Structural Performance of Geopolymer Concrete with Recycled Concrete Aggregate: A review

Geopolymer concrete (GPC) is an emerging construction material with a promising role in the industry. Recent research confirms the suitability of GPC in structural applications due to the higher compressive strength, better fire resistance, low permeability, and alkali and acid resistance compared to ordinary Portland concrete (OPC). Moreover, geopolymer concrete allows replacing the natural aggregate with more recycled concrete aggregate (RCA) than OPC. At the same time, its mechanical properties remain acceptable for structural applications. Thus, it will help waste reduction and natural resource preservation simultaneously. However, RCA adversely impacts concrete's rheological and mechanical properties, which is crucial for an optimum concrete mix. Recently, there has been a growing knowledge development on the structural applications of Portland concrete with RCA. However, there is a need to conduct a comprehensive assessment of the potential structural applications of RCA-based GPC. Hence, in the present study, previous research on various parameters that affect the structural behaviour of RCA-based GPC will be critically assessed and reviewed. These parameters include the type and content of alumina silicate materials, alkaline activator, curing regime, and RCA content. Besides, the load capacity, failure mode, and structural behaviour of composite elements with RCA-based geopolymer concrete, such as columns, beams, thin wall panels, and steel tubular columns, have