1、Designation: D3319 11Standard Practice for theAccelerated Polishing of Aggregates Using the BritishWheel1This standard is issued under the fixed designation D3319; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. 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 practice covers a laboratory procedure by which anestimate may be made of the extent to which different coarseaggregates
3、 may polish.1.2 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are mathemati-cal conversions to SI units that are provided for informationonly and are not considered standard. Regarding sieves, perSpecification E11, “The values stated in SI u
4、nits shall beconsidered standard for the dimensions of the wire clothopenings and the diameter of the wires used in the wire cloth.”When sieve mesh sizes are referenced, the alternate inch-pounddesignations are provided for information purposes and en-closed in parentheses.1.3 This standard does not
5、 purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility 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.2. Referenced Documents2.1 ASTM Standards
6、:2C778 Specification for SandD75 Practice for Sampling AggregatesD1415 Test Method for Rubber PropertyInternationalHardnessD3666 Specification for Minimum Requirements for Agen-cies Testing and Inspecting Road and Paving MaterialsE303 Test Method for Measuring Surface Frictional Prop-erties Using th
7、e British Pendulum TesterE501 Specification for Rib Tire for Pavement Skid-Resistance Tests3. Terminology3.1 Definitions:3.1.1 initial friction value (PV-i)the initial British Pendu-lum Tester readings on the test specimens before they arepolished in the accelerated polishing machine.3.1.2 polish va
8、lue (PV-n)a measure of the state of polishreached by a test specimen subjected to the specified hours (n)of accelerated polishing using the materials, equipment, andprocedures described in this method. The measurement is madeusing the British Pendulum Tester as described in 5.3 and TestMethod E303.3
9、.1.3 residual polish value, (RPV-n)the residual polishvalue is obtained when a constant PV-n is achieved fourconsecutive times with repeated swings of the pendulum.4. Significance and Use4.1 This practice simulates the polishing action of vehiculartraffic on coarse aggregates used in bituminous pave
10、ments.4.2 A polish value is determined that may be used to rate orclassify coarse aggregates for their ability to resist polishingunder traffic.NOTE 1The quality of the results produced by this standard aredependant upon the competence of the personnel performing the proce-dure and the capability, c
11、alibration, and the maintenance of the equipmentused. Agencies that meet the criteria of Standard Practice D3666 aregenerally considered capable of competent and objective testing / sam-pling / inspection / etc. Users of this standard are cautioned thatcompliance with D3666 alone does not completely
12、 assure reliable results.Reliable results depend on many factors: following the suggestions ofD3666 or similar acceptable guideline provides a means of evaluating andcontrolling some of those factors.5. Apparatus5.1 Accelerated Polishing Machine3An accelerated pol-ishing machine, also known as the B
13、ritish Wheel, and basedupon a 1958 design by the Road Research Laboratory of Great1This practice is under the jurisdiction of ASTM Committee D04 on Road andPaving Materials and is the direct responsibility of Subcommittee D04.51 onAggregate Tests.Current edition approved June 1, 2011. Published June
14、 2010. Originallyapproved in 1974. Last previous edition approved in 2006 as D3319 06. DOI:10.1520/D3319-11.2For 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 stan
15、dards Document Summary page onthe ASTM website.3Available from Wessex Engineering and Metal Craft Co., Ltd., MerchantsBarton, Frome, Somerset, England. If you are aware of alternative suppliers, pleaseprovide this information to ASTM International Headquarters. Your comments willreceive careful cons
16、ideration at a meeting of the responsible technical committee,1which you may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Britain. This machine shall be mounted on a firm, rigid, andlevel base. The equipment shall include t
17、he following:5.1.1 Cylindrical WheelHereafter referred to as the roadwheel, and having a flat-surface periphery and of such size andshape as to permit 14 specimens described below to beclamped onto the periphery to form a continuous surface ofaggregate particles, 134 in. (44.45 mm) wide and 16 in. (
18、406.4mm) in diameter.5.1.2 A means of rotating the road wheel about its own axisat a speed of 320 6 5 rpm.5.1.3 A means of bringing the surface of a rubber-tiredwheel 8 in. (203.2 mm) in diameter and 2 in. (50.8 mm) wideto bear on the aggregate specimens mounted on the surface ofthe road wheel with
