Definition of holistic sustainability criteria for transport infrastructure

In line with the Paris Agreement, the European Council supported the goal of making the EU climate-neutral by 2050. In order to attain sustainable development goals, it is vital to evaluate the sustainability of potential solutions while considering the design principles, building practices, and infrastructure materials (SDGs). Carbon footprint is a measure of total greenhouse gases (GHG) emissions created directly and indirectly by a person, organization, event, or product, covering emissions over the entire lifespan of that product or service. In order to choose the most “sustainable” option, calculated carbon footprints should be compared for alternative solutions Embodied carbon (EC), as an indicator of cumulative carbon emissions is used in the adopted solution, can be defined as the rate of CO2 emissions released in the extraction, manufacture, and transport of the Material. There has been an ever-increasing environmental awareness and recognition of the significance of reducing waste production and exploitation of non-renewable natural resources to promote sustainable development over the past few years.
The construction and road industry are one of the largest exploiters of both renewable and non-renewable natural resources, and it is inevitable that they would be at the center of concerns regarding environmental impact. The construction and operation of roads consumes a great deal of materials throughout its service life cycle. The selection and use of sustainable infrastructure materials play an important role in the design and construction of green infrastructure. Transportation and highway orientation has been putting sustainable and recyclable material to use for their superstructure and substructure resulting in great benefits for the road industry.
Permeable pavements provide new opportunities to unveil transportation infrastructure and to improve the urban climate. Because of limited durability, conventional materials for permeable pavements are used only selectively in urban areas. Thus, the development of innovative infrastructure materials for durable permeable pavements is required. A full substitution of bitumen by an innovative synthetic binder has been restrictively applied within road-construction engineering so far, although the performance potential as well as the characteristic versatility are very high. Particularly, regarding the considered exploitation of raw materials, polyurethane (PU) can be used as an alternative to bitumen.
The successful development of a high-tech pavement system can contribute to an efficient and permanent transportation infrastructure. Particularly regarding the limited durability of conventional Porous Asphalt (PA), permeable PU-asphalt represents a competitive alternative. The potential of PU-asphalt as a heavy-duty permeable pavement could be demonstrated on a laboratory scale. The mechanical and environmental performance of PU-asphalt are significantly increased compared to conventional reference materials.
RWTH Aachen University’s Institute of Sustainability in Civil Engineering (INaB) is collaborating with the Center for Building and Infrastructure Engineering (CBI) to create a framework for sustainability assessment of superstructure in road pavement. As a project partner, INaB aims to develop a science-based sustainability assessment system that can be applied to other structures. The project is divided into two modules: one for sustainability assessment of Hot Mix Asphalt (HMA) and the other for life cycle assessment of PU asphalt.
The framework for the LCA is defined as functional unit definition, mentioning the reference flows, defining the scope and system boundaries, and the calculation method for conducting the LCA. The life cycle assessment for PU asphalt consists of material extraction, production, and construction as cradle to gate assessment. It is then compared with the conventional scenario, followed by sensitivity and hotspot analysis.

Contact: Manouchehr Shokri M.Sc.
Tel.: +49 241 80 22766