This specification covers quality-controlled graded aggregates that, when hauled to and properly spread and compacted on a prepared grade to appropriate density standards, may be expected to provide adequate stability and load support for use as highway or airport bases or subbases. Coarse aggregate retained on the sieve shall consist of durable particles of crushed stone, gravel, or slag capable of withstanding the effects of handling, spreading, and compacting without degradation productive of deleterious fines. Fine aggregate passing through the sieve shall normally consist of fines from the operation of crushing the coarse aggregate. Where available and suitable, addition of natural sand or finer mineral matter, or both, is not prohibited. The following tests shall be performed: grain-size test (dry and wet sieving), liquid limit test, plastic limit test, plasticity index test, sand equivalent value test, and expansion test.1.1 This specification covers quality-controlled graded aggregates that, when hauled to and properly spread and compacted on a prepared grade to appropriate density standards, may be expected to provide adequate stability and load support for use as highway or airport bases or subbases.NOTE 1: The engineer is cautioned to provide appropriate construction specifications to ensure compaction to an extent that further densification from traffic loadings on the completed pavement will be insignificant. The method suggested is to require compaction on a firm foundation of a short control strip of the material at a suitable moisture content, by means of vibratory or other proven effective rollers or tampers, until no further increase in density results. Compaction requirements should ensure that an average density of certain appropriate percentages of the control strip maximum density be achieved on the balance of the job; for base courses, 98 % is suggested as the minimum average requirement.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.1.3 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.1.4 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.1.5 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.

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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 (3). The report states that based on friction values from a Mu Meter Mark II using Dunlop tires, and tests conducted by NASA in the 1970s using a Boeing 727, Table 1 of Mu Meter friction level classifications for runway pavement surfaces was established for friction measurements at test speeds of 65 km/hr. Additionally, tests were conducted again with the Mu Meter Mark II outfitted with the Dico tire at 95 km/h. Then a second-order correlation was performed for the Mu Meter operating at 95 km/h and at 65 km/h resulting in the values shown in Table 2. These values were then fixed and used with correlations of other CFMEs to establish the present maintenance levels given in Table 3.2 of FAA Advisory Circular AC/150/5320-12. From the Wallops 1993 data, the IFI values were calculated and the 65 km/hr data in Table 2 was used to calculate the FM60 value for each level. The data for the two speeds for the four CFMEs in the FAA report (3) were used to establish the SMp values for each level. Then a new level, New Grooved, was added based on the differences of grooved and un-grooved sites at the NASA Wallops test facility. Table 3 is a list of these values to be the standard values FM60 and SMp for any future calibration of CFME. 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.

定价： 515元 / 折扣价： 438 元 加购物车