Ippei Maruyama, Ngoc Kien Bui, Amr Meawad, Ryo Kurihara, Yuji Mitani, Hikotsugu Hyodo, Manabu Kanematsu, Takafumi Noguchi
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引用次数: 0
摘要
由于波特兰水泥生产过程中会排放大量二氧化碳,因此水泥基材料的碳足迹通常较大。这是因为石灰石是一种重要的 CaO 资源,其煅烧分解过程会排放二氧化碳。从这个角度来看,城市建筑中的混凝土可被视为 CaO 资源的城市矿山。在这项研究中,我们建议通过粉碎所有废弃混凝土、碳化、用碳酸氢钙溶液加压和干燥来获得固化产品。实验结果表明,碳酸氢盐溶液、高温条件和加载时间的延长可产生更高的强度。此外,扫描电子显微镜还证实了碳化混凝土细料接触面的颈部生长。因此,所提出的方法表明,硬化机制是碳化混凝土细粒表面的碳酸钙冷烧结。通过这种方法,开发出的砌块可以通过反复破碎和再加压,以相对较低的能耗实现半永久性使用。
Cold-sintered Carbonated Concrete Waste Fines: A Calcium Carbonate Concrete Block
Cementitious materials generally have large carbon footprints because of the high CO2 emitted during Portland cement production. This is because limestone is used as an essential CaO resource, and its decomposition by calcination emits CO2. From this perspective, the concrete in urban buildings can be considered an urban mine of CaO resources. In this study, we propose obtaining a solidified product by crushing all the waste concrete, carbonating it, pressurizing it with a calcium bicarbonate solution, and drying it. The experimental results show that the bicarbonate solution, high-temperature conditions, and extended loading period produce a higher strength. In addition, neck growth at the contact surfaces of the carbonated concrete fines was confirmed using scanning electron microscopy. Consequently, the proposed method indicates that the hardening mechanism is the cold sintering of calcium carbonate on the surface of fine-carbonated concrete particles. This method allows the developed blocks to be used semi-permanently with relatively low energy consumption through repeated crushing and re-pressurization.
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Scope:
*Materials:
-Material properties
-Fresh concrete
-Hardened concrete
-High performance concrete
-Development of new materials
-Fiber reinforcement
*Maintenance and Rehabilitation:
-Durability and repair
-Strengthening/Rehabilitation
-LCC for concrete structures
-Environmant conscious materials
*Structures:
-Design and construction of RC and PC Structures
-Seismic design
-Safety against environmental disasters
-Failure mechanism and non-linear analysis/modeling
-Composite and mixed structures
*Other:
-Monitoring
-Aesthetics of concrete structures
-Other concrete related topics