Life-Cycle Benefits of Recycled Material in Highway Construction

Abstract

The use of recycled materials in highway construction can achieve significant benefits affecting the triple bottom line (environment, prosperity, and society). Although state departments of transportation have been at the forefront of introducing recycled materials, they have been unable to clearly convey the benefits in a quantitative and transparent manner using easily understood metrics. Information on sustainability assessment characteristics—that is, energy and water consumption—is lacking. To determine the benefits of using recycled materials for six member state departments of transportation in a pooled fund, the Recycled Materials Resource Center at the University of Wisconsin–Madison was tasked with a project that would quantify the environmental and economic life-cycle benefits associated with the incorporation of recycled materials and industrial by-products in highway construction. An analysis of the environmental benefits (i.e., carbon dioxide emissions, energy consumption, and water consumption) associated with the substitution of recycled materials for conventional virgin materials in highway construction was conducted using the pavement life-cycle assessment tool for environmental and economic effects, a tool developed with the sponsorship of the Recycled Materials Resource Center. An economic impact analysis was conducted by comparing the unit prices of virgin and recycled materials. The analysis showed significant environmental and economic savings in all member states. Total environmental savings from use of recycled materials were approximately equal to the energy consumption of 110,000 U.S. households per year, 9,300 bathtubs of water, and the carbon dioxide emissions produced by 58,000 cars per year. Total systemwide economic savings from use of recycled materials was estimated to be $62.5 million.

Environmental assessment of warm mix asphalt incorporating steel slag and high reclaimed asphalt for wearing courses: a case study

“…The environmental impact of each of the aforementioned mixtures was evaluated using PaLATE, a life cycle assessment (LCA) tool tailored to the use of pavement construction evaluations (Aurangzeb et al, 2014;Del Ponte et al, 2017;Hong & Prozzi, 2018). PaLATE incorporates a robust modelling framework, which considers complex relationships among pavement construction materials and processes and disaggregates the construction process into tasks that are then used to compute the environmental impacts (Horvath, 2004).…”

“…PaLATE outputs relate to the life-cycle inventory (energy, water consumption, emissions, and generated hazardous waste) and to life-cycle impact assessment (LCIA), including effects on humans due to leaching or airborne fumes and particulate matter (Nathman et al, 2009). It is worth noting that PaLATE incorporates a transparent programming and user interface, thus, providing flexibility in the LCA model design as well as in updating the inventory databases (Del Ponte et al, 2017;Nathman et al, 2009).…”

Recycled Asphalt Pavement Materials in Transport Pavement Infrastructure: Sustainability Analysis & Metrics

“…The material obtained from this process is referred to as RAP. Ventura et al [6], and more recently, AL-Qadi et al, [7], Aurangzeb et al [8], and Del Ponte et al, [9] discussed the potential environmental and economic benefits and trade-offs of using RAP in pavements. However, only a limited percentage of RAP was included in these analyses.…”

“…Thus, a more comprehensive analysis of life cycle economic benefits and environmental impact analysis is needed [11]. Furthermore, previous studies on the LCA analysis using RAP materials focused on the economics and/or environmental impacts during the material production process, AL-Qadi et al, [7], Aurangzeb et al [8], and Del Ponte et al, [9]. Thus, there is a need to consider all stages in the roadway life-cycle performance phases (i.e., construction, maintenance, rehabilitation) in order to address all potential impacts and benefits of using RAP in the LCA analysis of roadway projects.…”

Life Cycle Costs Analysis of Reclaimed Asphalt Pavement (RAP) Under Future Climate

“…Reclaimed asphalt (RA) is a byproduct of asphalt pavement rehabilitation and has been used as an alternative material in hot mix asphalt (HMA). Recycled asphalt pavement (RAP) containing RA has been found to have lower life cycle environmental and economic impacts compared to HMA pavements [1][2][3][4][5]. In practice, the use of RA is usually driven by economic/environmental benefits in the production and transportation of the materials [6].…”