Properties and hydration characteristics of an iron-rich sulfoaluminate cementitious material under cold temperatures

Abstract

In this study, an iron-rich steel-slag-based sulfoaluminate cementitious material (SSCM) was prepared using steel slag, flue gas desulphurisation gypsum, aluminium ash, and limestone tailings. The basic and cold-temperature characteristics of SSCM were studied. The results show that Fe2O3 introduced by steel slag promotes the transformation of C4A3S¯-o to C4A3S¯-c, making SSCM more resistant to freezing injuries than Portland cement. As the curing temperature decreases, the formation rate of ettringite in the early stage slows down obviously. With the hydration progressing, the ettringite content in pastes cured at low temperatures (0–5 °C) becomes similar to that cured at 20 °C, and the proportion of harmful pores is decreased. Although the pastes cured at negative temperatures still contain a large amount of unhydrated phase and a significantly increased proportion of harmful pores, the hydration reaction can still be maintained. The performance of SSCM shows a promising application prospect for construction in cold regions.