Life Cycle Assessment of Inverted Pavement Case Studies in the United States

Traditional pavement structures are composed of layers with increasing stiffness from the bottom up. On the other hand, inverted pavements (IPs) incorporate a stiffer subbase, typically stabilized with cement, and placed under a less stiff granular base. The surfacing generally comprises a sprayed seal or a thin asphalt concrete (AC) layer. IPs are common in South Africa owing to their low initial construction costs and relatively simple maintenance requirements. In the US, there are only a few documented cases of IP. In addition to potential cost benefits, IPs are considered an environmentally friendly alternative, as they could reduce the carbon footprint of pavements. This paper presents a sustainability assessment of IP case studies in the US using an environmental life cycle assessment (LCA) approach. The results indicate that it is possible to reduce environmental impacts by adopting IPs, although this was not observed in all the case studies. In some cases, the IP performance was inferior to conventional pavement (CP) performance, which could lead to higher life cycle environmental impacts if the IP requires more frequent maintenance and rehabilitation activities.