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[NTC2014-SU-R-17] Quantification of System-wide Life Cycle Benefits of Recycled Materials in Highways


FHWA and various governmental agencies have developed fact sheets on various recycled materials and industrial byproducts for their use in highway construction applications. These fact sheets typically have addressed the engineering properties and environmental suitability issues relevant to various applications and in some cases incorporated design guidelines and construction specifications. What is lacking is direct information on sustainability assessment characteristics, i.e., greenhouse emissions, energy and water consumption and life cycle cost benefits. Agencies may track system-wide use of quantities for major recycled materials such as fly ash, recycled asphalt pavement, recycled concrete aggregate, foundry sand, coal combustion byproducts, steel slag, etc., but they cannot readily calculate the benefits accrued by substitution of these materials for conventional materials. Although state transportation departments have been in the forefront of introducing recycled materials, they have not been able to clearly convey the benefits in a quantitative and transparent manner using readily understood metrics. The first objective of this study is to develop/update factsheets on various recycled materials and industrial byproducts that are used in highway construction. New information generated in recent years relative to their engineering properties and environmental impact questions will be added as well as relevant life cycle assessment data. The second objective of this study is to develop a tool by which the state system-wide material use quantities can be used to calculate the life cycle benefits associated with the incorporation of recycled materials and industrial byproducts to highway pavement construction.