1、Designation: D3387 11Standard Test Method forCompaction and Shear Properties of Bituminous Mixturesby Means of the U.S. Corps of Engineers Gyratory TestingMachine (GTM)1This standard is issued under the fixed designation D3387; the number immediately following the designation indicates the year ofor
2、iginal adoption or, in the case of revision, 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.1. Scope1.1 This method employs a testing machine (Fig. 1) thatgenerates
3、a precisely controlled gyratory kneading processwhich is used to prepare and test specimens of bituminouspaving mixtures. This method is intended for use in bituminousmixtures design and control testing as well as acceleratedtraffic simulation. The objective is to compact to the ultimate inplace den
4、sity under the anticipated vertical stress while moni-toring the process in terms of unit mass, and shearing resis-tance including the plastic properties. Particular attention isgiven to the development of the plastic properties associatedwith the compaction phenomenon. The maximum permissiblebitume
5、n content is indicated directly by the first evidence of aprogressive increase in shear strain (as indicated by a progres-sive increase in the gyratory angle) accompanied by a progres-sive reduction in shear strength (as indicated by a progressivereduction in roller pressure.) The procedures describ
6、ed here arefor mix design and plant control as well as accelerated trafficsimulation.1.2 This test method covers two separate modes of opera-tion of the Gyratory Testing Machine (GTM), namely: (1)GTM oil-filled roller mode; and (2) GTM air-filled roller mode.With the air filled roller, the GTM machi
7、ne angle variesaccording to the resistance encountered during the gyratorykneading process. Thus the GTM using the air-filled roller isconsidered a better mechanical analog of the interactionbetween pneumatic tire and pavement structure.1.3 This test method is for use with mixtures containingasphalt
8、 cement, asphalt binder cutback asphalt, asphalt emul-sion. Test molds are available in 4- in. (101.6 mm), 6-in. (152.4 mm), and 8-in. (203.2 mm)diameters with correspondingheight of 8-in (203.2 mm), 10-in.(254.0 mm), and 12-in. (304.8mm) respectively. These molds can accommodate maximumparticle siz
9、es of 1 in. (25.4 mm) 1.5-in. (38.1 mm) and 2.0-in.(50.8 mm) respectively.1.4 UnitsThe values stated in inch pound units are to beregarded as standard. The values given in parentheses aremathematical conversions to SI units that are provided forinformation only and are not considered standard.1.5 Th
10、e text of this standard references notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of the standard.1.6 This standard may involve hazardous materials, opera-tions, and equipment. This standa
11、rd does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM
12、Standards:2D3666 Specification for Minimum Requirements for Agen-cies Testing and Inspecting Road and Paving MaterialsE1 Specification for ASTM Liquid-in-Glass Thermometers3. Terminology3.1 Definitions:3.1.1 Critical roller pressure, pthe roller pressure re-quired for a Gyratory Shear Factor (GSF) e
13、qual to unity. Thatis, the roller pressure when SG = tmax. (See Annex A1)3.1.2 Equilibrium densitydensity when a rate of densifi-cation of 1 lb/ft3(16 kg/m3) per 100 revolutions of the GTMroller carriage is reached. This rate of densification is intendedto duplicate the ultimate in place density.3.1
14、.3 Gyratory Anglemeasure of the magnitude of thegyratory strain u. Four pertinent angles are defined as follows:3.1.3.1 Machine angle (machine setting) u0.3.1.3.2 Minimum gyratory angle or shear strain umin.3.1.3.3 Maximum gyratory angle or shear strain umax.3.1.3.4 Final gyratory angle uf. This is
15、the angle at theconclusion of test.1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.26 onFundamental/Mechanistic Tests.Current edition approved Aug. 1, 2011. Published September 2011. Originallyapproved
16、 in 1974. Last previous edition approved in 2003 as D3387 03. DOI:10.1520/D3387-11.2For 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 to the standards Document Summary pa
17、ge onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.FIG. 1 Largest Model of Gyratory Testing MachineD3387 1123.1.4 Gyratory Compactibility Index (GCI)the ratio of theunit mass (total mix) at 30 revolutions of the GT
18、M to the unitmass (total mix) at 60 revolutions of the GTM.3.1.5 Gyratory Compression Modulus (Eg)a calculatedvalue based upon the gyratory shear modulus Gg and ameasured or assumed value of Poissons ratio . Eg=2Gg(1+)3.1.6 Gyratory Shear Factor (GSF)the ratio of the mea-sured gyratory shear strengt
