Embodied Energy and Carbon Footprint of Concrete Compared to Other Construction Materials

Abstract

The main objective of infrastructure design codes is to protect the public’s welfare, health, and safety, none of which appear directly related to the current sustainability movement that has focused on protecting the natural environment, conserving resources, and minimizing the toxicity of construction materials and processes. Some United States jurisdictions have adopted language related to sustainability based on the United States Green Building Council to curtail adverse effects of global climate change, minimize environmental impact of new construction of built assets (i.e., buildings and infrastructure), and in some cases, improve air quality in the community. The focus of this paper is to compare the embodied energy and carbon footprint of various construction materials: concrete, steel, timber, masonry, and fiber reinforced composites. To properly compare these materials from a sustainability standpoint, we propose an index that characterizes material ecological properties by dividing strength and stiffness by embodied energy. The index is similar to the structural specific properties index used to characterize the mechanical properties of materials (i.e., strength and stiffness divided by density). Using this ecological index, concrete and steel appear to be the most sustainable materials. As a result of their higher strength and stiffness, concrete and steel require less embodied energy to satisfy specific structural demands. Keywords: embodied energy, carbon footprint, LEED, specific embodied energy