Effect of Rubber Deposits on Runway Pavement Friction Characteristics

This purpose of this paper is to evaluate the effect of rubber deposits on pavement friction characteristics on the basis of macroscopic and microscopic measurements. Runway pavement sections at the Kaohsiung (Taiwan) International Airport were chosen for field and laboratory testing over a 16-month period. In the first step of the field testing, the monthly variation in friction was established by using the Saab surface friction tester (SFT) and British pendulum testing. In the second step, macro-texture measurements were made by the grease patch method. The last step of field testing was to take samples of rubber deposits for laboratory analyses by optical microscope and scanning electron microscopy. Results showed that rubber deposits had strong effects on runway surface friction. An aircraft landing appeared to result in an increase in the thickness of rubber deposits by approximately 0.05 mu m. The microstructure of rubber deposits was shown to be accumulated by the directional distribution of multiple layers of polymer scale. The friction value measured in the backward direction was higher than that measured in the forward direction. The rate of decrease in the SET friction value was found to be about 0.05 for an increase in rubber thickness of 0.1 mm.