19、h to the theoretical maximuminduced pavement shear stress; SG / tmax. This is a factor ofsafety type index with regard to failure in simple shear for thedefined loading conditions. The GSF value is not applicablewhen GSI 1.03.1.7 Gyratory Shear Modulus (Gg)The gyratory shearSG divided by the gyrator
20、y shear strain tanu,(Gg=SG/ tan u0)3.1.8 Gyratory Shear Strength (SG)the shear resistance ofthe specimen which is, among other things, a function of theimposed vertical pressure and degree of strain. The SGvalue isinfluenced by the characteristics of the aggregate, binder andlevel of densification a
21、chieved.3.1.9 Gyratory Stability Index (GSI)the ratio of the maxi-mum gyratory angle to the minimum gyratory angle umax/umin.4. Significance and Use4.1 The GTM test method described here is intended to beused to determine the maximum allowable bitumen content,establish unit mass requirements, and ar
22、rive at a rational shearstrength. The GTM is also used to conduct accelerated trafficsimulation. It is essential that the vertical pressure correspondsto the maximum anticipated vertical contact pressure betweentire and pavement, since the theoretical stress for compactionand maximum induced shear i
23、s based on the concept ofemploying maximum anticipated loads.4.2 The use of this method fin the selection of the optimumbitumen content is limited to mixtures that are susceptible tothe development of excess pore pressure when the voidsbecome overfilled with bitumen. This applies to dense gradedHMA
24、but does not apply to SMA mixes or to open gradedfriction courses. (This restriction does not apply to the gyratorystrength factor, GSF.)Agyratory stability index (GSI) in excessof unity, overfilled voids and therefore serves to establish themaximum permissible bitumen content. The optimum bitumenco
25、ntent should be selected at a value of GSI equals one. Thisis established by interpolation of a graph of GSI vs. bitumencontent. An increase in this index indicates an excessivebitumen content for the compaction pressure employed andforetells instability of the bituminous mixture for the loadingempl
26、oyed.Areduction in roller pressure during the compactionprocess likewise indicates loss of stability because of overfilledvoids; this phenomenon also serves as an indicator of maxi-mum allowable bitumen content as does the increase ofgyratory angle which gives a stability index in excess of unity.4.
27、3 It must be pointed out that the gyratory angle, being ameasure of shear strain, is highly sensitive to temperature,especially on the rich side of optimum where the voids areoverfilled and the shear stress is being transferred to thebituminous phase.Also, once the voids become over-filled, thebitum
28、inous mixture is subject to the phenomenon that may bebest described as “stress-softening”, that is flattening of thestress-strain curve (reduction in stability) with continuedkneading. Attempts to relate GSI values to performance is notrecommended other than to identify the maximum permissiblebitum
29、en content as that at which the GSI value starts to exceedone.NOTE 1The quality of the results produced by this standard aredependent on the competence of the personnel performing the procedureand the capability, calibration, and maintenance of the equipment used.Agencies that meet the criteria of S
30、tandard Practice D3666 are generallyconsidered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance withD3666 alone does not completely assure reliable results. Reliable resultsdepend on many factors; following the suggestions of D3
31、666 or somesimilar acceptable guideline provides a mean of evaluating and controllingsome of those factors.5. Apparatus5.1 Gyratory Testing Machine (GTM) and AppurtenancesThe primary equipment for this test is the Gyratory TestingMachine (GTM) and appurtenances. Fig. 1 is a photograph ofthe largest
32、model GTM which is equipped to test 4-in. (101.6mm), 6-in. (152.4 mm), or 8-in. (203.2 mm) specimens. Referto manufacturers manual for more information.5.2 Supplementary Equipment the following conventionalmaterials testing laboratory equipment will be required:5.2.1 OvensVentilated ovens shall be p
33、rovided for heatingaggregates, bituminous material, and specimen molds and forcuring cut-back mixes and emulsion mixes. It is recommendedthat the heating units be thermostatically controlled so as tomaintain the required temperature within 5F (2.8C).5.2.2 Balances, one having a capacity of 5 kg or m
34、ore,sensitive to 1.0 g and one having a capacity of 2 kg, sensitiveto 0.1 g.5.2.3 ThermometersArmored glass or dial-type thermom-eters with metal stems are recommended. A range from 50 to400F (9.9 to 20.4C) with sensitivity of 5F (2.8C) isrequired.5.2.4 Miscellaneous ApparatusTrowels, spatulas, scoo
