1、Designation: D 6307 05Standard Test Method forAsphalt Content of Hot-Mix Asphalt by Ignition Method1This standard is issued under the fixed designation D 6307; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. 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 test method covers the determination of asphaltcontent of hot-mix asphalt (HMA) paving mixtures and pave-ment samples by re
3、moving the asphalt cement in an ignitionfurnace. The means of sample heating may be the convectionmethod or direct irradiation method.NOTE 1Aggregate obtained by this test method may be used for sieveanalysis. Particle size degradation may occur with some aggregates.1.2 This standard does not purpor
4、t 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 limitation prior to use.2. Referenced Documents2.1 ASTM Standards:2C 670
5、Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC 702 Practice for Reducing Samples of Aggregate toTesting SizeD75 Practice for Sampling AggregatesD 140 Practice for Sampling Bituminous MaterialsD 979 Practice for Sampling Bituminous Paving MixturesD 14
6、61 Test Method for Moisture or Volatile Distillates inBituminous Paving MixturesD 4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD 5444 Test Method for Mechanical Size Analysis of Ex-tracted Aggregate3. Summary
7、 of Test Methods3.1 The asphalt cement in the paving mixture is ignitedusing the furnace equipment applicable to the particularmethod. The asphalt content is calculated by difference fromthe mass of the residual aggregate and moisture content. Theasphalt content is expressed as mass percent of moist
8、ure-freemixtures. Test Method A is intended for furnaces with aninternal, automated weighing system. Test Method B is in-tended for furnaces without an internal weighing system.4. Significance and Use4.1 This test method can be used for quantitative determi-nation of asphalt content in HMA paving mi
9、xtures and pave-ment samples for quality control, specification acceptance, andmixture evaluation studies. This test method does not requirethe use of solvents. Aggregate obtained by this test methodmay be used for gradation analysis according to Test MethodD 5444.5. Apparatus5.1 Balance, readable t
10、o 0.1 g, and capable of measuring themass of sample, sample trays, and catch pan. The balance shallbe in accordance with Guide D 4753, Class GP2.5.2 Sample Tray(s), of appropriate size that allows thesamples to be spread thinly and allows air to flow up throughand around the sample particles. The sa
11、mple shall be enclosedcompletely with screen mesh, perforated stainless steel plate,or other suitable material.NOTE 2Screen mesh or other suitable material with maximum andminimum openings of 3.35 mm and 600 m, respectively, has been foundto perform well.5.3 Catch Pan, of appropriate size to hold th
12、e sample traysso that aggregate particles and melting asphalt binder fallingthrough the screen mesh are caught.5.4 Catch Pan/Sample Tray(s) Handling Apparatus, suitablefor inserting catch pan and sample tray(s) into furnace andremoving hot catch pan and sample tray(s) from furnace.5.5 Assorted Spatu
13、las, Pans, Bowls, and Wire Brushes, forpreparing HMAmixtures and removing aggregate from sampletray(s) and catch pan.1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.25 onAnalysis of Bituminous Mixtures
14、.Current edition approved June 1, 2005. Published July 2005. Originally approvedin 1998. Last previous edition approved in 2004 as D 6307 04.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volu
15、me 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.5.6 Protective Gloves, well insulated and capable of with-standing 580C.5.7 OvensMechanical ovens, convec
16、tion or forced draft,shall be provided for drying aggregates and HMA mixtures,and for preheating HMA mixtures prior to ignition testing.5.8 Ignition Furnace, as described in 8.1.1 or 11.1.1.6. Hazards6.1 The temperature of the furnace, sample, sample tray(s),and catch pan after removal from the furn
17、ace is extremely high.Caution, therefore, must be exercised at all times whenhandling these items as failure to do so could result in seriousinjury, severe burns, or fire. The sample, sample tray(s), andcatch pan should be placed inside a safety cage and should notbe allowed to cool near any materia
18、ls that are subject toignition at the high temperatures used in this procedure. Thefurnace manufacturers instruction manual must be followed totake all necessary precautions.7. Sampling7.1 Obtain samples of aggregate in accordance with PracticeD75.7.2 Obtain samples of HMA in accordance with Practic
