Sustainable Pavement Asset Management Based on Life Cycle Models and Optimization Methods.

Abstract

Pavement systems provide critical infrastructure services to society but also pose significant impacts related to high material consumption, energy inputs, and capital investment. A new pavement asset management approach, using economic, social, and environmental metrics, is proposed to enhance the sustainability of transportation infrastructure systems. This dissertation develops methods for evaluating and enhancing the sustainability of pavement infrastructure. Four methods are presented: (1) integrated life cycle assessment and life cycle cost analysis modeling of pavement overlay systems comparing new material Engineered Cementitious Composites (ECC) to conventional materials, (2) project-level pavement asset management system using life cycle optimization, (3) multi-objective and multi-constraint optimization informing policy and enhancing sustainability, and (4) network-level pavement asset management system integrated with geographic information systems. The integrated life cycle model results indicated that the application of ECC can significantly improve overlay system sustainability. Compared to conventional concrete and hot mixed asphalt (HMA) overlay systems, the ECC overlay system reduces life cycle energy consumption by 15% and 72%, greenhouse gas (GHG) emissions by 32%and 37%, and costs by 40% and 47%, respectively. A project-level pavement asset management system was developed to determine the optimal pavement preservation strategy using life cycle optimization methods. The results showed that the optimal preservation strategies reduce the total life cycle energy consumption by 5%-30%, the GHG emissions by 4%-40%, and the costs by 0.4%-12% for the concrete, ECC, and HMA overlay systems, respectively. Multi-constraint and multi-objective optimization was conducted to study the relationship between material consumption, traffic congestion, and roughness effects. The influence of fuel prices, fuel taxes and government subsidies on sustainability performance was explored and specific policy recommendations were provided. The network-level pavement asset management system provides highway agencies the capability to better maintain a well functioning pavement network and to minimize life cycle cost. A case study application showed that the optimal preservation strategy can reduce life cycle cost by 13% compared to current planning methods for the entire pavement network.