Airfield Pavement

an artificially covered surface for runways, taxiways, aircraft parking areas, ramps, and hangar aprons of airfields used to ensure uninterrupted year-round operation.

Two basic forms of airfield pavement are used, depending on the operating conditions: the rigid type, which is made of materials that are sufficiently resilient to distribute aircraft loads over a large area by their flexing action, and the nonrigid type, which has very low flexing resistance and functions chiefly in compression to transmit aircraft loads to a comparatively small area.

The types of airfield pavements and their construction depend on the classes of airfields and their designated categories of loading. An airfield surface must provide for the safe movement of aircraft at the required speeds and for the natural drainage of surface water. The maximum permissible longitudinal and transverse gradients and the radii of the vertical adjustment curves on different portions of an airfield pavement are determined by special engineering requirements.

Airfield pavements of the rigid type can be either monolithic and made of prestressed ferroconcrete, unstressed reinforced concrete, or cement concrete, or sectional—that is, built from manufactured prestressed reinforced-concrete slabs. The principal type of monolithic prestressed airfield pavement is long-line prestressed concrete reinforced longitudinally with high-strength wire. It is reinforced transversely with iron rods that tense the set concrete. Monolithic reinforced-concrete airfield pavements are made in slabs 20 to 25 meters long and in widths equal to the width of the concrete-laying machine. The sectional airfield pavements made of prestressed ferroconcrete slabs are used chiefly when pavements must be built and put into service in a limited time or under winter conditions, as well as for taxiways, parking areas, and other areas where it is difficult to employ concrete-laying machines efficiently.

The dimensions of the slabs used in sectional airfield pavements are the largest possible based on the technological capabilities for their manufacture, the carrying capacity of the transportation facilities and the cranes used to assemble the pavements, but are never less than 2x4 meters for rectangular slabs and 3 x 3 for the square ones. The stability of the slabs in a pavement is ensured by utilizing special welded butt joints.

The nonrigid type of airfield pavement includes asphalt, blacktop of crushed rock and gravel (made by impregnation or mixing on the site), and earth reinforced with binders.