Ive' got no image of it. I'd say that this: https://upload.wikimedia.org/wikipedia/commons/9/9b/%EC%82%BC%EC%9D%BC%EA%B3%B5%EC%9B%90_1.jpg isn't all that far off.

It's definitively not asphalt. Looks more like natural rock cut flat. I'd probably set 'stone' as surface, but I'm open to other ideas.