aircraft arresting beds constructed of cellular concrete at ends of runways may be subject to damaging effects of jet blast phenomena . arresting units resistant to such effects are described . a block of compressible material , such as cellular concrete , provides compressive failure characteristics suitable for arresting travel of an aircraft overrunning a runway . relatively thin frangible material positioned above the block provides a stronger , more damage resistant surface , while still readily fracturing in an arresting incident . intermediate material , such as a foam layer , positioned under the frangible material may be included to provide a protective cushioning effect by mitigating transmission of external phenomena forces to the block . a fastening configuration at least partially enclosing other portions of the arresting unit provides a stable unified composite , without destroying desired compressive failure characteristics of the unit . arresting units may also include a bottom layer of material stronger than the block of compressible material and a sealant coating with water resistant properties .