1、Designation: D6927 06D6927 15Standard Test Method forMarshall Stability and Flow of BituminousAsphalt Mixtures1This standard is issued under the fixed designation D6927; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast 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 test method covers measurement of resistance to plastic flow of 102 mm (4 in.)4 in. (102 mm) cylindrical specimens
3、of bituminousasphalt paving mixture loaded in a direction perpendicular to the cylindrical axis by means of the Marshall apparatus.This test method is for use with dense graded bituminousasphalt mixtures prepared with asphalt cement (modified and unmodified),cutback asphalt, tar, and tar-rubber with
4、 maximum size aggregate up to 25 mm (1 in.)1 in. (25 mm) in size (passing 25 mm (1 in.)1in. (25 mm) sieve).1.2 UnitsThe values stated in SIinch-pound units are to be regarded as the standard. The values given in parentheses are forinformation only. mathematical conversions to SI units that are provi
5、ded for information only and are not considered standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicabilit
6、y of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction MaterialsD1188 Test Method for Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using Coated SamplesD2726 T
7、est Method for Bulk Specific Gravity and Density of Non-Absorptive Compacted Bituminous MixturesD3549 Test Method for Thickness or Height of Compacted Bituminous Paving Mixture SpecimensD3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving MaterialsD6752 Te
8、st Method for Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using Automatic VacuumSealing MethodD6926 Practice for Preparation of Bituminous Specimens Using Marshall ApparatusE2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids3. Terminolog
9、y3.1 Definitions:3.1.1 lab mix lab compacted (LMLC) asphalt mixture, nasphalt mix samples that are prepared in the laboratory by weighingand blending each constituent then compacting the blended mixture using a laboratory compaction apparatus.3.1.1.1 DiscussionLMLC typically occurs during the asphal
10、t mixture design phase. Laboratory compaction devices such as the Superpave GyratoryCompactor, Marshall Hammer, or other laboratory compaction devices may be used.3.1.2 plant mix laboratory compacted (PMLC) asphalt mixture, nasphalt mixture samples that are manufactured in aproduction plant, sampled
11、 prior to compaction, then immediately compacted using a laboratory compaction apparatus.3.1.2.1 Discussion1 This test method is under the jurisdiction ofASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.20 on MechanicalTests of BituminousAsphalt Mi
12、xtures.Current edition approved July 1, 2006Feb. 1, 2015. Published November 2006April 2015. Originally approved in 2004. Last previous edition approved in 20052006 asD6927 05D6927 06.1 . DOI: 10.1520/D6927-06.10.1520/D6927-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or c
13、ontactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have
14、been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official docum
15、ent.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1PMLC specimens are often used for quality control testing. The asphalt mixture is not permitted to cool substantially and it maybe necessary to place the mixture in a laboratory oven
16、 to equilibrate the mixture to the compaction temperature before molding.Laboratory compaction devices such as the Superpave Gyratory Compactor, Marshall Hammer, or other laboratory compactiondevices may be used.3.1.3 reheated plant mix lab compacted (RPMLC) asphalt mixture, nasphalt mixture samples
17、 that are manufactured in aproduction plant, sampled prior to compaction, allowed to cool to room temperature, then reheated in a laboratory oven andcompacted using a laboratory compaction apparatus.3.1.3.1 DiscussionRPMLC are often used for quality acceptance and verification testing. The reheating
18、 time should be as short as possible to obtainuniform temperature to avoid artificially aging the specimens. Asphalt mixture conditioning, reheat temperature, and reheat timeshould be defined in the applicable specification. Laboratory compaction devices such as the Superpave Gyratory Compactor,Mars
19、hall Hammer, or other laboratory compaction devices may be used.4. Significance and Use4.1 Marshall stability and flow values along with density; air voids in the total mix, voids in the mineral aggregate, or voidsfilled with asphalt, or both, filled with asphalt are used for laboratory mix design a
20、nd evaluation of bituminousasphalt mixtures.In addition, Marshall stability and flow can be used to monitor the plant process of producing bituminousasphalt mixture. Marshallstability and flow may also be used to relatively evaluate different mixes and the effects of conditioning such as with water.
