1、Designation: D 2844 07Standard Test Method forResistance R-Value and Expansion Pressure of CompactedSoils1This standard is issued under the fixed designation D 2844; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the procedure for testing bothtreated and untreated laboratory compacted soils or aggregateswith
3、the stabilometer and expansion pressure devices to obtainresults indicative of performance when placed in the base,subbase, or subgrade of a road subjected to traffic.1.2 The values stated in SI units are to be regarded as thestandard. However, use of equipment manufactured to bereadable in inch-pou
4、nd units only should not be considered asnon-conformance to the test method. Many stabilometers andexpansion pressure devices are manufactured to be readable ininch-pound units only.1.3 All observed and calculated values shall conform to theguidelines for significant digits and rounding established
5、inPractice D 6026.1.3.1 For purposes of comparing measured or calculatedvalue(s) with specified limits, the measured or calculatedvalue(s) shall be rounded to the nearest decimal or significantdigits in the specified limits.1.3.2 The procedures used to specify how data are collected/recorded or calc
6、ulated, in this standard are regarded as theindustry standard. In addition, they are representative of thesignificant digits that generally should be retained. The proce-dures used do not consider material variation, purpose forobtaining the data, special purpose studies, or any consider-ations for
7、the users objectives; and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations. It is beyond the scopeof this standard to consider significant digits used in analyticalmethods for engineering design.1.4 This standard does not purp
8、ort 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. Referenced Documents2.1 ASTM Standards:2C 6
9、70 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsD 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 3740 Practice for Minimum Requirements for AgenciesEngaged in the Testing and/or Inspection of Soil and Rockas Used in Engineering Design a
10、nd ConstructionD 6026 Practice for Using Significant Digits in Geotechni-cal DataE4 Practices for Force Verification of Testing MachinesE11 Specification for Wire Cloth and Sieves for TestingPurposes2.2 AASHTO Documents:T 190 Test Method for Resistance R-Value and ExpansionPressure of Compacted Soil
11、s32.3 ASTM Adjuncts:4Exudation DeviceExpansion Pressure ApparatusStabilometer3. Terminology3.1 For definitions of terms in this test method, refer toTerminology D 653.4. Significance and Use4.1 This test method is used to measure the potentialstrength of subgrade, subbase, and base course materials
12、foruse in road and airfield pavements. The R-value is used by1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.08 on Special andConstruction Control Tests.Current edition approved Feb. 1, 2007. Published March 2007.
13、Originallyapproved in 1969. Last previous edition approved in 2001 asD 2844 01e1.2For 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 page
14、 onthe ASTM website.3Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.4Copies of detailed drawings of the apparatus shown in Figs. 4 (1 drawing), 6 (4drawings), 7 and 8 (7 d
15、rawings) are available at a nominal cost from ASTMInternational Headquarters. RequestAdjunct Nos.ADJD284401,ADJD284402, andADJD284403, respectively.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
16、PA 19428-2959, United States.some agencies as criteria for acceptance of aggregates for basecourse and bituminous courses.4.2 The expansion pressure testing has been used in con-junction with the R-value test to determine cover requirements(thickness) and construction controls to reduce pavementdist
17、ortion from expansive subgrade soils.NOTE 1The quality of the result produced by this standard isdependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D 3740 are generally considered capable of
18、competentand objective testing/sampling/inspection/etc. Users of this test methodare cautioned that compliance with Practice D 3740 does not in itselfensure reliable results. Reliable results depend on many factors; PracticeD 3740 provides a means of evaluating some of those factors.5. Apparatus5.1
19、Kneading Compactor, capable of applying an averagecontact pressure of 24106 110 kPa (350 6 16 psi) to thetamper foot shown in Fig. 1 and with provisions for maintain-ing this pressure during changes in sample height. The load-time trace shall be free of “chatter” or evidence of impact-associated cha
