Explosive Testing of Polymer Retrofit Masonry Walls

TLDR

Improvised explosive devices are the most common terrorist tactic, causing most casualties through wall fragmentation and shattering rather than blast pressure, prompting the Air Force Research Laboratory to investigate wall retrofits since 1995. This paper reports on recent tests of a sprayed‑on polymer designed to increase the blast resistance of unreinforced concrete masonry walls. The study evaluated the polymer retrofit by testing material properties, effectiveness mechanisms, and research challenges on unreinforced concrete masonry walls. The results show that the sprayed polymer markedly improves the blast resistance of these walls.

Abstract

The most widely used terrorist tactic is the improvised explosive device, which can range in size from hand-held to truck-size. Most casualties and injuries sustained in such an attack are not caused by the blast itself, but rather by the disintegration and fragmentation of walls, the shattering of windows, and by nonsecured objects propelled at high velocities by the blast. Since 1995, the Air Force Research Laboratory at Tyndall Air Force Base has investigated methods of retrofitting wall structures to better resist blast loads from external explosions. This paper summarizes results from recent tests that involve an innovative use of a sprayed-on polymer to increase blast resistance of unreinforced concrete masonry walls. Test methodology, retrofit materials considered, material properties, mechanisms of effectiveness, and research challenges are discussed.