Airfield rubber removal, also known as runway rubber removal, is the use of high pressure water,

abrasives An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflec ...

chemicals A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wit ...

and other mechanical means to remove the

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

from tires that builds up on airport

runway According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt, concrete ...

s. In the United States, the

Federal Aviation Administration The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic ...

(FAA) specifies

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of ...

levels for safe operation of planes and measures friction coefficients for the evaluation of appropriate friction levels. Individual airports incorporate rubber removal into their

maintenance Maintenance may refer to: Biological science * Maintenance of an organism * Maintenance respiration Non-technical maintenance * Alimony, also called ''maintenance'' in British English * Champerty and maintenance, two related legal doct ...

schedules based on the number of take offs and landings that each airport experiences.

Source of airfield rubber build-up

When a plane lands, the tires are not spinning. The time it takes for the tires to get up to speed is referred to as "spin up time" (Speidel, 2002). During this time the tires are effectively dragging on the runway as well as being put under

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country a ...

by the

weight In science and engineering, the weight of an object is the force acting on the object due to gravity. Some standard textbooks define weight as a vector quantity, the gravitational force acting on the object. Others define weight as a scalar qua ...

of the airplane. This can be seen in the slight puff of smoke that comes from a landing aircraft's tires as they first touch the runway surface. The friction built up causes the rubber to

polymerize In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many for ...

and harden to the runway surface.

Effects of rubber buildup

The buildup of rubber affects the level of friction of the runway, most noticeably as a reduction in braking and ground handling performance. This can lead to incidents such as runway overrun or a lateral slide off the runway.

The contributing factors for viscous hydroplaning are a damp or wet pavement, medium to high speed, poor pavement texture, and worn tire tread. If a runway has good microtexture and grooving and the aircraft tires have a good tread design, viscous hydroplaning could be alleviated.(NTSB, p.92)

Macrotexture is visible to the naked eye. Without the aid of a microscope, microtexture can only be felt. The buildup of rubber directly affects these variables and therefore reduces the friction available for landing which increase the possibility of

hydroplaning Aquaplaning or hydroplaning by the tires of a road vehicle, aircraft or other wheeled vehicle occurs when a layer of water builds between the wheels of the vehicle and the road surface, leading to a loss of traction (engineering), traction that ...

of the landing airplane.

Methods

High pressure water and ultra high pressure water

Sometimes referred to as hydrocleaning, high pressure and ultra high pressure work on the same principle of applying a spinning jet or set of jets to the surface to break the hardened rubber free from the runway surface. The main difference between the two is the pressure and flow. High pressure removal uses water at at up to while ultra high pressure removal uses up to with a water usage between (Speidel, 2002, p. 4). High pressure and ultra high pressure water operations rely on the impact of water alone, with no other chemicals used. High pressure and ultra high pressure water operations are known for destroying the integrity of the airfield and break down the surface of the runway after multiple uses.

Chemical removal

Cleaning the runway using chemicals involves the application of proprietary cleaners that are brushed into the surface of the runway and then washed off using low pressure water. There is a time between applying the chemicals and washing the runway when the chemicals are allowed to react with and break down the rubber. During this time the runway is unusable for landing operations and therefore could not be used safely in an emergency situation. The chemicals used can be expensive and require special handling. There are currently a newer generation of non-caustic rubber removal chemicals that are also environmentally superior, non-corrosive, non-toxic and relatively inexpensive to use. Some runway maintenance crews like the ability to do their rubber removal in-house using existing or lower cost machinery with a more regular, preventive maintenance program. Chemicals for rubber removal have proven to have no long-term effect on either asphalt or concrete runways. Using equipment to recover waste water/chemical/rubber allows control and safety of disposal with no runoff.

High velocity impact removal

This method employs the principle of throwing abrasive particles at a very high velocity at the runway pavement surface, thus blasting the contaminants from the surface (Speidel, 2002). Also known as

sandblasting Sandblasting, sometimes known as abrasive blasting, is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface or remove s ...

, this method can introduce foreign object debris to the runway if not contained and cleaned up properly.

Mechanical removal

This type of removal involves the milling of the first off the runway surface.

References

US. Department of Transportation.(1997). Measurement, Construction, and Maintenance of Skid-Resistand Airport Surfaces. Federal Aviation Administration Advisory Circular.Speidel, Donna J., (2002, February). Airfield Rubber Removal Paper presented at the 2002 Federal Aviation Administration Technology Transfer Conference.National Transportation Safety Board. 2001. Runway Overrun During Landing, American Airlines Flight 1420, McDonnell Douglas MD-82, N215AA, Little Rock, Arkansas, June 1, 1999. Aircraft Accident Report NTSB-AAR-01-02. Washington, DC.
{{DEFAULTSORT:Airfield Rubber Removal Airport infrastructure