4-9.4 Brittle Mode of Behavior.
The brittle behavior of reinforced concrete is composed of three types of concrete failure: direct spalling, scabbing and post-failure fragments. Direct spilling consists ofthe dynamic disengagement of the concrete cover over the flexural reinforcement due tohigh intensity blast pressures. Scabbing also consists of the disengagement of theconcrete cover over the flexural reinforcement, however, scabbing is due to theelement attaining large deflections. Finally post-failure fragments are the result of thecollapse of an element and are usually the more serious. Post-failure fragments aregenerally large in number and/or size with substantial velocities which can result inpropagation of explosion. Spalling and scabbing are usually only of concern in thoseprotective structures where personnel, equipment, or sensitive explosives requireprotection. Controlled post-failure fragments are only permitted where the acceptorsystem consists of relatively insensitive explosives.