Microstructure and mechanical properties of CO2-cured steel slag brick in pilot-scale. (15th February 2021)

• Record Type: Journal Article
• Authors: Hou, Guihua; Yan, Ziwei; Sun, Jinfeng; Naguib, Hamdy M.; Lu, Bao; Zhang, Zuhua
• Is Part Of: Construction & building materials. Volume 271(2021)
• Publication Date: 2021-02-15
• Subjects: Steel slag -- Carbonation -- Building materials -- CO2 utilization -- Volume stability -- Freeze-thaw resistance; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.121581
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: This paper studied the microstructure and mechanical properties of CO2 -cured steel slag brick in pilot-scale. The CO2 -cured steel slag bricks showed a better compressive strength and excellent volume and freeze-thaw stability. The carbonation technology can turn steel slag into cementitious material and absorb CO2 . Abstract: This paper reports a pilot study of beneficial CO2 use in the manufacture of steel slag building bricks. The effects of steel slag fineness, mix proportion and carbonation time on the CO2 uptake, compressive strength, volume stability and freeze–thaw resistance of steel slag bricks were systematically studied. The results showed that the CO2 cured bricks containing 25 wt% steel slag reached the highest CO2 uptake of 7.5% (kg/kg steel slag), and they presented the highest compressive strength of 27.7 MPa at 7 day, which meets the standard requirement of load bearing perforated brick. The steel slag brick after CO2 cured for 30 min exhibited good volume stability under the steam curing testing conditions at 3 MPa, and its freeze–thaw resistance was shown excellent as well. In composition, C2 S, C3 S, Ca(OH)2, f-CaO and MgO presented in steel slag reacted with CO2 and formed carbonates and silica gels; on the other hand, as expected, Ca2 (Al, Fe)2 O5 and FeO remained much more stable. The results of this study have demonstrated that the carbonation technology can effectively turn steel slag into cementitious material, and the utilization of CO2 has the feasibility of industrialization.