19、a total load of 88 6 1 lbf (391.44 6 4.45N). The tire shall be treated, if necessary, to obtain a truerunning surface. The tire shall be free to rotate about its ownaxis, which should be parallel to the axis of the road wheel. Theplane of rotation of the tire shall coincide with that of the roadwhee
20、l. Before a new tire is used on a test, it shall beconditioned by a preliminary run of 6 h with a 150-grit siliconcarbide using dummy specimens (extra or used) on the roadwheel.5.1.3.1 Alternate Tire No. 1An industrial 8 by 2 pneu-matic smooth-tread hand-truck tire (Note 2). The tire rubberhardness
21、shall be 55 6 5 IRHD measured in accordance withTest Method D1415. The tire shall be inflated to a pressure of45 6 2 psi (310.26 6 13.79 kPa).NOTE 2This is the tire originally supplied with the AcceleratedPolishing Machine3and known by the tire manufacturers designationDunlop RLI 8 by 2. Dunlop disc
22、ontinued manufacturing of this tire inFebruary 1979. It is retained as an alternate in this practice for those userswho may still have a supply and in the event that Dunlop should resumemanufacturing it in the future.5.1.3.2 Alternate Tire No. 2An industrial 2.80 by 4 (8 in.OD by 4 in. ID), 4 NHS-4
23、ply, cross-hatch pattern treadhand-truck tire (Notes 3 and 4). The tire shall be inflated to apressure of 35 6 2 psi (241.32 6 13.79 kPa).NOTE 3When it became known that the Dunlop tire (5.1.3.1) was nolonger being manufactured, the necessity of finding a replacement tire forthe practice was evident
24、. A search and study by the Texas StateDepartment of Highways and Public Transportation culminated in findingthis tire, a Goodyear Industrial All Weather Hand-Truck tire size 2.80 by4 (Goodyear Product Code 202-008-002), to give Polish Values equal tothose obtained with the Dunlop tire.4A suitable i
25、nner tube such asGoodyear G250-4 (Product Code 199-010-700) is necessary. It was alsofound necessary to modify the 4-in. (101.6-mm) wheel furnished with theAccelerated Polish Machine3to facilitate mounting the Goodyear tire.Approximately 0.10 in. (2.54 mm) should be removed from the wheeldiameter an
26、d a larger hole provided for the value stem. This did not affectmounting and use of the Dunlop tire. Goodyear is no longer manufactur-ing this tire.NOTE 4A1998 study conducted by the Texas Department of Trans-portation shows that the use of cross-hatch tire results in differential wearof the test sp
27、ecimen surface that mirrors the pattern of the tire. Thisdifferential wear pattern produces falsely higher polish values, particularlyfor softer aggregates. Other research has shown that increased tire wearhas an effect of accentuating the polishing of the test specimens andresulting in lower polish
28、 values. Laboratory control specimens should beused to monitor the effect of the tire wear on accelerated polishing andtests results.5.1.3.3 Alternate Tire No. 3An 8-in. (203.2-mm) diametersolid rubber tire (Note 5). The tire rubber hardness shall be 696 3 IRHD measured in accordance with Test Metho
29、d D1415.It is necessary to move the cylindrical wheel approximately316in. (4.76 mm) away from the polishing machine to allow thetire to center over the test specimens. The tire shall be replacedwhen the RPV-10 of the control specimens described in7.2have decreased by more than four points from the R
30、PV-10obtained from a new tire.NOTE 5This is the tire presently supplied by the manufacturer of theAccelerated Polishing Machine.3Research has shown that increased tirewear has an effect of accentuating the polishing of the test specimens andresulting in lower polish values. Laboratory control specim
31、ens should beused to monitor the effect of the tire wear on accelerated polishing and testresults.5.1.4 A means to feed the 150-grit silicon carbide abrasiveat the rate given in 8.5. The grit shall be fed continuously andwith a uniform distribution across the width of the specimens.The grit shall be
32、 applied directly onto the road wheel surfaceahead of the point of contact with the rubber-tired wheel.5.1.5 A means to feed the water at the rate given in 8.5 insuch a way that the water is spread continuously and uniformlyover the surface of the road wheel ahead of the point of contactwith the rub
33、ber-tired wheel.5.2 Metal MoldsA number of accurately machined metalmolds for preparing specimens. The specimen formed is 3.5 by1.75 by 0.63 in. (88.90 by 44.45 by 16.0 mm) and shall becurved to fit on a surface having an 8-in. (203.2-mm) radius ofcurvature.5.3 British Pendulum TesterA friction-meas
34、uring device.The British Pendulum Tester used shall conform to MethodE303.5.3.1 The slider contact path shall be 3 6116 in. (76.20 61.59 mm).5.3.2 The slider width shall be 114 in. (31.75 mm).5.3.3 The rubber that is bonded to the slider shall be14 by1by114 in. (6.35 by 25.4 by 31.75 mm).5.3.4 The r
