Green Cement: Comparative Assessment of Portland Cement Alternatives to Reduce Carbon Dioxide Emissions

The cement industry has steadily increased carbon dioxide (CO2) emissions over the past several decades, along with other global industries emitting greenhouse gasses, contributing significantly to climate change. Cement is the binding agent in concrete and the primary structural material that is used in construction of transportation infrastructure, buildings, public utilities, and water systems. Alternative methods to create cement, differing from Portland cement the most commonly used type of cement, are explored in this paper to evaluate how effective the alternatives would be in mitigating carbon emissions from the cement industry while maintaining material strength. In order to quantify the environmental impact of different cement materials, a systematic analysis tool called the Life Cycle Assessment (LCA) was used. LCA was used to explore the amount of carbon emissions across the life of 1 ton of Portland cement throughout its raw material extraction, creation, and transportation. Alternatives such as replacement of limestone with geopolymers and Supplementary Cementitious Materials (SCMs) significantly decrease the amount of CO2 emissions during raw material extraction. On the other hand, using different fuel types and enzymatic self-healing cement significantly decrease the amount of CO2 emissions throughout its entire life cycle. Further research on the alternatives, especially the enzymatic self-healing cement and its optimal conditions, will allow the cement industry to crucially reduce carbon dioxide emissions contributing to global climate change.