Influence of different curing methods on mechanical and durability properties of alkali activated binders

Abstract

Alkali-activated binders are suitable alternatives to carbon-intensive conventional cement. Although earlier research studies stated the superior performance of alkali-activated concrete, the performance is mainly governed by the curing conditions. Several studies have been reported primarily on the strength and durability properties of alkali-activated binders; however, a systematic review on the effect of different curing methods on the characteristics of alkali-activated binders is highly limited. Therefore, the present review mainly focuses on the influence of ambient, heat, water, and other curing methods on the performance of slag, fly ash, and a few other precursors based alkali-activated binders. Moreover, the influence of different replacement levels of precursors, curing durations, and activator concentration on the mechanical and durability properties of alkali-activated concrete subjected to various curing methods are critically compared. Ambient cured slag based alkali-activated binders exhibited better strength gain compared to ambient cured fly ash-based binders. Fly ash-based binders require high temperature to initiate the reaction, and higher temperature curing guaranteed higher early strength gain for both slag and fly ash-based binders. A combination of slag and fly ash is superior as slag contributes to early-age strength, whereas fly ash contributes to the later age strength. Water curing of alkali-activated binders is not a well-appreciated method due to the leaching of the activator. The curing method is found to be significantly influencing the strength, porosity, water absorption, and drying shrinkage of alkali activated binder.