I am curious on the way on how some road segments of the Cavitex (former coastal road) are constructed.

I noticed that some segments of the road are paved with two layers of asphalt over a sand like material which is not like I commonly see on some roads where asphalt is paved over a cured concrete layer.

I noticed that those segments are located on the old previously concreted/paved road. Because the road levels are heightened.

I am curious what is that material and is it a normal way on applying it? If it is sand, will rain water penetrate asphalt and wash away the sand like material with it.