What are the specs for runways at international airports?
Runways for international airports are usually man made, which means that they are made up of asphalt or concrete and sometimes are a mixture of both. The depth for the runways are 29cm to 33cm.
Runways are usually around 150ft wide. For an international airport will have a runway around 6,000ft long, but depending on the size of the aircraft that land there a runway will need to be 8,000ft or more.
I found this link which should give you information on runway maintenance.