Life cycle model for evaluating the sustainability of concrete infrastructure systems

Concrete infrastructure systems require large capital investments and resource flows to con- struct and maintain. An integrated life cycle assessment and cost model was developed to evaluate infrastruc- ture 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 re- inforced concrete (SRC) deck with mechanical steel expansion joints, and the other an SRC deck with engi- neered 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 envi- ronmental pollutant damage costs are quantified for each system over a 60-year bridge service life. Results show that the ECC link slab system consumes 40% less total primary energy, produces 39% less carbon diox- ide, and has a 37% cost advantage over the conventional system.