1、Designation: C341/C341M 06C341/C341M 13Standard Practice forLength Change Preparation and Conditioning of Cast,Drilled, or Sawed Specimens of Hydraulic-Cement Mortarand Concrete Used for Length Change Measurements1This standard is issued under the fixed designation C341/C341M; the number immediately
2、 following the designation indicates the yearof original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This pract
3、ice covers the determination of the length changes procedures for the preparation and conditioning of cast, drilled,or sawed specimens of hydraulic-cement mortar and concrete for length change due to causes other than externally applied forcesand temperature changes. forces. It can be readily adapte
4、d, if desired, to studies of length change involving differentalternateschedules or environmental treatment other than the standard procedures prescribed by this practice.1.2 The values stated in either inch-pound units or SI units shall be regarded separately as standard. The units stated in eachsy
5、stem may not be exact equivalents; therefore, each system must be used independently of the other, without combining in anyway. The inch-pound units are shown in brackets.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibili
6、tyof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A276 Specification for Stainless Steel Bars and ShapesC31/C31M Practice for Making and Curing Concrete
7、Test Specimens in the FieldC42/C42M Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of ConcreteC157/C157M Test Method for Length Change of Hardened Hydraulic-Cement Mortar and ConcreteC192/C192M Practice for Making and Curing Concrete Test Specimens in the LaboratoryC490 Practice
8、 for Use of Apparatus for the Determination of Length Change of Hardened Cement Paste, Mortar, and ConcreteC666/C666M Test Method for Resistance of Concrete to Rapid Freezing and Thawing3. Terminology3.1 Definition3.1.1 length change, nan increase or decrease in a linear dimension of a test specimen
9、, which has been caused to change byany factor other than externally applied forces and temperature changes.4. Significance and Use4.1 Measurements of length change permit assessment of the potential for volumetric expansion or contraction of cast, drilled,or sawed specimens of hydraulic-cement mort
10、ar, and concrete due to various causes other than externally applied forces andtemperature changes. This practice is particularly useful for comparative evaluation of this potential in different mortar or concretespecimens.1 This practice is under the jurisdiction ofASTM Committee C09 on Concrete an
11、d ConcreteAggregates and is the direct responsibility of Subcommittee C09.68 on VolumeChange.Current edition approved June 1, 2006Dec. 15, 2013. Published June 2006January 2014. Originally approved in 1954. Last previous edition approved in 20052006 asC341/C341M 05.C341/C341M 065. DOI: 10.1520/C0341
12、_C0341M-06.10.1520/C0341_C0341M-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an AS
13、TM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In a
14、ll cases only the current versionof the standard as published by ASTM is to be considered the official document.*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 States15. Appara
15、tus5.1 Length ComparatorThe length comparator shall generally conform to the requirements of Specification C490, except thatit shall be constructed to accommodate the specimens to be tested under this practice, which shall have gauge lengths of 75 mm3 in. or more.5.1.1 Gauge Studs in Ends of Specime
16、nsWhen the comparator is to be used to measure between gauge studs in the ends ofspecimens, the gauge length for computing percentage length change shall be considered to be the distance between the innermostends of the gauge studs, and the contact terminals of the comparator shall be plane, polishe
17、d, heat-treated surfaces as describedin Specification C490. Fig. 3 of Specification C490 shows one type of comparator that has been found suitable for such specimens.Ahorizontal comparator is desirable for specimens that are considered too large to be handled by the type of comparator illustratedin
18、Fig. 3 of Specification C490.5.1.2 Gauge Studs on Sides of SpecimenWhen the comparator is to be used to measure between gauge studs on the sides ofspecimens, the contact terminals shall be conical, heat-treated surfaces as shown in Fig. 1, which illustrates a type of comparatorthat has been found sa
19、tisfactory for this type of specimen. In this case, the gauge length shall be the distance between the referencepoints located in the exposed ends of the gauge studs (see 5.2).5.2 Gauge StudsGauge studs shall be Type 316 stainless steel, meeting Specification A276.5.2.1 For Ends of SpecimensGauge st
20、uds that are to be located in the ends of specimens shall have a rounded surface toprovide point contact with the terminals of the comparator. The types of studs described in Specification C490 are suitable forinsertion in drilled holes. Spherical studs having a diameter of 6 to 10 mm 14 to 38 in.,
21、or studs that are sections of spheres ofsimilar diameter, are suitable for cementing to the ends of specimens.5.2.2 For Sides of SpecimensThe exposed end of gauge studs that are to be located on the sides of specimens shall have aplane surface with a diameter or diagonal of 10 to 13 mm 38 to 12 in.
