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

Abstract

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. Additional 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 specifically 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.

An Experimental Investigation on the Fill Properties of Industrial By-Products Generated in Turkey

“…Parametreler ÇC (1) UK (2) III.SD Limit (3) (mg/L) Analiz Yöntemleri (mg/L) (mg/L) (1) Çelik cürufu (2) Uçucu kül (3) Çevre Bakanlığı'nın Atıkların Düzenli Depolanmasına Dair Yönetmeliği'ne göre III. Sınıf depolama tesisleri için sınır değerler [65] 7. SONUÇLAR Dünya'da ve ülkemizde hızla önem kazanmakta olan sıfır atık hedefinin gerçekleşmesi; ancak yerel yan ürünlerin doğru karakterizasyonu ile mümkün olabilir.…”

“…o aralığında elde etmiştir. Bu çalışmada da elde edilen deney sonu içsel sürtünme açısı sunulan bu aralıkla uyumludur[65]. Pik içsel sürtünme açısı ise deney sonu için elde edilen değere oldukça çok yakındır.…”

Separation Process and Microstructure-Chemical Composition Relationship of Cenospheres from Lignite Fly Ash Produced from Coal-Fired Power Plant in Thailand

“…It should be noted herein that a spontaneous imbibition is a measure of particle-level wettability. In this circumstance, water does not experience spontaneous imbibition into dry fly ash; however, wettability of the particles with intra-porous grains and accessible porosity is more pronounced for water to imbibe the ash particles [47]. Thus, in this study mixing procedure was adopted to facilitate such imbibition process for preparing the suspension prior to sedimentation and separation, while the fly ash sample was presumed to have a certain amount of such accessible porosity [18].…”

Effect of grain dissolution on sloping ground

“…The time scale for chemical processes is typically quite long and the "inert assumption of soils" applies to many engineering applications. However, dissolution and precipitation can also take place within relatively short time scales in advective regimes such as infiltration-induced carbonate dissolution and when systems are taken far from equilibrium in young systems such as dam foundations, mine tailings, fly ash, volcanic ash, and CO 2 injection [1][2][3][4][5][6][7][8][9][10][11][12][13] .Waste is particularly vulnerable to dissolution and degradation because its components are suddenly exposed to new environmental conditions outside equilibrium. Heavy metals and acid drainage from mine tailings and fly ash ponds are early signs of ongoing dissolution processes 14,15 .…”

“…The time scale for chemical processes is typically quite long and the "inert assumption of soils" applies to many engineering applications. However, dissolution and precipitation can also take place within relatively short time scales in advective regimes such as infiltration-induced carbonate dissolution and when systems are taken far from equilibrium in young systems such as dam foundations, mine tailings, fly ash, volcanic ash, and CO 2 injection [1][2][3][4][5][6][7][8][9][10][11][12][13] .…”