The current status and future of solid waste recycled building bricks

Solid waste (SW) has become a problem hindering the economic and social development. Achieving the full green cycle from raw material to production of recycled building bricks (RBB) using SW is the focus of future research. In this paper, the research results of RBB manufacturing using SW in recent years are reviewed. According to the consolidation principle of RBB, the effects of different types of SW on the physicochemical properties and microstructure of RBB are summarized based on the recycled unsintered brick (RUSB) and recycled sintered brick (RSB). By comparing and evaluating the two consolidation methods, it is proposed that RSB has good practicality due to its higher SW utilization rate, higher strength, and faster consolidation speed. Furthermore, the difference between MWS and conventional sintering (CS) is analyzed, and the research on the application of MWS in SW-RBB manufacturing in recent years is reviewed in detail. It is pointed out that microwave sintering (MWS) technology can solve many drawbacks in traditional sintering technology and has great prospects in manufacturing SW-RBB due to the low energy consumption, low pollution, and high efficiency. Finally, the shortcomings and possible challenges in the current research on manufacturing SW-RBB using MWS technology are discussed, which provides guidance for the future development of SW-RBB manufacturing.