A comparison of the 10-year properties of converter steel slag activated by high temperature and an alkaline activator

摘要

This paper aims to study the late-stage cementitious properties of converter steel slag activated under different conditions. Three methods, including an early high-temperature curing, an alkaline activator and application of the two methods simultaneously, were used. Steel slag without an activator at room temperature was selected as the control sample. The long-term (10 years) properties at the same solution-steel slag ratio (0.3), including the characteristics of the hydration products, reaction degree and pore structure, were investigated. The results show that the hydration products consist of a C-A-S-H gel mainly comprising a Q(2) structure and Ca(OH)(2). The different activation methods have little influence on the types and morphologies of the products. Although using an early high-temperature curing or an alkaline activator can reduce the Ca/Si and Al/Si ratios in the gel, using the two activation methods simultaneously can significantly improve the ratios. Adding an alkaline activator is more effective in increasing the amounts of late-stage hydration products, increasing the reaction degree and improving the pore structure than increasing the early curing temperature. Using the two methods simultaneously can reduce the amounts of late-stage hydration products, decrease the reaction degree and deteriorate the pore structure. Therefore, adding an alkaline activator has a more substantial influence on improving the late-stage cementitious properties than increasing the early curing temperature. However, using the two methods simultaneously has a negative influence on the properties. (C) 2019 Published by Elsevier Ltd.