1、Designation: D5918 13Standard 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 revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These laboratory test methods cover the frost heave andthaw weakening susceptibilities of soil that is tested in thelaboratory b
3、y 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 frost-susceptibility considerations, based on particle size such as thelimi
4、t 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 frost classifica-tion. The frost heave susceptibility is determined from
5、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 pavement systems. It cannotbe used to predict the amount of frost heav
6、e 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 temperature control. It is suggested that fourspecimens be tested simultane
7、ously 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 procedures used to specify how data are collected/recorded and calculated in
8、 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 the data, special purpose studies, or any consider-ations for the users
9、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 analysismethods for engineering design.1.4.2 Measurements made to more significant
10、 digits orbetter sensitivity than specified in this standard shall not beregarded a nonconformance with this standard.1.5 This standard is written using SI units. Inch-pound unitsare provided for convenience. The values stated in inch poundunits may not be exact equivalents; therefore, they shall be
11、used independently of the SI system. Combining values fromthe two systems may result in nonconformance with thisstandard.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 fo
12、r massis slugs. The rationalized slug unit is not given, 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 sys
13、tems of units; that is, the absolute system and thegravitational 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 slu
14、gunit for mass. However, the use of balances or scales 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 theresponsibil
15、ity 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.1These test methods are under the jurisdiction ofASTM Committee D18 on Soiland Rock and are the direct responsibility of Subcommittee D18.19
16、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. DOI:10.1520/D5918-13.2Sometimes called California Bearing Ratio (CBR).3The Army Corps of Engineers uses a frost susceptibility classifi
17、cation 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 used forseasonal freezing and thawing conditions and not for long-term freezing ofpermafrost or of foundations of refrigerated structure
18、s.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12. Referenced Documents2.1 ASTM Standards:4C670 Practice for Preparing Precision and Bias Statementsfor Test Methods fo
19、r Construction MaterialsD75 Practice for Sampling AggregatesD420 Guide to Site Characterization for Engineering Designand Construction Purposes (Withdrawn 2011)5D653 Terminology Relating to Soil, Rock, and ContainedFluidsD698 Test Methods for Laboratory Compaction Character-istics of Soil Using Stan
20、dard Effort (12 400 ft-lbf/ft3(600kN-m/m3)D1587 Practice for Thin-Walled Tube Sampling of Soils forGeotechnical PurposesD1883 Test Method for CBR (California Bearing Ratio) ofLaboratory-Compacted SoilsD2216 Test Methods for Laboratory Determination of Water(Moisture) Content of Soil and Rock by Mass
21、D2940 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 Engineerin
22、g 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 Avera
23、ge for a Characteristic of aLot or Process2.2 Military Standards:6Army 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 te
24、rms 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 of t
25、he frost-susceptibility of soils and supple-ment those in Practice D4083 and in the glossary on permafrostterms by Harris et al.73.2.1.1 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 change
26、.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 systemfreezin
27、g 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 pure
28、 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 pr
29、opensity 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 unidirectional f
30、reezing 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, chilled
31、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 reduction i
32、n 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.3.2.1.17 thaw weakening susceptibilityt
33、he propensity forthe strength or stiffness modulus of a soil to decrease below thenormal warm season values.4For 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 stan
34、dards Document Summary page onthe ASTM website.5The last approved version of this historical standard is referenced onwww.astm.org.6Available from Superintendent of Documents, U.S. Government PrintingOffice, Washington, DC 20402.7Harris, S. A., et al., Glossary of Permafrost and Related Ground-Ice T
35、erms,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, K1A0R6,1988.D5918 1323.2.1.18 unidirectional freezingsoil freezing that occurs i
36、none direction only.4. Summary of Test Methods4.1 Two freeze-thaw cycles are imposed 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,
37、 with or without water freely available at thebase; a surcharge of 3.5 kPa (0.5 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 bearing
38、ratio is determined. The entire testing procedure can becompleted within a five-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 pa
39、vement systems. Both thefrost heave susceptibility and the thaw weakening susceptibil-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 th
40、an pavement systems.5.3 These test methods cannot be used to predict the amountof 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 res
41、ult 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 D3740 are generally considered capable of competentand objective testing/sampling/inspection/etc. Users of t
42、his standard arecautioned that compliance with Practice D3740 does not in itself 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 b
43、ase plate, a steel hollow cylinder splitinto three sections longitudinally, two 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
44、.) recess to receive and retain the steel side walls andbase of the specimen. Two 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.),
45、 and a length of 165.1 mm (6.5 in.). Thecylinder is to be made in three sections 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
46、and a 185-mm (7.25-in.) outside diameter with a152.4-mm (6-in.) diameter recess 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
47、 place.6.1.4 Spacer DiskTwo circular acrylic spacer disks (seeFig. 1), 158.8 mm (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 acryli
48、c 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 s
49、quare notch cut in one edge to receive the topand bottom temperature sensor leads. Each ring shall have asplit cut through its height at a location diametrically oppositethe temperature sensor hole.6.1.6 Clamping RodsTwo 9.5-mm (0.375-in.) diameter by215.9-mm (8.5-in.) long threaded steel rods with two wing nutsto clamp the assembly together.6.1.7 Rubber MembraneA 0.36-mm (0.014-in.) thick rub-ber membrane without holes or defects. This is required to sealthe sides of a soil specimen that shall be 146.0 mm (5.25 in.)in diameter. The length of the membran
