1、Standard Method of Test for Effect of Heat and Air on a Moving Film of Asphalt Binder (Rolling Thin-Film Oven Test) AASHTO Designation: T 240-131ASTM Designation: D2872-04 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 200
2、01 TS-2b T 240-1 AASHTO Standard Method of Test for Effect of Heat and Air on a Moving Film of Asphalt Binder (Rolling Thin-Film Oven Test) AASHTO Designation: T 240-131ASTM Designation: D2872-04 1. SCOPE 1.1. This test is used to measure the effect of heat and air on a moving film of asphalt binder
3、 and to provide residue for additional testing. The effects of this treatment are determined from measurements of the properties of the asphalt binder before and after the test. 1.2. The values stated in SI units are to be regarded as the standard. 1.3. This standard may involve hazardous materials,
4、 operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
5、 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 231, Weighing Devices Used in the Testing of Materials M 320, Performance-Graded Asphalt Binder R 16, Regulatory Information for Chemicals Used in AASHTO Tests R 18, Establishing and Implementing a Quality Management System for Construction Materials
6、 Testing Laboratories 2.2. ASTM Standards: C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials E1, Standard Specification for ASTM Liquid-in-Glass Thermometers E220, Standard Test Method for Calibration of Thermocouples By Comparison Techni
7、ques E644, Standard Test Methods for Testing Industrial Resistance Thermometers 2.3. NCHRP Document: NCHRP Web-Only Document 71 (Project 09-26), Precision Estimates for AASHTO Test Method T 308 and the Test Methods for Performance-Graded Asphalt Binder in AASHTO Specification M 320 2015 by the Ameri
8、can Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 240-2 AASHTO 3. SUMMARY OF TEST METHOD 3.1. A moving film of asphaltic material is heated in an oven for 85 min at 163C (325F). The effects of heat and air are dete
9、rmined from changes in physical test values as measured before and after the oven treatment. The residue from this test is also used for additional testing as required in M 320. An optional procedure is provided for determining the change in sample mass. 3.2. Precision values for this test method ha
10、ve been developed for viscosity at 60C (140F), ductility at 15.6C (60F), and mass change. 4. SIGNIFICANCE AND USE 4.1. This method indicates the approximate change in properties of asphalt binder during conventional batch plant mixing at about 150C (302F) as indicated by viscosity and other rheologi
11、cal measurements. The residue from this test is also used to determine the conformance of an asphalt binder to M 320. It yields a residue that approximates the condition of the asphalt binder immediately after the pavement is constructed. If the mixing temperature differs appreciably from 150C (302F
12、), more or less effect on the properties will occur. This method can also be used to determine mass change, which is a measure of asphalt binder volatility and mass changes resulting from oxidation. 5. APPARATUS 5.1. OvenA double-walled electrically heated convection type with inside dimensions as f
13、ollows: a height of 381 mm (15 in.), a width of 483 mm (19 in.), and a depth (with door closed) of 445 13mm (171/2 1/2in.). The door shall contain a symmetrically located window with dimensions of 305- to 330-mm (12- to 13-in.) wide by 203- to 229-mm (8- to 9-in.) high. The window shall contain two
14、sheets of heat-resistant glass separated by an air space. The window should permit an unobstructed view of the interior of the oven. The heating element shall be located below the oven floor and shall be adequate to maintain the required temperature. The oven shall be vented at the top and bottom. T
15、he bottom vents shall be located symmetrically to supply incoming air around the heating elements. They shall have an open area of 15.0 0.7 cm2(2.31 0.11 in.2). The top vents shall be symmetrically arranged in the upper part of the oven and have an open area of 9.3 0.45 cm2(1.45 0.07 in.2). 5.1.1. T
16、he oven shall have an air plenum covering the side walls and ceiling, the air space being 38 mm (11/2in.) deep from the walls and ceiling. At a midpoint in the width of the oven and 152 mm (6 in.) from the face of the circular metal carriage to its axis, a squirrel cage-type fan 133.4 mm (51/4in.) o
17、utside diameter by 73 mm (27/8in.) wide shall be turned at 1725 r/min by an externally mounted motor. The squirrel cage fan shall be set so that the fan turns in an opposite direction to its vanes. The air flow characteristics of the fan-plenum system shall be suctioned from the floor of the oven th
