A comprehensive review on the factors influencing engineering characteristics of lightweight geopolymer concrete

Abstract

Geopolymer concrete (GPC) is a new kind of concrete produced through a polymerisation process. This production of GPC involves the mixture of aluminosilicate materials and alkali-activated solution (AAS). Moreover, GPC offers environmental advantages by reducing the carbon dioxide emissions during production of cement. Lightweight geopolymer concrete (LWGPC) is a special type of concrete that is lighter than conventional concrete. Additionally, due to the lesser density of LWGPC, it is easy to handle and transport from one place to other during construction. Hence, the production of LWGPC enhances the sustainability of the environment. Different types of binder and aggregate wastes were substituted in the production of LWGPC. However, the limited application of LWGPC containing several types of waste may be explained by a lack of understanding of the different factors that affect its production. This review manuscript addresses the factors (i.e. binders, alkaline activators, alkaline activator solution (AAS ratio), constituents, CSH phase, AAS- binder ratio, aggregates, molarity, superplasticizers, fibres and curing conditions) and highlights the engineering properties (such as fresh, hardened, physical and durability properties) that make LWGPC a viable choice globally. The fresh and hardened properties, such as workability and mechanical strength, are increased by enhancing the binder content and molarity of the sodium hydroxide (NaOH) in LWGPC. Similarly, physical and durability properties depend more on the constituents, AAS-binder ratio and curing conditions of the LWGPC. Furthermore, environmental impact analysis (EIA) was found to be better for LWGPC instead of GPC. Hence, it will be beneficial to develop LWGPC with industrial wastes, which leads to a lower carbon footprint for practical applications.