35、ps,spoons, gloves, rubber gloves, metal pans.5.36. Test Specimens6.1 Refer to manufacturers manual for detail information.6.2 Prepare at least three specimens for each combination ofaggregate and bitumen. Include a range of bitumen contents soas to fully develop the compaction curve, develop a smoot
36、hcurve of GSI vs. bitumen content and have at least threebitumen contents in which the gyratory angle shows progres-sive increase with continued compaction. Conduct check testson outliers as necessary to insure smooth curves of density,GSI and gyratory shear vs. bitumen content6.3 Preparation of Agg
37、regatesSeparate the aggregate intothe various size fractions necessary for accurately recombininginto test mixtures conforming to specified grading require-ments.6.4 Preparation of MixturesCombine the freeoven-driedaggregates into appropriate size batches. See 6.6 for size ofcompacted specimens. Hea
38、t the aggregate to the desiredD3387 113temperature, into the aggregate mixture. Mixing of the aggre-gate and bitumen shallshould be as thorough and rapid aspossible; mechanical mixing is recommended.NOTE 2For estimating purposes use 156.0 pounds/cubic foot ( 2.5Mg/m3) as the unit weight of compacted
39、 specimen.6.5 For mixes employing penetration/viscosity/PG grades ofasphalt, the temperature of the aggregate and asphalt at thetime of mixing should correspond to the temperatures antici-pated to be used at the plant during manufacture of the pavingmix. These temperatures will generally be somewher
40、e in therange of 250 to 325F (121 to 163C).6.6 For mixtures employing liquid bitumen (cutbacks oremulsions), the asphalt need not be heated but the aggregateshould be dried to constant weight at 221 to 230 F (105 toFIG. 2 GTM Compaction and Shear TestD3387 114110C). Cool the aggregate to room temper
41、ature and then mixwith liquid bitumen. Following mixing, cure the loose mixturein a ventilated oven maintained at 221 to 230 F (105 to110C) for at least 12 hours prior to compaction at thistemperature. The mix may be stirred occasionally duringcuring to accelerate loss of volatiles.6.7 Size of Speci
42、mensThe GTM can prepare a wide rangeof specimen lengths in the different diameter molds, includingduplications of actual pavement thickness. It is recommendedthat for most purposes, a ratio of 1 to 1 of diameter to heightbe used so as to obtain the most favorable ratio of particle sizeto mold size f
43、or height as well as diameter. Recommendedsizes are:Mold Diameter Specimen Height4 to 4.01 inches (101.6 to101.9 mm)3.5 to 4 inches (88.9 to 101.6mm)6 to 6.01 inches (152.4 to152.7 mm)5.5 to 6 inches (139.7 to 152.4mm)8 to 8.01 inches (203.2 to203.5 mm)7.5 to 8 inches (190.5 to 203.2mm)NOTE 3Trial b
44、atches might be needed to verify the batch weights toobtain desired specimen heights.7. Calibration and Standardization7.1 Refer to manufacturers manual for detail information.8. Test Procedure8.1 Compaction and Shear Test8.1.1 Set the GTM heater control to the maximum antici-pated pavement temperat
45、ure. Install the mold chuck frontclamp piece and turn the heater on. Allow sufficient time forthe heater indicator light to show that the temperature has beenattained by lighting up intermittently (approximately 1 hour isrequired).8.1.2 Prepare three initial batches of mix at each of thefollowing su
46、ggested bitumen contents: (1) At the estimatedoptimum bitumen content (2) 0.5% less than estimated opti-mum (3) 0.5% greater than estimated optimum. Conductadditional tests and check tests for outliers as required ensuringfully developed smooth curves of density, GSI and gyratoryshear vs. bitumen co
47、ntent. Include at least three specimens forwhich GSI exceeds one.8.1.3 Test parameters to be checked, input, or recordedinclude the following:8.1.3.1 Material Type bituminous mix8.1.3.2 Location where test material will be in pavementstructure surface/subsurface including thickness of coverlayers8.1
48、.3.3 Contact Pressure to be estimated from anticipatedmaximum tire pavement contact pressure as pavement designcriteria8.1.3.4 Vertical Pressure the program calculates and dis-plays the needed vertical pressure based on the design contactpressure, thickness of cover layers and type of materials inpu
49、tby the operator8.1.3.5 Quantity of Material8.1.3.6 Percent bitumen8.1.3.7 Specimen Description8.1.3.8 Test Termination Condition (Equilibrium Density,Specimen Height, Density or Number of Revolutions)NOTE 4New GTM program allows the user four different options forcontrolling the end-point of the compaction process. Refer to manufac-turers manual for more information8.1.4 Set Vertical Pressure which the specimen will besubjected to under design contact pressure during use. Sub-surface material will obviously experience lower st
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