Life cycle assessment of alkali-activated materials: a systematic literature review

Abstract

The physical–mechanical, chemical, and durability characteristics of alkali-activated materials (AAMs) have been widely investigated. However, a critical gap in the literature is the lack of a comprehensive overview of recently published literature regarding the life cycle assessment (LCA) of these binders. This study aims to fill that gap by conducting a systematic literature review of globally published literature on the topic. This paper consolidates knowledge by searching different databases, focusing on LCA studies that used AAMs as pastes, mortars, concretes, bricks, and rammed earth/soil blocks. The selected articles were reviewed and categorized based on precursors, alkaline activators, functional units, system boundaries, life cycle inventory databases, allocation, impact methodologies, and software used.Additionally, this paper also critically analyzes the key challenges of LCA for AAMs. The major challenges were identified as selecting a functional unit, subjectivity in boundary systems, and data interpretation. This work concludes that AAMs show substantial advantages in global warming potential compared to ordinary Portland cement-based materials; however, the average of other categories such as marine ecotoxicity and ozone layer depletion has been reported to be higher than for the reference samples.