Construction of three cross taxiways adjacent to Runway 18R/36L required nighttime closures to minimize disruptions at this busy hub airport. The contract was let using 21 inch thick, conventional Portland cement concrete pavement. Concrete pavers were subsequently used owing to their ease of construction and ability to reduce the number and duration of these closures during the project. The Air Transport Association calculated the cost of the closure reduction as a saving of approximately $4.25 million. An additional advantage was that the runway could be opened far quicker in emergency situations than with the concrete option. NNP undertook the design, detailing and specification of the project with Pavement Consultants Inc. undertaking a peer review as prime consultant. A technical paper presented at the ASCE “Aircraft/Pavement Interaction” Conference in 1991 is included in the Appendices for further details on this project.
Subsequent to this paper the FAA have reinstated the Airport Improvement Program funds that they withheld pending successful performance. In 1995 NNP participated in a pavement evaluation of the taxiways and compared the results with data taken prior to opening. Falling Weight Deflectometer testing indicated that the pavement was performing within expectations, and is expected to achieve it’s design life. The airport has investigated the use of pavers for other new projects but found the system to be more expensive when there is not a problem with closures.
Some minor repair work has been necessary. During construction the lime injection process was omitted from the shoulder areas and, owing to the expansive nature of the clay soils, deferential movement has occurred at the edge of the pavers resulting in bedding sand loss. Opening of construction joints in the cement treated base course also resulted in some sand loss from under the pavers. These items have been repaired and have not recurred, although some valuable lessons have been learned for future applications.