1、Designation: D 3319 06Standard Practice for theAccelerated Polishing of Aggregates Using the BritishWheel1This standard is issued under the fixed designation D 3319; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 coarseaggrega
3、tes may polish.1.2 The values stated in inch-pound units are to be regardedas the standard.1.3 This standard does not 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 practi
4、ces and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 778 Specification for SandD75 Practice for Sampling AggregatesD 1415 Test Method for Rubber PropertyInternationalHardnessE 303 Test Method for Measuring Surface Frictional Prop-er
5、ties Using the British Pendulum TesterE 501 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
6、.1.2 polish value (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 Tes
7、tMethod E 303.3.1.3 residual polish value, (RPV-n)the residual polishvalue is obtained when a constant PV-n is acheived 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
8、bituminous pavements.4.2 A polish value is determined that may be used to rate orclassify coarse aggregates for their ability to resist polishingunder traffic.5. Apparatus5.1 Accelerated Polishing Machine3An accelerated pol-ishing machine, also known as the British Wheel, and basedupon a 1958 design
9、 by the Road Research Laboratory of GreatBritain. This machine shall be mounted on a firm, rigid, andlevel base. The equipment shall include the 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 spec
10、imens described below to beclamped onto the periphery to form a continuous surface ofaggregate particles, 134 in. (44.45 mm) wide and 16 in. (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-ti
11、redwheel 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 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
12、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 roadwheel. 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
13、) on the roadwheel.1This 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 July 1, 2006. Published July 2006. Originally approvedin 1974. Last previous edition approv
14、ed in 2000 as D 3319 00.2For 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 onthe ASTM website.3Available from Wessex Engineering an
15、d 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 consideration at a meeting of the responsible technical committee,1which you may attend.
16、1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.3.1 Alternate Tire No. 1An industrial 8 by 2 pneu-matic smooth-tread hand-truck tire (Note 1). The tire rubberhardness shall be 55 6 5 IRHD measured in accordance withTest Method D
17、1415. The tire shall be inflated to a pressure of45 6 2 psi (310.26 6 13.79 kPa).NOTE 1This is the tire originally supplied with the AcceleratedPolishing Machine3and known by the tire manufacturers designationDunlop RLI 8 by 2. Dunlop discontinued manufacturing of this tire inFebruary 1979. It is re
18、tained 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 ply, cross-hatch pattern treadhand-truck tire (Notes 2 and 3)
19、. The tire shall be inflated to apressure of 35 6 2 psi (241.32 6 13.79 kPa).NOTE 2When 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. A search and study by the Texas StateDepartment of Highways
20、 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 inner tube such asGoodyear G250-4 (Product Code 199-010-700) i
21、s necessary. It was alsofound necessary to modify the 4-in. wheel furnished with the AcceleratedPolish Machine3to facilitate mounting the Goodyear tire. Approximately0.10 in. should be removed from the wheel diameter and a larger holeprovided for the value stem. This did not affect mounting and use
22、of theDunlop tire. Goodyear is no longer manufacturing this tire.NOTE 3A 1998 study conducted by the Texas Department of Trans-portation shows that the use of cross-hatch tire results in differential wearof the test specimen surface that mirrors the pattern of the tire. Thisdifferential wear pattern
23、 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 values. Laboratory control specimens should beused to monitor the effect of the t
24、ire wear on accelerated polishing andtests results.5.1.3.3 Alternate Tire No. 3An 8-in. diameter solid rubbertire (Note 4). The tire rubber hardness shall be 69 6 3 IRHDmeasured in accordance with Test Method D 1415.Itisnecessary to move the cylindrical wheel approximately316 in.away from the polish
25、ing machine to allow the tire to centerover the test specimens. The tire shall be replaced when theRPV-10 of the control specimens described in 7.2have de-creased by more than four points from the RPV-10 obtainedfrom a new tire.NOTE 4This is the tire presently supplied by the manufacturer of theAcce
26、lerated 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 specimens should beused to monitor the effect of the tire wear on accelerated polishing and testresults.5.1.
