“I forget what they called those preformed runway slabs”
I’m pretty sure they were actually sheets of grated steel.
I found it:
Marston Mat
https://en.wikipedia.org/wiki/Marston_Mat
Marston Mat was extensively used during World War II by Seabees (construction battalions) and other front line construction personnel to build runways and other readily usable surfaces over all kinds of terrain.
On Pacific islands the matting was typically covered with crushed and rolled coral or soil to form a level surface. The perforated and channeled design of the matting created strength and rigidity and facilitated drainage. A runway two hundred feet wide and 5000 feet (1500 m) long could be created within two days by a small team of engineers.
Post 54 has it. Marston Mats.