1、Designation: D2844 071Standard Test Method forResistance R-Value and Expansion Pressure of CompactedSoils1This standard is issued under the fixed designation D2844; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEAdded research report information to Section 12 editorially in September 2010.1. Scope*1.1 This test method covers the procedure fo
3、r testing bothtreated and untreated laboratory compacted soils or aggregateswith 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
4、 as thestandard. However, use of equipment manufactured to bereadable in inch-pound 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 value
5、s shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.3.1 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 lim
6、its.1.3.2 The procedures used to specify how data are collected/recorded or calculated, 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, pur
7、pose forobtaining the data, special purpose studies, or any consider-ations for 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
8、used in analyticalmethods for engineering design.1.4 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 re
9、gulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsD653 Terminology Relating to Soil, Rock, and ContainedFluidsD3740 Practice for Minimum Requirements for AgenciesEngaged in
10、Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD6026 Practice for Using Significant Digits in GeotechnicalDataE4 Practices for Force Verification of Testing MachinesE11 Specification for Woven Wire Test Sieve Cloth and TestSieves2.2 AASHTO Documents:T 190 Tes
11、t Method for Resistance R-Value and ExpansionPressure of Compacted Soils32.3 ASTM Adjuncts:4Exudation DeviceExpansion Pressure ApparatusStabilometer3. Terminology3.1 For definitions of terms in this test method, refer toTerminology D653.1This test method is under the jurisdiction ofASTM Committee D1
12、8 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. Originallyapproved in 1969. Last previous edition approved in 2001 as D2844011. DOI:10.1520/D2844-07.2For referenced ASTM st
13、andards, 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 onthe ASTM website.3Available from American Association of State Highway and TransportationOfficials (A
14、ASHTO), 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 drawings) are available at a nominal cost from ASTMInternational Headquarters. RequestAdjunct Nos.ADJD284
15、401,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, PA 19428-2959, United States.4. Significance and Use4.1 This test method is used to measure the potentia
16、lstrength of subgrade, subbase, and base course materials foruse in road and airfield pavements. The R-value is used bysome 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 t
17、o determine cover requirements(thickness) and construction controls to reduce pavementdistortion 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 us
18、ed. Agencies that meet thecriteria of Practice D3740 are generally considered capable of competentand objective testing/sampling/inspection/etc. Users of this test methodare cautioned that compliance with Practice D3740 does not in itselfensure reliable results. Reliable results depend on many facto
19、rs; PracticeD3740 provides a means of evaluating some of those factors.5. Apparatus5.1 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 heig
20、ht. The load-time trace shall be free of “chatter” or evidence of impact-associated changes 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, s
21、hall not be less than0.15 nor more than 0.45 s. The pressure-release or removaltime shall 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 betw
22、een tamps to give 5 to 7 tamps per revolution ofthe mold. The holder shall firmly restrain 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
23、in.) and a height of 3.2 mm. (18 in). The plateshall be an integral part of the base of 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
24、 have proven satisfactory.5.2 Compression Testing Machine, with a minimum capac-ity of 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,
25、 100 mm (31516 in. ) in diameter by 3 mm(18 in.) thick and having a durometer hardness 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
26、, as shown in Fig. 5.5.8 Filter Paper, 100 mm in diameter and .15 mm (0.006in.) thick, 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
27、, with accessories as shownin Fig. 6.4There should be at least three of these devices foreach 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. 8.4
28、5.13 Standard Metal Specimen, 101.60 mm. (4 in) in outsidediameter by 152.2 mm (6 in.) 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 Equip
29、ment, including mixing pans,spoons, spatulas, and gallon cans with close-fitting lids.6. 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.) sie
30、ve. When 75 % or morepasses the 19.0mm (34-in). sieve, use that part of the samplepassing 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 samp
31、les of soil with theamount of water estimated to equal one half to two thirds of thewater 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 require
32、d to produce saturation. TheFIG. 1 Tamper Shoe for Kneading CompactorD2844 0712first sample is used as a pilot specimen to assist in determiningthe 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.Compact
33、ed specimens having heights from 62 to 65 mm (2.45to 2.55 in.) are acceptable. Compact 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 th
34、e mold for approximately 3-mm (18-in. ) clearancebetween the lower edge of the mold and 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. Redistri
35、bute the sample remaining in trough as needed tofeed the balance of the soil into the mold 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 pr
36、essure of 2410 kPa (350 psi). Stop compactingthe soil at any time before 100 tamps if water 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 compa
37、cted specimenfrom the compactor. Level the tamped surface by hand tampingwith a 38-mm (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
38、is on the bottom. Placethe solid walled, metal specimen follower into the mold. Usingthe 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 pr
39、esent to produce saturation.Stop the loading and record the exudation pressure to thenearest 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 ex
40、udation pressure of 5520 kPa (800psi).7.4 Mold at least two more specimens with differentamounts 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 speci
41、mens having exudationpressures lower than 100 psi may be necessary to obtainFIG. 2 Compactor with Sample Feed TroughD2844 0713expansion pressures that are low enough to provide a suitablerange of data for a complete expansion pressure analysis of thesoil.NOTE 3Occasionally, material from very plasti
42、c, clay-test specimenswill extrude from under the mold and around the follower ram during theloading 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 san
43、ds mayrequire the use of paper baskets to permit testing.8. Calibration of Expansion-Pressure 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 def
44、lection dial indicator.8.2 The steel spring bar is considered in calibration whenthe measured 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
45、.00 (32) 0.2206 0.005 (0.0084 6 0.0002)8.3 If the deflection dial indicator does not check 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
46、apparatus have setscrew adjustments in lieu of shims.9. Expansion-Pressure Testing9.1 Allow 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-b
47、earing end of thegage base resting on the adjustment ring.9.3 Using an allen wrench, raise 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 t
48、he face ofthe compacted specimen in the mold and place the mold in theexpansion-pressure 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 defl
49、ection dial indicator reads zero.If the device was properly adjusted, according to 7.3, 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
