Strength and microstructural characterization of iron- based binder as carbon absorbing material for sustainable concrete
摘要
The study utilized iron oxide, a waste byproduct from steel manufacturing, as the primary binding material. The concept involves the reaction of iron oxide with CO₂ in the presence of a weak acid, resulting in the formation of iron carbonates, which exhibit binding properties. The novelty of this study lies in the optimised ratios of raw materials, incorporating varying levels of oxalic acid and CO2 utilisation. It further incorporates detailed microstructural analysis to identify optimum mix. Sixteen mixes were investigated with varying raw materials ratios and carbon curing duration as 2, 3, 4, 5, and 6 days followed by 3 air curing days. The Unconfined Compressive Strength (UCS) test was conducted to identify the optimum mix ratio along with carbon curing day corresponding to highest strength. Energy Dispersive X-ray Spectroscopy (EDS) provided insights into the elemental composition of raw materials and the iron carbonate binder, revealing a significant reduction in iron oxide after 4 days of carbon curing compared to 2 days, indicating its reaction with CO₂. X-ray Diffraction (XRD) analysis identified the mineral phases, and Scanning Electron Microscopy (SEM) visualized the microstructural development of the composites. A carbonation test confirmed the absorption of CO₂ by the iron-based binder during hardening. Results show iron carbonate binder not only provides substantial binding ability and compressive strength but also serves as a sustainable solution for CO₂ sequestration. This innovative approach offers a significant potential substitute for cement for enhanced strength and carbon negative structures. Use of ferrock promotes environmental sustainability through reduced usage of cement and the utilization of industrial waste.