SDFlex: A Framework for the Assessment and Construction of Sustainable Flexible Pavements

There is a growing recognition that highway construction and maintenance have major environmental impacts. Despite the lack of a clear protocol for designing and constructing an environmentally-friendly highway, the industry experimented with sustainable alternatives since the 1970s. With an ultimate goal to develop sustainable guidelines for highway construction practices, this paper presents a general framework for the design and construction of sustainable flexible pavement system. This framework follows a similar approach to the Leadership in Energy and Environmental Design (LEED^®) methodology by employing a point system to award a rating that quantifies the sustainability of the structure. The proposed framework divides factors related to highway design and construction into six major categories: sustainable sites (eight points), energy efficiency (five points), site air quality (four points), materials (ten points), water efficiency (four points), and innovative and design process (three points). The developed rating framework, referred to as Sustainable Design of Flexible Pavements (SDFlex), may be used to award a certification for sustainable highway design and construction. Different levels of certification may be awarded depending on the total earned credits from the six categories (Platinum, Gold, Silver, and Certified). A maximum score of 34 may be achieved under the aforementioned categories. It is proposed that a highway construction that satisfies the prerequisites and achieves a passing score of 10 be awarded a certified rating. The developed framework takes into consideration available technologies and the nature of the highway industry.