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Executive SummaryThere is interest in determining and validating the environmental and economic benefits of incorporating recycled materials into road construction using life cycle assessments (LCA) and life cycle cost analysis (LCCA) tools. However, the process of collecting the necessary data for LCAs and LCCAs from departments of transportations (DOTs) and road construction contractors is not well defined. This thesis provides a study of real-time data collection to compare with the results of pre-construction estimated LCA data. The goal of this comparison is to determine a data collection precedent for environmental analyses of future transportation projects. Additionally, two prominent LCA tools were used in conducting the assessment and the results were compared to validate the predicted impacts.The primary body of this thesis focuses on a specific, project-based LCA and LCCA of the reconstruction and expansion of a 2.4-km (1.5-mi) stretch of the eastbound Beltline Highway in Madison, Wisconsin. Recycled materials used in this reconstruction include: fly ash, slag, recycled asphalt shingles (RAS), recycled asphalt pavement (RAP), and recycled concrete aggregate (RCA). Fly ash and slag were used as a partial replacement of cement in the ready-mix concrete.RAP was used in both hot mix asphalt (HMA) pavement as well as a base course material. RAS was substituted for binder and aggregate material in some HMA mix designs. RCA, both recycled onsite and imported, was substituted for base and subbase material.Two data collection methodologies were employed to gather the necessary inputs for the LCA of the reconstruction: 1) material quantities estimated from designs and specifications as planned prior to construction (referred as Planned), and 2) material quantities explicitly tracked and collected while construction was on-going (referred as Constructed). In the Planned data collection methodology, quantities were calculated using plan drawings and average mix designs.In the Constructed data collection methodology, key site-specific Wisconsin DOT (WisDOT) and contractor files were accessed for material quantity information. When comparing the LCAs of two or more products, a relative ranking of alternatives can be analyzed as well as the absolute impacts. For this study, the design of the actual roadway that incorporated recycled material (referred to as Recycled) was compared to a hypothetical design comprised of no recycled material (referred to as Virgin). In the Virgin design, recycled material quantities were replaced with equivalent virgin materials. This method demonstrates the impact reductions from the use of recycled material. To validate the LCA results, impacts predicted by PaLATE versus SimaPro were compared, with the primary focus on the common impact categories of energy and CO2 emissions.Results show that the material quantities obtained from the two data collection methods are within one order of magnitude for all categories, demonstrating general agreement regardless of Constructed or Planned da...

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Life cycle assessment (LCA) of using recycled materials in roadways is currently not well-understood or documented. A research team from the Recycled Materials Resource Center (RMRC) analyzed the use of recycled materials in the reconstruction of the Beltline Highway in Madison, Wisconsin, to assess quantitatively and accurately the environmental and economic benefits of sustainable road construction. Recycled materials used in the reconstruction and expansion of an urban, 2.4 kilometer (1.5 mile) stretch of the highway included fly ash, recycled concrete aggregate, recycled asphalt shingles and recycled asphalt pavement. In addition to assessing the benefits of recycled material use, the RMRC used this project to better determine a methodology for gathering input data for a LCA and a life cycle cost analysis (LCCA) using PaLATE program. PaLATE is a spreadsheet-based LCA/LCCA tool was used to conduct the analyses for the Beltline case study. In past case studies looking at LCA/LCCA of recycled materials use, the RMRC was unable to utilize LCA and LCCA technology without significant assumptions for the program's inputs. The Beltline project offered a unique opportunity to develop a method for data collection that reduces assumptions for the analyses. The actual design with recycled material use was compared to a reference design using only virgin materials. Results show that the actual design reduced environmental impacts over the highway's lifetime in all criteria, including energy use (13% reduction), water consumption (12% reduction) and CO2 emissions (13% reduction). The LCCA showed overall economic savings of approximately $250,000 (10% savings). These results suggest that incorporating recycled materials improves the sustainability of road construction. The knowledge gained from this project will set the precedent for future analyses of department of transportation projects that use recycled materials.