| Title |
Principles for waste concrete recycling and basic problems of recycled concrete |
| ID_Doc |
17231 |
| Authors |
Xiao, JZ; Zhang, HH; Tang, YX; Lu, ZY; Ye, TH; Duan, ZH; Sui, TB; Xiao, XW |
| Title |
Principles for waste concrete recycling and basic problems of recycled concrete |
| Year |
2023 |
| Published |
Chinese Science Bulletin-Chinese, 68, 5 |
| DOI |
10.1360/TB-2022-0521 |
| Abstract |
The discovery and development of contemporary concrete have made substantial contributions to the industrial revolution and urbanization over the last two centuries. The tremendous use of concrete results in a large amount of solid waste and considerable carbon emissions. The effort on waste concrete recycling is significant and vital in light of the national strategy of "carbon peaking and neutrality". The previous research on the recycled concrete focused on the traditional ideas of aggregate substitution and parameter modification to normal concrete. However, new ideas for waste concrete recycling and low-carbon application of recycled concrete should be further investigated. The theory and methods of concrete composition, decomposition, and recycling are examined. In general, the synthesis of concrete necessitates managing the characteristics of raw ingredients to increase overall performance. A mature concrete synthesis system was established by the steady physical qualities of sand and gravels, the hydration reaction of cementitious materials, and scientific combination design. Furthermore, the changes in the physical qualities of concrete components provide a theoretical foundation for crushing and sieving to produce recycled materials. To make recycled concrete (RC), recycled aggregates (RAs) and recycled powder are employed. However, the use of RC is complicated by the uncertainty of raw material sources, variations in the hydration process and microstructures, and discrepancies in basic attributes. Multi-way modification strategies have been developed to improve the qualities of RAs and RC to realize the conversion of difficult-to-control wastes into controllable recycled materials. The qualities of RC are improved and the variability of these features is reduced by incorporating artificial intelligence technologies into the mixture design of RC based on big data. In addition, three criteria for the preparation of RC are proposed, including a safe application criterion, an economically durable criterion, and a low-carbon sustainable criterion, to encourage the promotion of RC and improve its economic and environmental benefits. For the further development of waste concrete recycling, full recycled aggregate concrete (FRAC), which uses 100% recycled coarse and fine aggregates, is proposed as a new generation of RC to increase the economic and low-carbon benefits of RC. Meanwhile, alkali-activated cementitious materials are being used to prepare recycled aggregate concrete for even further carbon reduction, and 3D printing RC technology is being used to reduce carbon emission and fresh concrete waste during construction. We also suggest a specific concrete design concept for recycling, in which decomposition agents (such as nano-TiO2) could be employed to easily peel off the attached old mortar from RAs during microwave treatment. The photoelectric effect of nano-TiO2 could also be used to make concrete with oxygen-releasing properties. The low-carbon properties of concrete would be a consensus to accomplish its green and high performance with the development of the construction materials sector. Waste concrete recycling is beneficial to enhance waste concrete's resource reuse value and low-carbon potential, as well as create a concrete circular economy development model. |
| Author Keywords |
waste concrete recycling; recycled concrete; recycled aggregate; recycled powder; full recycled aggregate concrete; mixture design for recycling |
| Index Keywords |
Index Keywords |
| Document Type |
Other |
| Open Access |
Open Access |
| Source |
Emerging Sources Citation Index (ESCI) |
| EID |
WOS:000934809200008 |
| WoS Category |
Multidisciplinary Sciences |
| Research Area |
Science & Technology - Other Topics |
| PDF |
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