Role of sulphate-based additives on the early age properties of Portland cement incorporating alumina-rich ladle furnace slag
Ladle furnace slag (LFS) is a by-product of the steelmaking industry, mainly comprises calcium aluminate in the form of C12A7, forming C3AH6 upon hydration, which offers lower strength lower strength than metastable products like CAH10 and C2AH8. Introducing sulphate into LFS enhances mechanical str...
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Elsevier
2025-07-01
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| Series: | Case Studies in Construction Materials |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214509525001342 |
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| author | Chee Lok Yong Tee How Tan Haider Hamad Ghayeb Suhana Koting Kim Hung Mo |
| author_facet | Chee Lok Yong Tee How Tan Haider Hamad Ghayeb Suhana Koting Kim Hung Mo |
| author_sort | Chee Lok Yong |
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| description | Ladle furnace slag (LFS) is a by-product of the steelmaking industry, mainly comprises calcium aluminate in the form of C12A7, forming C3AH6 upon hydration, which offers lower strength lower strength than metastable products like CAH10 and C2AH8. Introducing sulphate into LFS enhances mechanical strength through the formation of ettringite. This paper proposes using different sulphate-based additive, namely calcium sulphate anhydrite (CS) and sodium sulphate (SS) to activate the early age properties of alumina-rich LFS blended cement, aiming to induce ettringite and calcium silicate hydrate (C-S-H). In the present work, CS and SS at 1 %, 3 %, and 5 % dosages are added to blended cement containing 25 % and 50 % LFS replacement to investigate the setting time, soundness and strength development. The inclusion of 5 % SS results in a reduction of 50–57 % in setting times for specimens with 25 % LFS compared to the control. Notably, 1 % CS exhibits superior mechanical strength in specimens containing 25 % LFS, with increment of 38 %, 85 %, and 49 % at 2d, 7d, and 28d, respectively. Despite the improved mechanical properties and shortened setting times with these additives, soundness remains within the standard expansion limits stipulated by EN 197–1. The hydration mechanism is examined through microstructural characterisation using FESEM, XRD, and TGA. Results indicate that CS addition promotes the formation of ettringite and C-S-H, while SS addition leads to gel-like structures with high Na precipitation, hindering the formation of ettringite. The findings show a strong correlation with the hydration products derived from the microstructural analysis. |
| format | Article |
| id | doaj-art-cbcfc8ed0e86416a929651937dd9fe91 |
| institution | Kabale University |
| issn | 2214-5095 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Elsevier |
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| series | Case Studies in Construction Materials |
| spelling | doaj-art-cbcfc8ed0e86416a929651937dd9fe912025-02-06T05:11:48ZengElsevierCase Studies in Construction Materials2214-50952025-07-0122e04336Role of sulphate-based additives on the early age properties of Portland cement incorporating alumina-rich ladle furnace slagChee Lok Yong0Tee How Tan1Haider Hamad Ghayeb2Suhana Koting3Kim Hung Mo4Department of Civil Engineering, Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, MalaysiaDepartment of Construction Management, Faculty of Built Environment, Tunku Abdul Rahman University of Management and Technology, 53300 Kuala Lumpur, MalaysiaDepartment of Civil and Construction Engineering, Faculty of Engineering and Science, Curtin University Malaysia, CDT 250, 98009 Miri, Sarawak, MalaysiaDepartment of Civil Engineering, Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia; Corresponding authors.Department of Engineering, School of Engineering and Technology, Sunway University, No. 5, Jalan Universiti, Bandar Sunway, 47500 Selangor Darul Ehsan, Malaysia; Corresponding authors.Ladle furnace slag (LFS) is a by-product of the steelmaking industry, mainly comprises calcium aluminate in the form of C12A7, forming C3AH6 upon hydration, which offers lower strength lower strength than metastable products like CAH10 and C2AH8. Introducing sulphate into LFS enhances mechanical strength through the formation of ettringite. This paper proposes using different sulphate-based additive, namely calcium sulphate anhydrite (CS) and sodium sulphate (SS) to activate the early age properties of alumina-rich LFS blended cement, aiming to induce ettringite and calcium silicate hydrate (C-S-H). In the present work, CS and SS at 1 %, 3 %, and 5 % dosages are added to blended cement containing 25 % and 50 % LFS replacement to investigate the setting time, soundness and strength development. The inclusion of 5 % SS results in a reduction of 50–57 % in setting times for specimens with 25 % LFS compared to the control. Notably, 1 % CS exhibits superior mechanical strength in specimens containing 25 % LFS, with increment of 38 %, 85 %, and 49 % at 2d, 7d, and 28d, respectively. Despite the improved mechanical properties and shortened setting times with these additives, soundness remains within the standard expansion limits stipulated by EN 197–1. The hydration mechanism is examined through microstructural characterisation using FESEM, XRD, and TGA. Results indicate that CS addition promotes the formation of ettringite and C-S-H, while SS addition leads to gel-like structures with high Na precipitation, hindering the formation of ettringite. The findings show a strong correlation with the hydration products derived from the microstructural analysis.http://www.sciencedirect.com/science/article/pii/S2214509525001342Ladle furnace slagMortarSulphateCement additiveMechanical propertiesMicrostructure |
| spellingShingle | Chee Lok Yong Tee How Tan Haider Hamad Ghayeb Suhana Koting Kim Hung Mo Role of sulphate-based additives on the early age properties of Portland cement incorporating alumina-rich ladle furnace slag Case Studies in Construction Materials Ladle furnace slag Mortar Sulphate Cement additive Mechanical properties Microstructure |
| title | Role of sulphate-based additives on the early age properties of Portland cement incorporating alumina-rich ladle furnace slag |
| title_full | Role of sulphate-based additives on the early age properties of Portland cement incorporating alumina-rich ladle furnace slag |
| title_fullStr | Role of sulphate-based additives on the early age properties of Portland cement incorporating alumina-rich ladle furnace slag |
| title_full_unstemmed | Role of sulphate-based additives on the early age properties of Portland cement incorporating alumina-rich ladle furnace slag |
| title_short | Role of sulphate-based additives on the early age properties of Portland cement incorporating alumina-rich ladle furnace slag |
| title_sort | role of sulphate based additives on the early age properties of portland cement incorporating alumina rich ladle furnace slag |
| topic | Ladle furnace slag Mortar Sulphate Cement additive Mechanical properties Microstructure |
| url | http://www.sciencedirect.com/science/article/pii/S2214509525001342 |
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