Life-Cycle Cost Model for Evaluating the Sustainability of Bridge Decks
Concrete infrastructure systems require large capital investments and resource flows to construct and maintain. An integrated life cycle assessment and cost model was developed to evaluate infrastructure sustainability, and compare alternative materials and designs using environmental, economic and social indicators. The model is applied to two alternative concrete bridge deck designs: one a conventional steel reinforced concrete (SRC) deck with mechanical steel expansion joints, and the other an SRC deck with engineered cementitious composite (ECC) link slabs. Life cycle energy, greenhouse gas emissions, agency costs for construction and rehabilitation, and social costs including construction-related user delay costs and environmental pollutant damage costs are quantified for each system over a 60-year bridge service life. Results show that the ECC link slab system has a 37% cost advantage over the conventional system, consumes 40% less total primary energy, and produces 39% less carbon dioxide.