Evaluation of Sustainable and Cost-Effective Concrete Pavement Life

Caltrans jointed plain concrete pavements (JPCP) and continuously reinforced concrete pavements (CRCP) are currently designed for a 40-year life (based on 10% fatigue transverse cracking and 10 punchouts per mile criteria, respectively). While this is already a long-life design, there is the concern that it may not result in the minimum possible life cycle cost and environmental impacts. The current Caltrans Highway Design Manual (HDM), including the Rigid Pavement Design Catalog, and the Standard Specifications applicable to concrete pavements, are based on this 40 year design life. This study includes recommendations for the materials, design, and construction of concrete pavements aimed at extending the design life up to 100 years. These recommendations are based on existing knowledge and tools and indicate the changes necessary to Caltrans’s existingspecifications and practices. However, uncertainties remain in traffic load and climate predictions, as well as the limitations of current durability and structural design models, all of which complicate efforts to accurately predict pavement life beyond the current 40-year standard. As part of this study, the web version of the Rigid Pavement Design Catalog has been updated to allow any design life up to 100 years. This study includes the pavement structural design, life cycle cost analysis (LCCA), and the environmental life cycle assessment (LCA) of three case studies, each designed for 40-, 60-, and 100-year lives. The increase in design life from 40 to 60 years required an increase in JPCP thickness of 0.05 ft. for all three case studies, which carried an increase in the initial agency construction cost of around 5%. The LCCA and LCA results indicate that increasing the design life from 40 to 60 years is expected to result in 3% life cycle agency cost savings and 24% life cycle infrastructure global warmingpotential (GWP) savings. Some road user cost savings were seen from fewer construction work zone (CWZ) closures. Smaller life cycle costs and GWP reductions were found when the design life increased from 60 to 100 years, due in part to the relatively high discount rate used in this study (3.2% per year) and the fact that the reconstruction activity for the 60-year design life already lay beyond the end of the 100-year analysis period adopted in this study.