1、Designation: C 341/C 341M 06Standard Practice forLength Change of Cast, Drilled, or Sawed Specimens ofHydraulic-Cement Mortar and Concrete1This standard is issued under the fixed designation C 341/C 341M; the number immediately following the designation indicates the yearof original adoption or, in
2、the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice covers the determination of the lengthchanges of cast, drilled, or s
3、awed specimens of hydraulic-cement mortar and concrete due to causes other than externallyapplied forces and temperature changes. It can be readilyadapted, if desired, to studies of length change involvingdifferent schedules or environmental treatment than the stan-dard procedures prescribed by this
4、 practice.1.2 The values stated in either inch-pound units or SI unitsshall be regarded separately as standard. The units stated ineach system may not be exact equivalents; therefore, eachsystem must be used independently of the other, withoutcombining in any way. The inch-pound units are shown inbr
5、ackets.1.3 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 regulatory limitations prior to use.2. Refer
6、enced Documents2.1 ASTM Standards:2A 276 Specification for Stainless Steel Bars and ShapesC 31/C 31M Practice for Making and Curing Concrete TestSpecimens in the FieldC 42/C 42M Test Method for Obtaining and Testing DrilledCores and Sawed Beams of ConcreteC 157/C 157M Test Method for Length Change o
7、f Hard-ened Hydraulic-Cement Mortar and ConcreteC 192/C 192M Practice for Making and Curing ConcreteTest Specimens in the LaboratoryC 490 Practice for Use of Apparatus for the Determinationof Length Change of Hardened Cement Paste, Mortar, andConcreteC 666/C 666M Test Method for Resistance of Concre
8、te toRapid Freezing and Thawing3. Terminology3.1 Definition3.1.1 length change, nan increase or decrease in a lineardimension of a test specimen, which has been caused to changeby any factor other than externally applied forces and tempera-ture changes.4. Significance and Use4.1 Measurements of leng
9、th change permit assessment ofthe potential for volumetric expansion or contraction of cast,drilled, or sawed specimens of hydraulic-cement mortar, andconcrete due to various causes other than externally appliedforces and temperature changes. This practice is particularlyuseful for comparative evalu
10、ation of this potential in differentmortar or concrete specimens.5. Apparatus5.1 Length ComparatorThe length comparator shall gen-erally conform to the requirements of Specification C 490,except that it shall be constructed to accommodate the speci-mens to be tested under this practice, which shall
11、have gaugelengths of 75 mm 3 in. or more.5.1.1 Gauge Studs in Ends of SpecimensWhen the com-parator is to be used to measure between gauge studs in theends of specimens, the gauge length for computing percentagelength change shall be considered to be the distance betweenthe innermost ends of the gau
12、ge studs, and the contactterminals of the comparator shall be plane, polished, heat-treated surfaces as described in Specification C 490.Fig.3ofSpecification C 490 shows one type of comparator that hasbeen found suitable for such specimens. A horizontal compara-tor is desirable for specimens that ar
13、e considered too large to behandled by the type of comparator illustrated in Fig. 3 ofSpecification C 490.5.1.2 Gauge Studs on Sides of SpecimenWhen the com-parator is to be used to measure between gauge studs on thesides of specimens, the contact terminals shall be conical,1This practice is under t
14、he jurisdiction of ASTM Committee C09 on Concreteand ConcreteAggregates and is the direct responsibility of Subcommittee C09.68 onVolume Change.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1954. Last previous edition approved in 2005 as C 341/C 341M 05.2For refer
15、enced 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 onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copy
16、right ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.heat-treated surfaces as shown in Fig. 1, which illustrates atype of comparator that has been found satisfactory for thistype of specimen. In this case, the gauge length shall be thedistance
17、 between the reference points located in the exposedends of the gauge studs (see 5.2).5.2 Gauge StudsGauge studs shall be Type 316 stainlesssteel, meeting Specification A 276.5.2.1 For Ends of SpecimensGauge studs that are to belocated in the ends of specimens shall have a rounded surfaceto provide
18、point contact with the terminals of the comparator.The types of studs described in Specification C 490 are suitablefor insertion in drilled holes. Spherical studs having a diameterof6to10mm14 to38 in., or studs that are sections of spheresof similar diameter, are suitable for cementing to the ends o
19、fspecimens.5.2.2 For Sides of SpecimensThe exposed end of gaugestuds that are to be located on the sides of specimens shall havea plane surface with a diameter or diagonal of 10 to 13 mm 38to12 in. For dry setting, the length of the stud shall be 13 to16 mm 12 to58 in. Shorter lengths of stud, inclu