18、rough the wall plenums with the air exiting through the fan. Figures 1 and 2 show details of this fan-plenum system. 5.1.2. The oven shall be equipped with a proportional temperature controller capable of maintaining a temperature of 163 1.0C (325 1.8F). The sensing element of the controller may be
19、placed at any location that enables the oven to maintain temperature control as specified in this standard. The temperature controller shall be capable of bringing the fully loaded oven back to the test temperature within a 10-min period after insertion of the samples in a preheated oven. 5.1.3. A t
20、hermometer shall be hung from or affixed to a mounting in the ceiling, which is 51 mm (2 in.) from the right side of the oven at a midpoint in the depth of the oven so that the bulb of the 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication
21、 is a violation of applicable law.TS-2b T 240-3 AASHTO thermometer or the tip of the sensor of the alternative thermometric device is within 25 mm (1 in.) of an imaginary line level to the shaft of the circular metal carriage. 5.1.4. The oven shall be provided with a 305-mm (12-in.) diameter vertica
22、l circular carriage (see Figure 2 for details). This carriage shall be provided with suitable openings and clips for firmly holding eight glass containers (see Figure 3) in a horizontal position. The vertical carriage shall be mechanically driven through a 19-mm (3/4-in.) diameter shaft at a speed o
23、f 15 0.2 r/min. 5.1.5. The oven shall be equipped with an air jet positioned to blow heated air into each container at its lowest point of travel. The air jet shall have an outlet orifice 1.02 mm (0.04 in.) in diameter (No. 60 drill) connected to a 7.6-m (25-ft) length of 7.9-mm (5/16-in.) O.D. refr
24、igeration copper tubing. This tubing shall be coiled to lie flat on the bottom of the oven and lead to a source of fresh-dried, dust-free, regulated air. The tubing in the bottom of the oven shall be exposed to the plenum of the oven and shall not be covered by aluminum foil or other material. Figur
25、e 1Schematic of Air Flow Front View 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.Figure 2Circular Metal Carriage Drill for 6.4-mm (1/4-in.) DiaMechanical Screw, 4 placesequally spaced on279.4-mm 0.8 m
26、m(11-in. 1/32in.) Dia B.C.Eight 66.7-mm 0.8 mm(15/8-in. 1/32in.) DiaHoles equally spaced on203.2-mm 0.8 mm(8-in. 1/32in.) Dia B.C.3.2 mm 0.8 mm (1/8in. 1/32in.) thick 304.8-mm 0.8 mm (12-in. 1/32in.) DiaAluminum Discs, 3 requiredSample Bottle RetainerSpring Clips282.6 mm 12.7 mm (111/8in. 1/2in.)228
27、.6 mm 3.2 mm (9 in. 1/8in.)ThermocoupleSensorThermometerSample BottleCopper Tube Air Line7.9 mm 0.8 mm(5/16in. 1/32in.) DiaOrifice1.016 mm 0.051 mm(0.040 in. 0.002 in.)6.4 mm 1.6 mm(1/4in. 1/16in.)12.7-mm 0.8 mm O.D. 6.4-mm 0.8 mm I.D. 55.6 mm 1.6 mm Long (1/2-in. 1/32in. O.D. 1/4-in. 1/32in. I.D. 2
28、3/16-in. 1/16in. Long)Spacers, 4 required12.7-mm 0.8 mm O.D. 6.4-mm 0.8 mm I.D. 20.6 mm 1.6 mm Long (1/2-in. 1/32in. O.D. 1/4-in. 1/32in. I.D. 13/16-in. 1/16in. Long)Spacers, 4 required19.0-mm (3/4-in.) DiaShaftOven111.1 mm 4.8 mm(43/8in. 3/16in.)Air Plenum88.9 mm 3.2 mm(31/2in. 1/8in.)190.5mm5.6mm(
29、71/2in.7/32in.)177.8mm6.4mm(7in.1/4in.)Front View Side ViewTS-2bT240-4AASHTO 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 240-5 AASHTO Figure 3Sample Container Note 1Activated Silica Gel treat
30、ed with an indicator is a satisfactory desiccant for the dried air. 5.2. FlowmeterThe flowmeter may be any suitable type capable of measuring the airflow at a rate of 4000 100 mL/min. The flowmeter shall be located downstream of all regulating devices and upstream of the copper coil. The flowmeter s
31、hall be positioned so it is maintained at approximately room temperature. The flowmeter shall be standardized at least every 12 months using a wet-test meter or other method. This standardization shall be based on airflow exiting the air jet and shall be conducted with the oven off and at room tempe
32、rature. 5.3. ThermometerAn ASTM 13C (13F) thermometer as prescribed in ASTM E1 with an accuracy of 0.2C (0.5F). The thermometer shall be calibrated according to the requirements specified in R 18. This thermometer shall be used to make all temperature measurements required by this method. In order t
33、o reduce the risks associated with thermometer breakage, the thermometer may be fully or partially encapsulated in an optically transparent polymer sheath having a maximum thickness of 0.25 mm (0.01 in.). If a sheath is used, it shall be installed such that there is substantial mechanical contact wi
34、th the thermometer. The thermometer shall be standardized after installation of the sheath. 5.3.1. The test thermometer may be replaced with an alternative thermometric device, provided the following requirements are met: 2015 by the American Association of State Highway and Transportation Officials