22、For dry setting, the length of the stud shall be 13 to 16mm 12 to 58 in. Shorter lengths of stud, including plane disks, shall be satisfactory for studs that are to be cemented.5.3 Drying Room and ControlsAdrying room and controls as described in Test Method C157/C157M shall be used for storingspeci
23、mens in air.6. Sampling6.1 Samples of drilled or sawed hydraulic cement mortar or concrete shall be obtained in accordance with the section onSampling of Test Method C42/C42M.6.2 Samples of field cast hydraulic cement mortar or concrete shall be cast in accordance with Practice C31/C31M.6.3 Constitu
24、ent materials for concrete or mortar specimens made in the laboratory for use in this practice shall be sampled usingapplicable standard methods.FIG. 1 Type of Suitable Extensometer for Measurement of Length Change of Specimens Having Gauge Studs on SidesC341/C341M 1326.3.1 The specimens for use in
25、this practice prepared from the constituent materials in the laboratory shall be cast prisms orcylinders made and cured in accordance with the applicable requirements of Practice C192/C192M and Practice C490.7. Test Specimens7.1 Test specimen geometry shall be either cylindrical or rectangular prism
26、s. Specimens shall be either cast from freshly mixedmaterials or drilled or sawn from existing concrete or mortar structures. Specimens shall be free from reinforcing steel, visiblecracks, or other structural defects. They shall be of any size but specimens that are to be compared shall not differ i
27、n theircross-sectional dimensions by more than 10 % or in length by more than 20 % (Note 1). The gauge length shall be at least six timesthe maximum nominal size of the coarse aggregate but not less than 75 mm 3 in., and that the minimum cross-sectional dimensionbe at least three times the maximum n
28、ominal size of the coarse aggregate but not less than 50 mm 2 in. When the gauge studsare to be located on the sides of the specimen, the over-all length of the specimen shall exceed the gauge length by at least 50 mm2 in.NOTE 1Specimens used for length change measurements during freeze thaw resista
29、nce testing as described in Test Method C666/C666M shouldfollow the dimensional requirements of that method.8. Setting Gauge Studs8.1 Gauge studs shall either be cast in place, dry-set or cemented in drilled holes, or cemented directly to the surface of thespecimen.8.2 Drilling HolesFor gauge studs
30、that are to be cemented, holes shall be drilled (Note 2) only slightly larger than the studs.For gauge studs that are to be dry-set, holes shall be drilled about 0.1 mm 0.005 in. smaller in diameter than the studs. In thecase of small specimens, take care that the specimens are not damaged by the dr
31、illing operation. The location and depth of holesshall be as given in 8.2.1 and 8.2.2.NOTE 2Carbide-tipped masonry drills have been found most suitable for this purpose.8.2.1 For Gauge Studs in Ends of SpecimenDrill holes in the ends of a specimen so that their longitudinal axes coincide withthe lon
32、gitudinal axis of the specimen. The depth of the holes shall be such that the gauge studs will project from 3 to 5 mm 18in. to 316 in. beyond the ends of the specimen.8.2.2 For Gauge Studs in Sides of SpecimenDrill a pair of holes in each of two opposite sides of the specimen to compensatefor warpin
33、g and to provide a better average for length change. Position both pairs of holes in a plane containing the longitudinalaxis of the specimen and space to conform to the length of the comparator. The center of each hole shall be at least 25 mm 1 in.from the end of the specimen. The depth of the holes
34、 shall preferably be such that the top surfaces of the gauge studs can be setabout 3 mm 0.1 in. below the surface of the specimen.8.3 Cementing Methods:8.3.1 Studs Set in HolesPosition gauge studs in holes at the depth specified in 8.2.1 or 8.2.2, as appropriate, with the exposedend parallel to the
35、surface of the specimen in the case of studs having plane end surfaces. The cementing material shall be stableand effective in either a wet or dry environment and at temperatures up to 120 C 250 F. The following cementing materialshave been found satisfactory:8.3.1.1 Epoxy ResinEpoxy resins for this
