ASTM D1754_D1754M-09 英文版

Designation: D 1754/D 1754M – 09 Standard Test Method for Effects of Heat and Air on Asphaltic Materials (Thin-Film Oven Test)1 This standard is issued under the fixed designation D 1754/D 1754M; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval. 1. Scope 1.1 This test method covers the determination of the effects of heat and air on a film of semisolid asphaltic materials. The effects of this treatment are determined from measurements of selected asphalt properties before and after the test. 1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.3 Warning—Mercury has been designated by the United States Environmental Protection Agency and many state agen- cies as a hazardous material that can cause central nervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury containing products. See the applicable Material Safety Data Sheet (MSDS) for details and EPA’s website—http://www.epa.gov/ mercury/index.htm—for additional information. Users should be aware that selling mercury and/or mercury containing products into your state may be prohibited by state law. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility 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 Documents 2.1 ASTM Standards:2 D 5 Test Method for Penetration of Bituminous Materials D 113 Test Method for Ductility of Bituminous Materials D 2170 Test Method for Kinematic Viscosity of Asphalts (Bitumens) D 2171 Test Method for Viscosity of Asphalts by Vacuum Capillary Viscometer D 3666 Specification for Minimum Requirements for Agen- cies Testing and Inspecting Road and Paving Materials D 4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing E 1 Specification for ASTM Liquid-in-Glass Thermometers E 145 Specification for Gravity-Convection and Forced- Ventilation Ovens E 1137/E 1137M Specification for Industrial Platinum Re- sistance Thermometers 3. Summary of Test Method 3.1 A film of asphaltic material is heated in an oven for 5 h at 163°C [325°F]. The effects of heat and air are determined from changes incurred in physical properties measured before and after the oven treatment. An optional procedure is provided for determining the change in sample mass. 3.2 Precision values for the method have been developed for viscosity, viscosity change, penetration change, mass change, and ductility. 4. Significance and Use 4.1 This method indicates approximate change in properties of asphalt during conventional hot-mixing at about 150°C [302°F] as indicated by viscosity, penetration, or ductility measurements. It yields a residue which approximates the asphalt condition as incorporated in the pavement. If the mixing temperature differs appreciably from the 150°C [302°F] level, more or less effect on properties will occur. NOTE 1—The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of Specification D 3666 are generally considered capable of competent and objective testing and sampling. 1 This test method is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.46 on Durability and Distillation Tests. Current edition approved July 1, 2009. Published July 2009. Originally approved in 1960. Last previous edition approved in 2002 as D 1754 – 97 (2002). 2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website. 1 Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. 5. Apparatus 5.1 Oven—The oven shall be electrically heated and shall conform to the performance requirements of Specification E 145, Type IB (Gravity-Convection), for operating tempera- tures up to 180°C [356°F]. During the tests for compliance to Specification E 145 requirements, the oven shelf, properly centered as described in 5.1.2 shall be in place and rotating. 5.1.1 Construction—The oven shall be rectangular, and each interior dimension (exclusive of space occupied by the heating element) shall be a minimum of 330 mm [13 in.] and a maximum of 535 mm [21 in.]. The oven shall have, in front, a tightly fitted hinged door, which shall provide a clear opening substantially the same as the interior height and width of the oven. The door may contain a window with dimensions of at least 100 by 100 mm [4 by 4 in.] and with two sheets of glass separated by an air space, through which a vertical thermom- eter, located as specified in 5.2, may be read without opening the door; or the oven may be provided with an inner glass door, through which the thermometer may be observed on opening the outer door momentarily. The oven shall be adequately ventilated by convection currents of air and for this purpose shall be provided with openings for the entrance of air and for the exit of heated air and vapors. Openings may be of any size and arrangement provided the requirements of Specification E 145, Type IB, are met. 5.1.2 Rotating Shelf—The oven shall be provided with a single metal circular shelf having a minimum diameter of 250 mm [9.8 in.] and a maximum diameter of 450 mm [18 in.]. The shelf construction shall be such that it provides a flat surface for support of the containers without blocking all air circulation through the shelf when the containers are in place. The shelf shall be suspended by a vertical shaft and centered with respect to the horizontal interior dimensions of the oven and shall be provided with a mechanical means of rotating it at the rate of 5.5 6 1.0 r/min. The preferred vertical position for the shelf is 150 mm [6 in.] above the bottom of the oven (exclusive of space occupied by the heating element), and the shelf shall be located as close to this position as permitted by compliance with the requirements of 5.2 regarding thermometer placement. The shelf shall be constructed or marked in such a way that the sample containers can be placed in the same position during each test. There shall be a minimum of two and a maximum of six sample container positions. Each sample container position shall be symmetrical with respect to the shaft and to any holes in the shelf. The number of sample container positions shall be the maximum that will fit on the shelf without violating the above requirements and without excessive overhang. 