Life Cycle Assessment of Icelandic Volcanic Pozzolans as Low-Carbon Supplementary Cementitious Materials

Abstract

The cement industry is a major contributor to global greenhouse gas emissions, predominantly due to clinker production. Supplementary Cementitious Materials (SCMs) represent an effective mitigation strategy, yet conventional SCMs such as Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) are becoming increasingly scarce. Volcanic pozzolans offer a promising natural alternative, and Iceland possesses extensive deposits that have not yet been evaluated from an environmental perspective. This study presents the first cradle-to-gate Life Cycle Assessment (LCA) of Icelandic Volcanic Pozzolan (VPI) production, drawing on primary data from three extraction sites and a planned processing facility in Þorlákshöfn—Lambafell, Litla Sandfell, and Landeyjahöfn—and secondary data from GaBi and Ecoinvent. A declared unit of one tonne of VPI is assessed across all ReCiPe 2016 midpoint impact categories. Results show that VPI’s climate change impact of 25.5 kg CO2-eq/t falls between FA (3–10 kg CO2-eq/t) and GGBFS (50–80 kg CO2-eq/t), confirming its competitiveness with established SCMs while offering the strategic advantage of abundant local supply. Marine dredging operations emerge as the dominant environmental hotspot, accounting or approximately 48.1% of total CO2-equivalent emissions. The findings confirm VPI as a robustly low-carbon SCM and support its large-scale adoption in sustainable cement production.