Evaluation of Carbon Emission Reduction in Concrete Using Fly Ash and Slag: Case Studies from Vietnam

Concrete is one of the most widely used construction materials; however, its high cement content is a major contributor to global carbon emissions. This study applies Life Cycle Assessment (LCA) to evaluate carbon emissions from various cement replacement scenarios using fly ash and slag, based on multiple studies in Vietnam. Experimental results show that replacing 20%–40% of cement with fly ash reduces emissions by 9.14%–40%, while 40% slag replacement achieves a 31.84% reduction. A combined mix with 20% fly ash and 20% slag offers the best balance, reducing emissions by 32.16% while maintaining a compressive strength of approximately 50 MPa. These findings highlight the potential of industrial by-products in reducing carbon footprints while maintaining concrete performance. This study provides insights for optimizing sustainable concrete mix designs in Vietnam, promoting greener construction practices.