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Caltrans District 4 (Bay Area) is deploying Cold in-place recycling (CIR), an emerging pavement repair technique that produces reclaimed asphalt pavement (RAP) and recycles it into new pavement onsite. Although CIR is often discussed qualitatively as a more economic and sustainable alternative to conventional pavement repair, methods to quantify the life cycle costs and global warming potential of CIR are not well developed.
As an innovative leader, staff in District 4 developed life cycle cost analysis (LCCA) and life cycle assessment (LCA) methodologies to assess the benefits for CIR. This allows staff to quantify the costs and global warming potential related to CIR construction. These methods can be adapted beyond CIR, and may be used whenever LCCA is required for pavement design alternatives. In addition to longstanding parameters such as material performance, constructability, cost, and traffic impact, global warming potential can now be used to judge pavement design alternatives if climate change and the environment are key project considerations.
To implement this into existing processes, staff modified life cycle assessment tools already used by project staff to more accurately capture the benefits of CIR. In one case study in San Mateo County, deploying CIR reduced 20-year life cycle costs by more than $6 million, and reduced global warming potential over the same time period by 45%.
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