21、4.1.1 Marshall stability and flow are bituminousasphalt mixture characteristics determined from tests of compacted specimensof a specified geometry. The Marshall Test can be conducted with two different types of equipment: (1) MethodAusing a loadingframe with a load ring and a dial gauge for deforma
22、tion or flow meter (Traditional Method) or (2) Method Busing aload-deformation recorder in conjunction with a load cell and linear variable differential transducer (LVDT) or other automaticrecording device (Automated Method).4.1.2 Typically, Marshall stability is the peak resistance load obtained du
23、ring a constant rate of deformation loading sequence.However, depending on the composition and behavior of the mixture, a less defined type of failure has been observed, as illustratedin Fig. 1. As an alternative method, Marshall stability can also be defined as the load obtained, when the rate of l
24、oading increasebegins to decrease, such that the curve starts to become horizontal, as shown in the bottom graph of Fig. 1. The magnitude ofMarshall Stability varies with aggregate type and grading and bitumen type, grade and amount. Various agencies have criteria forMarshall stability.FIG. 1 Flow D
25、etermination for Two Types of Specimen FailureD6927 1524.1.3 Marshall flow is a measure of deformation (elastic plus plastic) of the bituminousasphalt mix determined during thestability test. In both types of failure, the Marshall flow is the total sample deformation from the point where the project
26、ed tangentof the linear part of the curve intersects the x-axis (deformation) to the point where the curve starts to become horizontal.As shownin Fig. 1, this latter point usually corresponds to the peak stability; however, as an alternative when the failure condition is notclearly defined, it can b
27、e selected as the point on the curve which is six (0.01 in.) flow points (or 1.5 or 0.01 in. (1.5 mm) to theright of the tangent line. There is no ideal value but there are acceptable limits. If flow at the selected optimum binder content isabove the upper limit, the mix is considered too plastic or
28、 unstable and if below the lower limit, it is considered too brittle.4.1.4 The Marshall stability and flow test results are applicable to dense-graded bituminousasphalt mixtures with maximum sizeaggregate up to 25 mm (1 in.)1 in. (25 mm) in size. For the purpose of mix design, Marshall stability and
29、 flow test results shouldconsist of the average of a minimum of three specimens at each increment of binder content where the binder content varies inone-half percent increments over a range of binder content. The binder content range is generally selected on the basis ofexperience and historical te
30、sting data of the component materials, but may involve trial and error to include the desirable rangeof mix properties. Dense-graded mixtures will generally show a peak in stability within the range of binder contents tested.Stability, flow, density, air voids, and voids filled with asphalt binder,
31、may be plotted against binder content to allow selection ofan optimum binder content for the mixture. The above test properties may also be weighted differently to reflect a particular mixdesign philosophy. In addition, a mixture design may be required to meet minimum voids in the mineral aggregate
32、based onnominal maximum aggregate size in the mixture.4.1.5 Field laboratory Marshall stability and flow tests on specimens made with plant-produced bituminous mix plant mixlaboratory compacted (PMLC) asphalt mixture mix may vary significantly from laboratory design values because of differencesin p
33、lant mixing versus laboratory mixing. This includes mixing efficiency and aging.4.1.6 Significant differences in Marshall stability and flow from one set of tests to another or from an average value of severalsets of data or specimens, prepared from plant-produced mix may indicate poor sampling, inc
34、orrect testing technique, change ofgrading, change of binder content, or a malfunction in the plant process. The source of the variation should be resolved and theproblem corrected.4.1.7 Specimens will most often be prepared using Practice D6926 but may be prepared using other types of compactionpro
35、cedures as long as specimens satisfy geometry requirements. Other types of compaction may cause specimens to have differentstress strain characteristics than specimens prepared by Marshall impact compaction. Marshall stability and flow may also bedetermined using field cores from in situ pavement fo
36、r information or evaluation. However, these results may not compare withresults from laboratory-prepared Lab Mix Lab Compacted (LMLC) Asphalt Mixture, Plant Mix Laboratory Compacted (PMLC)Asphalt Mixture, or Reheated Plant Mix Lab Compacted (RPMLC) Asphalt Mixture specimens and shall not be used for
37、specification or acceptance purposes. One source of error in testing field cores arises when the side of the core is not smooth orperpendicular to the core faces. Such conditions can create stress concentrations in loading and low Marshall stability.NOTE 1The quality of the results produced by this
38、standard are dependent on the competence of the personnel performing the procedure and thecapability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capableof competent and objective testing/sampling/inspection/etc.
