Self-hydration characteristics of ground granulated blast-furnace slag (GGBFS) by wet-grinding treatment

Abstract

The aim of this paper is to evaluate the self-hydration characteristic of GGBFS activated by wet-grinding treatment (WGT). Three slag slurries with different fineness were prepared through milling with varying duration (20 min, 40 min and 60 min, abbreviated as S2, S4 and S6, respectively). The reaction kinetics, mechanical properties, hydration products and microstructure of hardened GGBFS pastes were analyzed to assess the effect of WGT on the self-hydration process of GGBFS. The results indicated that self hydration was achieved after grinding without chemical activation and the rate of self-hydration was improved with the increased grinding duration. The setting times were dramatically shortened and the compressive strength was notably increased when prolonging the grinding time. The hydration process of GGBFS slurry after 20 min milling included incubation period, but the others did not. The electrical resistivity development of samples S2 and S4 decreased during the initial period, followed by setting, acceleration and deceleration stage. However, sample S6 exhibited an absence of the initial stage. The self-hydration products analyses indicated that the main products were calcium silicate hydrate, calcium aluminosilicate hydrate (C-A-S-H), hydrotalcite, akermanite and calcite.