My Airport Operations

don't remember how long,want to say 30 plus days. What we have found out is the rock has too much iron, and when we grooved the runway that caused it to rust. You can see it on the highways around here also. So far no one can find a solution, short of an overlay.  

How long did you wait to paint after the asphalt was laid down, I wonder if it is the oil bleeding through...We did a partial rehab of our 18L with P-401 and did not have any problem at all with bleed through...

You can try using a modified paint formulation of TT-P-1952 to resist the rust staining. Otherwise, water blast, repaint (using the above paint spec) and lay new bead is the only viable option. Per Ken Miller, Sightline is a good organization to seek help. I was part of the Sightline team that developed the manual "Airfield Marking Handbook" (available at http://www.iprf.org/products/Final%20Report%2005-1.pdf ). The other option is to reconstruct the pavement with a different mix that reduces the soil impact. Obviously, not going to happen.

Thanks Ken, yes I know Betsy and Sightline well, and they have offered a lot of help that we are going to try. They have lots of knowledge and very good contacts.

Just an update: we tried a cold slury seal and the rust bleed through it. Will try the paint Betsy was talking about.

Thanks everyone for their help.

Glen, try this e-mail.  I believe they have the answer for you. Betsy@sightline.us

I would:

remove paint, dry the surface with gas heater, apply some deep penetration primer, repaint, repaint, repaint, repaint...

Here in RIX we repaint at least twice a year, centre line within tdz gets treated some 3-4 times, depending on how hot the summer is.

Paint markings at PHL don't last that long. Centerline on 27R usually lasts a week in the summer. Other markings are done on a yearly basis  high traffic areas once in the spring and again in the fall. Nearly 500,000 operations wear on the paint.  Runway deicing chemicals don't help the paint either.

This is a common problem seen on airfields.  I have experience with a water based paint which will seal the asphalt and inhibit the rust beedthrough.  If you would like more information on the product, please contact me.  I would be happy to show you before and after photos of the problem being solved.

Thank you for you help, I have forward it to our engineers. This has been a torn in our side since we repaved the runway and our certification inspector is wanting us to find a more permanent solution, other than painting over them.

We have experienced this problem throughout our system.  Our analysis indicates that the aggregate used in the P-401 asphaltic concrete mix included slag, a byproduct from the production of steel.  Resultant effects; rust stains and in some extreme cases 2"-3" eruptions in the surface of the pavement.  We have had success by applying a fog seal to the pavement which precludes water infiltration and the subsequent effects of oxidation.

JJJ