39、 Users of this standard are cautioned that compliance with Specification D3666 alone does notcompletely assure reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or some similar acceptableguideline provides a means of evaluating and controllin
40、g some of those factors.5. Apparatus5.1 Breaking HeadThe testing head (Fig. 2) shall consist of upper and lower cylindrical segments of cast gray or ductile iron,cast steel, or annealed steel tubing. The lower segment shall be mounted on a base having two perpendicular guide rods or posts(minimum 12
41、.5 mm (12 in.)in. (12.5 mm) in diameter) extending upwards. Guide sleeves in the upper segment shall direct the twosegments together without appreciable binding or loose motion on the guide rods. A circular testing head with an inside bevelhaving dimensions other than specified in Fig. 2 has been sh
42、own to give results different from the standard testing head.5.2 Compression Loading MachineThe compression loading machine (Fig. 3) may consist of a screw jack mounted in atesting frame and shall be designed to load at a uniform vertical movement of 50 6 5 mm/min. (2.00 6 0.15 in./min).2.00 6 0.15i
43、n./min (50 6 5 mm/min). The design in Fig. 3 shows power being supplied by an electric motor. A mechanical or hydrauliccompression testing machine may also be used provided the rate of loading can be maintained at 50 6 5 mm/min (2.00 6 0.15in./min).2.00 6 0.15 in./min (50 6 5 mm/min).5.3 Load Measur
44、ing DeviceAs a minimum, a calibrated nominal 20 kN (5000 lb)5000 lb (20 kN) ring dynamometer (Fig. 3)with a dial indicator to measure ring deflection for applied loads is required. The 20 kN (5000 lb)5000 lb (20 kN) ring shall havea minimum sensitivity of 50 N (10 lb).10 lb (50 N). The dial indicato
45、r should be graduated in increments of 0.0025 mm (0.0001in.)0.0001 in. (0.0025 mm) or finer. The ring dynamometer should be attached to the testing frame (see ring holding bar, Fig. 3)and an adapter (see ring dynamometer adapter, Fig. 3) should be provided to transmit load to the breaking head. The
46、ringdynamometer assembly may be replaced with a load cell connected to a load-deformation recorder or computer provided capacityand sensitivity meet above requirements.NOTE 2A higher capacity ring dynamometer may be required for high-stability mixes. These include mixes with harsh, crushed aggregate
47、 and densegradation, as well as mixes made with very stiff binders.D6927 1535.4 FlowmeterThe Marshall flowmeter consists of a guide sleeve and a gage (Fig. 4). The activating pin of the gage shall slideinside the guide sleeve with minimal friction and the guide sleeve shall slide freely over the gui
48、de post (see Fig. 4) of the breakinghead. These points of frictional resistance shall be checked before tests. Graduations of the flowmeter gage shall be increments of0.25 mm (0.01 in.)0.01 in. (0.25 mm) or finer. Instead of a flowmeter, other devices such as an indicator dial or linear variablediff
49、erential transducer (LVDT) connected to a load-deformation recorder or computer may be used. These alternate devices shouldbe capable of indicating or displaying flow (deformation) to the required sensitivity. These devices must be designed to measureand record the same relative movement between the top of the guide post guide-post and the upper breaking head.5.5 Water BathThe water bath shall be deep enough to maintain the water level a minimum of 30 mm (1.25 in.)1.25 in. (30mm) above the top of specimens. The bath shall be thermostatically controlled so as