27、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 applied directly onto the road wheel surfaceahead of the point of contact with the rubber-tired wheel
28、.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 rubber-tired wheel.5.2 Metal MoldsA number of accurately machined metalmolds for preparing specimens. The
29、 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-mm) radius ofcurvature.5.3 British Pendulum TesterA friction-measuring device.The British Pendulum Tester used shall conform to MethodE 303.5.3.1 The slider contact path
30、 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 rubber shall meet the requirements of Specifica-tion E 501.5.3.5 The zero adjustment shall be checked be
31、fore and aftertesting the specimens and as often as the operator deemsnecessary.5.3.6 The calibration procedures of Test Method E 303 shallbe used. However, after calibration the small slider shall beinserted.5.3.7 Sanding BlockA rigid metal block with a planedsurface of 7.5-in. (190-mm) radius of c
32、urvature that is consis-tent with the radius of curvature of the road wheel bearingsurface.6. Materials and Supplies6.1 WaterA supply of tap water for use where water isrequired for any purpose in this method.6.2 Fine SandA supply of fine sand for sifting into theinterstices of the aggregate prior t
33、o placing of the bondingmaterial. Standard sand conforming to Specification C 778 hasbeen found suitable for this purpose.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 releaseage
34、nt and paste wax as used for automobiles and floors hasbeen found suitable. The user should use care to prevent thisagent 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 polishi
35、ng agent. Grit should bechecked for gradation using Nos. 100 (150 m), 140 (106 m)and 200 (75 m) sieves and separated if necessary to maintaina uniform gradation passing the 100 (150 m) sieve andretained on the 200 (75 m) sieve.6.5 Bonding AgentA supply of polyester resin and cata-lyst (or another su
36、itable bonding material, such as an epoxyresin) having a pot life of 20 to 30 min and a curing 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 visc
37、ousso that it will not flow completely around the aggregate4Supporting Data are available from ASTM Headquarters. Request RR: D04-1002.D3319062particles and become part of the surface of the test specimen.Examples of suitable materials are given in Appendix X1.6.5.2 Follow the manufacturers precauti
38、ons 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 Practice D75. The aggregate shall be normalplant run but laboratory-crushed material may be tested, if soidentified.7. Test and
39、 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 consistency in specimen preparation andpolishing. Four control specimens shall be included with twosets containing five test specimens
40、each for each run. Aggre-gates used for fabrication of control specimens should be ofconsistent property and RPV-10 test history.NOTE 5It has been found that the polishing surface of controlspecimen can be successfully replicated by filling the bottom of the metalmold with a uniform mixture of 4 par
41、ts 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 surfacebearing against the road wheel.7.3 The aggregate to be tested shall pass the12-in (12.7-mm) sieve and shall be retained on a38
42、-in. (9.5-mm) sieve.NOTE 6Aggregate gradation may be varied to meet the needs of theuser if reported with the test results. However, aggregates larger than12 in.(12.7 mm) may not be accommodated by the mold, and aggregates smallerthan38 in. (9.5 mm) may not be adequately bonded in the specimenmoldin
43、g process to be retained for the duration of the test. For laboratoriesand agencies evaluating and monitoring multiple aggregate sources, analternate aggregate size of passing38-in (9.5-mm) sieve and retained on a14-in. (6.4-mm) sieve may be used to represent the critical size of thebituminous mixtu
44、re. The two aggregate sizes described should not be usedalternately for quality monitoring of friction aggregates.7.4 Thoroughly wash and dry the aggregate to be tested at110 6 5C to essentially constant weight.7.5 Coat the mold with mold-release agent.7.6 Each specimen shall contain a single layer
45、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 7Particles selected should be representative of the material tobe evaluated. Flat, elongated, or unusually shaped particles can causedifficulty
46、 in placement and bonding. Misleading polish values can resultfrom inadequate surface area for polishing.7.7 Fill the interstices between the aggregate with the finesand, described in 6.2, from one fourth to one half of theaggregate depth.7.7.1 An optional method eliminates the sand by using aviscou
47、s polyester resin. This material is described in 6.5.7.8 Prepare the bonding agent described in 6.5 and inaccordance with the manufacturers instructions. The consis-tency of the bonding agent shall be such that it will flow freelybetween the aggregate particles but not so thin as to impregnatethe sa
48、nd or to bond this sand to the specimen surface laterpreventing its removal. An ideal consistency would be suchthat the bonding agent must be forced into the voids betweenthe aggregate particles by gentle hand pressure with a spatula.7.8.1 The optional bonding agent requires a heavier consis-tency s
49、uch that it will not flow except with the aid of a spatula.7.9 Fill the prepared mold to overflowing with the bondingmaterial.NOTE 8Care should be used to ensure that the bonding agent is notallowed to penetrate near the aggregate surface to be polished in such away that the rubber slider may contact it.7.10 When the bonding material has stiffened sufficiently,strike off the excess material even with the curved sides of themold.7.11 When the bonding material has cured properly (3 to6 h) remove the specimen from the mold.NOTE 9When warpi
