Niveditha, M. and Palanisamy, T. (2026) Upcycling iron-rich industrial waste into a carbon-sequestering composite binder through optimized carbonation curing for structural applications. International Journal of Construction Management, 26(8), pp. 1471-1489. ISSN 1562-3599
Abstract
Background: Steel production generates large quantities of mill scale, a by-product rich in iron oxides, with global generation estimated at 13.5 million tons annually. Simultaneously, Portland cement production, essential for concrete, contributes nearly 8% of global CO2 emissions, highlighting the urgent need for low-carbon alternatives. Iron carbonate (FeCO3), typically regarded as a corrosion product, offers an underexplored opportunity for deliberate synthesis in binders to achieve both structural performance and CO2 sequestration. Repurposing mill scale into carbon-sink binders thus provides a dual pathway for waste valorization and climate change mitigation, while advancing circular economy and industrial symbiosis principles. Methods: A composite binder was developed using mill scale, fly ash, metakaolin, and limestone, with oxalic acid employed as a chelating agent to promote iron dissolution and carbonate formation. Specimens were subjected to carbonation curing under controlled CO2 pressures (1.5–3 bar) and analyzed using XRD, TGA/DTG, FTIR, and FESEM to evaluate phase development, carbonate formation, and microstructural features. Results: An oxalic acid dosage of 4% resulted in a 133% increase in compressive strength compared to the control. Specimens cured at 3 bar CO2 achieved compressive strength exceeding 65 MPa within 7 days, whereas 1.5 bar curing required 9 days. TGA confirmed CO2 uptake of approximately 10–11% by binder mass, while microstructural analysis revealed the presence of stable siderite and calcite phases. Conclusions: The carbon-sink binder, composed of more than 75% industrial by-products, substantially reduces carbon emissions and energy demand compared to cement-based systems. It shows strong potential as a low-carbon alternative for precast concrete, masonry, and pavement applications. Future work should focus on long-term durability, large-scale implementation, and life cycle performance to support its adoption in sustainable construction and policy frameworks.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | building material; carbon capture and utilization; carbon sequestration; carbonation curing; carbonation depth; circular economy; sustainable construction; waste upcycling |
| Index terms: | corrosion, energy demand, composite, carbon emission, fly ash, sustainable construction, presence, life cycle, climate change, metakaolin, industrial waste, precast concrete, durability, curing, compressive strength, CO2 emissions, dosage, implementation, mitigation, carbonation, building material, circular economy, agent, sequestration |
| Subjects: | waste management, environmental science, air quality, concrete and cementitious materials, building materials, financial risk, climate science, practitioner, sustainable design, sustainable construction, material analysis and testing, materials science, value management, energy systems, material degradation and durability, contractual arrangements, health monitoring assessment and metrics |
| Topics: | Sustainability, Roles and Professions, Construction Materials, Design Practice, Project Management, Health and Safety, Cost Management, Procurement |
| Descriptive scope: | 2 PC |
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