Izak Said strives to strengthen airfields' performance and environmental impacts

With a yearly market that surpasses 3.5 billion passengers and 51.5 million tons of products valued at almost $6 trillion worldwide, air transport is one of the leading and most relevant industries worldwide.

The U.S. has the most extensive air transportation market in the world, amounting 800 million passengers and 40 million takeoffs and landings each year. As of 2017, the U.S. had more than 19,367 airports with 5,104 being public airports.

Airport agencies spend $4 billion annually to repair, maintain, and rehabilitate airfields nationwide. In such a large, complex industry, careful design, construction, operation, and maintenance of U.S. airfields are vital for the mobility and safety of people and goods.

That’s a problem University of Illinois Urbana-Champaign Department of Civil and Environmental Engineering doctoral candidate Izak Said wanted to help solve.

In fact, Said, who is advised by Illinois Center for Transportation Director Imad Al-Qadi, was awarded the 2017-18 Grant Research Award sponsored by the Federal Aviation Administration and administered by the Airport Cooperation Research Program.

The objective of the award is to promote applied research on airport and related aviation system issues to help the public sector continue its improvements in quality, reliability, safety, and security of the civil aviation system. The FAA places a significant amount of effort to improve airfield pavement sustainability. Said’s framework plan takes these efforts a step further by creating a direct link between design and environmental impacts (Figure 1).

The main goal of a durable and sustainable airfield is to withstand repeated aircraft traffic loading as well as optimize movement while minimizing environmental impact.

In this study, Said developed a framework for a holistic airport pavement evaluation based on both structural and environmental performance. To achieve this goal, he presented three steps, including: (1) design adequacy assessment of the pavement section, (2) performance verification, and (3) Life Cycle Assessment.

The first step includes assessing the structural adequacy of a proposed airfield configuration using the FAA Rigid and Flexible Iterative Elastic Layered Design (FAARFIELD) software. This tool checks the section’s ability to withstand repeated traffic loading over the pavement’s total design life.

In the second step, Said used accelerated airfield testing and instrumentation data to validate the performance predicted by FAARFIELD software. The data were collected from airfield sections built and tested at the National Airport Pavement Test Facility as part of the Construction Cycle seven, funded by the FAA (Figure 2).

The third step comprises the computation of greenhouse gases and energy demand associated with the airfield section construction. The LCA is performed based on materials used, airfield structure, construction techniques, and equipment. Finally, an optimization of airfield sections can be performed based on structural adequacy and environmental impacts.

Said’s study shows the environmental impact of airfield pavement is highly affected by pavement characteristics and design, including asphalt concrete thickness and materials, which are interdependent. Optimal performance and least environmental impact are achieved after several design alternatives are considered for each project.

To facilitate the implementation of the findings of this study, Said introduced Airfield Sustainable Design Tool. The tool checks the structural adequacy of an airfield section and computes, deterministically and probabilistically, the global warming potential and energy demand associated with the material acquisition and construction of a studied airfield section (Figure 3).

Said acknowledges the guidance and support provided by Larry Goldstein, senior program officer of the ACRP GRA program; Dominique Pittenger, University of Oklahoma professor; Marry Sandy, ACRP project manager; and Sarah Pauls, ACRP program assistant.

Navneet Garg, program manager of the FAA’s national airport pavement and materials research, was instrumental in sharing data and providing advice throughout the work.

Said presented his work at the 2019 Transportation Research Board Annual Meeting in Washington, D.C. and published it in the Transportation Research Record.