1、Designation: C 1262 07Standard Test Method forEvaluating the Freeze-Thaw Durability of ManufacturedConcrete Masonry Units and Related Concrete Units1This standard is issued under the fixed designation C 1262; the number immediately following the designation indicates the year oforiginal adoption or,
2、 in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the resistance to freezing andthawing manufactured con
3、crete masonry and related concreteunits. Units are tested in a test solution that is either water or3 % saline solution depending on the intended use of the unitsin actual service.NOTE 1Concrete masonry and related concrete units include unitssuch as hollow and solid concrete masonry units, concrete
4、 brick, segmen-tal retaining wall units, concrete pavers, and concrete roof pavers.1.2 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
5、determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 140 Test Methods of Sampling and Testing ConcreteMasonry Units and Related UnitsC 1093 Practice for the Accreditation of Testing Agenciesfor Unit MasonryC 1209 Terminology of Concrete Mas
6、onry Units and Re-lated Units3. Terminology3.1 Terminology defined in Terminology C 1209 shall applyfor this test method.4. Significance and Use4.1 The procedure described in this test method is intendedto determine the effects of freezing and thawing on concreteunits in the presence of water or sal
7、ine solution.4.2 The procedure is not intended to provide a quantitativemeasure to determine an expected length of service for aspecific type of concrete unit.NOTE 2The testing laboratory performing this test method should beevaluated in accordance with Practice C 1093.NOTE 3Compressive strength and
8、 absorption tests should be per-formed on different but representative specimens. While compressivestrength and absorption values by themselves have been shown byresearch to not be reliable indicators of durability, they have been shownto be good reference values for units manufactured from a given
9、set ofmaterials.5. Apparatus5.1 Freezing-and-Thawing Apparatus:5.1.1 In the event that a chamber or chambers are used tosubject the specimens to the specified freezing or thawingcycles, or both, the chamber or chambers shall be capable ofmaintaining the air temperature throughout the chamber withint
10、he specified test ranges when measured at any given time. Ifthe apparatus operates automatically, it must be able to providereproducible cycles within the specified temperature require-ments.5.1.2 The apparatus includes a non-rigid plastic containerfor each test specimen and test specimen supports a
11、s illustratedin Fig. 1. The containers shall be of sufficient size to provide aminimum of18 in. (3 mm) and a maximum of 112 in. (38 mm)test solution surrounding the specimen. The container shallhave a tightly fitting lid to reduce evaporation. Test specimensupports to hold the specimen above the con
12、tainer bottom shallbe18 6124 in. (3 6 1 mm) rods of a solid noncorrosive,nonabsorptive material (brass, plastic, etc.). Support the speci-men in both the longitudinal and transverse directions (seeNote 4). The container shall be flat enough that when thespecimen coupon is set on the support rods the
13、 specimen shallnot deviate from level by more than116 in. (2 mm) from oneend of the specimen to the opposite end.NOTE 4Examples of longitudinal and transverse support configura-tions include placing the supports in I, Z, or box configurations.5.2 Temperature-Measuring Equipment:5.2.1 Reference Tempe
14、rature-Measuring Device, shall bereadable and accurate to 60.5F (0.2C) within the range ofuse. A certificate or report that verifies the accuracy shall be1This test method is under the jurisdiction of ASTM Committee C15 onManufactured Masonry Units and is the direct responsibility of SubcommitteeC15
15、.03 on Concrete Masonry Units and Related Units.Current edition approved July 15, 2007. Published August 2007. Originallyapproved in 1994. Last previous edition approved in 2005 as C 1262 05a.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at ser
16、viceastm.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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Un
17、ited States.available in the laboratory for review. Verify the accuracy ofliquid-in-glass reference temperature measuring devices atleast once. Verify the accuracy of direct-reading resistancereference temperature-measuring devices every twelve months.The certificate or report shall provide document
18、ation that thereference standard used in the verification is traceable to theNational Institute of Standards and Technology (NIST).5.2.2 Temperature-Measuring Devices, capable of measur-ing the temperature at various points within the test chamber towithin 2F (1C). Verify the accuracy of the tempera
