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Effect of Fly Ash on the Behavior of Expansive Soils: Microscopic Analysis

2013; Geological Society of America; Volume: 19; Issue: 1 Linguagem: Inglês

10.2113/gseegeosci.19.1.85

1558-9161

Binshan Lin, Amy B. Cerato, Andrew S. Elwood Madden, Andrew S. Elwood Madden,

Clay minerals and soil interactions

Research Article| February 01, 2013 Effect of Fly Ash on the Behavior of Expansive Soils: Microscopic Analysis BOTAO LIN; BOTAO LIN School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK 73019 Search for other works by this author on: GSW Google Scholar AMY B CERATO; AMY B CERATO 1 School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK 73019 1Corresponding author email: acerato@ou.edu. Search for other works by this author on: GSW Google Scholar ANDREW S MADDEN; ANDREW S MADDEN ConocoPhillips School of Geology and Geophysics, University of Oklahoma, Norman, OK 70319 Search for other works by this author on: GSW Google Scholar MEGAN E ELWOOD MADDEN MEGAN E ELWOOD MADDEN ConocoPhillips School of Geology and Geophysics, University of Oklahoma, Norman, OK 70319 Search for other works by this author on: GSW Google Scholar Author and Article Information BOTAO LIN School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK 73019 AMY B CERATO 1 School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK 73019 ANDREW S MADDEN ConocoPhillips School of Geology and Geophysics, University of Oklahoma, Norman, OK 70319 MEGAN E ELWOOD MADDEN ConocoPhillips School of Geology and Geophysics, University of Oklahoma, Norman, OK 70319 1Corresponding author email: acerato@ou.edu. Publisher: Association of Environmental & Engineering Geologists First Online: 02 Mar 2017 Online ISSN: 1558-9161 Print ISSN: 1078-7275 © 2013 Association of Environmental & Engineering Geologists Environmental & Engineering Geoscience (2013) 19 (1): 85–94. https://doi.org/10.2113/gseegeosci.19.1.85 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation BOTAO LIN, AMY B CERATO, ANDREW S MADDEN, MEGAN E ELWOOD MADDEN; Effect of Fly Ash on the Behavior of Expansive Soils: Microscopic Analysis. Environmental & Engineering Geoscience 2013;; 19 (1): 85–94. doi: https://doi.org/10.2113/gseegeosci.19.1.85 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search Abstract Two expansive soils were studied from a microscopic point of view to better understand the physicochemical, mineralogical, and microstructural changes that occur during Class C Fly Ash (CFA) stabilization. These changes were then related to macroscopic mechanical characteristics in order to better understand the mechanisms controlling expansive soil behavior. CFA stabilization achieved similar results as lime by activating cation exchange and pozzolanic reactions, which resulted in flocculation of clay particles and creation of interconnected assemblages. It was found that the CFA stabilization process reduced the plasticity index (PI), clay size fraction (CF), percent of swell (Δh), swell pressure (ps), and volumetric water contents of the soil water characteristic curves (SWCCs), and increased the unconfined compressive strength (qu). X-ray diffraction (XRD) analyses showed that there were negligible changes in mineralogy caused by CFA stabilization; however, there were reductions in the total amount of clay minerals. Significant changes in microstructure were revealed, however, as qualified from scanning electron microscopy (SEM) images. The existence of iron-oxide coating was verified by both XRD and energy-dispersive X-ray spectroscopy (EDXS) analyses. The coating resulted in chemically stable aggregates that resisted dispersion with hexametaphosphate. The combined effects of flocculation and coating reduced the water-retention property of the stabilized soils, decreased their swell potential, and increased the soil strength. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.