1、Designation: D3791/D3791M 11Standard Practice forEvaluating the Effects of Heat on Asphalts1This standard is issued under the fixed designation D3791/D3791M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a procedure for evaluating some ofthe effects on asphalts of heating in the presence of little or noair.1.2 Th
3、e values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the st
4、andard.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 practices and determine the applica-bility of regulatory limitations prior to use.2. Refer
5、enced Documents2.1 ASTM Standards:2D5 Test Method for Penetration of Bituminous MaterialsD36 Test Method for Softening Point of Bitumen (Ring-and-Ball Apparatus)D140 Practice for Sampling Bituminous MaterialsD1079 Terminology Relating to Roofing and WaterproofingD2170 Test Method for Kinematic Visco
6、sity of Asphalts(Bitumens)D2171 Test Method for Viscosity of Asphalts by VacuumCapillary ViscometerD4402 Test Method for Viscosity Determination of Asphaltat Elevated Temperatures Using a Rotational ViscometerE1 Specification for ASTM Liquid-in-Glass ThermometersE145 Specification for Gravity-Convec
7、tion and Forced-Ventilation OvensE230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized ThermocouplesE1137/E1137M Specification for Industrial Platinum Resis-tance Thermometers3. Terminology3.1 DefinitionsDefinitions of terms used in this practicecan be found in Terminol
8、ogy D1079.4. Summary of Practice4.1 A sample of asphalt in a loosely covered container isheated to a temperature chosen by the investigator for a periodof5h6 10 min. Certain characteristics of the asphalt after heatexposure at the test temperature chosen are then compared withthose characteristics b
9、efore exposure.NOTE 1Aset temperature is required when this practice is used as partof a specification. Historically, a temperature of 204C 400F has beenused.5. Significance and Use5.1 When asphalts are maintained at elevated temperaturesin the presence of air, their characteristics may change. Cert
10、ainblown asphalts also soften when maintained near, and particu-larly above, their final blowing temperatures under virtuallyair-free conditions. This may happen if the asphalt is over-heated for application purposes. This practice provides auniform heat-treatment procedure and methods for evaluatin
11、gthe effect of this treatment on some of the characteristics ofasphalts. Changes observed when asphalts are overheated arenot indicative of changes to be expected when asphalts areheated to normal application temperatures.6. Apparatus6.1 OvenA forced-ventilation oven conforming to therequirements fo
12、r Type IIA as prescribed in Specification E145,capable of maintaining temperatures up to 300C 572F, andwith a chamber at least 300 by 300 by 300 mm 12 by 12 by12 in.6.2 ThermometerASTM Low-Distillation Thermometer,having a range from 1 to + 300C 30 to 580F andconforming to the requirements for Therm
13、ometers 7C or 7F asprescribed in Specification E1.1This practice is under the jurisdiction ofASTM Committee D08 on Roofing andWaterproofing and is the direct responsibility of Subcommittee D08.03 on Surfacingand Bituminous Materials for Membrane Waterproofing and Built-up Roofing.Current edition app
14、roved Nov. 1, 2011. Published November 2011. Originallyapproved in 1979. Last previous edition approved in 2011 as D3791/D3791M 04(2011)1. DOI: 10.1520/D3791_D3791M11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual
15、Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2.1 As an alternative, any other thermometric device usedshall be at least: (
16、1) of equal accuracy to that of the thermom-eter specified in Specification E1,(2) capable of indicatingtemperature to within 1C 2F, and (3) stable to within 1C2F for the duration of the exposure.6.2.2 When used, platinum resistance thermometers shall bein accordance with the requirements of Specifi
17、cation E1137/E1137M.6.2.3 When used, thermocouples shall be in accordancewith the requirements of Specification E230.6.3 Containers, triple-seal, friction-top, 1-L1-qt and 0.5-L1-pt cans with lids, free of any interior resinous or lacquercoatings.6.4 Laboratory Timer.6.5 Hot Plate.7. Sampling7.1 Sam
18、ple the asphalt in accordance with Practice D140.8. Test Specimen and Sample8.1 Heat a minimum of 1 L 1 qt of the asphalt on the hotplate. Stir occasionally to prevent local overheating. Keepcovered whenever possible to minimize volatiles loss. Heat thematerial until sufficiently fluid to pour, but
19、in no case more than93C 200F above the softening point of the asphalt.8.2 When molten, pour the asphalt into a 0.5-L 1-ptcontainer to within 25 6 2 mm 1.0 6 0.1 in. of the top, andalso pour test specimens for determination of the characteris-tics of the original material in accordance with the metho
20、dslisted in Section 10. Test these specimens within the time limitsspecified by the respective test procedures.NOTE 2Pour a small amount of the asphalt in the groove around thetop of the can, sufficient to act as a seal when the lid is placed loosely inposition.8.3 Cover the container loosely with a
21、 lid and set aside tocool. Subject the sample to heat treatment within 18 to 24 hafter pouring.9. Procedure9.1 Preheat the test oven to the selected temperature. Placethe container on a shelf in the oven so as to permit aircirculation around it.9.2 Start the laboratory timer when the container has b
22、eenplaced in the oven and the door closed. Continue the heatingfor5h.9.3 Remove the container from the oven after 5 h. Removethe lid; if a skin is present, remove it carefully before allowingthe asphalt to cool. Stir the molten asphalt gently.9.4 Cool the sample to approximately the original pouring
23、temperature. Gently stir the sample to avoid air entrapment.Then, proceed to pour the test specimens.10. Test Methods10.1 Characteristics of asphalt before and after heat expo-sure may be evaluated in duplicate by any desired procedures,but the following methods are recommended:10.1.1 Softening Poin
24、tTest Method D36.10.1.2 PenetrationTest Method D5.10.1.3 ViscosityTest Method D2170 or D2171 or D4402.11. Report11.1 Report the heat-exposure temperature used.11.2 Report the presence or absence of a skin on theheat-exposed sample.11.3 Report the tests used to evaluate the sample before andafter hea
25、t exposure and the individual test result from eachprocedure.12. Keywords12.1 asphalts; heat exposure; overheated; physical propertychangesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this s
26、tandard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years
27、andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee
28、, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2
29、959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D3791/D3791M 112
