The Synergistic Effect And Mechanism Of Ground Carbonatite And Slag In Alkali-Activated Carbonatite-Slag Cementitious Material

Mortar specimens of alkali-activated carbonatite-slag cementitious materials (AACSCM) were prepared, in which finely ground zirconite, being inactive under the reaction condition of this experiment, was also used to replace ground carbonatite or ground granulated blast-furnace slag (GGBFS) by iso-volume, so as to investigate the contribution of each material to the strength of AACSCM. According to the test results of mortar strength and the composition of pore solution of pastes, the effect of GGBFS on the strength improvement of alkali-activated cementitious material (AACCM) was discussed. The results indicate that, at the late stage of reaction, there does exist a synergistic effect between GGBFS and ground carbonatite under the activation of alkaline. The mechanism ties in: during the late period of reaction, the, amount of Ca2+, Mg2+ provided by GGBFS to the reaction system is much decreased, while much more Al3+ are retained. The shortage of Ca2+, Mg2+ in the system is compensated by the dissolution of ground carbonatite, leading the reaction be continued, and Al3+ are consumed simultaneously in the reaction, which promotes the dissolution of GGBFS in return. With the repeat of this process the reaction degree of AACSCM is much improved.