Life Cycle Modeling of Concrete Bridge Design: Comparison of Engineered Cementitious Composite Link Slabs and Conventional steel Expansion Joints
Concrete infrastructure represents an enormous investment of materials, energy, and capital, and results in significant environmental burdens and social costs. There is an ongoing effort to identify material alternatives to conventional concrete. Life cycle assessment (LCA) is an important tool to evaluate the environmental performance of alternative infrastructure materials and systems. Here, we present a comparative LCA of two bridge deck systems over a 60 year service life: one using conventional steel expansion joints and the other based on a link slab design using a concrete alternative, engineered cementitious composites (ECC). The ECC link slab design is expected to extend the bridge deck service life and reduce maintenance activities. A life cycle model was developed that accounts for materials production and distribution, construction and maintenance processes, construction-related traffic congestion, and end-of-life management. Results indicate that the ECC bridge deck system has significant advantages in environmental performance: 40% less life cycle energy consumption, 50% less solid waste generation, and 38% less raw material consumption. Construction related traffic congestion is the greatest contributor to most life cycle impact categories.