1、Designation: E 660 90 (Reapproved 2007)Standard Practice forAccelerated Polishing of Aggregates or Pavement SurfacesUsing a Small-Wheel, Circular Track Polishing Machine1This standard is issued under the fixed designation E 660; the number immediately following the designation indicates the year ofo
2、riginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe Small-Wheel Circular Track Wear and Polishing Machine2i
3、s a device developed to rateaggregates and paving mixtures on their skid resistance after exposure to wearing and polishing. It isa small-diameter, circular track machine capable of accelerated wearing and polishing of pavementspecimens. Correlation and comparison can be accomplished through the use
4、 of control specimens thatare tested simultaneously with regular test specimens. Track capacity is twelve individual specimensper test run.The actual wearing and polishing for bituminous pavement specimens and exposed aggregatespecimens are provided by the action of four smooth pneumatic tires to el
5、iminate, as much as possible,the variables associated with tire tread pattern effects. The wheels are adjusted for camber and fortoe-out to provide scrubbing action for polishing without the aid of water or grinding compounds.To provide accelerated wear sufficient to remove the top textured layer fr
6、om portland-cement-concrete pavement specimens and to expose the coarse aggregate, as often encountered on wornpavements, that have been in use for substantial periods of time, the wear and polish procedure canbe modified by use of steel wheels having studs mounted in the periphery. The procedure fo
7、r concretespecimens consists of a period of operation with four smooth pneumatic tires to polish the as-builtsurface, followed by a period of accelerated wear using the steel wheels to expose the coarseaggregate, followed by a final polishing cycle using the four rubber tires again to polish the exp
8、osedaggregate.1. Scope1.1 This practice describes a laboratory procedure for esti-mating the extent to which aggregates or pavement surfaces arelikely to polish when subjected to traffic. Specimens to beevaluated for polishing resistance are placed in a circular trackand subjected to the wearing act
9、ion of four small-diameter,pneumatic tires without use of abrasive or water. Terminalpolish is achieved after approximately8hofexposure.2. Referenced Documents2.1 ASTM Standards:3C 192/C 192M Practice for Making and Curing ConcreteTest Specimens in the LaboratoryD 2240 Test Method for Rubber Propert
10、yDurometerHardnessE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 274 Test Method for Skid Resistance of Paved SurfacesUsing a Full-Scale TireE 303 Test Method for Measuring Surface Frictional Prop-erties Using the British Pendulum Tester1This practice is under the jurisd
11、iction of ASTM Committee E17 on Vehicle -Pavement Systems and is the direct responsibility of Subcommittee E17.23 onSurface Characteristics Related to Tire Pavement Slip Resistance.Current edition approved Dec. 1, 2007. Published January 2008. Originallyapproved in 1978. Last previous edition approv
12、ed in 2002 as E 660 90 (2002).2Mullen, W. G., Whitfield, J. K., Gibson, D., and Matlock, T. L., “Implemen-tation for Use of Variable Speed Friction Tester and Small Wheel Circular TrackWear and Polishing Machine,” Highway Research Program Project ERSD 110-76-2,Final Report; Available from National T
13、echnical Information Service, Springfield,VA 22161.3For 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 onthe ASTM website.1Copyright
14、 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E 707 Test Method for Skid Resistance Measurements Us-ing the North Carolina State University Variable-SpeedFriction Tester43. Summary of Practice3.1 The circular track is fitted with twelve spec
15、imen holdersthat can be adapted to specimens of various shapes andthicknesses, but when mounted in the track, form a continuousplane running surface for the polishing wheels. A complete setof twelve specimens exposed to wear and polishing at the sametime is counted as a round of testing. Usually spe
16、cimens aretested in sets of three per variable per round of test with threecontrol specimens of a standard surface included in each roundto allow comparison between rounds of testing. It is recom-mended that each variable be repeated in three separate rounds,making a minimum of nine specimens per va
17、riable to obtain anaverage polishing curve.3.2 To obtain a polishing curve, specimens are subjected topolishing action in the track until friction measurements showno substantial decrease in level with continued polishing effort.Measurements are recorded at the beginning of the test andperiodically
18、throughout the test cycle to establish the shape ofthe polishing curve. Usually8hofexposure on the track at 30r/min or 7200 wheel passes per hour is sufficient to completethe polishing cycle for bituminous bound mixtures and exposedaggregate specimens. For portland-cement-concrete boundmixtures, it
19、is recommended that a polish curve be obtained onthe original textured surface followed by removal of thesurface to expose the coarse aggregate using the steel-studdedabrading wheels. A polishing curve is then obtained for theexposed aggregate surface.3.3 Friction measurements can be obtained for bi
20、tuminousplant mix type surfaces using the British Pendulum Tester inaccordance with Test Method E 303. The British PendulumTester has been found to be ineffective in obtaining frictionmeasurements on highly textured surfaces such as bituminoussurface treatments and portland-cement-concrete surfaces.
