Doctoral Dissertations

Junnan Cao

Abstract

"This study experimentally investigated the bio-inspired improvement on geomaterials, including enzyme induced calcite precipitation (EICP) and biopolymers. This study also developed several innovative characterization tools to advance the state-of-the-art testing techniques, including SIP-BE column, rotational sedimental panel, and backpressure saturated constant hydraulic gradient break through column. Firstly, EICP test was performed on Ottawa 50-70 sand in a newly developed SIP-BE column. Nondestructive techniques -- spectral induced polarization (SIP) and bender element were used to monitor the precipitation process and shear wave velocities (Vs). SIP, Vs, and SEM results all suggest contact cementation as the preferential precipitation pattern of calcite. Secondly, a series of sedimentation tests were conducted on kaolinite in biopolymers (xanthan gum, chitosan, polyacrylic acid and polyacrylamide) solutions with time-lapsed photography technique. The interaction mechanisms of biopolymers and kaolinite particles were revealed to be electrostatic force (xanthan gum), charge neutralization (chitosan and PAA) and steric stabilization (PAM), respectively. Thirdly, A column test setup was developed with constant hydraulic gradient and full soil sample saturation using a triaxial cell to measure the retardation factors (Rd) of Sr and Cs for natural silty sand. The measured Rd values of the tested sand for Sr and Cs were 3.561 and 27.369, respectively. The column setup developed in this study eliminates the uncertainties from partial saturation and fluctuating pressure difference across the sample column in a traditional flow-through column test setup, and is recommended to be used for future breakthrough curve measurements. In the study of SWCC, biopolymers were found to significantly increase the water retention capacity, especially at pendular regime"--Abstract, page iv.

Advisor(s)

Bate, Bate
Deng, Wen

Committee Member(s)

Mormile, Melanie R.
Rogers, J. David
Wang, Jianmin

Department(s)

Civil, Architectural and Environmental Engineering

Degree Name

Ph. D. in Civil Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2018

Journal article titles appearing in thesis/dissertation

  • Influences of size and content of enzyme induced calcite precipitations on the stiffness of a fine sand -- A spectral induced polarization study
  • Complex conductivity and shear wave velocity responses of sand-calcite mixture
  • Microscopic and physicochemical studies of polymer-modified kaolinite suspensions
  • On the soil water characteristic curves of poorly-graded granular materials in aqueous polymer solutions
  • Measuring retardation factors of 133cesium and 88strontium cations using column test

Pagination

xvi, 172 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2018 Junnan Cao, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11415

Electronic OCLC #

1084472613

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