Comprehensive phase characterization of crystalline and amorphous phases of a Class F fly ash

Effect of fly ash characteristics on the behaviour of pastes prepared under varied brine conditions

“…Thus fly ash B is coarser than fly ash A and according to literature finer particles are more reactive than coarser particles which are generally rich in unburned carbon (Chancey et al, 2010;Campbell, 1999;Mahlaba and Pretorius, 2006).…”

“…Finer ash particles are richer in the glassy phase and are more reactive while coarser fractions are richer in carbon (Ward and French, 2006;Nochaiya et al, 2009;Chancey et al, 2010). Spherical fly ash particles reduce friction between particles and improve workability at lower water demands in a paste (Campbell, 1999;Chindaprasirt et al, 2005).…”

Identifying Glass Compositions in Fly Ash

“…Two capabilities of the SEM have been used to collect this information: point X-ray analysis, which calculates the actual composition of a point in the fly ash image using standards-based or standardless algorithms, and X-ray mapping using energy dispersive spectroscopy (EDS), which maps the location and relative concentration of individual elements in the fly ash (but does not typically give actual compositional data, depending on the software package used). Several researchers (Williams et al, 2005;Chancey et al, 2010;Bumrongjaroen et al, 2011;Kruse, 2012;Dhole et al, 2013;Durdziński et al, 2015) have used SEM X-ray point-counting methods to establish the chemical composition of the various glasses within fly ash in an attempt to better understand its internal structure and potential for reactivity. Investigations on interparticle and intraparticle chemical differences in fly ashes have been completed using EDS mapping (Joshi et al, 1984;Stevenson and Huber, 1986;Williams et al, 2005;Chancey et al, 2010;Bumrongjaroen et al, 2011;Durdziński et al, 2015).…”

“…Several researchers (Williams et al, 2005;Chancey et al, 2010;Bumrongjaroen et al, 2011;Kruse, 2012;Dhole et al, 2013;Durdziński et al, 2015) have used SEM X-ray point-counting methods to establish the chemical composition of the various glasses within fly ash in an attempt to better understand its internal structure and potential for reactivity. Investigations on interparticle and intraparticle chemical differences in fly ashes have been completed using EDS mapping (Joshi et al, 1984;Stevenson and Huber, 1986;Williams et al, 2005;Chancey et al, 2010;Bumrongjaroen et al, 2011;Durdziński et al, 2015). The collected EDS maps can be analyzed using multispectral image analysis (MSIA), in which the maps of individual elements taken over the same field of view are stacked on top of each other and the image is assessed for regional differences using the stack of all element maps at each pixel location.…”

“…The paper describes a modification to the method published by Chancey et al (2010) to analyze fly ashes for glassy phase composition using SEM coupled with MSIA. K-means analysis was employed to help in the MSIA phase segmentation process.…”