Abstract
Replacing cement with solid waste materials is a key approach to preserving natural resources and mitigating carbon dioxide emissions. In this research, we explored elemental complementation as an eco-friendly and low-carbon approach to develop composite cementitious materials (CCMs) by partially substituting cement with steel slag (SS) and metakaolin (MK), thereby overcoming the low reactivity of SS and facilitating its broader application. We scrutinized the synergistic effects of SS-MK CCMs on parameters such as solubility, water demand, setting time, compressive strength, the formation of hydration products, and microstructure. Employing a suite of analytical techniques, including Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), measurement of hydration heat, and X-ray computed tomography. The findings revealed that the alkaline environment produced by SS-cement powder promoted the breakdown of Si-O and Al-O bonds within MK, facilitating both the early hydration process and the development of strength.MK compensates for the lack of strength caused by the slow hydration of SS in the early stage, while the SS accelerated a pozzolanic reaction of MK, leading to a 28d compressive strength of 54.77 MPa for the composite, while the 28d strength of SS20 was 39.74 MPa; MK effectively utilized portlandite, enhancing the hydration of SS and increasing the production of calcium silicate hydrate, which optimized the pore structure and improved sphericity. Furthermore, the SS-MK CCMs addressed the issues of f-CaO excess and prolonged setting times in the SS-cement system, while also ameliorating the high calcium demand and reduced fluidity in the MK-cement system. Additionally, its lower cumulative heat release from hydration enhances the material’s volumetric stability. This study presents a strategy for the large-scale application of SS and contributes to the value-added, eco-friendly use of industrial solid wastes.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
