable In-Situ Wind Erosion Laboratory ( PI-SWERL) on untreated and EICP-treated materials as well as soil characterization and penetrometer tests. The characterization tests included micro-scale analysis methods, such as carbonate content, scanning electron microscopy (SEM), and X-ray diffraction (XRD. The results of this study demonstrate the ability of EICP to mitigate fugitive dust in three different geotechnical materials by forming a soil crust on the ground surface via the precipitation of carbonate.
ContributorsYu, Xi (Author) / Kavazanjian, Edward EK (Thesis advisor) / Salifu, Emmanuel ES (Committee member) / Khodadadi Tirkolaei, Hamed HK (Committee member) / Arizona State University (Publisher)
Created2023
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Bio-Based Scour Mitigation for Underwater Foundation Systems

Description
In the marine ecosystem, mangrove forests protect the coastline due to their unique prop root system functions as a natural barrier to stabilize sediment and mitigate erosion. Such distinct characteristics provide a design inspiration to reduce local scour around underwater foundation systems such as the monopile foundation of offshore wind…

In the marine ecosystem, mangrove forests protect the coastline due to their unique prop root system functions as a natural barrier to stabilize sediment and mitigate erosion. Such distinct characteristics provide a design inspiration to reduce local scour around underwater foundation systems such as the monopile foundation of offshore wind turbines. In this study, a ring of skirt piles in a circular layout inspired by the mangrove root structure has been proposed which aims to protect the centered monopile foundation. Three main aspects of the mangrove prop root system have been extracted to investigate the scour mitigation effect from the hydraulic, geotechnical, and bio-cementation perspectives. Laboratory flume tests have been conducted to evaluate the anti-scour potential using the proposed skirt pile groups. 3D reconstruction using the photogrammetric method has been employed to reconstruct the scoured bed for quantitative analysis. Computational fluid dynamics (CFD) and discrete element method (DEM) simulations have been performed to investigate the pile-flow and pile-sediment interactions, respectively. Results indicate the proposed skirt pile group reduces the scour depth and the volume of the scour hole by up to 57% and 85%, respectively. DEM simulation implied the installation of skirt piles demonstrates not only hydraulic but also geotechnical benefits due to the soil plug effect. In addition, a reactive transport model framework that simulates the bio-grouting process using microbially induced calcite precipitation (MICP) via shallow underwater injection has been developed to model the key processes such as bacterial attachment and detachment, urea hydrolysis, and calcite precipitation. The simulated cementation distribution exhibits a decent agreement with the experimental results, which could potentially be served for strategic optimization before conducting large or field-scale underwater injection tests. The model framework has been incorporated to simulate the MICP injection using skirt piles. Preliminary findings from this study demonstrated the feasibility of using mangrove-inspired skirt piles to mitigate scour for underwater foundation systems.
ContributorsLi, Xiwei (Author) / Tao, Junliang JT (Thesis advisor) / van Paassen, Leon LVP (Committee member) / Kavazanjian, Edward EK (Committee member) / Arizona State University (Publisher)
Created2024
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Enzyme Induced Carbonate Precipitation: Examining Protein-Enhanced Adhesion and Application for Surficial Stabilization of a Mine Tailing

Description
The introduction of milk powder into conventional Enzyme Induced Carbonate Precipitation (EICP) solutions, comprised of urea, calcium chloride, and urease enzyme, has been shown to increase the unconfined compressive strength of treated soil columns. The casein protein in milk is well known for its adhesive properties and could potentially alter…

The introduction of milk powder into conventional Enzyme Induced Carbonate Precipitation (EICP) solutions, comprised of urea, calcium chloride, and urease enzyme, has been shown to increase the unconfined compressive strength of treated soil columns. The casein protein in milk is well known for its adhesive properties and could potentially alter the soil-crystal interface, enhancing the adhesion. This research primarily seeks to compare the difference in adhesion of EICP precipitates without powdered milk and those modified with powdered milk, while also examining the distribution of milk proteins within the samples. Borosilicate glass slides (22mm × 22mm) served as representative substrates for soil in this investigation. Additionally, the study evaluates the viability of EICP treatment for surficial stabilization of mine tailings, employing a combination of laboratory experiments and large-scale field deployments for feasibility analysis.
ContributorsAryal, Abishek (Author) / Khodadadi Tirkolaei, Hamed HK (Thesis advisor) / Kavazanjian, Edward EK (Committee member) / Hamdan, Nasser NH (Committee member) / Arizona State University (Publisher)
Created2024