Abstract

Canada has committed to achieving net zero greenhouse gas emissions by 2050, and the construction sector plays a critical role in meeting this target. Cement production alone contributes nearly 8% of global CO2 emissions, making it essential to explore alternatives to Ordinary Portland Cement (OPC). One promising solution is the use of alkali-activated materials (AAMs), which are produced from industrial by-products and can substantially reduce both carbon emissions and energy consumption in concrete production. Among these, one-part alkali-activated slag (AAS), often referred to as “just add water AAM,” is particularly attractive because of its ease of application and ability to achieve high early strength without heat curing. Despite these advantages, one-part AAS still faces significant challenges, including low workability, rapid slump loss, and short setting times, which limit its practical use in ready-mix and on-site applications. While some studies have examined chemical admixtures to enhance AAM performance, there remains limited research on the specific behavior of one-part AAS systems. In particular, little attention has been given to the effects of mixing protocols, retarders, and viscosity-modifying admixtures on both fresh and hardened properties. To address these gaps, this research is divided into four phases. The first phase evaluates the effect of changing ingredient addition sequences on reaction kinetics. Based on these findings, the optimized sequence is carried into the following phases. The second phase investigates the influence of mixing times, speeds, and styles (continuous versus discrete) on the fresh and rheological behavior of one-part AAS. The third phase examines the use of chemical retarders to improve workability and extend slump life without compromising strength. Finally, the fourth phase explores the role of viscosity-modifying admixtures (VMAs) in stabilizing the mix and enhancing flowability and setting behavior. By systematically studying these variables, this research advances understanding of one-part AAS and highlights pathways to improve its fresh properties. The outcomes are expected to support broader adoption of sustainable binders in construction and contribute to Canada’s net-zero emission goals.