Characterization and Engineering Properties of Dry and Ponded Class-F Fly Ash
Abstract
Introduction
Previous Studies
Property | Symbol | Reported cases | Unit | Rangea | Statisticsb | ||
---|---|---|---|---|---|---|---|
Minimum | Maximum | ||||||
Chemical composition | 47 | % by weight | 27 | 64 | 47.7 | 11.0 | |
% by weight | 7.0 | 38 | 23.6 | 7.5 | |||
% by weight | 1.7 | 33 | 10.4 | 7.5 | |||
CaO | % by weight | 0.5 | 27 | 7.0 | 7.5 | ||
Basicity | pHc | 9 | — | 7.2 | 12.6 | 9.4 | 2.1 |
Grain-size distribution | 68 | μm | 60 | 1,960 | 442 | 464 | |
μm | 8.0 | 120 | 32 | 22.6 | |||
μm | 2.5 | 50 | 13.6 | 9.8 | |||
μm | 0.4 | 15 | 5.0 | 3.8 | |||
— | 2.1 | 25 | 7.8 | 5.5 | |||
— | 0.6 | 3.9 | 1.4 | 0.8 | |||
Specific surface | 18 | 0.09 | 1.3 | 0.45 | 0.39 | ||
Liquid limit | LL | 11 | % | 30 | 62 | 44.1 | 10.4 |
Specific gravity | 76 | — | 1.50 | 3.02 | 2.27 | 0.3 | |
Porosity | 26 | — | 0.36 | 0.64 | 0.50 | 0.08 | |
Hydraulic conductivity | d | 172 | |||||
Friction angle | 95 | Degrees | 26 | 43 | 36.7 | 4.9 | |
Compressibility | 92 | — | 0.04 | 0.37 | 0.11 | 0.08 | |
Range | N/A | N/A |
Sources: Data from Acosta et al. (2003), Aineto et al. (2005, 2006), Amonette et al. (2003), Bin-Shafique et al. (2002), Cheerarot and Jaturapitakkul (2004), Cousens and Stewart (2003), Das and Yudhbir (2006), DiGioia Jr. et al. (1995), Du et al. (2013), Gray and Lin (1972), Kaniraj and Gayathri (2004), Kim and Prezzi (2008), Kim et al. (2005), Mishra and Das (2008), Mishra and Karanam (2006), Palmer et al. (2000), Pandian (2004), Prashanth et al. (2001), Premchitt and Evans (1995), Reyes and Pando (2007), Senol et al. (2003), Siddique et al. (2007), Torrey (1978), Trivedi and Sud (2004), Trivedi and Sud (2007), Tu et al. (2007), and Young (1993).
Experimental Study: Procedures and Results
Scope of the Study: Specimens and Tests
Test category | Test | Number of tests | Typical results |
---|---|---|---|
Imaging | SEM | 45 | Cenospheres (some show gypsum crystals) |
X-ray (Shelby tube) | 14 | Layered stratigraphy | |
Index | Specific gravity | 32 | 1.96–2.66 |
Liquid limit | 9 | 26%–62% | |
Plastic limit | 9 | 22%–55% | |
Electrical sensitivity | 4 | Low electrical sensitivity to pore fluid chemistry | |
Grain-size distribution | 24 | –0.04 mm | |
–4.2a | |||
pH | 31 | 6–12 | |
New index tests | Realizable unit weight | 68 | ; |
Formation effects | 9 | Segregation and layering developed in all sedimentations tests | |
Ferromagnetism | 29 | Some present in all specimens. Up to 20% by weight | |
Contact angle | 6 | Nonwetting (water) | |
Advanced tests | Oedometer and diagenesis | 9 | High-pH specimens are prone to early diagenetic cementation |
Oedometer and shear-wave velocity | 17 | Undisturbed: ; | |
Remolded: ; b | |||
Hydraulic conductivity | 15 | to | |
Constant-volume shear in AC triaxialc | 44 | CD: | |
CU: | |||
Cyclic triaxial | 7 | Response depends on relative realizable density |
Note: CD = consolidated drained; CU = consolidated undrained; and SEM = scanning electron microscope.
General Characteristics: Index Properties
Particle Shape
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Grain-Size Distribution
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Fines Classification: Atterberg Limits and Electrical Sensitivity
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Specific Gravity
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pH and Spontaneous Imbibition
Ferromagnetism
Depositional Characteristics
Realizable Unit Weights
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Segregation, Layering, and Hydraulic Conductivity
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Hydraulic Conductivity
Static Compressibility and Stiffness
Compressibility
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Small-Strain Stiffness: Shear-Wave Velocity
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Early Diagenetic Cementation
Oedometer Tests
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Small-Strain Shear-Wave Velocity
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pH as Predictor of Early Diagenetic Behavior
Summary
Deviatoric Load-Deformation Response
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