20、ding planedisks, shall be satisfactory for studs that are to be cemented.5.3 Drying Room and ControlsA drying room and con-trols as described in Test Method C 157/C 157M shall be usedfor storing specimens in air.6. Sampling6.1 Samples of drilled or sawed hydraulic cement mortar orconcrete shall be o
21、btained in accordance with the section onSampling of Test Method C 42/C 42M.6.2 Samples of field cast hydraulic cement mortar or con-crete shall be cast in accordance with Practice C 31/C 31M.6.3 Constituent materials for concrete or mortar specimensmade in the laboratory for use in this practice sh
22、all be sampledusing applicable standard methods.6.3.1 The specimens for use in this practice prepared fromthe constituent materials in the laboratory shall be cast prismsor cylinders made and cured in accordance with the applicablerequirements of Practice C 192/C 192M and Practice C 490.7. Test Spec
23、imens7.1 Test specimen geometry shall be either cylindrical orrectangular prisms. Specimens shall be either cast from freshlymixed materials or drilled or sawn from existing concrete ormortar structures. Specimens shall be free from reinforcingsteel, visible cracks, or other structural defects. They
24、 shall be ofany size but specimens that are to be compared shall not differin their cross-sectional dimensions by more than 10 % or inlength by more than 20 % (Note 1). The gauge length shall beat least six times the maximum nominal size of the coarseaggregate but not less than 75 mm 3 in., and that
25、 theminimum cross-sectional dimension be at least three times themaximum nominal size of the coarse aggregate but not lessthan 50 mm 2 in. When the gauge studs are to be located onthe sides of the specimen, the over-all length of the specimenshall exceed the gauge length by at least 50 mm 2 in.NOTE
26、1Specimens used for length change measurements duringfreeze thaw resistance testing as described in Test Method C 666/C 666Mshould follow the dimensional requirements of that method.8. Setting Gauge Studs8.1 Gauge studs shall either be cast in place, dry-set orcemented in drilled holes, or cemented
27、directly to the surfaceof the specimen.8.2 Drilling HolesFor gauge studs that are to be ce-mented, holes shall be drilled (Note 2) only slightly larger thanthe studs. For gauge studs that are to be dry-set, holes shall bedrilled about 0.1 mm 0.005 in. smaller in diameter than thestuds. In the case o
28、f small specimens, take care that theFIG. 1 Type of Suitable Extensometer for Measurement of Length Change of Specimens Having Gauge Studs on SidesC 341/C 341M 062specimens are not damaged by the drilling operation. Thelocation and depth of holes shall be as given in 8.2.1 and 8.2.2.NOTE 2Carbide-ti
29、pped masonry drills have been found most suitablefor this purpose.8.2.1 For Gauge Studs in Ends of SpecimenDrill holes inthe ends of a specimen so that their longitudinal axes coincidewith the longitudinal axis of the specimen. The depth of theholes shall be such that the gauge studs will project fr
30、om 3 to5mm18 in. to316 in. beyond the ends of the specimen.8.2.2 For Gauge Studs in Sides of SpecimenDrill a pair ofholes in each of two opposite sides of the specimen tocompensate for warping and to provide a better average forlength change. Position both pairs of holes in a plane contain-ing the l
31、ongitudinal axis of the specimen and space to conformto the length of the comparator. The center of each hole shallbe at least 25 mm 1 in. from the end of the specimen. Thedepth of the holes shall preferably be such that the top surfacesof the gauge studs can be set about 3 mm 0.1 in. below thesurfa
32、ce of the specimen.8.3 Cementing Methods:8.3.1 Studs Set in HolesPosition gauge studs in holes atthe depth specified in 8.2.1 or 8.2.2, as appropriate, with theexposed end parallel to the surface of the specimen in the caseof studs having plane end surfaces. The cementing materialshall be stable and
33、 effective in either a wet or dry environmentand at temperatures up to 120 C 250 F. The followingcementing materials have been found satisfactory:8.3.1.1 Epoxy ResinEpoxy resins for this purpose shallcure at room temperatures and not soften upon exposure towater immersion. Holes shall be free of loo
34、se particles andvisually dry to ensure good bond.8.3.1.2 Portland-Cement PasteUse a thick paste of TypeIII Portland cement. Moisten each hole with about 5 mL ofwater, cement the studs in place after the water has beenabsorbed, and moist-cure the paste for approximately 24 h.8.3.1.3 Other Cementing M
35、ediaSulfur and Rose metalhave also proven satisfactory.8.3.2 Studs Cemented to SurfaceAn epoxy resin systemthat cures at room temperature and does not soften at atemperature of 120 C 250 F or soften upon exposure towater immersion is the most satisfactory material for cement-ing studs to the surface
36、 of a specimen. To ensure good bond, itis essential that the surface be clean. Acid etching followed byflushing with water and drying is a satisfactory preparation ofthe surface for bonding. The locations of the studs on thespecimen are the same as those prescribed for drilled holes in8.2.1 and 8.2.