36、 purpose shall cure at room temperatures and not soften upon exposure to waterimmersion. Holes shall be free of loose particles and visually dry to ensure good bond.8.3.1.2 Portland-Cement PasteUse a thick paste of Type III Portland cement. Moisten each hole with about 5 mL of water,cement the studs
37、 in place after the water has been absorbed, and moist-cure the paste for approximately 24 h.8.3.1.3 Other Cementing MediaSulfur and Rose metal have also proven satisfactory.8.3.2 Studs Cemented to SurfaceAn epoxy resin system that cures at room temperature and does not soften at a temperatureof 120
38、 C 250 F or soften upon exposure to water immersion is the most satisfactory material for cementing studs to the surfaceof a specimen. To ensure good bond, it is essential that the surface be clean. Acid etching followed by flushing with water anddrying is a satisfactory preparation of the surface f
39、or bonding. The locations of the studs on the specimen are the same as thoseprescribed for drilled holes in 8.2.1 and 8.2.2. The exposed end surface of each stud having a plane end surface shall be parallelto the surface of the specimen.8.4 Dry-Setting MethodDrive the gauge studs to the depth specif
40、ied in 8.2.1 or 8.2.2, as appropriate, into holes that areapproximately 0.1 mm 0.005 in. smaller in diameter than the gauge studs, being careful not to deform the exposed ends of thegauge studs during the driving operation.8.5 Reference Points on Gauge StudsOn each gauge stud located on the side of
41、a specimen, establish a reference point bydrilling a hole approximately 1 mm in diameter (see Note 3) in the end of the stud to a depth sufficient to provide clearance betweenthe bottom of the hole and the point of the comparator, as shown in Fig. 1.Atemplate (Fig. 1) will aid in spacing the holes a
42、t propergauge length, which shall be as nearly equal to the mean gauge length of the comparator as practicable. Remove burred edges fromthe reference point holes.C341/C341M 133NOTE 3A No. 56 American Standard Twist Drill or other bit suitable to drill a hole approximately 1 mm or 0.046 in. in diamet
43、er is suitable for thispurpose.9. Determination of Gauge Length of Specimens9.1 Determine the gauge length of each specimen to an accuracy of 1 %. In the case of specimens having gauge studs on thesides, determine the gauge length by direct measurement between the reference points with a suitable sc
44、ale. Determine the gaugelength of specimens having gauge studs in the ends by first measuring the distance between the ends of the gauge studs withsuitable calipers and subtracting the lengths of the two gauge studs.10. Conditioning of Specimens for Measurement of Base Length10.1 Prior to the initia
45、l measurement for length, condition specimens by immersion in lime-saturated water.10.2 Maintain the temperature of the conditioning water at 23 6 2 C 73.5 6 3.5 F, except that during the last 1 h ofimmersion immediately before making any measurement for length maintain the temperature at 23.0 6 0.5
46、 C 73.4 6 1.0 F(Note 4). When measuring for length, remove the specimens from water one at a time, wipe with a damp cloth, and immediatelymeasure for length using the comparator specified in 5.1. Make length measurements at 7-day intervals and continue conditioninguntil the change in length over a 7
47、-day period is less than 0.001 %. Use the length measurement that determines that this criterionis met as the basis for calculating length change occurring during the air or water storage period.NOTE 4Specimens used for length change measurements during freeze thaw resistance testing as described in
48、 Test Method C666/C666M shouldfollow the conditioning of that method.11. Storage of Specimens11.1 After measurement at the end of the conditioning period, store the specimens as described in either 11.2 or 11.3, unlessanother condition of storage is specified.11.2 Water StorageImmerse specimens in l
49、ime-saturated water at 23 6 2 C 73.5 6 3.5 F. Take observations of the lengthof each specimen after 1, 2, 4, 8, 16, 32, and 64 weeks unless otherwise specified. Make these observations immediately after thespecimens have been subjected to storage in water at 23.0 6 0.5 C 73.4 6 1.0 F for a period of at least 1 h. When measuringfor length, remove the specimens from water one at a time, wipe with a damp cloth, and immediately measure for length usingthe comparator specified in 5.1.11.3 Air Storage
