Probabilistic Embodied Carbon Assessments for Alkali-Activated Concrete Materials

This study evaluates the environmental impact of alkali-activated concrete materials (AACMs) as alternatives to conventional concrete. The influence of binder and activator content and type, along with other mix parameters, is analysed using a probabilistic embodied carbon assessment on a large dataset that includes 580 mixes. Using a cradle-to-gate approach with region-specific life-cycle inventory data, emissions are analysed against binder intensity, activator-to-binder and water-to-binder ratios, and fresh/mechanical properties. A multicriteria assessment quantifies the best-performing mix in terms of embodied carbon, compressive strength, and slump. AACM environmental impact is compared to conventional concrete through existing classification schemes and literature. AACM emissions vary between 41 and 261 kgCO₂eq/m³, with activators contributing the most (3–198 kgCO₂eq/m³). Uncertainty in transport-related emissions could shift these values by ±38%. AACMs can achieve up to four-fold less emissions for high-strength materials compared to conventional concrete, although this benefit decreases with lower mechanical properties. AACM environmental sustainability depends on activator characteristics, curing, mix design, and transportation.