Here in Denver, at least, our runways are all made of cement instead of tarmac. I knew one of the civil engineers who worked on the special blend of cement the used, and from what I remember of what he told me, it is much thicker than I expected, and has other stuff in it compared even to highway-grade cement to make it more durable. The freeze-thaw cycle is still rough on the cement, in 2007 $11 million of cement slabs had to be replaced due to that. The airport as a whole has 15,000 20-square-foot slabs across its multiple runways.
Of course, one could still have buckling with cement if the expansion joints are too close together for the expansion of adjoining slabs over a certain temperature. Perhaps this is what actually happened here?