Fly ash for sustainable construction: A review of fly ash concrete and its beneficial use case studies

Comparative effects of different real conditions in the microstructure and properties of ternary blended cement mortars for being used in rehabilitation works

“…3). The fly ash pozzolanic reactions are very sensitive to the environmental humidity (Ortega et al, 2017) and to the presence of portlandite (Wang et al, 2004;Meena et al, 2023;Nayak et al, 2022). These rainy days would produce a high relative humidity in the environment B, as indicated the fact that maximum values of this parameter around 100% were registered (see Fig.…”

“…As has been described in subsection 2.2, the environment A was an optimum condition, with constant temperature of 20 • C and with approximately 100% RH. Under this environment, there was enough water available for an adequate progress of slag and clinker hydration (Çakır and Aköz, 2008;Bouikni et al, 2009;Loke et al, 2022), and for the development of fly ash pozzolanic reactions (Wang et al, 2004;Papadakis, 1999;Meena et al, 2023;Nayak et al, 2022;Khankhaje et al, 2023). Their products are solid phases, which progressively filled the pores, entailing a refinement of pores with time.…”

“…In general, mortars with active additions (series S, F, SL, SF and FL) showed more pore refinement, with higher percentage of finer pores (size interval <10 nm), after 250 days compared to other studied mortars (series REF and L). This may be caused by slag hydration effects (Çakır and Aköz, 2008;Bouikni et al, 2009), as well as by those produced by pozzolanic reactions of fly ash (Wang et al, 2004;Papadakis, 1999;Nayak et al, 2022), producing additional solids formation. In addition, regarding the comparison between mortars with active additions, it is noteworthy to highlight that this pore refinement was overall higher for mortars with fly ash (series F, SF and FL) compared to mortars with only slag (series S and SF).…”

“…Furthermore, most of the exposure time period corresponded to the spring and summer seasons in the location, in which scarce rain was registered and the number of daily sunshine hours were greater. These factors would contribute to a gradual material drying (Ortega et al, 2015(Ortega et al, , 2017, avoiding the progress of hydration and pozzolanic reactions, which need an enough presence of water for their development (Nayak et al, 2022;Ortega et al, 2015Ortega et al, , 2017, so their effects in the long term would be more limited in the properties and pore network of the mortars. In addition, several authors have reported (Ortega et al, 2015;Kanna et al, 1998) that the progressive drying of the material could produce de formation of shrinkage microcracks, which may also affect the behaviour of the mortars.…”

The Emergence of Non-Energy Uses of Coal and the Future of Lignite Mining in a Region of Low Carbon Footprint, a Case Study

“…), in the construction of concrete dams with RCC (rolling concrete) technology, in the construction of rigid pavements, self-compacting concretes, in tunnel cladding, in cementing, in the production of ready-made mortars and in the manufacture of utilitarian objects (pots, etc.). It can also be applied in soil treatment and stabilization, in the production of synthetic zeolites, in road construction (for the construction of embankments, bases and bases and as a component of asphalt concrete) and in waste management facilities for the absorption of toxic elements [39,40].…”