Abstract:
THE RUNWAYS OF THE WASHINGTON NATIONAL AIRPORT, SURFACED WITH 3 1/2 IN OF BITUMINOUS CONCRETE ON A STABILIZED GRAVEL BASE 9 IN THICK, ARE LOCATED ALMOST ENTIRELY IN WHAT WAS ORIGINALLY SHOAL WATER AND MUD FLATS ALONG THE VIRGINIA SHORE OF THE POTOMAC RIVER. THIS LOW AREA WAS FILLED TO AN ELEVATION OF 12 TO 16 FT ABOVE THE NORMAL WATER LEVEL WITH MATERIAL CONSISTING OF SAND, GRAVEL COBBLES, SILT AND MUCK PUMPED BY MEANS OF HYDRAULIC DREDGES FROM BORROW PITS LOCATED IN THE RIVER ON THE OUTSKIRTS OF THE FIELD. BY PLACING THE PIPELINES OF THE HYDRAULIC DREDGES LONGITUDINALLY ALONG THE RUNWAYS, THE GRANULAR MATERIAL WAS COLLECTED IN THE RUNWAY AREAS AND THE SILT AND MUCK FLOATED OFF TO BE DEPOSITED BY PONDING THE INTERMEDIATE AREAS BETWEEN AND OUTSIDE OF THE RUNWAYS. THE GRAVEL IN THE RUNWAYS WAS COMBINED WITH SOIL FROM THE ADJACENT UPLAND AREAS TO PRODUCE A DENSE, WELL GRADED, STABLE BASE COURSE FOR THE BITUMINOUS CONCRETE SURFACING. THE WORK OF STABILIZATION CONSISTED OF SCARIFYING THE GRADED GRAVEL RUNWAYS, REMOVING OVERSIZE STONE, ADDING THE PROPER AMOUNT OF SOIL, MIXING THE GRAVEL AND SOIL BY MEANS OF CULTIVATORS, DISK HARROWS, AND PLOWS, COMPACTING WITH ROLLERS, AND SHAPING WITH MOTOR GRADERS AND DRAGS. CONTROL OVER THE BASE STABILIZATION IN ACCORDANCE WITH ESTABLISHED REQUIREMENTS AS TO GRADATIONS, PHYSICAL PROPERTIES AND DENSITIES WAS ACCOMPLISHED BY COORDINATING THE CONSTRUCTION OPERATIONS WITH THE TESTS PERFORMED ON THE RAW MATERIALS AND THE MIXTURES. /AUTHOR/
Supplemental Notes:
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