35、ubber shall meet the requirements of Specifica-tion E501.5.3.5 The zero adjustment shall be checked before and aftertesting the specimens and as often as the operator deemsnecessary.5.3.6 The calibration procedures of Test Method E303 shallbe used. However, after calibration the small slider shall b
36、einserted.5.3.7 Sanding BlockA rigid metal block with a planedsurface of 7.5-in. (190.5-mm) radius of curvature that isconsistent with the radius of curvature of the road wheelbearing surface.6. Materials and Supplies6.1 WaterA supply of tap water for use where water isrequired for any purpose in th
37、is method.6.2 Fine SandA supply of fine sand for sifting into theinterstices of the aggregate prior to placing of the bonding4Supporting Data are available from ASTM Headquarters. Request RR:D04-1002.D3319 112material. Standard sand conforming to Specification C778 hasbeen found suitable for this pu
38、rpose.6.3 Mold Release AgentThe use of a mold release agent isoptional. A mold release agent may be used to prevent bondingbetween the mold and the bonding material. Silicon releaseagent and paste wax as used for automobiles and floors hasbeen found suitable. The user should use care to prevent this
39、agent from being absorbed by the aggregate as it could affectthe measured polish value.6.4 Silicon Carbide GritA supply of silicon carbide grit(150-grit size) to be used as the polishing agent. Grit should bechecked for gradation using Nos. 150m (No. 100), 106 m(No. 140) and 75 m (No. 200) sieves an
40、d separated ifnecessary to maintain a uniform gradation passing the No. 150m (No. 100) sieve and retained on the No. 75 m (No. 200)sieve.6.5 Bonding AgentA supply of polyester resin and cata-lyst (or another suitable bonding material, such as an epoxyresin) having a pot life of 20 to 30 min and a cu
41、ring time of 3to 6 h. This bonding agent shall not be so fluid as to flowthrough the fine sand.6.5.1 An optional bonding agent may be used to eliminateuse of the fine sand. This bonding agent must be quite viscousso that it will not flow completely around the aggregateparticles and become part of th
42、e surface of the test specimen.Examples of suitable materials are given in Appendix X1.6.5.2 Follow the manufacturers precautions concerningstorage and use of resin and catalyst.6.6 Coarse AggregateApproximately a12 ft3(0.014 m3)supply of coarse aggregate to be tested and sampled inaccordance with P
43、ractice D75. The aggregate shall be normalplant run but laboratory-crushed material may be tested, if soidentified.7. Test and Control Specimens7.1 Five test specimens for each coarse aggregate shall betested.7.2 Standard laboratory control specimens shall be includedin each run to develop consisten
44、cy in specimen preparation andpolishing. Four control specimens shall be included with twosets containing five test specimens each for each run. Aggre-gates used for fabrication of control specimens should be ofconsistent property and RPV-10 test history.NOTE 6It has been found that the polishing su
45、rface of controlspecimen can be successfully replicated by filling the bottom of the metalmold with a uniform mixture of 4 parts 20-30 grade Ottawa sand and 1parts polyester resin. The backing of the Ottawa sand control specimensshould be 100% polyester resin to facilitate preparation of the surface
46、bearing against the road wheel.7.3 The aggregate to be tested shall pass the 12.5mm(12-in) sieve and shall be retained on a 9.5-mm (38-in.) sieve.NOTE 7Aggregate gradation may be varied to meet the needs of theuser if reported with the test results. However, aggregates larger than 12.5mm (12 in.) ma
47、y not be accommodated by the mold, and aggregatessmaller than 9.5 mm (38 in.) may not be adequately bonded in thespecimen molding process to be retained for the duration of the test. Forlaboratories and agencies evaluating and monitoring multiple aggregatesources, an alternate aggregate size of pass
48、ing 9.5 mm (38 in.) sieve andretained on a 6.3-mm (14-in.) sieve may be used to represent the criticalsize of the bituminous mixture. The two aggregate sizes described shouldnot be used alternately for quality monitoring of friction aggregates.7.4 Thoroughly wash and dry the aggregate to be tested a
49、t230 6 9F (110 6 5C) to essentially constant weight.7.5 Coat the mold with mold-release agent.7.6 Each specimen shall contain a single layer of dryaggregate placed by hand as densely as possible with a flatsurface down to cover the bottom 3.5 by 1.75-in. (88.9 by44.45-mm) surface of the mold.NOTE 8Particles selected should be representative of the material tobe evaluated. Flat, elongated, or unusually shaped particles can causedifficulty in placement and bonding. Misleading polish values can resultfrom inadequate surface area for pol
