Hydraulic activity of water-cooled slag and air-cooled slag at different temperatures

• Published in: Cement and concrete research 2001-03, Vol.31 (3), p.475-484
• Main Authors: Mostafa, N.Y., El-Hemaly, S.A.S., Al-Wakeel, E.I., El-Korashy, S.A., Brown, P.W.
• Format: Article
• Language: English
• Subjects: Aggregates and other concrete constituents; Air-cooled slag; Applied sciences; Buildings. Public works; Calcium silicate hydrates; Cement concrete constituents; Concrete additives (fillers, pozzolanic and hydraulic materials); Exact sciences and technology; Gehlenite; Hydrothermal; Materials; Plazolite; Water-cooled slag
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/S0008-8846(00)00462-2

Water-cooled slag (WS) and air-cooled slag (AS) with similar chemical compositions and produced from the same blast furnace were investigated for their hydraulic activities at different temperatures. The kinetics of hydration of WS–lime and AS–lime pastes were investigated at room temperature, 100°C, and 180°C by the determination of unreacted lime and combined water. The hydration products were identified by XRD. The variations in mechanical properties were correlated with the reaction kinetics and the types of the hydration products. The change in the mechanism of slag hydration was also predicted. The AS studied exhibited significant reactivity at room temperature. Increasing the temperature to 100°C has no significant effect on the reactivity of either type of slag except during early hydration. However, the reactivity of AS increased much more than WS with hydrothermal activation at 180°C. Calcium silicate hydrate (CSH) and plazolite formed in AS mixes. CSH, plazolite, and α-C 2SH formed in WS mixes at 180°C.