19、eD 979.7.3 Preparation of Test Specimens:7.3.1 If the mixture is not soft enough to separate with aspatula or trowel, place it in a large, flat pan and warm in anoven set at 110 6 5C until it can be separated or mixed. Splitor quarter the material in accordance with Practice C 702 untilthe mass of m
20、aterial required for the test is obtained.7.3.2 The size of the test sample shall be governed by thenominal maximum aggregate size of the mixture and shallconform to the mass requirement shown in Table 1 (see Note3).NOTE 3When the mass of the test specimen exceeds the capacity ofthe equipment used (
21、for a particular method), the test specimen may bedivided into suitable increments, tested, and the results combined forcalculation of asphalt content based on the weighted average of the massesused in the increments.7.4 Obtain samples of asphalt cement in accordance withPractice D 140.TEST METHOD A
22、8. Apparatus8.1 In addition to the apparatus listed in Section 5, thefollowing apparatus is required for Test Method A.8.1.1 Ignition FurnaceA forced air ignition furnace thatheats the sample by either convection method or direct-irradiation method. The convection-type furnace must have aminimum tem
23、perature capability of 580C. The furnace shallhave an internal weighing system capable of measuring themass of sample sizes of at least 2500 g. The furnace chambershall be of sufficient size to accommodate sample sizes of atleast 2500 g. A data collection system also shall be included sothat the sam
24、ple mass loss can be determined automatically toan accuracy of 0.1 g and displayed during a test. The test isdeemed complete when the difference between consecutivemeasured mass loss does not exceed 0.01 % of the sample massfor three consecutive 1-min intervals. The equipment shallprovide a printout
25、 of the test results. A system capable ofreducing furnace emissions to an acceptable level also shall beincorporated in the furnace. The furnace shall be vented into ahood or to the outside and when set up properly will have nonoticeable odors escaping into the laboratory. The furnace willhave a fan
26、 with the capability to pull air through the furnace toexpedite the test and to reduce escape of smoke into thelaboratory. The furnace shall be equipped so that the doorcannot be opened during the ignition test.8.1.2 Filters, if required, of the type specified by the furnacemanufacturer.9. Calibrati
27、on9.1 The type of aggregate in the mixture may affect theresults of this test method because different aggregates losemass on ignition to varying degrees. The results also may beaffected by the presence of additives and modifiers in the HMAsample. Accordingly, to optimize accuracy, a calibration fac
28、torshall be established by testing three calibration samples foreach mix type. The calibration shall be performed on aprepared sample of asphalt mixture, which also shall includeadditives and modifiers, if any, to be used.9.2 Obtain samples of blended aggregate to be used in HMAin accordance with 7.
29、1. The sample should be approximatelythe same mass and gradation as that to be used for the HMAtest sample (10.1).9.3 Obtain samples of asphalt cement to be used in HMA inaccordance with 7.4.9.4 Oven-dry the aggregate samples to a constant mass.9.4.1 For the convection-type furnace, set the furnace
30、tem-perature to 540 6 5C for calibration using mixtures.9.4.2 For the direct-irradiation-type furnace, set the burnprofile to the DEFAULT mode.9.5 Heat the aggregates and asphalt cement to approxi-mately 150C. Heat all mixing bowls and tools to approxi-mately 150C.9.6 Prior to the mixing of calibrat
31、ion samples, an initial or“butter” mix is required to condition the mixing equipment.Remove and discard the “butter” mix from the bowl byscraping, leaving a uniform coating of asphalt mix residue.NOTE 4The “butter” mix prevents calibration samples from beingbiased by residual asphalt mix retained in
32、 the mixing bowl.9.7 Prepare three calibration samples at the design asphaltcement content (P). Incorporate additives and modifiers, if any,to be used.9.8 Determine and record the mass of the sample tray(s) andcatch pan to the nearest 0.1 g.TABLE 1 Size of SampleNominal Maximum Aggregate SizeStandar
33、d, mm Minimum Mass of Sample, kg4.75 0.59.5 112.5 1.519.0 225.0 337.5 4D63070529.9 Evenly distribute the sample in the sample tray(s).9.10 Determine the mass of the sample, sample tray(s), andcatch pan to the nearest 0.1 g. Calculate and record the initialmass of the sample (MI).9.11 Heat the calibr
34、ation sample in the convection-typefurnace at 540 6 5C; or in the direct irradiation type furnaceusing the DEFAULT mode until the change in mass of thesample during three consecutive 1-min intervals does notexceed 0.01 % of the sample mass (MI).9.12 Measure and record the mass (ML) of the sample aft