20、nges in slope. The rise time for application offoot pressure, in the range from 240 to 2070 kPa (35 to 300psi), shall not be less than 0.07 nor more than 0.20 s. The dwelltime, measured at 300 psi foot pressure, shall not be less than0.15 nor more than 0.45 s. The pressure-release or removaltime sha
21、ll not be greater than 0.60 s.5.1.1 The compactor shall include a counter or timer formeasuring the number of tamps applied to a specimen and amold holder, for use in compacting specimens, that rotatesequally between tamps to give 5 to 7 tamps per revolution ofthe mold. The holder shall firmly restr
22、ain the mold duringcompaction. The base of the mold holder shall have a metalplate 100.8. (33132 in mm) in diameter and 12.7 mm (0.5 in.)high to which is cemented a rubber disk having a diameter of100.0 mm (31516 in.) and a height of 3.2 mm. (18 in). The plateshall be an integral part of the base of
23、 the mold holder. Thecompactor shall also include a trough for feeding the sampleinto the mold in 20 increments (Fig. 2). Troughs with asemicircular cross section of 39 cm2(6 in.3) in area and 50.8 cm(20 in.) long have proven satisfactory.5.2 Compression Testing Machine, with a minimum capac-ity of
24、45 kN(10 000 lbf ) and satisfying the requirements ofPractices E4.5.3 Mold, 101.6 6 0.05 mm (4 6 0.002 in.) inside diameterby 127 6 0.20 mm (5 6 0.008 in.) high. (See Fig. 3 for surfaceroughness.)5.4 Rubber Disks, 100 mm (31516 in. ) in diameter by 3 mm(18 in.) thick and having a durometer hardness
25、of 60 6 15.5.5 Metal Follower, solid-walled, metal specimen follower100.33 6 0.13 mm (3.95 6 0.005 in. ) in outside diameter by127 mm (5 in.) long.5.6 Exudation Device, as shown in Fig. 4.45.7 Phosphor Bronze Disk, as shown in Fig. 5.5.8 Filter Paper, 100 mm in diameter and .15 mm (0.006in.) thick,
26、smooth surface, medium filtering speed, mediumretention.5.9 Filter Paper, 110 mm in diameter and .15 mm (0.006in.) thick, creped surface, medium-fast filtering speed, mediumretention.5.10 Expansion-Pressure Device, with accessories as shownin Fig. 6.4There should be at least three of these devices f
27、oreach sample to be tested within a days time.5.11 Deflection Gage, with divisions of 0.002 mm (0.0001in.) and an allen wrench as shown in Fig. 6.5.12 Stabilometer, with accessories, as shown in Fig. 7 andFig. 8.45.13 Standard Metal Specimen, 101.60 mm. (4 in) in outsidediameter by 152.2 mm (6 in.)
28、high as shown in Fig. 8.5.14 Balance, 5000-g capacity, accurate to 1 g.5.15 Sieves, 25.0 mm (1 in.), 19.0 mm (34 in.) and 4.75 mm(No. 4) conforming to the requirements of Specification E11.5.16 Miscellaneous Equipment, including mixing pans,spoons, spatulas, and gallon cans with close-fitting lids.6
29、. Soil Preparation6.1 Remove any coatings from coarse aggregate and breakclay lumps to pass the 4.75-mm (No. 4) sieve.6.2 Adjust the soil graduation when some of the material isretained on the 19.0-mm (34-in.) sieve. When 75 % or morepasses the 19.0mm (34-in). sieve, use that part of the samplepassi
30、ng the 19.0mm (34-in.) sieve. If less than 75 % of thesample passes the 1-in. sieve use that part of the samplepassing the 25.0-mm (1-in. ) sieve.7. Preparation of Soil Specimens7.1 Thoroughly mix four 1200-g samples of soil with theamount of water estimated to equal one half to two thirds of thewat
31、er required to produce saturation as defined in 7.3 and 7.4.Place the samples in covered containers and allow them tostand overnight. Just prior to compaction, mix the samples withthe final amount of water required to produce saturation. Thefirst sample is used as a pilot specimen to assist in deter
32、miningthe final amount of water required.7.2 Weigh out enough material to fabricate a compactedsample 101.6 mm (4 in.) in diameter by 63 mm (2.5 in.) high.FIG. 1 Tamper Shoe for Kneading CompactorD 2844 072Compacted specimens having heights from 62 to 65 mm (2.45to 2.55 in.) are acceptable. Compact
33、the soil into the mold bymeans of the kneading compactor as follows: Place the mold inthe mold holder which has a rubber disk, 100 mm (31516 in.)in diameter and 3 mm (18 in.) thick, cemented to the plate.Adjust the mold for approximately 3-mm (18-in. ) clearancebetween the lower edge of the mold and
34、 base of the moldholder. Spread the sample along the length of the trough. Withthe compactor-foot pressure set at 1720 6 170 kPa (250 6 25psi), feed 76 mm (3 in.) of the soil from the trough into themold. Redistribute the sample remaining in trough as needed tofeed the balance of the soil into the m
35、old in 20 equalincrements with one application of the ram after each incre-ment. Allow 10 additional tamps to level the soil, then place arubber disk on top of the specimen.Apply 100 additional tampswith a foot pressure of 2410 kPa (350 psi). Stop compactingthe soil at any time before 100 tamps if w
