Rubber Reduction

[Cougar]

I believe that aerodrome operators must remove rubber from runways every number of months (12 is it)?? Can anyone shed light on this and how it is done?
Cheers

[avioniker]

There are a number of ways and companies to do the removal.
I have seen it done with abrasives and high power water jets.
The water seems to do the least damage to the concrete strips.
On one airfield I worked with asphalt we had to repave and regroove after abrasives were used.

[747FOCAL]

When I remove rubber it usually goes down the toilet......... :E

[OverRun]

Rubber removal is required when the rubber deposits from wheel spin-up upon landing have filled the micro-cavities or grooves in the surfacing and the texture drops below the critical level (typically 0.4 mm).

The time between removal depends on traffic type and frequency. The FAA suggestions are to evaluate each runway end separately, and remove rubber as follows:

< 15 jets daily landing per runway end = 2 years
16-30 jets daily landing per runway end = 1 year
31-90 jets daily landing per runway end = 6 months
91-150 jets daily landing per runway end = 4 months
151-210 jets daily landing per runway end = 3 months
> 210 jets daily landing per runway end = 2 months

and if more than 20% are widebodies, then select the next higher level of aircraft operations.

High pressure water, chemicals, abrasion and grinding are the methods. As avioniker indicated, abrasion can lead to problems. Over time, even high pressure water hydroblasting deteriorates the surface of runway pavement. The high pressure water is 2000-2500 bar (up to 36,000 psi), covering 1500 to 2000 sq.m. per five hour shift. And don't forget to vacuum up the remains. High pressure water seems the most popular, and widely available. I've tried the airport fire trucks a couple of times, but apart from getting wet and everyone standing around having fun, not much rubber got cleaned off. The chemicals are pretty nasty stuff, although various firms claim to have environmentally friendly chemicals. I've always found that the nastier the chemical, the better it cleans, but that doesn't do much for the environment.

There is an American firm - Cyclone – which reportedly uses a zamboni-like contraption with a closed-loop cleaning solution that removes the rubber without scraping up bits of the concrete or further burning it. They then recycle the rubber. Zamboni is an ice-resurfacing machine.

But let's not dismiss 747FOCAL quickly - the same latex used to make condoms is also used to make SBR-modified bitumen/asphalt cement. Those of you landing at JNB over the last few years were landing on asphalt made from such a product. It was sheer hard work at the asphalt plant having to individually hand wash every . . . . . .