Alkali-activated slag (AAS) has emerged as a potentially sustainable alternative to ordinary
Portland cement (OPC) in various applications since OPC production contributed about 12% of
global CO2 emissions in 2020. AAS offers great ecological advantages over OPC at some levels
such as the utilization of industrial by-products and overcoming the issue of disposal, low energy
consumption, and low greenhouse gas emission. Apart from these environmental benefits, the novel
binder has shown enhanced resistance to high temperatures and chemical attacks. However, many
studies have mentioned the risk of its considerably higher drying shrinkage and early-age cracking
compared to OPC concrete. Despite the abundant research on the self-healing mechanism of OPC,
limited work has been devoted to studying the self-healing behavior of AAS. Self-healing AAS is a
revolutionary product that provides the solution for these drawbacks. This study is a critical review
of the self-healing ability of AAS and its effect on the mechanical properties of AAS mortars. Several
self-healing approaches, applications, and challenges of each mechanism are taken into account and
compared regarding their impacts.