1、Designation: D5918 131Standard Test Methods forFrost Heave and Thaw Weakening Susceptibility of Soils1This standard is issued under the fixed designation D5918; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEEditorially updated units of measurement statement in April 2018.1. Scope*1.1 These laboratory test methods cover the frost heave andth
3、aw weakening susceptibilities of soil that is tested in thelaboratory by comparing the heave rate and thawed bearingratio2with values in an established classification system. Thistest was developed to classify the frost susceptibility of soilsused in pavements. It should be used for soils where fros
4、t-susceptibility considerations, based on particle size such as thelimit of 3 % finer than 20 mm in Specification D2940, areuncertain. This is most important for frost-susceptibility crite-ria such as those used by the Corps of Engineers,3that requirea freezing test for aggregates of inconclusive fr
5、ost classifica-tion. The frost heave susceptibility is determined from theheave rate during freezing. The thaw weakening susceptibilityis determined with the bearing ratio test (see Test MethodD1883).1.2 This is an index test for estimating the relative degree offrost-susceptibility of soils used in
6、 pavement systems. It cannotbe used to predict the amount of frost heave nor the strengthafter thawing, nor can it be used for applications involvinglong-term freezing of permafrost or for foundations of refrig-erated structures.1.3 The test methods described are for one specimen anduses manual temp
7、erature control. It is suggested that fourspecimens be tested simultaneously and that the temperaturecontrol and data taking be automated using a computer.1.4 All recorded and calculated values shall conform to theguide for significant digits and rounding established in PracticeD6026.1.4.1 The proce
8、dures used to specify how data are collected/recorded and calculated in this standard are regarded as theindustry standard. In addition, they are representative of thesignificant digits that should generally be retained. The proce-dures used do not consider material variation, purpose forobtaining t
9、he 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 used in analysismet
10、hods for engineering design.1.4.2 Measurements made to more significant digits orbetter sensitivity than specified in this standard shall not beregarded a nonconformance with this standard.1.5 The values stated in SI units are to be regarded asstandard. The values given in parentheses after SI units
11、 areprovided for information only and are not considered standard.1.5.1 The gravitational system of inch-pound units is usedwhen dealing with inch-pound units. In this system, the pound(lbf) represents a unit of force (weight), while the unit for massis slugs. The rationalized slug unit is not given
12、, unless dynamic(F=ma) calculations are involved.1.5.2 It is common practice in the engineering/ constructionprofession to concurrently use pounds to represent both a unitof mass (lbm) and of force (lbf). This implicitly combines twoseparate systems of units; that is, the absolute system and thegrav
13、itational system. It is scientifically undesirable to combinethe use of two separate sets of inch-pound units within a singlestandard. As stated, this standard includes the gravitationalsystem of inch-pound units and does not use/present the slugunit for mass. However, the use of balances or scales
14、recordingpounds of mass (lbm) or recording density in lbm/ft3shall notbe regarded as nonconformance with this standard.1.6 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-pri
15、ate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for the1These
16、test methods are under the jurisdiction ofASTM Committee D18 on Soiland Rock and are the direct responsibility of Subcommittee D18.19 on Frozen Soilsand Rock.Current edition approved Feb. 1, 2013. Published March 2013. Originallyapproved in 1996. Last previous edition approved in 2006 as D5918 06. D
17、OI:10.1520/D5918-13E01.2Sometimes called California Bearing Ratio (CBR).3The Army Corps of Engineers uses a frost susceptibility classification proce-dure (TM 5-818-2) based on particle size criteria and the Unified Soil ClassificationSystem (MIL-STD-619) field. Furthermore, this test should only be
18、 used forseasonal freezing and thawing conditions and not for long-term freezing ofpermafrost or of foundations of refrigerated structures.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29
