AnalogPackrat
Well-known member
Not sure what you mean by "block" but before continuous pour technology was viable concrete roads were poured in segmented slabs 10-12' wide and 15-20' long. These can be removed and repoured. Continuous pour can be cut and replaced if there are local failures due to voids or substandard mix issues. Concrete is a very energy intensive material to make, but done right it can last for a very long time.That's funny. I was in the US last month and a friend pointed out to me more than once how (he thought) in the US concrete blocks are used for roads, so that you can simply replace a broken element.
Asphalt has poor wear characteristics under heavy (freight truck) loads, gets very soft when the weather is hot (a large part of the US experiences daytime summer temps over 90F for a few months) which allows ruts to develop, and as it ages becomes brittle which allows cracks to develop. Water intrusion through cracks into the roadbed leads to further failure (alligatoring, depressions, potholes). Asphalt is easier to patch, but longevity isn't great. It's also made from fossil fuel sources.
There are actually roads made of concrete blocks as wells as made from asphalt in both countries. The earliest Autobahnen (the ones the Nazis build) were in fact concrete blocks, but nowadays it's mostly asphalt.