Gelling and Hardening Properties of Fly Ash, Granulated Blastfurnac Slag and Shirasu in the Presence of Lime and Gypsum

Since fiy ash consists mainly of vitreous phase, the present authors supposed that gelling should be applied for it to manufacture of lightweight concretes.　Lime and gypsum were chosen as reactants with fly ash to form calcium sulphoaluminate hydrates and C-S-H by gelling, as fly ash is rich in SiO₂ and Al₂O₃ content. They have already reported elsewhere that these formations are preferable for vitreous aluminosilicates such as volcanic ash and granulated blastfurnace slag to obtain good lightening effect.
　In this report, gelling and hardening properties of fly ash are compared with those of granulated blastfurnace slag and volcanic ash.