Cold Recycling of Asphalt Pavements: Toward a Roadmap for Wider Implementation by Road Agencies

Cold recycling is a proven alternative to traditional remove-and-replace maintenance and rehabilitation strategies. However, implementation by road agencies across the United States has been limited, which can be attributed to a number of reasons. One primary reason is believed to be that cold recycling strategies do not readily fit current agency flexible pavement management frameworks, which have been established around remove-and-replace maintenance and rehabilitation strategies, or fit the traditional definitions for routine, preventative and corrective maintenance, and minor and major rehabilitation. These frameworks, and the decision processes associated with them, need to be updated to better accommodate new strategies, in conjunction with traditional strategies, to make the best use of available resources to cost-effectively and more sustainably extend the life of pavement networks and improve the overall condition of the network. This paper summarizes developments in cold recycling, identifies barriers to implementing cold recycling in agencies, and suggests a roadmap framework for updating policies and procedures to make better use of cold recycling. When designed and built appropriately, cold recycling strategies can be more cost-effective and more sustainable than traditional remove-and-replace strategies. Optimizing the recycling depth to remove distresses and provide the required structural support for the asphalt concrete surfacing for a given set of traffic, climate, environmental, and resilience criteria is critical for a successful outcome. Attempting to align recycle depths within maintenance and rehabilitation categories that are specific to traditional remove-and-replace strategies will yield less-than-optimal results and the potential for significant benefits will not be realized.