AACMs, or alkali-activated cements, represent a class of cementitious materials produced at room temperature through a chemical reaction between a poorly crystalline aluminosilicate material (referred to as the precursor) and a highly alkaline solution (known as the activator). This reaction results in the formation of a hardened solid (Provis, 2018). These cements are employed as partial or complete substitutes for Portland Cement (PC), utilising binders primarily derived from by-products with previously accounted carbon legacies, notably Fly Ash (FA) and/or Ground Granulated Blast Furnace Slag (GGBS). Since these materials are only latently hydraulic, they require chemical activation to release their hydraulic properties. Common activators include highly alkaline or caustic liquid materials like sodium/potassium hydroxides and/or sodium silicate.
Research has extensively explored the total replacement of PC in concrete systems using AACMs. Those based on Ca-rich precursors, such as GGBS, are presently utilised in the production of mortars and concretes for both structural and non-structural applications (Juenger et al., 2011; Buchwald et al., 2015). Manufacturing processes include precast and cast-in-situ methods.
AACMs have been available in various forms for over a century, employing different combinations of alkali-activating species. Historically, their use has been limited due to the ready availability and cost-effectiveness of Portland cement, making them suitable primarily for special projects requiring high chemical resistance.
However, the growing emphasis on sustainability and environmental concerns has spurred increased interest in AACM development and usage. This trend is expected to continue and may be further propelled by legislative and regulatory measures encouraging environmentally friendly construction practices.