An Airfield Pavement Forensic Analysis: Cairo East Air Base

Ahlrich, Randolph Charles; Anderton, Gary Lee; ,

An Airfield Pavement Forensic Analysis: Cairo East Air Base

by Randolph Charles Ahlrich, US Army Engineer Waterways, Experiment Station, Vicksburg, United States,
Gary Lee Anderton, US Army Engineer Waterways, Experiment Station, Vicksburg, United States,

Document Type: Proceeding Paper

Part of: Materials: Performance and Prevention of Deficiencies and Failures

Abstract:

The US Army Engineer Waterways Experiment Station (WES) was requested by the Middle East/Africa Projects Office in April 1989 to provide technical assistance in analyzing an unstable asphalt concrete airfield pavement in Cairo, Egypt. An asphalt concrete overlay had been constructed on an aircraft parking apron and taxiway. The asphalt concrete overlay had exhibited significant deformation and depressions under parked aircraft traffic. The performance of the unstable asphalt concrete pavement was unacceptable. WES was requested to perform laboratory tests on asphalt concrete specimens to determine asphalt cement, aggregate, and asphalt concrete mixture properties. This analysis was to evaluate the in-place asphalt concrete material for compliance with specifications, determine possible causes for pavement failure, suggest procedures to avoid these problems in the future, and recommend options for the repair of this airfield pavement. The laboratory evaluation of the asphalt concrete material indicated that the poor performance was due to an improperly designed and produced asphalt concrete mixture. Several factors contributed to the unstable mixture: (1) the aggregate gradations were consistently out of specification and were gap graded, (2) the amount of natural sand in both the surface course and intermediate course was extremely high, and (3) the mix designs for the surface course and intermediate course mixtures did not meet the minimum requirements of the specification.

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