19、ture-measuring devices at least every six months.5.2.3 To verify the accuracy of the temperature-measuringdevices, position the reference temperature-measuring devicein the chamber in a readable position as near to thetemperature-measuring device probe as possible. Close thedoor and leave undisturbe
20、d for at least 5 min. Read thetemperature immediately after opening the chamber door.Record the temperature readings of both devices. If thetemperature readings differ by more than 2F, adjust or replacethe temperature-measuring device.5.3 ScalesScales for weighing full-size specimens shallhave a cap
21、acity of at least 50 % greater than the weight of thelargest specimen tested and shall be accurate to at least 1 g(0.002 lb). Scales for weighing the filter paper and specimenresidue (spall), as required in 8.2.3, shall be accurate to at least0.2 g (0.0005 lb).6. Sampling6.1 Selection of Test Specim
22、ensSelect whole units repre-sentative of the lot from which they are selected. The unitsshall be free from visible cracks or structural defects.6.2 Number of SpecimensSelect five units for freezingand thawing tests. If compression and absorption tests are to beperformed on the same set of units in a
23、ccordance with TestMethods C 140, select additional units as required. Specimens(coupons) used for Test Methods C 140 tests shall not be usedas specimens for freezingandthawing tests.6.3 IdentificationMark each freezingandthawing speci-men so that it is identifiable at any time.7. Preparation of Tes
24、t Specimens7.1 FreezingandThawing Test SpecimensTest speci-mens shall consist of solid coupons saw-cut from full sizedunits. Do not saw-cut test specimens from units that have beenpreviously oven-dried. Do not subject test specimens to oven-drying prior to completion of freezingandthawing testing.7.
25、1.1 Cut one coupon from each of the five sampled units.Using a water-cooled saw, cut the coupon from the exposedsurface of the unit as the unit is used in service unless theexposed surface is an architectural or other nonplanar surface(see Note 5). In the case of a unit with an exposed architectural
26、or other nonplanar surface, cut the coupon from another flatmolded surface ideally as far as possible from the architecturalor other non-planar face and in no case less than 2 in. (50 mm)from that surface. Immediately following saw-cutting, removeloose particles and residue from the coupon by rinsin
27、g in tapwater and brushing with a soft bristle brush. Do not fullyimmerse coupons in water.NOTE 5Split-faced surfaces are the most common surfaces used toprovide an architectural appearance to segmental retaining walls. How-ever, other means could be used to obtain similar architectural effects like
28、tumbling, grinding, and slumping.7.1.2 Place the coupons on edge on a38 in. (10 mm) orcoarser mesh such that there is an air space of not less than 1in. (25 mm) between coupons.Allow the coupons to dry for notless than 48 h in laboratory air at a temperature of 75 6 15F(24 6 8C) and a relative humid
29、ity of less than 80 %.7.1.3 The thickness of each coupon shall be 114 in. (32 mm)6116 in. (2 mm), unless the unit does not permit this minimumthickness, in which case the thickness shall be the maximumthickness that can be obtained from the unit. The thickness ofthe coupon shall not be less than34 i
30、n. (19 mm).7.1.4 The area of the submerged surface of the test specimenshall be at least 25 in.2(161 cm2) and shall not exceed 35 in.2(225 cm2), unless the unit does not permit a coupon meetingthe minimum area, in which case the test specimen shallconsist of two coupons. The combined area of the two
31、 couponsshall be at least 25 in.2(161 cm2) and shall not exceed 35in.2(225 cm2). These two coupons shall be tested as andconsidered to be a single specimen.8. Procedure8.1 Specimen Conditioning:8.1.1 After preparation of the freezingandthawing testspecimens in accordance with Section 7, place the sp
32、ecimen inthe container face down on the specimen supports such that thenon-saw-cut surface of the specimen is in contact with thespecimen supports. Add a sufficient amount of test solution ata temperature of 60 to 80F (16 to 27C) to the container toachieve a test solution depth of12 6116 in. (13 6 2
33、 mm) (seeNote 6 and Note 7). Do not pour test solution directly onto thespecimen. The test solution shall be either potable tap water ora36 0.1 % (by weight) sodium chloride saline solution (seeNote 8). Close the container lid tightly and store the containeron a level surface in laboratory air as de
34、fined in 7.1.2.NOTE 6The submerged portion of the specimen is38 in. (10 mm) ofits thickness. There is18 in. (3 mm) of test solution between the bottomof the container and the face of the specimen.NOTE 7One way to repeatedly achieve the specified water depth is toadd a consistent volume of water whic
