1、Designation:C 671 94Standard Test Method forCritical Dilation of Concrete Specimens Subjected to Freezing1This standard is issued under the fixed designation C 671;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revi
2、sion.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the testperiod of frost immunity of concrete specimens as measured bythe length of tim
3、e of water immersion required to producecritical dilation when subjected to a prescribed slow-freezingprocedure.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsi
4、bility 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.Referenced Documents2.1 ASTM Standards:C 192 Practice for Making and Curing Concrete Test Speci-mens in the Laboratory2C 490 Practice fo
5、r Use of Apparatus for Determination ofLength Change of Hardened Cement Paste,Mortar,andConcrete3C 682 Practice for Evaluation of Frost Resistance of CoarseAggregates in Air Entrained Concrete by Critical DilationProcedures22.2 ASTM Adjuncts:Adjunct C 671 Two detailed drawings of a strain frame,1dra
6、wing of gage point installation,and a table of metricequivalents.43.Significance and Use3.1 This test method is suitable for ranking concretesaccording to their resistance to freezing and thawing fordefined curing and conditioning procedures.The significanceof the results in terms of potential field
7、 performance willdepend upon the degree to which field conditions can beexpected to correlate with those employed in the laboratory.3.2 This test method is suitable for estimating the frostsusceptibility of aggregates in concrete as described in PracticeC 682.3.3 This test method is also suitable fo
8、r use by those peopleengaged in research and development in the field of concretedurability.It is believed that a fundamental understanding oflength change of concrete subjected to freezing will lead tomore durable concrete.4.Apparatus4.1 Cooling Bath,of sufficient size and depth to completelyimmers
9、e the test specimens in silicone oil or water-saturatedkerosine(Note 1).The bath shall have a sufficient volume ofkerosine per specimen and shall be provided with controls so asto permit lowering its temperature and that of the test speci-mens uniformly from 1.7 to 9.4C(35 to 15F)at the rate of2.8 6
10、 0.5C/h(5 6 1F/h).Suitable bath temperature record-ing facilities shall be provided.NOTE1Very little water is required to saturate kerosine.Excess watershould be avoided as it will form ice crystals in the bath.As an alternativeto kerosine,the use of silicone oil may be preferable to reduce odors an
11、dfire hazards.4.2 Constant-Temperature Water Bath A refrigerated wa-ter bath capable of containing the specimens completelyimmersed,and equipped with control facilities capable ofmaintaining the temperature of the specimens at 1.7 6 0.9C(35 6 2F)before and between test cycles.4.3 Strain-Measuring an
12、d Recording Facilities,(Note 2)and a supply of strain frames to support the specimens in thecooling bath and to provide alignment for the strain-measuringapparatus(Fig.1).3The strain-measuring apparatus shall havea capability for measuring 2 millionths or less.NOTE2Linear variable differential trans
13、formers(LVDT)with theappropriate associated electronic actuating and indicating apparatus ap-pear to give the best results with respect to stability,sensitivity,andreliability.Multichannel recording of outputs has been found to bepractical and efficient(see Fig.2).As an alternate to the recordingapp
14、aratus shown in Fig.2,a data logger5can be used to excite the LVDTand record the LVDT both temperature and time outputs.The data can bestored directly in a personal computer for graphing of test results.4.4 Room or Cabinet,for storing specimens at the desiredtemperature and relative humidity with pr
15、ovision for constantcirculation of air in the immediate vicinity of the specimens.1This test method is under the jurisdiction ofASTM Committee C-9 on Concreteand Concrete Aggregatesand is the direct responsibility of Subcommittee C09.67onResistance of Concrete to Its Environment.Current edition appr
16、oved May 15,1994.Published July 1994.Originallypublished as C 671 71 T.Last previous edition C 671 86.2Annual Book of ASTM Standards,Vol 04.02.3Annual Book of ASTM Standards,Vol 04.01.4Available from ASTM Headquarters,100 Barr Harbor Drive,West Consho-hocken,PA 19428.Request ADJC0671.5Asuitable data logger is manufactured by Campbell Scientific Inc.,Model 21X,P.O.Box 551,Logan,Utah 84321.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.NOTICE:This standard has
