Effect of accelerated precarbonation on hydration activity and volume stability of steel slag as a supplementary cementitious material

• Published in: Journal of thermal analysis and calorimetry Vol. 147; no. 11; pp. 6181 - 6191
• Main Authors: Fang, Yanfeng, Su, Wen, Zhang, Yuzhuo, Zhang, Miao, Ding, Xiangqun, Wang, Qinghe
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.06.2022; Springer; Springer Nature B.V
• Subjects: Analysis; Analytical Chemistry; Calcite; Calcite crystals; Calcium silicate hydrate; Carbonates; Carbonation; Chemistry; Chemistry and Materials Science; Compressive strength; Hydration; Impact analysis; Inorganic Chemistry; Manufactured products; Measurement Science and Instrumentation; Minerals; Mortars (material); Nucleation; Pastes; Physical Chemistry; Polymer Sciences; Slag; Stability analysis; Steel; Hydration activity; Volume stability; CO; uptake; Steel slag; Accelerated precarbonation
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-021-10914-z

Utilization of steel slag as a supplementary cementitious material is limited due to its poor volume stability and weak hydration activity. Moreover, the alkaline minerals of steel slag make it highly susceptible toward carbonation. Thus, this study aims to analyze the impact of accelerated precarbonation on the volume stability and hydration activity of steel slag. To this end, through exposing steel slag to CO 2 for accelerated carbonation, mortars and pastes containing 30% carbonated steel slag were prepared and their compressive strength and volume expansion were measured. The results indicate steel slag shows a rapid carbonation rate in the first three minutes and reaches an extent of carbonation of 15.55%. Furthermore, the 3-day compressive strength of the mortars containing the steel slag carbonated for one and three minutes increases by 17.0 and 5.7%, respectively, which is attributed to the “nucleation site” of the calcite and calcium silicate hydrate (C–S–H) formed in the accelerated precarbonation progress. However, the compressive strength of the mortar obviously drops with an increase in carbonation time due to the consumption of the minerals of the steel slag. On the contrary, the volume stability of steel slag strongly depends on accelerated precarbonation time and it positively relates to carbonation degree. Thus, a balance between the hydration activity and volume stability of the steel slag should be achieved by adjusting the accelerated precarbonation conditions.