“…Fluidized fly ash is composed of irregular porous grains (contrary to spherical vitreous grains of conventional fly ash). It contains higher amount of calcium compounds including CaSO4 (Pacewska, Blonkowski, & Wilińska, 2008;Li, Chen, Huang, Ma, & Wu, 2012;Sheng, Li, & Zhai, 2012;Xia, Yan, & Hu, 2013;Škvára et al, 2016;Zhang, Choi, Sagawa, & Hama, 2017;. Properties of this kind of fly ash do not meet PN-EN 450-1 (Polski Komitet Normalizacyjny, 2012) standard requirements for fly ash to be used in concrete.…”