5.2 Thermometric Device—An ASTM Loss on Heat Ther- mometer having a range from 155 to 170°C and conforming to the requirements for Thermometer 13C, as prescribed in Specification E 1, or a Grade A platinum resistance thermom- eter, commonly known as a PRT or an RTD (or both), conforming to Specification E 1137/E 1137M, connected to a meter readable to 0.1°, and verified accurate at 163°C [325°F], shall be used for determining the test temperature. The 13C thermometer, if used, shall be supported from the shaft of the circular shelf in a vertical position at a point equidistant from the center and outer edge of the shelf. The bottom of the thermometer bulb shall be 40 mm [1.5 in.] above the top of the shelf. The thermometer shall be radially centered over a sample container position. If a PRT or RTD is used for determining the test temperature, it shall be independent of the oven tempera- ture control system and the tip of the measuring sensor shall be positioned 40 mm [1.5 in.] above the top of the shelf and centered over the arc of the rotating pans. Thermometric devices shall be calibrated when initially installed, and their accuracy at 163°C [325°F] shall be verified at least annually thereafter. 5.3 Container—Cylindrical pans, 140 6 1 mm [5.5 6 0.04 in.] in inside diameter and 9.5 6 1.5 mm [3⁄8 6 1⁄16 in.] deep with a flat bottom. Fifty millilitres of the sample in this size container give a film thickness of approximately 3.2 mm [1⁄8 in.]. Pans shall be made of stainless steel and shall have a metal thickness of approximately 0.64 mm [0.025 in.]. NOTE 2—Pans have a tendency to become warped or bent with use. Although tests indicate that a small amount of warping does not significantly affect results, frequent inspection to eliminate warped or damaged pans is advisable. The indicated metal thickness has been found to provide adequate rigidity without excessive weight. Stainless steel pans manufactured from 0.6-mm thick [No. 24] stainless sheet gauge steel comply with the recommended thickness. Pans made from 0.48 mm-thick [No. 26] stainless sheet gauge metal are also acceptable but have a greater tendency to warp during use. 5.4 Balance—A balance conforming to the requirements of guide D 4753, Class G2. 6. Preparation of Oven 6.1 Ensure that the thermometric device tip is positioned 40 mm [1.5 in.] above the top of the shelf and centered over the arc of the rotating pans. 6.2 Ensure the oven is level so that the shelf rotates in a horizontal plane. The maximum tilt during rotation shall not be more than 3° from the horizontal. 6.3 Preheat oven for a minimum of two hours prior to testing, with the control setting adjusted to the setting that will be used during the test. The setting shall be selected such that when the oven is fully loaded, the oven will equilibrate at 163.0 6 1°C [325 6 2°F]. NOTE 3—Removing sample containers will affect convection patterns in the oven, and may cause the temperature reading to change from the desired reading. This is normal, and occurs because the thermometric device is not in the same location as the temperature control sensor. Replacing the containers should cause the temperature reading to return to the original reading. 7. Preparation of Samples 7.1 Place sufficient material for the test in a suitable container and heat to a fluid condition. Extreme care should be taken so that there is no local overheating of the sample and that the highest temperature reached is not more than 163°C [325°F]. Stir the sample during the heating period, but avoid incorporating air bubbles in the sample. Transfer 50 6 0.5 g into each of two or more tared containers meeting the require- ments of 5.3. 7.2 At the same time, pour a portion of the sample into the containers specified for measurement of original asphalt prop- erties. Complete the tests by appropriate ASTM Test Methods D 5, D 2170, or D 2171. D 1754/D 1754M – 09 2 7.3 If the quantitative value of the mass change is desired, cool the samples for the oven test to room temperature and determine the mass of each sample separately to the nearest 0.001 g. If the mass change is not required, allow the samples to cool to approximately room temperature before placing in the oven as directed in 8.1. 8. Procedure 8.1 With the oven preheated and adjusted as described in 6.3, quickly place the asphalt samples in the predetermined sample container positions on the circular shelf (Note 4 and Note 5). Fill any vacant positions with empty sample contain- ers, so that every sample container position is occupied. Close the oven door and start rotating the shelf. Maintain the specified temperature range for 5 h after the sample has been introduced and the oven has again reached that temperature. The 5-h period shall start when the temperature reaches 162°C [323°F] and in no case shall the total time that a sample is in the oven be more than 51⁄4 h. At the conclusion of the heating period, remove the samples from the oven. If the mass change is not being determined, proceed in accordance with 8.3. If the mass change is being determined, cool to room temperature, determine the mass to the nearest 0.001 g, and calculate the mass change on the basis of the asphalt in each container (Note 6). NOTE 4—Materials having different mass change characteristics should not generally be tested at the same time due to the possibility of cross-absorption. NOTE 5—This test method does not prohibit placing an asphalt sample in the position under the mercury thermometer. However, it is recom- mended that this position not be used for a sample, and that an empty pan remain in this position, in order to minimize the risk associated with thermometer breakage. NOTE 6—When complete tests cannot be made in the same day, and if the mass change is being determined, determine the masses of the residues and store them overnight before reheating. If the mass change is not being determined, transfer the residue to the 240-mL [8-oz] container as described in 8.3 before storing overnight. 8.2 After determining the mass of the samples, place them on a refractory-board and then on the shelf of the oven maintained at 163°C [325°F]. Close the oven and rotate the shelf for 15 min and immediately proceed as described in 8.3. 