Assessing Environmental Impacts of Work-Zones in Arterial Improvement Projects
Project Title
Assessing Environmental Impacts of Work-Zones in Arterial Improvement Projects
University
Syracuse University
Principal Investigator
Ossama (Sam) Salem, Ph.D.
Yabroudi Chair Professor of Sustainable Civil Infrastructures at Syracuse University, Syracuse University
PI Contact Information
Funding Sources and Amounts Provided
US Department of Transportation/ TranLIVE — $80,000
Syracuse University — $80,000
Total Project Cost
$160,000
Agency ID or Contract Number
TRT12GUTC17; KLK900-SB-0004
Start Date
9/1/12
End Date
12/31/14
Description of Research Project
Maintenance, repair and renewal activities have high environmental impacts due to the raw material extraction and construction procedures. In roadway sections where the existing capacity is approximately equal to the demand, these activities also cause work-zone congestion, which result in environmental degradation due to vehicle emissions and social impacts due to delays. Accelerated construction techniques can be used to reduce the project duration and hence, reduce environmental and social impacts of work-zones. Traditionally, maintenance, repair, and renewal activities are designed by considering the agency costs of various alternatives. The aim of this study is to identify environmental impacts of work-zones, and to examine the benefits of accelerated construction techniques in terms of GHG reduction.
Implementation of Research Outcomes
The environmental impacts of the arterial improvement projects have been presented in this study from a life cycle assessment point of view. Both traditional and innovative MRR activities were considered. The treatment processes for flexible and rigid pavements are considerably different due to the structural nature of the pavements. As flexible pavements are much older than rigid pavements, there are more innovative options available for flexible pavement MRR than that of rigid pavements. Life cycle assessment results are presented in two formats: a) annualized impact per square meter of the pavement, and b) impact over the design life of one center kilometer of a pavement.
LCA results showed that for flexible pavements, innovative rehabilitation techniques like partial or full depth reclamation have less life cycle environmental impacts than traditional techniques like milling and overlay or total reconstruction. One of the major reasons is that in pavement reclamation techniques the existing asphalt layer is recycled to produce a new stable layer which minimizes the need of raw virgin materials unlike traditional techniques. Again among maintenance processes, innovative techniques like microsurfacing have lesser resource usage, global warming potential, and energy consumption than traditional processes like chip seal. Minor treatment processes like fog seal, crack seal, and asphalt rout and seal have minimum impacts with maximum benefits when the corresponding life extensions are compared. Thus, it was observed that products with lower asphalt content and a lesser heat requirement use less energy and have minimum GHG emissions.
For rigid pavements, all the rehabilitation techniques are comparatively new. The GHG emissions and energy consumption due to material used, construction equipment, and transportation were found to be similar for both traditional techniques like full depth repair and accelerated techniques like precast concrete pavement systems. Similar to flexible pavements, minor treatment processes like concrete seal joints, diamond grinding, and partial depth repair have much less lifecycle environmental impacts with substantial benefits in terms of life expectancy. Thus, it can be concluded that the DOTs should make maximum utilization of all the treatment processes, and preferably the innovative strategies using recycling techniques, to achieve a sustainable arterial maintenance, repair, and rehabilitation plan.
Impacts and Benefits of the Project
- Sustainable construction practices employment
- GHG emissions reduction
- Construction time minimization
- Delay reduction
- Hydrocarbon Emission Reductions
- Fuel Usage Reductions
Papers
- Salem, O., and Ghorai, S. (2015). "Environmental Life-Cycle Assessment of Pavement Maintenance, Repair and Rehabilitation Activities." TRB 94th Annual Meeting, Washington, D.C., January 11-15, 2015.
Web Links
Final Report: SU_TranLIVE_Final Report_Assessing the Environmental Impacts of Work Zones in Arterial Improvement Projects
Keywords
- construction and maintenance
- rehabilitation (maintenance)
- social impacts
- environmental impacts
- work zones