Turning concrete waste powder into carbonated artificial aggregates

摘要

In recent years, sustainable management of construction waste has garnered increasing attention. However, most previous studies mainly focused on turning construction wastes into recycled aggregates, whereas, recycling of those construction wastes below 5 mm has often been challenged or ignored. This study attempted to effectively deal with such recycled fine powders by employment of granulation technology to produce artificial aggregates with a diameter of 5-20 mm. The optimal granulation parameters were identified through a systematic experimental test. Moreover, the effect of water and cement content, as well as curing regimes, on the properties (such as shape and strength) of the prepared artificial aggregates was also investigated. More importantly, influence of normal curing and CO2 curing on the strength development of artificial aggregates was examined and compared. In doing so, the scheme of preparation of artificial aggregates with optimal strength was developed. Findings from this study provide an alternative and viable solution to effectively dealing with construction wastes in an environmentally-friendly way and serve as a reference for follow-up studies in the future. Meanwhile, the carbonated artificial aggregate can be potentially used to replace natural aggregates in the preparation of low-strength concrete and blocks. (C) 2018 Elsevier Ltd. All rights reserved.