19、59. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical
20、Barriers to Trade (TBT) Committee.1Development of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:4C670 Practice for Preparing Precision and Bias Statementsfor Test Method
21、s for Construction MaterialsD75 Practice for Sampling AggregatesD420 Guide for Site Characterization for Engineering De-sign and Construction PurposesD653 Terminology Relating to Soil, Rock, and ContainedFluidsD698 Test Methods for Laboratory Compaction Character-istics of Soil Using Standard Effort
22、 (12,400 ft-lbf/ft3(600kN-m/m3)D1587 Practice for Thin-Walled Tube Sampling of Fine-Grained Soils for Geotechnical PurposesD1883 Test Method for California Bearing Ratio (CBR) ofLaboratory-Compacted SoilsD2216 Test Methods for Laboratory Determination of Water(Moisture) Content of Soil and Rock by M
23、assD2940 Specification for Graded Aggregate Material ForBases or Subbases for Highways or AirportsD3550 Practice for Thick Wall, Ring-Lined, Split Barrel,Drive Sampling of SoilsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Enginee
24、ring Design and ConstructionD4083 Practice for Description of Frozen Soils (Visual-Manual Procedure)D6026 Practice for Using Significant Digits in GeotechnicalDataE105 Practice for Probability Sampling of MaterialsE122 Practice for Calculating Sample Size to Estimate, WithSpecified Precision, the Av
25、erage for a Characteristic of aLot or Process2.2 Military Standards:5Army TM 5-818-2 Pavement Design for Frost Conditions,January 1985MIL-STD-619 Unified Soil Classification System for Roads,Airfields, Embankments and Foundations3. Terminology3.1 Definitions:3.1.1 For definitions of common technical
26、 terms in thisstandard, refer to Terminology D653.3.1.2 Definitions of the components of freezing and thawingsoils shall be in accordance with the terminology in PracticeD4083.3.2 Definitions of Terms Specific to This Standard:3.2.1 The following terms are used in conjunction with thedetermination o
27、f the frost-susceptibility of soils and supple-ment those in Practice D4083 and in the glossary on permafrostterms by Harris et al.63.2.1.1 degree of frost-susceptibility the relative propen-sity for frost heave or thaw weakening in comparison to that foranother soil or to an acceptable level of cha
28、nge.3.2.1.2 freeze-thaw cyclingthe repeated freezing andthawing of soil.3.2.1.3 freezing (soil)the changing of phase from water toice in soil.3.2.1.4 freezing, closed systemfreezing that occurs underconditions that preclude the gain or loss of any water in thesystem.3.2.1.5 freezing, open systemfree
29、zing that occurs underconditions that allow gain or loss of water in the system bymovement of pore water from or to an external source togrowing ice lenses.3.2.1.6 freezing-point depressionthe number of degreesby which the freezing point of an earth material is depressedbelow the freezing point of p
30、ure water.3.2.1.7 frost heavethe upward or outward movement ofthe ground or pavement surface (in the direction of heat flow)caused by the formation of ice in the soil.3.2.1.8 frost heave ratethe rate at which the ground orpavement surface moves upward or outward.3.2.1.9 frost heave susceptibilitythe
31、 propensity for a soilto accumulate ice during freezing and to heave.3.2.1.10 frost-susceptible soilsoil in which ice accumula-tion causes frost heave during freezing or thaw weakeningduring thawing, or both.3.2.1.11 ice lensa lens-shaped body of ice of any dimen-sion that forms during unidirectiona
32、l freezing of soil, the longdimension being in the direction normal to the direction of heatflow.3.2.1.12 ice nucleationthe formation of an ice nucleusfrom water.3.2.1.13 refrigerated structuresartificially refrigeratedstructures (cold storage facilities, liquefied gas tanks, iceskating rinks, chill
33、ed gas pipelines, and so forth) that cause thefreezing of their foundations.3.2.1.14 relative frost susceptibilitythe amount of frostheave or thaw weakening of a soil in relation to other soils.3.2.1.15 seasonally frozen groundground that freezes andthaws annually.3.2.1.16 thaw weakeningthe reductio
34、n in strength, bearingcapacity, or stiffness modulus below the normal warm-seasonvalues. This is caused by the decrease in effective stressresulting from the generation and slow dissipation of excesspore water pressures when frozen soils containing ice arethawing.4For referenced ASTM standards, visi
35、t 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.5Available from Superintendent of Documents, U.S. Government PrintingOffice, Washington, DC 20402