37、2. The exposed end surface of each stud havinga plane end surface shall be parallel to the surface of thespecimen.8.4 Dry-Setting MethodDrive the gauge studs to the depthspecified in 8.2.1 or 8.2.2, as appropriate, into holes that areapproximately 0.1 mm 0.005 in. smaller in diameter than thegauge s
38、tuds, being careful not to deform the exposed ends ofthe gauge studs during the driving operation.8.5 Reference Points on Gauge StudsOn each gauge studlocated on the side of a specimen, establish a reference point bydrilling a hole approximately 1 mm in diameter (see Note 3)inthe end of the stud to
39、a depth sufficient to provide clearancebetween the bottom of the hole and the point of the comparator,as shown in Fig. 1. A template (Fig. 1) will aid in spacing theholes at proper gauge length, which shall be as nearly equal tothe mean gauge length of the comparator as practicable.Remove burred edg
40、es from the reference point holes.NOTE 3A No. 56 American Standard Twist Drill or other bit suitableto drill a hole approximately 1 mm or 0.046 in. in diameter is suitable forthis purpose.9. Determination of Gauge Length of Specimens9.1 Determine the gauge length of each specimen to anaccuracy of 1
41、%. In the case of specimens having gauge studson the sides, determine the gauge length by direct measurementbetween the reference points with a suitable scale. Determinethe gauge length of specimens having gauge studs in the endsby first measuring the distance between the ends of the gaugestuds with
42、 suitable calipers and subtracting the lengths of thetwo gauge studs.10. Conditioning of Specimens for Measurement of BaseLength10.1 Prior to the initial measurement for length, conditionspecimens by immersion in lime-saturated water.10.2 Maintain the temperature of the conditioning water at23 6 2 C
43、 73.5 6 3.5 F, except that during the last1hofimmersion immediately before making any measurement forlength maintain the temperature at 23.0 6 0.5 C 73.4 6 1.0F (Note 4). When measuring for length, remove the speci-mens from water one at a time, wipe with a damp cloth, andimmediately measure for len
44、gth using the comparator specifiedin 5.1. Make length measurements at 7-day intervals andcontinue conditioning until the change in length over a 7-dayperiod is less than 0.001 %. Use the length measurement thatdetermines that this criterion is met as the basis for calculatinglength change occurring
45、during the air or water storage period.NOTE 4Specimens used for length change measurements duringfreeze thaw resistance testing as described in Test Method C 666/C 666Mshould follow the conditioning of that method.11. Storage of Specimens11.1 After measurement at the end of the conditioningperiod, s
46、tore the specimens as described in either 11.2 or 11.3,unless another condition of storage is specified.11.2 Water StorageImmerse specimens in lime-saturatedwater at 23 6 2 C 73.5 6 3.5 F. Take observations of thelength of each specimen after 1, 2, 4, 8, 16, 32, and 64 weeksunless otherwise specifie
47、d. Make these observations immedi-ately after the specimens have been subjected to storage inwater at 23.0 6 0.5 C 73.4 6 1.0 F for a period of at least1 h. When measuring for length, remove the specimens fromwater one at a time, wipe with a damp cloth, and immediatelymeasure for length using the co
48、mparator specified in 5.1.11.3 Air StorageStore the specimens in circulating airmaintained at a temperature of 23 6 2 C 73.5 6 3.5 F anda relative humidity of 50 6 4 % unless some other condition ofstorage is specified. See 5.3 for reference to a suitable dryingroom. The air movement past all specim
49、ens shall be such thatthe rate of evaporation is 77 6 30 mL/24 h from the atmometerreferenced in 5.3 or 13 6 5 mL/24 h from a 400-mL GriffinC 341/C 341M 063low-form beaker filled initially to 20 mm 34 in. from the top.Unless otherwise specified, measure specimens for length atweekly intervals and continue them in air storage until theirchange in length over a 7-day period is less than 0.001 %.Preferably, make these observations in a room maintained at arelative humidity of 50 6 4 % while the