21、Therefore, it is recommended that the North Carolina StateUniversity Variable-Speed Friction Tester2be used in accor-dance with Test Method E 707 as the friction measurementdevice on highly textured surfaces. With the Variable SpeedFriction Tester, speed gradients are obtainable in the laboratory.3.
22、4 Interpretation of the laboratory polishing curves for fieldapplication is not included as part of this practice.4. Significance and Use4.1 The use of laboratory obtained polishing curves andspeed gradients on proposed aggregate combinations andpavement mixtures are helpful tools in predicting the
23、polishingcharacteristics of these surfaces if placed in field service.5. Apparatus5.1 Small-Wheel Circular Track2A power-driven deviceconsisting of four equally spaced wheels, independently sus-pended, on each of which may be mounted a smooth-treadpneumatic tire, operating over a circular track that
24、 holdsspecimens to be polished (Fig. 1).NOTE 1Construction plans are published in the reference cited infootnote 2.5.1.1 Rotating Wheel AssemblyFour individuallymounted wheel assemblies, free rolling, attached to the centralshaft. Tires are 11 3 6.00 3 5 nylon smooth no-pattern treadtires, 2-ply rat
25、ing.5Each wheel may be individually adjustedfor distance from center shaft, plane of rotation (camber), andtoe-in or toe-out. Tire pressure is maintained at 20 psi (138kPa) resulting in 13 psi (90 kPa) average contact pressureunder normal 72-lbf (320-N) wheel loading. Each wheelassembly has a horizo
26、ntal fender onto which weights may be4Withdrawn.5The sole source of supply of the apparatus known to the committee at this timeis Goodyear Tire and Rubber Co., Akron, OH 44316. If you are aware of alternativesuppliers, please provide this information to ASTM International Headquarters.Your comments
27、will receive careful consideration at a meeting of the responsibletechnical committee,1which you may attend.FIG. 1 NCSU Wear and Polishing MachineMark IIE 660 90 (2007)2fastened to increase the wheel loading. One pair of oppositewheels is toed-out 2 while the other pair of wheels is toed in4 to prod
28、uce an accelerated polishing action.5.1.2 Drive mechanism for the vertical central shaft is anelectric motor geared to rotate the shaft and wheel assembly at30 6 2 r/min or approximately 7200 wheel passes per hour.5.1.3 The circular track is 36 in. (914 mm) in diameter to thecenter of the wheel trav
29、el path. There are spaces for individu-ally mounting twelve equally spaced specimen holders to makeup the track running surface. Specimen holders are clampedinto place to the supporting frame when testing is in progress.5.1.4 Specimen holders or track segments are metal platessupported by three adju
30、stable, lockable bolts for mounting andleveling each specimen before and during testing as necessary.5.1.4.1 Trapezoidal specimens sawed to size are mounted onthe bottom plate of the specimen holder. No top plate is used.5.1.4.2 Circular specimens or cores at least 6 in. (152 mm)in diameter are moun
31、ted on the bottom plate of the specimenholder, and a top plate with the appropriate diameter circularhole is used to complete the track running surface betweenadjacent circular specimens.5.1.4.3 Specimens are cemented to bottom plate using anepoxy glue or may be held in place by a clamping ring.NOTE
32、 2Thermoplastic cements are unsatisfactory as they allow speci-mens to rotate or shift during the progress of the test.5.2 Electrical SystemThe electrical system consists ofthree circuits.5.2.1 The motor circuit is equipped with a slow-blow fuse toprotect the motor in case of overheating or machine
33、lockup.5.2.2 The motor is controlled by a subtracting predeter-mined revolution counter.5.2.3 The safety guards are interlocked so that the motorwill not operate unless guards are in operating position.5.3 Studded Steel Abrading WheelThe steel abradingwheel, fabricated from 12-in. (305-mm) diameter
34、steel tubing,is mounted by inflating a pneumatic tire inside. Socket-headcap screws,14 20, used as studs, are arranged in 60 rows andspaced 1.125 in. (28.6 mm) apart within rows with each screwoffset 0.375 in. (9.5 mm) from the one above. Two wheels arerecommended. Abrading wheels can only be used o
35、n trapezoi-dal specimens where no top specimen holder plate is required(Fig. 2).NOTE 3Construction plans are published in the reference cited infootnote 2.5.3.1 A fiber bristle brush is mounted behind one wheel tosweep the track surface when the abrading wheel is used (Fig.2).5.4 WeightsWeights of 5
