Life Cycle Assessment of Representative Swiss Road Pavements for National Roads with an Accompanying Life Cycle Cost Analysis

The subject of this paper is an environmental Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) of processes needed to construct and maintain representative Swiss asphalt, concrete and composite pavements (including subbase layers) applicable for the Swiss national road network over a period of 75 years. The environmental indicators analyzed are the Global Warming Potential indicator, the non-renewable Cumulative Energy Demand and the Swiss Ecological Scarcity indicator. Processes of the use phase of the road (fuel consumption, noise, etc.) have been evaluated qualitatively based on intensive research. The study shows that the Global Warming Potential of concrete and asphalt pavements equilibrates over the analysis period and that concrete pavements compared to asphalt and composite pavements offer advantages in regards to the non-renewable Cumulative Energy Demand, the Ecological Scarcity Indicator and Life Cycle Costs. The qualitative evaluation of the processes of the use phase shows for example the positive qualities of concrete pavements regarding fuel consumption and permanent noise properties

Hidden Ecological Potentials in the Production of Materials for Swiss Road Pavements

Sustainability has become a major concern in the field of civil infrastructures in recent years. Developing road construction projects with lower ecological impacts over a project’s entire life cycle can help in making road infrastructure contribute to sustainable development. This study focuses on the ecological potentials in the production of road materials used in Swiss road pavements. The environmental assessment was performed using a cradle-to-gate life-cycle assessment (LCA) approach in which all processes from the raw material extraction to the finished product were considered. The comparison of the results of the best-case asphalt pavement and the standard asphalt pavement for Swiss highway construction shows ecological potentials of up to 55%. Use of the best-case concrete pavement lowers the environmental impact by up to 53% in comparison to the worst-case concrete pavement for Swiss highways. Concerning composite pavements, the best-case variant offers an ecological potential 38% higher than the standard pavement

Life Cycle Assessment of High-Performance Railway Infrastructure, Analysis of Superstructures in Tunnels and on Open Tracks

Almost 25% of the environmental pollution, measured by the indicator of global greenhouse emissions, is emitted by transport. Changes in the mobility behavior of the population will be essential if the 17 UN Sustainable Development Goals (SDGs) and the goals of the EU Commission’s Green Deal are to be attained. Accordingly, the existing infrastructure has to transform into a sustainable transport infrastructure through further optimizations in the future. Therefore, continuous optimizations and improvements of designs, materials, and processes are crucial to achieving long-term sustainability. This study investigates different superstructures with the method of life cycle assessment using the example of the emerging high-performance infrastructure at the Brenner Base Tunnel (BBT). The study analyzes all relevant life cycle stages (A1–C4) and validates different effects of service lifetimes of superstructure elements on the open track and in the tunnel. The results, which are presented in the form of GWP, AP, and NRCED, show that there is environmental reduction potential, especially in the stage of use. As more frequent modernization cycles and the associated remanufacturing of superstructure elements account for a significant proportion of the total environmental impact, lifetime extending optimization of products yields improvements in the ecological footprint

Life Cycle Assessment of Innovative Asphalt Mixtures Made with Crumb Rubber for Impact-Absorbing Pavements

This study applies the life cycle assessment methodology to evaluate the environmental impacts of shock-absorbing pavements fabricated with recycled materials (crumb rubber and a colored pigment called ferrotone), employing the “cradle-to-grave” approach, in which the impacts of all life cycle phases (from materials’ acquisition to the end-of-life of the pavement) are included. The analysis compares the impacts of standard and innovative asphalt materials, considering cold and hot production processes. In addition, three different lifespans are simulated for the pavement structures: the reference service life until the first intervention is considered to be 5 years, and the following scenarios consider that the alternative asphalt materials may last 20% less (4 years) or 20% longer (6 years) than the reference service life. The analysis uses non-renewable cumulative energy demand (nr-CED) and global warming potential (GWP) as main indicators to determine the environmental impacts over a 45-year analysis period. The results show that adopting the “dry process” (consisting of adding the rubber as a partial substitution for aggregates) increases the overall impacts due to the need for higher contents of binder. However, if the alternative pavement structures last 20% longer than the reference, they would generate lower impacts in terms of nr-CED and GWP

Life Cycle Assessment of Innovative Asphalt Mixtures Made with Crumb Rubber for Impact-Absorbing Pavements