35、.All rights reserved. Duplication is a violation of applicable law.TS-2b T 240-6 AASHTO 5.3.1.1. The thermometric device shall be mounted in the same position as the test thermometer it replaces. 5.3.1.2. The thermometric device shall (1) have a maximum scale error no greater than that of the test t
36、hermometer it replaces, and (2) be capable of indicating temperature within 0.1C (0.2F). 5.3.1.3. The thermometric device shall be standardized at the interval specified in R 18. Guidance for performing the standardization is given in ASTM E220 or E644. 5.4. ContainerThe container in which the aspha
37、lt binder is to be tested shall be of heat-resistant glass, with a smooth interior, conforming to the dimensions shown in Figure 3. Glass may be treated (e.g., frosted) on its exterior for handling purposes. 5.5. BalanceIf the loss on heating is desired, a Class B balance conforming to the requireme
38、nts of M 231 is required. If only the residue is desired, a Class G 2 balance conforming to M 231 may be used. The balance shall be standardized according to the requirements specified in R 18. 5.6. Cooling RackA wire or sheet metal rack, constructed of stainless steel or aluminum, which allows the
39、sample containers to cool in a horizontal position. The rack shall be constructed in a way that allows air to flow freely around each container with at least 25-mm (1-in.) clearance between containers, and at least 25-mm (1-in.) clearance between the containers and any solid surface. 5.7. Electronic
40、 Level (Optional)A precision level for measuring the levelness of the support provided by the circular openings in the metal carriage. The length shall be at least 125 mm (5 in.), and the width shall be 30 3 mm (1.2 0.1 in.). The bearing surface of the level shall be ground flat. Resolution, accurac
41、y, and repeatability shall be 0.1 degree. The level shall have a hold button freeze so that the level can be read after removing the level from the carriage. Note 2An SPI Tronic Digital Level PRO 360 or its equivalent has been found suitable for this purpose. The device may be purchased through loca
42、l or mail order suppliers of machine tools. 6. PREPARATION OF OVEN 6.1. Position the air outlet orifice so that it is 6.4 mm (1/4in.) from the opening of the glass container. The orifice shall also be so positioned that the jet blows horizontally into the center of the container opening when the rot
43、ating container is at its lowest position. 6.2. Position the thermometer specified in Section 5.3 so that the end of the bulb of the thermometer is within 25 mm (1 in.) of an imaginary line level to the center of the shaft holding the revolving carriage. If an alternative thermometric device is used
44、, position it as specified in Section 5.3 so that the tip of the sensor is within 25 mm (1 in.) and level to the center of the shaft holding the revolving carriage. 6.3. Adjust the oven so that the horizontal axes of the glass containers, when in position in the carriage, are level to within 1.0 deg
45、ree. This shall be accomplished by checking the carriage, not by checking the level of the oven. A recommended procedure for ensuring that the containers are level to 1.0 degree is given in the Appendix. Alternative procedures may be used to ensure that the carriage is level to within 1.0 degree. Ch
46、eck for wear in the bearing every 6 months and when the levelness of the carriage is checked. Note 3The bearing that supports the metal carriage is subject to wear, and excessive wear is known to allow the carriage to tilt. This affects the levelness of the containers and creates the potential for b
47、inder to creep from the bottles. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 240-7 AASHTO 6.4. Start the fan. The fan shall remain on when the oven heater is on and the oven door is closed. T
48、he fan may be stopped when the oven door is opened. Stopping the fan may be accomplished manually, with an electronic door interlock, or through other means. 6.5. Preheat the oven for a minimum of 2 h prior to testing, with the temperature controller adjusted to the setting that will be used during
49、the test. This setting shall be selected such that when the oven is fully loaded and the air is on, the oven will equilibrate at 163.0 1.0C (325 1.8F), as indicated by the test thermometer. Note 4Because the presence of sample containers affects the temperature distribution in the oven, containers must be present in the oven when the controller setting is determined. The use of empty containers is acceptable for this purpose. 7. PROCE