8.3 Remove each pan individually and transfer the contents by pouring and scraping into a seamless metal container of approximately 240-mL [8-oz] capacity. Remove substantially all of the material from the pans by scraping with a suitable tool such as a spatula or putty knife. While the residue is being removed from each pan, the oven door shall remain closed, with the heater power on, and the remaining samples rotating on the shelf. The final pan shall be removed from the oven within 5 min of the removal of the initial pan. Stir the combined residues thoroughly, in a semi fluid state, until homogenous. If needed, heat the combined residues in the covered metal container in an oven at a temperature not exceeding 163°C [325°F]. Complete the tests on residue by appropriate ASTM Test Methods D 5, D 2170, or D 2171 within 72 h of performing this test. NOTE 7—Care should be taken if the sample is reheated, since excessive reheating can affect the apparent severity of the test. 9. Report 9.1 Report the values of the original asphalt properties measured in 7.2 and the residue property values as measured in 8.3. Viscosity change may also be expressed as the ratio of the residual asphalt viscosity to the original asphalt viscosity. Penetration change is evaluated as the penetration of the residue expressed as the percentage of the original penetration. 9.2 Report ductility or other test results in accordance with the appropriate ASTM test methods. 9.3 When determined, report the average mass change of the material in all containers as mass percent of the original material. A mass loss shall be reported as a negative number, while a mass gain shall be reported as a positive number. NOTE 8—This test can result in either a mass loss or a mass gain. During the test, volatile components evaporate (causing a decrease in mass), while oxygen reacts with the sample (causing an increase in mass). The combined effect determines whether the sample has an overall mass gain or an overall mass loss. Samples with a very low percentage of volatile components will usually exhibit a mass gain, while samples with a high percentage of volatile components will usually exhibit a mass loss. NOTE 9—If a skin formation is noted during testing, it should be included in the report. 10. Precision and Bias 10.1 Criteria for judging the acceptability of the viscosity at 60°C [140°F] and 135°C [275°F], viscosity ratio at 60°C [140°F], change in penetration at 25°C [77°F], ductility at 15.6°C [60°F] (average of three measurements), and mass change test results obtained by this method are given in Table 1. The figures given in Column 2 are the standard deviations that have been found to be appropriate for unmodified materi- als and the conditions of test described in Column 1. The figures given in Column 3 are the limits that should not be exceeded by the difference between the results of two properly conducted tests. The figures given in Column 4 are the coefficients of variation that have been found to be appropriate for the materials and conditions of test described in Column 1. The figures given in Column 5 are the limits that should not be exceeded by the difference between the results of two properly conducted tests expressed as a percent of their mean. 10.2 Bias—The bias for this test method cannot be deter- mined because no material with an accepted reference value is available. 11. Keywords 11.1 aging; asphalt cement; Thin-Film Oven Test (TFOT) D 1754/D 1754M – 09 3 APPENDIX (Nonmandatory Information) X1. RECOMMENDED OVEN X1.1 Research conducted in 1992 indicates that the severity of this test is affected by thermometer position, number of sample containers used, oven geometry and shelf geometry. These factors were inadequately controlled in earlier versions of this test, and the 1993 revision addresses these issues. Factors relating to oven and shelf geometry are being handled in this appendix as a recommendation rather than a require- ment, in order to avoid obligating labs to purchase new ovens. X1.2 Recommended Oven Type and Control—The oven shall be electrically heated and shall conform to the perfor- mance requirements of Specification E 145, Type IB (Gravity- Convection), for operating temperatures up to 180°C [356°F]. During the tests for compliance to Specification E 145 require- ments, the oven shelf shall be in place and rotating, with an empty sample container in each of the four sample container positions. The oven temperature shall be regulated by a proportional temperature controller, using a platinum resis- tance temperature detector or a thermistor sensor mounted 25 mm [1 in.] below the roof of the test chamber, and beneath one of the vent holes. This temperature sensor shall not be used in place of the test thermometric device described in 5.2. X1.3 Recommended Oven Construction—The oven shall be rectangular with interior height of 380 mm [15 in.], interior width of 480 mm [19 in.], and interior depth of 460 mm [18 in.]. These dimensions are exclusive of space occupied by the heating elements and the door. All heating elements shall be located in the bottom of the oven. The oven shall have, in front, a tightly fitted hinged door, which shall provide a clear opening substantially the same as the interior height and width of the oven. The door shall contain a window with dimensions of at least 200 mm [8 in.] high and 300 mm [12 in.] wide. The window shall consist of two sheets of glass separated by an air space, through which a vertical thermometer, located as speci- fied in 5.2, may be read without opening the door. The top of the test chamber shall have exactly two vent openings, one on each side of the oven. Each opening shall have a diameter of 25 mm [1 in.]. Each opening shall be located 75 mm [3 in.] from the side, and centered between the front and back of the test chamber. These openings shall remain unobstructed when- ever the oven is in operation. There shall be no openings on the sides of the test chamber. Other openings may be of any size and type provided the requirements of Specification E 145, Type IB, are met. X1.4 Recommended Rotating Shelf—