الفهرس 
Classification and Brief Overview of Air Pollutants
DEVELOPMENT OF EGY-LCA MODELOnly 14 pages are availabe for public view
 |  | from | 226 |  |  |
| | | from | 226 | | |
Abstract
The complexity of climate change and research on its causes and impacts has resulted in new developments and approaches to reduce the life cycle greenhouse gas (GHG) emissions associated with construction and rehabilitation of highway infrastructure. To understand the life cycle performance of highway pavements and to investigate the methods of reducing their GHG emissions connected with construction and maintenance of roads, previous studies have developed many tools and databases (some commercialized) to facilitate the measurement of the environmental impacts of pavements construction using life cycle assessment (LCA) approaches for different phases of roads.
These approaches are country/region-specific which create difficulty applying these tools to a different environment where key data are missing or need validation. Egypt does not currently have an LCA tool to estimate emissions from construction of asphalt pavements. Consequently, the first goal of this research was to develop a model to evaluate the life cycle inventory for construction of asphalt pavements in Egypt (EGY-LCA).
Traffic emissions increased through the maintenance of roads due to lane and road closures (work zone). Therefore, the second goal was to use microsimulation traffic modelling (VISSIM) to evaluate emissions and energy consumption caused by delays at the work zones, for the selected traffic management options.
Data in EGY-LCA model came from different sources (e.g. Egypt plants, EU standards, and relevant pavement LCA results and databases). ISO14040 standards were followed to develop the framework of this model. The most significant variables in each unit process are identified and followed by data analysis. Several case studies were carried out to test the ability of the EGYLCA model to represent the environmental impacts in a real pavement asphalt project.
Results revealed that material production accounted for the highest value of energy consumption and emissions followed by transport operation and material placement in the project. The only exception is the NOx emission which was higher in transport operation than in material production. CO2 emission has the maximum value in each process. The category of climate change accounted for the largest proportion of energy use and emission followed by human toxicity, acidification, eutrophication, and photochemical oxidation respectively. The results could help researchers and road engineers dealing with LCA of pavement construction, and it will be useful to the decision-makers to improve the performance of pavement construction. Moreover, it can be used to put the base of the Egyptian framework LCA model to reduce air emissions and create a better environment.
The VISSIM model was calibrated and validated using the collected field traffic data. The results showed that the model with default parameters would be appropriate. Three scenarios investigated using the VISSIM model; Scenario 0 (base case scenario) with no traffic management, and two scenarios for the work zones. Scenario 1 (close one lane in both directions of travel) and scenario 2 (close one direction of travel) in different time of road works.
Results showed that emissions and energy consumption caused by the work zone traffic is minimal compared with other phases in the pavement LCA while the work zone increases air emissions and fuel consumption. CO emission has the maximum values in different scenarios followed by VOC and NOx. The road works at night time decrease air emissions and fuel consumption compared with the road works at the normal time. Generally, the vehicle emission levels at the studied roads are much more than the permissible limits according to the WHO guidelines, European emission limits and Egyptian law of environmental limits. The results could help researchers and road engineers dealing with traffic management scheme in road works, as well as to link air pollution measurements from traffic to life cycle modelling of construction in order to undertake a transport-related air pollution assessment.