Improvement of coal fly ash pozzolanic activity by different physical methods

Abstract

This paper presents the results of laboratory investigations performed in order to determine the possibility of improving the pozzolanic activity of coal fly ash from two Serbian Thermal Power Plants. The initial samples of fly ash were treated by different physical processes (mechanical activation, grinding and classification). On the obtained samples, the pozzolanic activity was determined using standard methods (with lime and Portland cement). It was found that the above procedures can significantly improve the pozzolanic activity of fly ash, and the best results were achieved when the fly ash was treated by mechanical activation process in the laboratory ring mill.

Coal mining wastes valorization as raw geomaterials in construction: A review with new perspectives

“…Kaolinite concentrations in the CMWGs investigated varies widely, from about 70% to as low as 14% (Rodríguez et al 2021), suggesting that kaolinite might not be the only constituent that yields pozzolanic properties upon thermal activation. The possibility of alternatives is well demonstrated with the success observed by employing coal fly ash as a pozzolanic replacement (Jovanovic et al 2014;Shamir et al 2020), which mainly comprises aluminosilicate glass (the first known pozzolans, sourced from southwest Italy, which were also glassy in nature ) rather than metakaolin or any other clay or clay derivative. Another alternative pozzolan synthesis method has been demonstrated by Wang et al (2021), who combined sodium hydroxide solutions with various mixtures of coal gangue and blast-furnace slag to yield prototype road-stabilization materials (a less demanding application, but nonetheless a legitimate example of pozzolanic activity).…”