ASTM E2666-09(2019)

5.1 Introduction—Mu numbers (friction values) measured by CFME can be used as guidelines for evaluating the surface friction deterioration of runway pavements and for identifying appropriate corrective actions required for safe aircraft operations. The original levels were based on the work of the FAA/AS-90-1 5.2 Airports—Routine testing is carried out in order to obtain data for scheduling remedial work on the runway surface. A single run on either side of the centerline may be regarded as sufficient or a set of runs covering the whole width of the runway may be preferred. At 3 m spacing, the friction map which can be prepared from a set of runs of this kind provides excellent information on rubber buildup and surface polishing. Standard test speeds are typically 65 km/hr or 95 km/hr and standard test water film thickness is typically 1 mm.

1.1 This practice covers the method of calculating frictional values from correlations of continuous friction measurement equipment (CFME), using the Specification E1551 tire, for use in performing airport summer maintenance evaluations.

1.2 The practice is intended to provide a unified friction index of levels for use in harmonizing the output of devices.

1.3 Airport operators use a variety of CFMEs to assess the friction levels of their paved runway surfaces. The measurements are used to determine when the surfaces should be considered for or subjected to maintenance. However, many are built differently and produce different values when measuring the same pavement surfaces. This practice provides a method to harmonize these measurements so that the friction values generated can be used to determine the maintenance requirements as established by the operating authority.

1.4 The practice provides correlations for four maintenance levels of friction: New Design/Construction with grooves, New Design/Construction without grooves, Maintenance Planning, and Minimum Acceptable.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 ASTM International takes no position with respect to the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.