James Vogt – i was involved in an FHWA project (LTPP – Long Term Pavement Performance) for 10 years, they maintain a public website that is very useful in regards to pavement evaluation research. I am providing a link to the Distress Identification Manual, it can be downloaded for free and provides complete descriptions and proper procedures for distress.data collection.
Moisture infiltration, Freeze-Thaw cycles and loading are the greatest contributors to concrete cracking.
ian – Isn’t the asphalt applied over the concrete once the concrete starts to wear? In order to support the weight of a wide body aircraft I would think that only steel re-enforced concrete would be suitable for a base, and a fairly thick slab of it at that. I can’t envision asphalt having the density to hold up under repeated landings of heavy aircraft without something much tougher underneath it.
Vogt – Keeping the moisture out (proper drainage) and the pavement sealed properly, no matter what the environment, is the main issue that will extend the life cycle of the concrete. Voids develop and cause issues after loading from vehicles/aircraft.
I think durability is the ability of concrete material to remain “in service” and protect the substrate over an extended period of time. The material must have low absorbtion, low permeability and good abrasion resistance.
It’s the low absorbtion rate that prevents damage to pavement (especially pavement repairs) and it’s deteriorization because of freeze/thaw cycling or chemical based attacks. I work where it snows.