A Life Cycle Assessment Framework for Pavement Maintenance and Rehabilitation Technologies

Abstract

Given a huge amount of annual investment and large inputs of energy and natural resources in pavement maintenance and rehabilitation (M&R) activities, significant environmental improvement and budget saving can be achieved by making eco-friendly and cost-effective decisions in scheduling M&R activities. Traditional scheduling of pavement M&R activities, however, is primarily determined based on cost optimization, using a life cycle cost analysis (LCCA). The environmental impacts of pavement M&R activities are usually ignored. Life cycle assessment (LCA) is an approach for determining the environmental sustainability of a system from cradle to grave. The purpose of this research is to develop an integrated LCA-LCCA framework in assisting decision-making for pavement M&R activities during the entire pavement life cycle. Based on literature review, an integrated LCA-LCCA optimization framework for pavement rehabilitation strategy selection is proposed. In the framework, the LCA model is divided into six modules: material, construction, distribution, congestion, usage, and end-of-life modules. Life cycle energy consumption, greenhouse gas (GHG) emissions, and air pollutants are identified as environmental impact factors. Life cycle agency cost, and user cost are selected as cost factors. Pavement M&R strategies are evaluated as the input variables of the integrated LCA-LCCA model. The LCA-LCCA output variable (e.g., energy consumption, agency cost) may be regarded as an objective function or as a constraint in the mathematical optimization of pavement M&R schedules. In addition, pavement roughness progression model after M&R activities is identified as an essential part of the integrated LCA-LCCA framework. Material, construction-related traffic congestion, and pavement surface roughness effects are three major contributors to energy consumption and GHG emissions for pavement M&R activities.