36、0 lb (22.7 kg) may be added towheel assembly aprons when portland-cement concrete isbeing tested.5.5 Friction-Measuring DeviceAny friction-measuringdevice that will operate to within the center 3.5 by 5.06-in. (89by 129-mm) portion of a 6-in. (152-mm) diameter specimenwould be suitable provided the
37、measurement can be taken inthe direction of traffic and the device can be taken into the fieldto be reasonably correlated with Test Method E 274 skid trailermeasurements.5.5.1 Friction measurements can be made on low macrotex-ture pavements or pavement samples using the British Pendu-lum Tester in T
38、est Method E 303.5.5.2 Friction measurements can be made on any pavementsor pavement samples using the Variable Speed Friction Tester.2In addition, speed gradients may be obtained using this device.5.6 MoldsSpecimen molds may vary in size and shapedepending upon aggregate, mixture, or surface to be
39、tested.5.6.1 Bituminous Laboratory SpecimenA 6-in. (152-mm)inside diameter mold is recommended for bituminous speci-men compaction. The base should be detachable for specimenextraction. If static compaction in a compression machine isused, a 5.875-in. (149-mm) diameter compaction mold plungershould
40、be provided.5.6.2 Concrete Laboratory SpecimensBecause of textur-ing, it is desirable to cast large concrete surfaces and to sawtrapezoidal specimens. A steel plate and angle iron mold 7.75by 28.0 by 2 in. (197 by 711 by 51 mm) deep will provide aslab from which three trapezoidal specimens can be sa
41、wed.FIG. 2 Studded Steel-Abrading Wheels and Bristle Sweeping BrushE 660 90 (2007)35.6.3 Exposed Aggregate Laboratory SpecimensA 6-in.(152-mm) inside diameter mold approximately 1.8 in. (46 mm)in height is recommended for exposed aggregate specimenpreparation. The base should be detachable for speci
42、menextraction.5.6.4 Cores and Thin SurfacingsThin or irregular backspecimens may be built up with plaster of paris to suitablemounting thicknesses of 1 to 2 in. (25 to 50 mm) using ringscut from paper concrete cylinder molds.6. Materials6.1 Laboratory-Made Bituminous SpecimensIt is recom-mended that
43、 a standard laboratory aggregate for manufactureof control specimens be stocked in sufficient quantity forapproximately 1 year of operation, and that sufficient quantityshall be retained for recalibration of a new supply before theoriginal supply is exhausted.6.2 Laboratory-Made Portland Cement Conc
44、reteSpecimensIt is recommended that standard laboratory coarseand fine aggregates for manufacture of control specimens bestocked in sufficient quantity for approximately 1 year ofoperation and that sufficient quantity shall be retained forrecalibration of a new supply before the original supply isex
45、hausted.6.3 Laboratory-Made Exposed Aggregate SpecimensIt isrecommended that standard laboratory coarse aggregate for themanufacture of control specimens be stocked in sufficientquantity for approximately one year of operation and thatsufficient quantity shall be retained for recalibration of a news
46、upply before the original supply is exhausted.6.4 Specimen Mounting CementCommercially availableepoxy cement or a clamping ring shall be used for mountingspecimens.7. Sampling7.1 Not applicable, as sampling schemes may be varied tomeet the needs of the user.8. Test Specimens8.1 Bituminous Laboratory
47、 SpecimensUse a minimum ofthree individual specimens to evaluate each aggregate or eachpavement mixture design. Three rounds of three are recom-mended.8.1.1 Prepare bituminous specimens using the aggregategradation and asphalt cement content desired.8.1.1.1 Mix preheated aggregates and asphalt using
48、 a me-chanical laboratory mixer.8.1.1.2 Preheat the mold assembly (5.5.1) to mixing tem-perature and place a filter paper in the bottom of the mold.8.1.1.3 Distribute the mixture in the mold using a spatula,rodding around the mold sides and rodding and leveling thesurface. Place filter paper over th
49、e mixture.8.1.1.4 Place the compaction plunger in the mold andcompact the specimen in a compression machine to 3000 psi(20.68 MPa) holding the load for 2 min.NOTE 4At pressures in excess of 3000 psi (20.68 MPa) someaggregate particles may be crushed, resulting in possible bias of the testresults.8.1.1.5 Remove the plunger, cool the mold and specimen toroom temperature, and extract the specimen from the moldusing a hydraulic press.8.1.1.6 Mark the bottom surface as compacted as the testsurface, and store the specimen prior to use on a flat surface.8.1.2 Po
