1、Designation: D2872 121Standard Test Method forEffect of Heat and Air on a Moving Film of Asphalt (RollingThin-Film Oven Test)1This standard is issued under the fixed designation D2872; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, 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.1NOTEThis standard was corrected editorially in 2013.1. Scope1.1 This test method is intended to measure the effect
3、ofheat and air on a moving film of semi-solid asphaltic materials.The effects of this treatment are determined from measure-ments of the selected properties of the asphalt before and afterthe test.1.2 The values stated in inch-pound units are to be regardedas the standard.1.3 This standard does not
4、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:
5、2D113 Test Method for Ductility of Bituminous MaterialsD2171 Test Method for Viscosity of Asphalts by VacuumCapillary ViscometerE1 Specification for ASTM Liquid-in-Glass ThermometersE644 Test Methods for Testing Industrial Resistance Ther-mometersE1137/E1137M Specification for Industrial Platinum Re
6、sis-tance Thermometers3. Summary of Test Method3.1 A moving film of asphaltic material is heated in an ovenfor 85 min at 325F (163C). The effects of heat and air aredetermined from changes in physical test values as measuredbefore and after the oven treatment. An optional procedure isprovided for de
7、termining the change in sample mass.3.2 Precision values for this test method have been devel-oped for viscosity at 140F (60C); ductility at 60F (15.6C);and mass change.4. Significance and Use4.1 This test method indicates approximate change in prop-erties of asphalt during conventional hot-mixing a
8、t about302F (150C) as indicated by viscosity and other rheologicalmeasurements. It yields a residue which approximates theasphalt condition as incorporated in the pavement. If themixing temperature differs appreciably from the 302F(150C) level, more or less effect on properties will occur. Thistest
9、method also can be used to determine mass change, whichis a measure of asphalt volatility.5. Apparatus5.1 OvenThis shall be a double-walled electrically heatedconvection-type oven. Its inside dimensions shall be 15 in.(381 mm) high, 19 in. (483 mm) wide (including the plenum),and 1712 612 in. (445 6
10、 13 mm) deep (with the door closed).The door shall contain a symmetrically located window withdimensions of 12 to 13 in. (305 to 330 mm) wide by 8 to 9 in.(203 to 229 mm) high. The window shall contain two sheets ofheat-resistant glass separated by an air space. The windowshould permit an unobstruct
11、ed view of the interior of the oven.The top of the upper heating element shall be 1 618 in. (25 63 mm) below the oven floor.5.1.1 The oven shall be vented at the top and bottom. Thebottom vents shall be located symmetrically to supply incom-ing air around the heating elements. They shall have an ope
12、narea of 2.31 6 0.11 in.2(15.0 6 0.7 cm2). The top vents shallbe symmetrically arranged in the upper part of the oven andhave an open area of 1.45 6 0.07 in.2(9.3 6 0.45 cm2).5.1.2 The oven shall have an air plenum covering the sidewalls and ceiling. The air space shall be 112 in. (38.1 mm) deepfrom
13、 the walls and ceiling. At a midpoint in the width of theoven, and 6 in. (152.4 mm) from the face of the circular metalcarriage to its axis, a squirrel cage-type fan 514 in. (133 mm)OD by 278 in. (73 mm) wide shall be turned at 1725 rpm by anexternally mounted motor. The squirrel cage fan shall be s
14、et sothat the fan turns in an opposite direction to its vanes. The air1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.46 onDurability and Distillation Tests.Current edition approved Aug. 1, 2012. Publi
15、shed August 2012. Originallyapproved in 1970. Last previous edition approved in 2012 as D2872 12. DOI:10.1520/D287212E012For 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
16、 to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1flow characteristics of the fan-plenum system shall be suctionfrom the floor of the oven through the wall plenums andexhaust of
17、 the air through the fan. Fig. 1 and Fig. 2 showdetails of this plenum system.5.1.3 The oven shall be equipped with a proportionalcontrol thermostat capable of maintaining a temperature of325F (163C) to within 61.0F (60.5C). The sensingelement of the thermostat may be placed at any location thatenab
18、les the oven to maintain temperature control as specifiedby this standard.5.1.4 The thermometer shall be hung or affixed to a mount-ing in the ceiling which is 2 in. (50.8 mm) from the right sideof the oven at a midpoint in the depth of the oven. Thethermometer shall hang down into the oven so that
