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Advances in Materials Science and Engineering
Volume 2017, Article ID 8753659, 12 pages
Research Article

Improving the Quality of Mixed Recycled Coarse Aggregates from Construction and Demolition Waste Using Heavy Media Separation with Fe3O4 Suspension

1Department of Energy, Minerals and Resources Engineering, Dong-A University, 37 Nakdong-Daero 550Beon-gil, Saha-gu, Busan 604-714, Republic of Korea
2Department of Architectural Engineering, Dong-A University, 37 Nakdong-Daero 550Beon-gil, Saha-gu, Busan 604-714, Republic of Korea

Correspondence should be addressed to Seong-Hoon Kee;

Received 6 July 2016; Revised 8 November 2016; Accepted 9 November 2016; Published 2 January 2017

Academic Editor: Carlo Santulli

Copyright © 2017 Heonchan Kang and Seong-Hoon Kee. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The primary objectives of this study are to investigate the feasibility of a heavy media separation process with magnetite (Fe3O4) suspension for upgrading the quality of mixed recycled coarse aggregates from construction and demolition waste (CDW) in Korea and to determine a range of effective operating density of Fe3O4 suspension for producing high-quality RCA acceptable to structural concrete applications. For the purposes, six 200 kg recycled coarse aggregates (RCAs) samples were collected from a conventional recycling plant in Korea. Subsequently, the samples were processed by a heavy media separation process using Fe3O4 suspensions with various densities from 2.65 g/cm3 to 2.40 g/cm3 with an interval of 0.05 g/cm3. Next, a series of tests was performed in the laboratory to evaluate properties of finished sink and float products from the HMS processes, including oven-dry density, absorption capacity, and physical durability. Furthermore, compressive strength of concrete cylinders (150 mm by 300 mm) made of the finished sink products from Fe3O4 suspensions with three different densities (2.4, 2.5, and 2.6 g/cm3) was tested in this study. As a result, it was demonstrated that the HMS process using Fe3O4 suspension with a density ranging between 2.40 and 2.65 g/cm3 was effective for upgrading mixed CDW RCAs in Korea to high-quality RCAs acceptable for structural concrete applications.