35、erignition to the nearest 0.1 g. The mass can be obtainedimmediately upon completion of the test from the printout ordisplay.9.13 Calculate the calibration factor (CF) as follows:CF5SMI MLMI3 100D P (1)where:MI= total mass of the mixture calibration sample prior toignition,ML= total mass of the mixt
36、ure calibration sample afterignition, andP = percentage of actual asphalt cement in the mix bymass of the total mix expressed as a percentage.9.14 Repeat steps 9.8 through 9.13 for two additionalcalibration samples. Calculate the average calibration factor(CF) by averaging the three CFvalues.9.15 Ca
37、libration Temperature Adjustments9.15.1 For the convection-type furnace, if the calibrationfactor exceeds 1.0 %, lower the test temperature to 482 6 5Cand repeat steps 9.2 through 9.14. Use the calibration factorobtained at 482C even if it exceeds 1.0 %.9.15.2 For the direct irradiation-type furnace
38、, the DE-FAULT burn profile should be used for most materials. Theoperator may select burn profile OPTION 1 or OPTION 2 tooptimize the burn cycle. OPTION 1 is designed for aggregateswith correction factor greater than 1.0 percent. OPTION 2 isdesigned for samples that may not burn completely using th
39、eDEFAULT burn profile.9.16 The temperature or burn profile for testing HMAsamples in 10.3 shall be the same temperature or burn profileselected for testing mixture calibration samples.10. Procedure10.1 Obtain an HMA sample in accordance with Section 7.The sample mass should be approximately the same
40、 as thatused for calibration (9.2).10.2 Oven dry the HMA sample to constant mass at atemperature of 110 6 5C or determine the moisture content ofsamples in accordance with Test Method D 1461, so that themeasured mass loss can be corrected for moisture.10.3 Set the furnace temperature or burn profile
41、 in accor-dance with Section 9. Samples can be placed in the furnace atsignificantly lower temperatures, since the furnace will quicklyheat to the desired temperature once the sample begins to burn.The furnace temperature is likely to increase during theignition phase of the test.10.4 Determine and
42、record the mass of the sample tray(s)and catch pan to the nearest 0.1 g.10.5 Evenly distribute the sample in the sample tray(s).10.6 Determine the mass of the sample, sample tray(s), andcatch pan to the nearest 0.1 g. Calculate and record the initialmass of the sample (MB).10.7 Heat the sample in th
43、e furnace at the specified tem-perature until the difference between consecutive measuredmass loss does not exceed 0.01 % of the sample mass (MB) forthree consecutive 1-min intervals. This point shall be deter-mined automatically by the furnaces data collection system.10.8 The furnaces data collecti
44、on system shall measure andrecord automatically the aggregate mass (MA) of the sampleafter ignition to the nearest 0.1 g. The mass shall be obtainedimmediately upon completion of tests by subtracting the massloss measured by the furnace from the initial mass of the mix(MB).10.9 The corrected asphalt
45、 content shall be calculated auto-matically by the furnaces data collection system as follows:% AC 5SMB MAMB3 100D CF(2)where:AC = measured asphalt content percent by mass of theoven-dry HMA sample,MA= total mass of aggregate remaining after ignition,MB= total mass of the HMA sample prior to ignitio
46、n, andCF= calibration factor obtained in Section 9 and enteredinto the furnaces data collection system.TEST METHOD B11. Apparatus11.1 In addition to the apparatus listed in Section 5, thefollowing apparatus is required for Test Method B.11.1.1 Furnace, having a minimum temperature capabilityof 580C
47、and equipped with a fan capable of pulling airthrough the furnace to expedite the test and to reduce escape ofsmoke into the laboratory. The furnace chamber shall be ofsufficient size to accommodate samples sizes of at least 2500 g.A system capable of reducing furnace emissions to an accept-able lev
48、el also shall be incorporated in the furnace. The furnaceshall be vented into a hood or to the outside, and when set upproperly, will have no noticeable odors escaping into thelaboratory. The furnace shall be equipped so that the doorcannot be opened during the ignition test.11.1.2 Filters, if requi
49、red, of the type specified by thefurnace manufacturer.12. Calibration12.1 The results of this test method may be affected by thetype of aggregate in the mixture because different aggregateslose mass on ignition to varying degrees. The results also maybe affected by the presence of additives and modifiers in theHMA sample. Accordingly, to optimize accuracy, a calibrationfactor shall be established by testing three calibration samplesfor each mix type. The calibration shall be performed on asample of prepared asphalt mixture, which also shall includeadditives