36、ater appears aroundthe bottom of the mold.NOTE 2Use lower compaction pressures when necessary to limitpenetration of the ram into the soil to not greater than 6 mm (14 in.).7.3 Remove the mold containing the compacted specimenfrom the compactor. Level the tamped surface by hand tampingwith a 38-mm (
37、1.5-in.) diameter rod. Place a phosphor-bronzedisk on the tamped surface of the soil and place a filter paperon top of the bronze disk. Invert the mold and place it on theexudation device so that the filter paper is on the bottom. Placethe solid walled, metal specimen follower into the mold. Usingth
38、e compression testing machine, apply a uniformly increasingpressure to the soil at the rate of 8900 N(2000 lbf )/min. Watershould be exuded from the soil at 2070 kPa (300 psi) asevidence that enough moisture is present to produce saturation.Stop the loading and record the exudation pressure to thene
39、arest 10 kPa (1 psi) when either five of the six outer lights onthe exudation pressure device are lighted or three outer lightsare lighted and free water is visible around the bottom of themold. Do not exceed a exudation pressure of 5520 kPa (800psi).7.4 Mold at least two more specimens with differe
40、ntamounts of moisture so that a range of exudation pressuresfrom 690 to 5520 kPa (100 to 800 psi) (Note 3) is obtainedwhich brackets the 2070 kPa (300 psi) value. For some highvolume-change soils, additional specimens having exudationpressures lower than 100 psi may be necessary to obtainexpansion p
41、ressures that are low enough to provide a suitablerange of data for a complete expansion pressure analysis of thesoil.NOTE 3Occasionally, material from very plastic, clay-test specimenswill extrude from under the mold and around the follower ram during theFIG. 2 Compactor with Sample Feed TroughD 28
42、44 073loading operation. If this occurs when the 5520-kPa(800-psi) point isreached and fewer than five lights are lighted, the soil should be reportedas less than 5 R-value. Coarse granular materials and clean sands mayrequire the use of paper baskets to permit testing.8. Calibration of Expansion-Pr
43、essure Apparatus8.1 Calibrate the spring-steel bar of the expansion-pressuredevice (Fig. 6) by applying upward measured loads at thecenter of the bar and measuring the respective deflections ofthe bar with the deflection dial indicator.8.2 The steel spring bar is considered in calibration whenthe me
44、asured deflections are within the following tolerances:Applied Load Dial Reading, in. (mm)3.75 (8) 0.055 6 0.005 (0.00216 0.0002)7.50 (16) 0.110 6 0.005 (0.0042 6 0.0002)11.25 (24) 0.1656 0.005 (0.0063 6 0.0002)15.00 (32) 0.2206 0.005 (0.0084 6 0.0002)8.3 If the deflection dial indicator does not ch
45、eck the abovereadings, loosen the top frame bar and adjust the position of theshims, between the frame and the spring steel bar, until therequired readings are obtained.NOTE 4Some models of the expansion-pressure apparatus have setscrew adjustments in lieu of shims.9. Expansion-Pressure Testing9.1 A
46、llow the test specimen to rebound in a covered moldfor at least 30 min after determination of the exudationpressure.9.2 Place deflection dial indicator in position on theexpansion-pressure device with the single-bearing end of thegage base resting on the adjustment ring.9.3 Using an allen wrench, ra
47、ise or lower the adjustmentplug until the deflection dial indicator measures 0.025 mm( 1.0010 in. ). The deflection dial indicator will read 00.229mm. (0090 in.).9.4 Place the perforated disk with stem firmly on the face ofthe compacted specimen in the mold and place the mold in theexpansion-pressur
48、e device after placing creped surface filterpaper on the turntable.9.5 Seat the perforated disk firmly on the specimen withpressure applied by the fingers. Raise the turntable on theexpansion device until the deflection dial indicator reads zero.If the device was properly adjusted, according to 7.3,
49、 this willapply the preset surcharge deflection of 0.025 mm (0.0010 in.).9.6 Rotate the specimen height measuring device toward thebase of the turntable until it rests on the outer edge of theturntable.9.7 Record the height of the specimen as indicated to thenearest 2.5 mm (0.1 in.).9.8 Put approximately 200 mL of water into the mold andallow pressure from expansion of the specimen to develop for16 to 24 h.NOTE 5Do not leave a test specimen unconfined by the expansion-pressure device while there is free water on top of the specimen in themold.9.9 Read the def
