- bsmart
That is PSP - Pierced Steel Planking (or sometimes PAP Pierced Aluminum Planking) Developed during WWII to allow quick Airfield building and repair. I've seen old movie footage showing sections as wide as a runway and hundreds of feet long being dragged into place by bulldozers.Doug or one of the other Vietnam Vets can probably provide stories and or pictures of it being used for improvised construction or vehicle mods.
It was also called Marston Matting. google marston mat for multiple articles on it
In VN it was also frequently referred to as "Perforated Steel Platform". Ubiquitous in VN, but not so much on helicopter bases as you might think in their original intended use ("peneprime" and that hokey thin asphalt who's name I forget was usually used for the pads). Often used as the basis for reinforced walls, revetments augmented with sandbags, and just about any other improvised construction project you can imagine.
Never saw on any actual armored vehcles, but on improvised ones, sometimes (guntrucks, etc).
In '05, I saw many examples in VN as rotting fences around some peoples homes, but the years and rust had taken their toll.