35、h has been calibrated for a givenspecimen and container size combination to yield the specified depth.NOTE 8The 3 % saline solution can be prepared by adding 0.03 lb ofsodium chloride to each 0.97 lb of water.8.1.2 After 1 h 6 15 min, open the container and add testsolution as necessary to maintain
36、the water level required inFIG. 1 Test Specimen in FreezingandThawing ContainerC12620728.1.1. Reseal the container. After another 23 h 6 1 h, removethe specimen from the test solution and allow to drain for 1 minby placing it on a38-in. (10-mm) or coarser sieve, removingvisible surface test solution
37、 with a damp cloth. Immediatelyweigh the specimen to the nearest 1 g (0.002 lb) and record asWp.NOTE 9The weight Wpas determined in 8.1.2 is not required to bereported at the conclusion of the test, nor is it used to calculate thereported weight loss of the specimen throughout the test. However,beca
38、use the initial dry-weight of the specimen is not determined until thecompletion of freezingandthawing testing by adding the dry-weight ofthe collected residue to the dry-weight of the remains of the specimen (see8.3.5), this Wpweight is needed as a reference weight to be used duringthe testing to e
39、stimate percentage weight loss and to predict relativeperformance between test specimens.8.1.3 Return the specimens to the container and adjust testsolution level as required in 8.1.1.8.1.4 Test solution added to the containers shall be at atemperature of 60 to 80F (16 to 27C).8.2 Cyclical Testing:8
40、.2.1 Begin the test with a freezing cycle. Place the con-tainers into the freezing test chamber such that each containeris surrounded by a minimum air space of12 in. (13 mm) on allsides. During testing the container shall be level within116 in.(2 mm). During the freezing cycle, maintain the air temp
41、eraturein the chamber at 0 6 10F (-18 6 5C) for a period of not lessthan 4.0 h and not more than 5.0 h. The cycle time does notinclude the time required for the air temperature in the chamberto reach the prescribed temperature. Periodically, at the end ofa freezing cycle, open the containers and vis
42、ually inspect thespecimens to determine if all the test solution surrounding thespecimen is frozen solid. If not, extend the length of thefreezing cycle to ensure that all test solution is frozen solid.NOTE 10Temperature probes should be used to monitor the airtemperature throughout the chamber. If
43、warm units are placed into afreezing chamber, the air temperature within the chamber rises. The startof the freezing cycle time period begins only after the temperature of theair within the chamber is within the permissible range. Typically, constanttemperature monitoring is not necessary, but it sh
44、ould be preformedthrough the first several cycles to ensure that the specimens remain in thefreezing chamber for the appropriate length of time to comply with thecycle requirements. The same procedures should also be used to verifycompliance with thawing cycle requirements in 8.2.6.8.2.2 After the f
45、reezing cycle, immediately begin the thaw-ing cycle. During the thawing cycle, maintain the air tempera-ture around the containers at 75 6 10F (24 6 5C) for aperiod of not less than 2.5 h and not more than 96 h. The cycletime does not include the time required for the air temperaturearound the speci
46、mens to reach the prescribed temperatures.Each container shall be surrounded by a minimum air space of12 in. on all sides. If the air surrounding the containers is notcontinuously circulated during the thawing cycle, the contain-ers shall be laid out in a single layer without stacking in thevertical
47、 direction. Periodically, at the end of a thawing cycle,open the containers and visually inspect the specimens todetermine if no ice remains. If ice is still present, extend thelength of the thawing cycle to ensure that all ice has thawed.8.2.3 One freezingandthawing cycle is defined as a com-pleted
48、 freezing cycle followed by a completed thawing cycle.8.2.4 At 20 cycle intervals for those specimens tested inwater and at 10 cycle intervals for those specimens tested insaline solution, remove containers from the test chamber andcollect residue in accordance with 8.3. Open containers tovisually i
49、nspect the condition of the specimens and to adjustthe test solution level to comply with 8.1.1.NOTE 11There is some evidence that frequency of sampling influ-ences results. Therefore, variations from cycle intervals for residuesampling are only appropriate when this method is used for researchpurposes rather than compliance purposes. Collecting and reportingresidue at regular intervals provides information about the performance ofthe specimens throughout the duration of the test and also permits plottingresults of weight
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