ConcordeBoy
Topic Author
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What Determines Material Used In Runway Making?

Fri Dec 19, 2003 10:43 am

What factors (aside from price) determine the most appropriate material; be it asphault, concrete, etc; for runway construction?
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BA
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RE: What Determines Material Used In Runway Making?

Fri Dec 19, 2003 11:19 am

If the ground is going to be prone to a lot of movement, asphault is prefered.

If the ground is relatively stable and the finances are available, concrete is prefered.

Regards
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PVD757
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RE: What Determines Material Used In Runway Making?

Fri Dec 19, 2003 12:31 pm

The FAA determines the actual materials allowed to be used to "make" the runway. When choosing between asphalt or concrete, it really comes down to price. Advisory Circulars (Airport Design) describe the materials to be used. Not only is the pavement important, but what is under it also. The FAA allows only certain types of base materials and mandates said materials be 100% compacted. www.faa.gov has free copies of the advisory circular.
 
grrtvc
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RE: What Determines Material Used In Runway Making?

Fri Dec 19, 2003 12:50 pm

The type of materials used to construct a runway depends on several factors. Like PVD757 mentioned the FAA has developed Advisory Circulars to assist civil engineers in design. But the major influence for what type of material to use, i.e. concrete or asphalt, is determined by the type of soil that the runway will be constructed on and the type of loads that will be placed upon it, i.e. aircraft loading.

Concrete will last for decades if maintained properly. But when maintenance/repair work needs to be done it can take several days for removal, replacement, and cure of the concrete before it is ready for service. Asphalt does not have the same lifespan, as it cannot withstand the repeated heavy impacts. The plus side is that in a few short hours it can be removed and replaced and ready for service a lot sooner than concrete.

Here in the US the majority of runways in the colder climates are concrete and in the warmer southern climates, runways have a tendency to be asphalt (notice I stated majority).

But all this engineering can be thrown out the window when economics come into play.
 
L-188
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RE: What Determines Material Used In Runway Making?

Fri Dec 19, 2003 4:17 pm

Here in the US the majority of runways in the colder climates are concrete and in the warmer southern climates, runways have a tendency to be asphalt (notice I stated majority).


I know you said majority, but I do want to pipe in that concrete is not desirable for use in a climate where frost heaving is going to be a major concern. The indiviual concrete plates have no give to them at all.

So what happens is that those concrete castings, plates, sections or whatever they are called that make up a runway are going to float on the substrait and will created sharp drops between the edges as one plate floats higher then another over the seasons.

Ashphat runways have more give, so you will end up in bumps over time, but at least you don't have those jarring edges.

And asphalt can be ground down and relayed, so it is easier to install, something that can't be said for concrete.
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APAOps5
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RE: What Determines Material Used In Runway Making?

Fri Dec 19, 2003 5:06 pm

There are other external issues as well that are considered. For one, type of a/c using it. At KAPA we have a 10,000 ft. long RY, made of asphalt. WE want asphalt because SN melts faster, much quicker to repair, and more considerably we are limited to land larger a/c. 10,000ft is alot of RY, anything can take off or land in that length, but we have a 75,000lb weight restriction. Which limits us to about a G-V and an occasional Global. If we had thicker asphalt or concrete larger a/c would try to land here which for political reasons is not favorable. Teetoboro is under this problem concerning BBJ traffic. But the main issue is long-term vs. short term costs, including associated maint. costs.