Environmental impact and life cycle assessment (LCA) of traditional and ‘green’ concretes: Literature review and theoretical calculations

With the current focus on sustainability, it is necessary to evaluate concrete’s environmental impact properly, especially when developing new ‘green’ concrete types. Therefore, we investigated the available literature on every step in the LCA of concrete. The adopted functional unit for which the environmental impact is calculated, influences the outcome significantly. When comparing different concrete compositions, this unit should incorporate differences in strength, durability and service life. Hence, a cradle-to-grave or modified cradle-to-gate approach is advised as system boundary. When using industrial by-products as cement replacing material in ‘green’ concrete, an economical allocation of impacts is recommended. Inventory data on energy use, CO2, PM10, SOx and NOx emissions were collected and assigned to the impact categories of the problem oriented CML 2002 and the damage oriented Eco-indicator 99 impact method. Compared to Portland cement, the impact of blast-furnace slag and fly ash is about an order of a magnitude lower.