Thanks for posting and very interesting.
Sounds too good to be true and if it is true then the oil companies who sell bitumen/tar and the cement companies will ensure it never is seen again.....nah, they wouldn't do that?

Out at the Jondaryan Woolshed is a roadmaking machine which was used on black soil roads - it dug the road up as it went along and burnt the black soil which hardened and was then rolled solid by the same machine. They used it for some time in the 30's on roads in black soil country. It's a very large machine and used wood to burn the soil. Trouble was that a few wet seasons killed the roads I think and bitumen did not have that problem so it became universal.

Here in the Top End all roads are made in a similar fashion.

Rip up the dirt, water it, compact it, roll it, grade it flat, apply bitumen.

NO gravel base whatsoever.

During the war the Stuart Hwy from Alice to Darwin (1500 Km) was bitumen sealed in 3 months.

Unfortunately, they had to redo it after the next Wet.