A Life-Cycle Methodology for Energy Use by In-Place Pavement Recycling Techniques

Abstract

Worldwide interest in using recycled materials in flexible pavements as an alternative to virgin materials has increased significantly over the past few decades. Therefore, recycling has been utilized in pavement maintenance and rehabilitation activities. Three types of in-place recycling technologies have been introduced since the late 70s: hot in-place recycling, cold in-place recycling, and full-depth reclamation. The main objectives of this project are to develop a framework and a life-cycle assessment (LCA) methodology to evaluate maintenance and rehabilitation treatments, specifically in-place recycling and conventional paving methods, and develop a LCA tool utilizing Visual Basic for Applications (VBA) to help local and state highway agencies evaluate environmental benefits and tradeoffs of in-place recycling techniques as compared to conventional rehabilitation methods at each life-cycle stage from the material extraction to the end of life. The ultimate outcome of this study is the development of a framework and a user-friendly LCA tool that assesses the environmental impact of a wide range of pavement treatments, including in-place recycling, conventional methods, and surface treatments. The developed tool provides pavement industry practitioners, consultants, and agencies the opportunity to complement their projects’ economic and social assessment with the environmental impacts quantification. In addition, the tool presents the main factors that impact produced emissions and energy consumed at every stage of the pavement life cycle due to treatments. The tool provides detailed information such as fuel usage analysis of in-place recycling based on field data.