Characterization and Engineering Properties of Dry and Ponded Class-F Fly Ash

Journal Article · 10 January 2019 · Journal of Geotechnical and Geoenvironmental Engineering

DOI: https://doi.org/10.1061/(asce)gt.1943-5606.0001986 · OSTI ID:1532665

Bachus, R. C. ^[1]; Terzariol, M.  ^[2]; Pasten, C. ^[3]; Chong, S. H. ^[4]; Dai, S. ^[5]; Cha, M. S. ^[6]; Kim, S. ^[7]; Jang, J. ^[2]; Papadopoulos, E. ^[8]; Roshankhah, S. ^[9]; Lei, L. ^[10]; Garcia, A. ^[2]; Park, J. ^[2]; Sivaram, A. ^[11]; Santamarina, F. ^[12]; Ren, X. ^[13]; Santamarina, J. C. ^[2]

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1. Geosyntec Consultants, Kennesaw, GA (United States)
2. King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia)
3. Univ. of Chile, Santiago (Chile)
4. Sunchon National Univ. (Korea, Republic of)
5. Georgia Inst. of Technology, Atlanta, GA (United States)
6. Texas A & M Univ., College Station, TX (United States)
7. Univ. of Nebraska, Lincoln, NE (United States)
8. Strategic Decisions Group, London (United Kingdom)
9. California Inst. of Technology (CalTech), Pasadena, CA (United States)
10. National Energy Technology Lab. (NETL), Morgantown, WV (United States)
11. Black & Veatch, Downers Grove, IL (United States)
12. Univ. of Washington, Seattle, WA (United States)
13. China Univ. of Geosciences, Wuhan (China)

Characterization studies conducted on Class-F fly-ash specimens gathered from different producers in the southeastern United States confirm general trends reported for fly ash worldwide. Further tests and detailed analyses explain the spread in specific gravity (interparticle porosity cenospheres), highlight the tendency to segregation and layering, and show marked ferromagnetism. Furthermore, data show that early diagenetic cementation—within days after wetting—hinders densification and produces a fabric that is prone to collapse. New procedures are particularly developed to diagnose and characterize early diagenesis, including (1) pH measurements as an indicator of diagenetic potential, (2) test protocols to assess early diagenesis using oedometer tests and shear-wave velocity, and (3) procedures to determine realizable unit weights as reference values for the analyses of contractive or dilative tendencies and instability. In the absence of early diagenetic cementation, dilative fly-ash behavior is expected in the upper ≈20 m under monotonic shear loading. Flow instability may follow the failure of the containment structure if the ponded ash is saturated and has experienced hindered densification.

• Research Organization: National Energy Technology Lab. (NETL), Morgantown, WV (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy (FE)
• OSTI ID: 1532665
• Journal Information: Journal of Geotechnical and Geoenvironmental Engineering, Vol. 145, Issue 3; ISSN 1090-0241
• Publisher: American Society of Civil EngineersCopyright Statement
• Country of Publication: United States
• Language: English