Sustainability Assessment of Green Concrete Using Building Material Sustainability Potential (BMSP) and Empathetic Added Sustainability Index (EASI)

Concrete remains the most widely used construction material owing to its affordability, local availability, mechanical performance, durability, and versatility. However, its production has a significant environmental impact, and its service life may be reduced under aggressive exposure conditions, affecting both the functionality and cost of structures. This study presents a sustainability assessment based on a harmonized database of previously developed concrete mixtures, rather than a new experimental campaign. Waste-containing mixtures and their corresponding conventional or reference controls were considered to anchor the comparison to reference concretes, rather than only to the minimum values within the analyzed dataset. The objective was to compare the consistency among sustainability index formulations: KSB and KSB,C, associated with the Building Material Sustainability Potential (BMSP), and the Empathetic Added Sustainability Index (EASI). These formulations integrate functional and environmental performance, although they differ in their aggregation approach and in the treatment of economic variables, such as cost and eco-cost. The indicators considered include 28-day compressive strength, carbonation rate, global warming potential (GWP), gross energy requirement (GER), natural raw material consumption (NRMC), eco-cost, and material cost. The results show that mixtures with higher replacement levels of natural aggregates by recycled concrete aggregate and partial replacement of cement by locally sourced ashes exhibited the best integrated performance. The 300/100RCAg mixture stood out, with index values close to 3.43, 3.52, and 3.99, up to approximately four times those of the control. Sensitivity and uncertainty analyses showed that the highest-ranked mixtures generally maintained favorable positions across assessment methods and under ±20% input variability, although some alternatives exhibited substantial method-dependent ranking changes. The results demonstrate that local waste materials can improve concrete sustainability; however, their benefits depend on waste type, conditioning requirements, functional performance, and the selected sustainability assessment method.