Heesup Choi, Myungkwan Lim^*, Hyeonggil Choi, Ryoma Kitagaki, Takafumi Noguchi

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Department of Civil Engineering, Kitami Institute of Technology, Hokkaido, Japan.
Department of Architecture, The University of Tokyo, Tokyo, Japan.
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Abstract: The aim of this study was to develop a technique for the complete recycling of concrete based on microwave heating of surface modification coarse aggregate (SMCA) with only inorganic materials such as cement and pozzolanic materials (silica fume, fly ash). The mechanical properties of SMCA, which was produced using original coarse aggregate (OCA) and inorganic admixtures, as well as its separation from the cement matrix and recovery performance were quantitatively assessed. The experimental results showed that micro structural reinforcement of the interfacial transition zone, which is a weak part of concrete, by coating the surface of the OCA with cement and admixtures such as pozzolanic materials can help suppress the occurrence of micro-cracks and improve the mechanical performance of the OCA. Microwave heating was observed to cause micro-cracking and hydrate decomposition. Increasing the void volume and weakening the hydrated cement paste led to the effective recovery of recycled coarse aggregate.

Keywords: Recycling, Surface Modification, Interfacial Transition Zone, Pozzolanic Reaction, Microwave, Recovery

Cite this paper: Choi, H. , Lim, M. , Choi, H. , Kitagaki, R. and Noguchi, T. (2014) Using Microwave Heating to Completely Recycle Concrete. Journal of Environmental Protection, 5, 583-596. doi: 10.4236/jep.2014.57060.

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