Life cycle assessment of ready-mixed concrete: paths towards more sustainable practices

Abstract

Concrete is the second most used material on Earth after water and its large-scale production generates heavy environmental burdens. Effective mitigation of this stress involves understanding the key factors contributing to it. In this work, a cradle-to-gate life cycle assessment was conducted on ready-mixed concrete (RMC) produced in two Portuguese plants. It was found that the extraction and processing of raw materials dominates most environmental impact categories, especially those relating to climate change, with cement production governing the overall global warming potential (GWP). Analysis of several short- to medium-term scenarios to reduce carbon dioxide emissions, as envisioned by the European Cement Association and the Portuguese cement industry, indicates a possible reduction of about 30% in GWP. Of this reduction, 20% is attributed to a decrease of up to 60% in the clinker content of the cement used to produce RMC, while most of the remaining 10% results from the natural carbonation of cement (a process already occurring naturally in the use stage of concrete).