1、Designation:D474810(Reapproved 2015)Standard Test Method forDetermining the Thickness of Bound Pavement LayersUsing Short-Pulse Radar1This standard is issued under the fixed designation D4748;the number immediately following the designation indicates the year oforiginal adoption or,in the case of re
2、vision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the nondestructive determina-tion of the thickness of bound pavement layers usin
3、g GroundPenetrating Radar(GPR).1.2 This test method may not be suitable for application topavements which exhibit increased conductivity due to theincreased attenuation of the electromagnetic signal.Examplesof scenarios which may cause this are:extremely moist or wet(saturated)pavements if free elec
4、trolytes are present and slagaggregate with high iron content.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theres
5、ponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Specific hazardstatements are given in Section 11.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,an
6、d ContainedFluidsD6087 Test Method for Evaluating Asphalt-Covered Con-crete Bridge Decks Using Ground Penetrating RadarD6429 Guide for Selecting Surface Geophysical MethodsD6432 Guide for Using the Surface Ground PenetratingRadar Method for Subsurface InvestigationE1778 Terminology Relating to Pavem
7、ent Distress3.Terminology3.1 Definitions:3.1.1 Definitions shall be in accordance with the terms andsymbols given in Terminologies D653 and E1778.3.1.2 Additional definitions can be found in section 3.1.3 ofGuide D6432,and in Ref(1).33.1.3 Additional definitions:3.1.3.1 bound pavement layerupper lay
8、ers of a pavementstructure consisting of aggregate materials mixed with cemen-titious binder such as bitumen or Portland cement paste.Examples of bound pavement layers include bituminousconcrete,portland cement concrete,and stabilized bases.Bound pavement layers do not include granular base andsubba
9、se materials.3.1.3.2 unbound pavement layerlower layers of a pave-ment structure consisting of untreated aggregate materials suchas sand,gravel,crushed stone,slag,and other stabilizedmaterials.Unbound pavement layers include base,subbase andcompacted subgrade.4.Apparatus4.1 The apparatus may consist
10、 of a vehicle or a cart that isequipped with the following:4.1.1 One or more GPR antennas mounted on the vehicle,cart,or on a trailer4.1.1.1 The antenna for this application typically has acenter frequency that ranges from 1.0 to 2.6 GHz.Atypical 1.0GHz antenna usually has a resolution sufficient to
11、 determine aminimum layer thickness of 40 mm(1.5 in.)to an accuracy of65.0 mm(60.2 in.).Antennas emitting short pulses containinga center frequency of 2.0 GHz and higher provide resolutionsufficient for determination of a minimum layer thickness lessthan 25 mm(1.0 in.)to an accuracy of 62.5 mm(60.1
12、in.).4.1.1.2 Two basic types of antenna systems are in use:(1)Air-launched antennas that are specifically designed toradiate into the air and are to be used at some distance abovethe pavement surface,typically 20 to 50 cm(8 to 20 inches).(2)Ground-coupled antennas that are specifically designedto op
13、erate in contact with the pavement surface.1This test method is under the jurisdiction of ASTM Committee E17 on Vehicle-Pavement Systems and is the direct responsibility of Subcommittee E17.41 onPavement Testing and Evaluation.Current edition approved May 1,2015.Published June 2015.Originallyapprove
14、d in 1987.Last previous edition approved in 2010 as D4748 10.DOI:10.1520/D4748-10R15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page
15、onthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.1.2 Control Unit consisting of a transmitter,receiver,andtiming control ele
16、ctronics.It transmits and receives low-powerbroad band Radio Frequency(RF)signals through the antenna.The RF signals are then converted into a signal suitable fordisplay and resulting interpretation.4.1.3 Distance Measuring Instrument(DMI)with an accu-racy of 6190 mm/km(61ft/mile)and a resolution of 305 mm(12 in.)or better.4.1.4 An optional Global Positioning System(GPS)with aninstantaneous positioning accuracy of 1 m(3 ft.)or better.4.1.5 Personal computer suitable for data acquisition,dis-play