19、the bulb ofthe thermometer is within 1 in. of an imaginary line level withthe shaft of the circular metal carriage. The heating controlsshall be capable of bringing the fully loaded oven back to thetest temperature within a 10-min period after insertion of thesamples in a preheated oven.5.1.5 The ov
20、en shall be provided with a 12-in. (304.8-mm)diameter, vertical circular carriage (see Fig. 2 for details). Thiscarriage shall be provided with suitable openings and clips forfirmly holding eight glass containers in a horizontal position(see Fig. 3). The vertical carriage shall be mechanically drive
21、nthrough a34-in. (19-mm) diameter shaft at a speed of 15 6 0.2r/min.5.1.6 The oven shall be equipped with an air jet positionedto blow heated air into each bottle at its lowest point of travel.The air jet shall have an outlet orifice 0.04 in. (1.016 mm) indiameter (No. 60 drill) connected to a 25-ft
22、 (7.6-m) length of516-in. (8-mm) outside diameter refrigeration copper tubing.This tubing shall be coiled to lie flat on the bottom of the ovenand lead to a source of fresh, dried, dust-free regulated air.NOTE 1Activated silica gel treated with an indicator is a satisfactorydesiccant for the dried a
23、ir.5.2 FlowmeterThe flowmeter may be any suitable typecapable of accurately measuring the airflow at a rate of 4000mL/min. The flowmeter shall be located downstream of allregulating devices and upstream of the copper coil. Theflowmeter shall be positioned so it is maintained at approxi-mately room t
24、emperature. The airflow shall be calibratedFIG. 1 Schematic of Air Flow Front ViewD2872 1212periodically using a wet-test meter or other displacementmethod. This calibration shall be based on airflow exiting theair jet and shall be conducted with the oven off and at roomtemperature.5.3 ThermometerTh
25、is shall be an ASTM Thermometerconforming to the requirements for Thermometer 13C asprescribed in Specification E1. This thermometer shall be usedto make all temperature measurements required by this testmethod. In order to reduce the risks associated with thermom-eter breakage, the thermometer may
26、be fully or partiallyencapsulated in an optically transparent polymer sheath havinga maximum thickness of 0.01 in. (0.25 mm). If a sheath is used,it shall be installed such that there is substantial mechanicalcontact with the thermometer. The thermometer shall berecalibrated after installation of a
27、sheath.5.3.1 The test thermometer may be replaced with an elec-tronic temperature measurement system, provided the follow-ing requirements are met:5.3.1.1 The electronic temperature sensor shall bea3or4wire, Grade A Platinum Resistance Thermometer (PRT) sub-stantially conforming to the requirements
28、of SpecificationE1137/E1137M. The temperature sensor shall be mounted inthe same position and orientation as the test thermometer itreplaces.5.3.1.2 The electronic sensor shall have a thermal responsetime that differs by no more than 30% from the thermalresponse time of the designated test thermomet
29、er. Thermalresponse shall be defined as the time required to achieve a 95%response to a temperature step change, starting in air at ambientFIG. 2 Circular Metal CarriageFIG. 3 Sample BottleD2872 1213temperature, and ending in air at any convenient and constanttemperature in the range of 165170C. Gui
30、dance for deter-mining thermal response time is given in Test Methods E644.5.3.1.3 The electronic measurement circuitry shall include adigital display having a resolution of 0.1C or better.5.3.1.4 The electronic temperature sensor and electronicmeasurement circuitry shall be calibrated and verified
31、as a unit.Calibration and verification shall be NIST traceable. Thetemperature measurement system shall be calibrated prior tobeing placed into service and verified annually thereafter.Guidance for performing the calibration is given in TestMethods E644.5.3.1.5 Verification shall be conducted with t
32、he test ovenequilibrated at normal operating temperature while the verifi-cation sensor is in mechanical contact with the normal testsensor. If the difference between the verification sensor and thenormal test sensor exceeds 0.2C, the verification will beregarded as having failed, and the temperatur
33、e measurementsystem shall be recalibrated.5.4 ContainerThe container in which the sample is to betested shall be of clear, transparent, heat-resistant glass con-forming to the dimensions shown in Fig. 3.5.5 Cooling RackA wire or sheet metal rack, constructedof stainless steel or aluminum, which allo
34、ws the samplecontainers to cool in a horizontal position, with each containerin the same horizontal plane. The rack shall be constructed ina way that allows air to flow freely around each container withat least 1 in. (2.5 cm) clearance between containers and at least1 in. (2.5 cm) clearance between
