Life Cycle Cost and Environmental Assessment of the Consequences of the Recycling Depth Restrictions

Abstract: Cold recycling is a proven alternative to traditional remove and replace maintenance and rehabilitation strategies, but its implementation in the United States has been limited. One of the primary factors limiting the wide scale implementation is that cold recycling strategies do not fit under the current agency flexible pavement management frameworks which have been established around remove and replace maintenance rehabilitation strategies. This has resulted in maintenance strategies using cold recycling based on a prescribed depth, instead of optimizing the recycling depths to remove distresses and to provide the required structural support for the asphalt concrete surfacing for a given set of climate, traffic, environmental, and resilience criteria.
This paper compares the environmental and cost impacts of using traditional maintenance strategies like “mill-and-fill” and cold recycling of a distressed flexible pavement using life cycle assessment (LCA) and life cycle cost assessment (LCCA), respectively. Three tools, developed for the California department of transportation (Caltrans) were used in this study which includes the mechanistic empirical (ME) design software called the CalME, the life cycle environmental analysis tool called eLCAP, and the life cycle cost analysis tool, the RealCost, to evaluate the environmental impacts and cost of using cold recycling compared to asphalt concrete for maintenance and rehabilitation, as well as the impacts of selecting a recycling depth based on distress depth, instead of using prescribed recycling depths.