Comparative Study of Water-Blasting Equipment for Airfield Surface Decontamination

Runway rubber removal is a maintenance function employed to ensure safe landing areas for aviation operations. Rubber deposits accumulate on runway areas where aircraft tires touchdown and braking occurs. This tire-rubber build-up occludes pavement microtexture and macrotexture, causing a significant loss in available skid resistance during wet conditions. Reduction of available pavement microtexture in a wet environment prevents the development of adhesional friction, which can result in viscous hydroplaning. Reduction of pavement macrotexture prevents the removal of bulk water from the tire-pavement contact area and also prevents the development of the hysteresis frictional component. To restore friction to safe levels for aircraft operations, rubber must be periodically removed. Several techniques for rubber removal are available. Water-blasting is a proven surface decontamination technique which employs the use of high-pressure or ultra-high-pressure water (UHPW) to blast rubber deposits from the runway surface. This effort provides a performance-based comparison between three commercially available UHPW water-blasting systems. The evaluation was conducted on an ungrooved portland cement concrete (PCC) runway with heavy rubber contamination along the touchdown and breaking zones. Several types of testing equipment such as a circular track meter (CTM) and dynamic friction tester (DFT) were used to characterize the surface properties of the runway before and after rubber removal. The measurements were used for statistical pairwise comparative analysis of International Friction Index (IFI), speed constant and mean profile depth (MPD). Treatment effect analysis of premeasured and postmeasured data revealed that UHPW systems improved the surface texture properties by at least 40% regardless of the decontamination equipment.