35、the containers and any solidsurface.6. Determination of Oven Preheat Time6.1 Determine the preheat time for the oven in accordancewith either 6.1.1 or 6.1.2. If Section 6.1.1 is used, thisdetermination must be made for each oven, and shall berepeated at least annually or whenever environmental condi
36、-tions or the test location change. If Section 6.1.2 is used, noannual determination is necessary.6.1.1 Adjust the oven control thermostat to the setting thatwill be used during the test. Select this setting so that when theoven is fully loaded and the air is on, the oven will equilibrateat 325 6 1F
37、 (163 6 0.5C), as indicated by the testthermometer. Turn the oven on and simultaneously record thestart time to the nearest whole minute. Determine and recordthe temperature of the oven at 15-minute intervals. Continuethis process until the oven reaches thermal equilibrium. Ther-mal equilibrium is c
38、onsidered to be the time when the oventemperature does not vary by more than 1F (0.5C) betweentwo consecutive readings. The oven preheat time is the timethat it takes to reach thermal equilibrium plus an additional 30minutes.6.1.2 In lieu of completing the steps described in Section6.1.1, a minimum
39、preheat time of 4 hours may be used.7. Preparation of Oven7.1 Position the air outlet orifice so that it is14 in. 618 in.(6 mm 6 3 mm) from the opening of the glass container. Theorifice shall also be so positioned that the jet blows horizontallyinto the central arc of the opening of the circling gl
40、asscontainer.7.2 Position the thermometer specified in 5.3 so that the endof the bulb of the thermometer is within 1 in. (25.4 mm) of animaginary line level with the center of the shaft holding therevolving carriage.7.3 Level the oven so that the horizontal axes of the glasscontainers when in positi
41、on in the carriage are level to within6 1.0.7.4 Start the fan. The fan shall remain on whenever the ovenheater is on and the oven door is closed. This standard permits(but does not require) the fan to be stopped when the oven dooris opened. Stopping the fan may be accomplished manually,with an elect
42、ronic door interlock, or through other means.7.5 Preheat the oven for the preheat time determined inSection 6 or longer prior to testing with the control thermostatadjusted to the setting that will be used during the test. Selectthis setting so that when the oven is fully loaded and the air ison, th
43、e oven will equilibrate at 325 6 1F (163 6 0.5C), asindicated by the test thermometer.NOTE 2Because the presence of sample containers affects the tem-perature distribution in the oven, containers should be present in the ovenwhen the thermostat setting is determined. The use of empty containers isac
44、ceptable for this purpose.8. Procedure8.1 The sample as received shall be free of water. Heat thesample in its container with a loosely fitted cover in an ovennot to exceed 302F (150C) for the minimum time necessaryto ensure that the sample is completely fluid. Manually stir thesample but avoid inco
45、rporating air bubbles.8.2 Pour 35 6 0.5 g of the sample into each of the requiredglass containers, providing sufficient material for characteriz-ing tests which are to be run on the residue.8.3 Immediately after pouring the sample into a glasscontainer, turn the container to a horizontal position. R
46、otate thecontainer slowly for at least one full rotation, and attempt topre-coat its cylindrical surface. It is not necessary to pre-coatthe open end of the container, and care should be taken toprevent the sample from flowing out of the container duringthis step. Place the container horizontally in
47、 a clean coolingrack that is maintained in a draft-free, room-temperaturelocation away from ovens and other sources of heat.NOTE 3Complete pre-coating may not be possible for certain binders.NOTE 4For maximum precision in determining mass change, thecooling rack should be in a location that is the s
48、ame temperature andhumidity as the balance used for measuring the mass of the containers.NOTE 5Static electricity may cause unstable mass measurements, duein part to the characteristics of the glass sample containers. This problemcan be minimized by mounting a passive ion source inside the balancedr
49、aft shield.33One such ion source is available as model 2U500 from NRD Inc., 2937 AltBoulevard North, Grand Island NY 140721292.D2872 12148.3.1 Allow the glass sample containers to cool in thecooling rack for a minimum of 60 min, and a maximum of 180min.8.3.2 When mass change is being determined, use twoseparate containers for this determination. After cooling, de-termine the mass of these containers using an analyticalbalance having a resolution of 0.001 g or better. Separatelyplace each container vertically on the balance,
