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 called for 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 in 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. Discussions were made on both the fresh and hardened properties of clay-based AACs. Discussions are held regarding the effects of various alkaline solution types, their concentrations, the combination of various 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 was placed on durability performance as these properties are critical to the behaviour of the AACs in various environments.