Condition Synthesis and Performance of Alkali-Activated Composites Incorporating Clay-Based Materials – A Review

Abstract

Studies over the years have shown that alkali-activated composite (AAC) binders are viable alternatives to conventional Portland cement (PC) composites. However, the increasing interest in AACs for the construction of various infrastructures has created a need to find alternatives to the conventional materials used in their production. Various types of 1:1 clay, which are available in different forms across different parts of the world, can be used as an aluminosilicate source in the production of AACs. However, compared to the use of conventional aluminosilicate sources such as slag and fly ash, there is limited understanding, research, and application of AAC incorporating clay-based materials. Thus, this comprehensive review was carried out to explore and discuss various properties of AACs made with clayey materials. Both the fresh and hardened properties of clay-based AACs are discussed, including the effects of different alkaline solution types, their concentrations, the combination of alkaline activators, the fine aggregate-to-binder ratio, the alkaline solution-to-binder ratio, and the curing temperature and duration. However, in terms of the hardened properties, more focus is placed on durability performance as these properties are critical to the behaviour of the AACs in various environments.