This study applies the life cycle assessment methodology to evaluate the environmental impacts of shock-absorbing pavements fabricated with recycled materials (crumb rubber and a colored pigment called ferrotone), employing the “cradle-to-grave” approach, in which the impacts of all life cycle phases (from materials’ acquisition to the end-of-life of the pavement) are included. The analysis compares the impacts of standard and innovative asphalt materials, considering cold and hot production processes. In addition, three different lifespans are simulated for the pavement structures: the reference service life until the first intervention is considered to be 5 years, and the following scenarios consider that the alternative asphalt materials may last 20% less (4 years) or 20% longer (6 years) than the reference service life. The analysis uses non-renewable cumulative energy demand (nr-CED) and global warming potential (GWP) as main indicators to determine the environmental impacts over a 45-year analysis period. The results show that adopting the “dry process” (consisting of adding the rubber as a partial substitution for aggregates) increases the overall impacts due to the need for higher contents of binder. However, if the alternative pavement structures last 20% longer than the reference, they would generate lower impacts in terms of nr-CED and GWP

The Influence of Alternative Fillers on the Adhesive Properties of Mastics Fabricated with Red Mud

The adhesion between bitumen and aggregates strongly influences the lifetime of pavements. To improve adhesiveness, the road construction industry has been using additives to alter the interfacial energy and improve the affinity of materials in the presence of water. However, the water sensitivity varies according to the mixture design, since the interaction may occur differently depending on the materials chosen. As the use of alternative materials is increasing in road constructions, further analysis of its affinity with aggregates and bitumen is necessary. In that sense, this study evaluates the adhesion performance of mastics mixed with traditional fillers, such as limestone and dolomite, and residues, such as fly ash and red mud. To assess possible interactions with the red mud, the fillers are mixed in distinct percentages and tested for adhesiveness, wettability, penetration, and softening point. The results show the importance of hydrophilicity, asphalt viscosity, and physical–chemical properties to define adhesive interactions

Optimizing Financial Allocation for Maintenance and Rehabilitation of Munster’s Road Network Using the World Bank’s RONET Model

This paper applies the Road Network Evaluation Tools (RONET) model to assess the economic impacts of urban pavement maintenance and rehabilitation in the city of Munster, Germany. The city’s road network includes main roads, main access roads, residential roads, and paved areas for pedestrians, cyclists, and parking spaces. The specific traffic loads applied to Munster’s network demand several different pavement materials, structures, and intervention procedures. This study aims to support stakeholders’ decision-making by assessing current expenditures, network conditions, and country-specific data to determine the appropriate financial allocation for recurrent maintenance, periodic maintenance, rehabilitation, and new pavement construction. Six scenarios comprising distinct pavement structures and maintenance strategies are modeled in RONET to perform the analysis. The outcomes include the future deterioration of pavements under different maintenance scenarios, the current and projected asset value of the network, and the total costs (road agency costs + user costs) of the network to society, considering each scenario being applied over a 20-year evaluation period. The RONET model also provides the annual average cost of each maintenance procedure and the additional costs to society while using a budget scenario other than ‘Optimal.’ The results indicate that Munster’s current investment program is in line with the ‘Optimal’ budget scenario proposed by RONET. In addition, the model suggests that performing recurrent and periodic interventions is more cost-effective than neglecting the conservation of pavements for an extended period and endorsing more extensive interventions in the future, such as rehabilitation or reconstruction

Optimizing Financial Allocation for Maintenance and Rehabilitation of Munster’s Road Network Using the World Bank’s RONET Model

This paper applies the Road Network Evaluation Tools (RONET) model to assess the economic impacts of urban pavement maintenance and rehabilitation in the city of Munster, Germany. The city’s road network includes main roads, main access roads, residential roads, and paved areas for pedestrians, cyclists, and parking spaces. The specific traffic loads applied to Munster’s network demand several different pavement materials, structures, and intervention procedures. This study aims to support stakeholders’ decision-making by assessing current expenditures, network conditions, and country-specific data to determine the appropriate financial allocation for recurrent maintenance, periodic maintenance, rehabilitation, and new pavement construction. Six scenarios comprising distinct pavement structures and maintenance strategies are modeled in RONET to perform the analysis. The outcomes include the future deterioration of pavements under different maintenance scenarios, the current and projected asset value of the network, and the total costs (road agency costs + user costs) of the network to society, considering each scenario being applied over a 20-year evaluation period. The RONET model also provides the annual average cost of each maintenance procedure and the additional costs to society while using a budget scenario other than ‘Optimal.’ The results indicate that Munster’s current investment program is in line with the ‘Optimal’ budget scenario proposed by RONET. In addition, the model suggests that performing recurrent and periodic interventions is more cost-effective than neglecting the conservation of pavements for an extended period and endorsing more extensive interventions in the future, such as rehabilitation or reconstruction