36、.6Harris, S. A., et al., Glossary of Permafrost and Related Ground-Ice Terms,Permafrost Subcommittee, Associate Committee on Geotechnical Research, Na-tional Research Council of Canada, Technical Memorandum No. 142, Availablefrom National Research Council of Canada, Ottawa, Ontario, Canada, K1A0R6,1
37、988.D5918 13123.2.1.17 thaw weakening susceptibilitythe propensity forthe strength or stiffness modulus of a soil to decrease below thenormal warm season values.3.2.1.18 unidirectional freezingsoil freezing that occurs inone direction only.4. Summary of Test Methods4.1 Two freeze-thaw cycles are imp
38、osed on compacted soilspecimens, 146 mm (5.75 in.) in diameter and 150 mm (6 in.)in height. The soil specimen is frozen and thawed by applyingspecified constant temperatures in steps at the top and bottomof the specimen, with or without water freely available at thebase; a surcharge of 3.5 kPa (0.5
39、lbf/in.) is applied to the top.The temperatures imposed on the specimen are adjusted to takeinto account the freezing point depression attributable to saltsin the soil. At the end of the second thawing cycle, the bearingratio is determined. The entire testing procedure can becompleted within a five-
40、day period.This testing procedure maybe conducted manually or it may be controlled by a computer.5. Significance and Use5.1 These test methods can be used to determine the relativefrost-susceptibility of soils used in pavement systems. Both thefrost heave susceptibility and the thaw weakening suscep
41、tibil-ity can be determined.5.2 These test methods should be used only for seasonalfrost conditions and not for permanent or long-term freezing ofsoil. These test methods also have not been validated foranything other than pavement systems.5.3 These test methods cannot be used to predict the amounto
42、f frost heave or thaw weakening in the field. Its purpose is todetermine the relative frost-susceptibility classification for usein empirical pavement design methods for seasonal frostregions.NOTE 1The quality of the result produced by this standard isdependent on the competence of the personnel per
43、forming it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D3740 are generally considered capable of competentand objective testing/sampling/inspection/etc. Users of this standard arecautioned that compliance with Practice D3740 does not in itself
44、 assurereliable results. Reliable results depend on many factors; Practice D3740provides a means of evaluating some of those factors.6. Apparatus6.1 Compaction MoldThe mold assembly (see Fig. 1)shall consist of a steel base plate, a steel hollow cylinder splitinto three sections longitudinally, two
45、acrylic spacer disks, sixacrylic rings, a steel collar, a rubber membrane, and four hoseclamps.6.1.1 Base PlateA 203-mm (8-in.) square steel base plate(see Fig. 1) with a thickness of 25 mm (1.0 in.) and a 6.0-mm(0.25-in.) recess to receive and retain the steel side walls andbase of the specimen. Tw
46、o 9.5-mm (0.375-in.) diameterthreaded holes at opposite corners accommodate clampingrods.6.1.2 Compaction CylinderA hollow steel cylinder withan inside diameter of 152.4 mm (6 in.), a wall thickness of 9.5mm (0.375 in.), and a length of 165.1 mm (6.5 in.). Thecylinder is to be made in three sections
47、 that part along thevertical axis (see Fig. 1).Arecess in the steel base plate acceptsthe steel cylinder and restrains it from expanding duringcompaction.6.1.3 CollarAsteel collar with a 146-mm (5.75-in.) insidediameter and a 185-mm (7.25-in.) outside diameter with a152.4-mm (6-in.) diameter recess
48、bored 6.35 mm (0.25 in.) intothe bottom. This collar slips over the top of the steel mold toconstrain expansion and to provide extra space for soil duringcompaction. Flanges slide over the steel rods to hold the collarin place.6.1.4 Spacer DiskTwo circular acrylic spacer disks (seeFig. 1), 158.8 mm
49、(6.25 in.) in diameter and 6.4 mm (0.25 in.)in height. One spacer disk is placed at the bottom of thecompaction mold. The second disk is placed on the top of thespecimen during transport and storage.6.1.5 RingsSix acrylic rings (see Fig. 1 and Fig. 2) havingan inside diameter of 146 mm (5.75 in.) and a height of 25 mm(1 in.) with a wall thickness of 3.18 mm (0.125 in.).A3.18-mmdiameter hole shall be drilled at the mid-height in each ring toreceive a temperature sensor. The top and bottom rings shallhave a 3.18-mm square notch cut in one edge to receive
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