Sustainable Base Course

At existing airports, re-aligning and replacing taxiways is a common practice due to reconfigurations of the operational area or just normal wear and tear. For example, with the arrival of the new "Super-Jumbo Jet" aircrafts, such as the Airbus A380, our nation's taxiways will need widening and increased load capacity to accommodate the large aircrafts. It is common practice when removing and re-aligning taxiways to dispose of the material and replace it with new material, either asphalt or other base courses. The Port Authority wanted to try and reuse some of this material to develop sustainable design, and reduce material costs. Preliminary research in the Port Authority of NY & NJ Materials Laboratory investigated the possibilities of reusing existing asphalt pavement (RAP), lime-cement-fly ash base course (LCF) and blending it with Portland cement to create a sustainable base course. This research was successful and lead to the option of using either a new asphalt base or a blend of existing pavement and Portland cement in a contract to upgrade the taxiways at John F. Kennedy International Airport. The low bidder chose to use recycled pavement materials and blend it with cement on-site. This sustainable option not only proved to be economical but efficient as well. The on-site blending of Portland cement with the removed pavement material saved in travel time and reduced truck traffic on the surrounding infrastructure. This paper will discuss in detail the following topics related to sustainable base courses: 1. Preliminary laboratory results, 2. Sustainable base course mix design, 3. Batching and placement methods, 4. QC/QA procedures, 5. Test results.