1、Designation: C 1262 08Standard Test Method forEvaluating the Freeze-Thaw Durability of Dry-CastSegmental Retaining Wall 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
2、 or, in the case of revision, the year of last revision. 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 This test method covers the resistance to freezing andthawing of dry-cast s
3、egmental retaining wall (SRW) units andrelated concrete units. Units are tested in a test solution that iseither water or 3 % saline solution depending on the intendeduse of the units in actual service.NOTE 1Related concrete units include units such as hollow and solidconcrete masonry units, concret
4、e brick, and concrete roof pavers.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all o
5、f 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. Referenced Documents2.1 ASTM Standards:2C 140 Test Methods for
6、Sampling and Testing ConcreteMasonry Units and Related UnitsC 1093 Practice for Accreditation of Testing Agencies forMasonryC 1209 Terminology of Concrete Masonry Units and Re-lated Units3. Terminology3.1 Terminology defined in Terminology C 1209 shall applyfor this test method.4. Significance and U
7、se4.1 The procedure described in this test method is intendedto determine the effects of freezing and thawing on SRW andrelated units in the presence of water or saline solution.4.2 The procedure is not intended to provide a quantitativemeasure to determine an expected length of service for aspecifi
8、c type of concrete unit.NOTE 2The testing laboratory performing this test method should beevaluated in accordance with Practice C 1093.5. 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 thawingcyc
9、les, or both, the chamber or chambers shall be capable ofmaintaining the air temperature throughout the chamber withinthe specified test ranges when measured at any given time. Ifthe apparatus operates automatically, it must be able to providereproducible cycles within the specified temperature requ
10、ire-ments.5.1.2 The apparatus includes a non-rigid plastic containerfor each test specimen and test specimen supports as 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 co
11、ntainer shallhave a tightly fitting lid to reduce evaporation. Test specimensupports to hold the specimen above the container 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
12、 directions (seeNote 3). The container shall be flat enough that when thespecimen coupon is set on the support rods the specimen shallnot deviate from level by more than116 in. (2 mm) from oneend of the specimen to the opposite end.NOTE 3Examples of longitudinal and transverse support configura-tion
13、s include placing the supports in I, Z, or box configurations.5.2 Temperature-Measuring Equipment:1This test method is under the jurisdiction of ASTM Committee C15 onManufactured Masonry Units and is the direct responsibility of SubcommitteeC15.03 on Concrete Masonry Units and Related Units.Current
14、edition approved July 1, 2008. Published July 2008. Originally approvedin 1994. Last previous edition approved in 2007 as C 1262 07.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume inform
15、ation, 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, United States.5.2.1 Reference Temperature-Measuring Device, sh
16、all bereadable and accurate to 60.5F (0.2C) within the range ofuse. A certificate or report that verifies the accuracy shall beavailable in the laboratory for review. Verify the accuracy ofliquid-in-glass reference temperature measuring devices atleast once. Verify the accuracy of direct-reading res
17、istancereference temperature-measuring devices every twelve months.The certificate or report shall provide documentation 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
18、-ing the temperature at various points within the test chamber towithin 2F (1C). Verify the accuracy of the temperature-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
19、 readable position as near to thetemperature-measuring device probe as possible. Close thedoor and leave undisturbed 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,
20、adjust or replacethe temperature-measuring device.5.3 ScalesScales for weighing full-size specimens shallhave a capacity 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 (s
21、pall), as required in 8.2.3, shall be accurate to at least0.2 g (0.0005 lb).6. Sampling6.1 Selection of Test SpecimensSelect 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 SRW un
22、its forfreeze-thaw tests.6.2.1 When compression and absorption testing will beconducted in addition to freeze-thaw testing, obtain a specimenfor each test from each of five SRW units to facilitatecorrelation among the properties. If this is not possible, thenobtain compressive strength and absorptio
23、n specimens fromdifferent units manufactured in the same production lot as thefreeze-thaw specimens. Take compressive strength and absorp-tion specimens in accordance with Test Methods C 140.Specimens (coupons) used for Test Methods C 140 tests shallnot be used as specimens for freeze-thaw tests.NOT
24、E 4While compressive strength and absorption values by them-selves have been shown by research to not be reliable indicators ofdurability, they have been shown to be good reference values for unitsmanufactured from a given set of materials.6.3 IdentificationMark each freezingandthawing speci-men so
25、that it is identifiable at any time.7. Preparation of Test 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-dr
26、ying prior to completion of freezingandthawing testing.7.1.1 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 Not
27、e 5). In the case of a unit with an exposed architecturalor 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, re
28、moveloose particles and residue from the coupon by rinsing 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 c
29、ould be used to obtain similar architectural effects liketumbling, 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 a
30、t a temperature of 75 6 15F(24 6 8C) and a relative humidity 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 un
31、it. The thickness ofthe coupon shall not be less than34 in. (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
32、shallconsist of two coupons. The combined area of the two 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
33、 testspecimens in accordance with Section 7, place the specimen 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 contai
34、ner toachieve a test solution depth of12 6116 in. (13 6 2 mm) (seeNote 6 and Note 7). Do not pour test solution directly onto thespecimen. The test solution shall be either potable tap water orFIG. 1 Test Specimen in FreezingandThawing ContainerC1262082a36 0.1 % (by weight) sodium chloride saline so
35、lution (seeNote 8). Close the container lid tightly and store the containeron a level surface in laboratory air as defined 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
36、the specimen.NOTE 7One way to repeatedly achieve the specified water depth is toadd a consistent volume of water which 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
37、 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 the water level required in8.1.1. 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
38、) or coarser sieve, removingvisible surface test solution 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 weig
39、ht loss of the specimen throughout the test. However,because 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 neede
40、d as a reference weight to be used duringthe testing to estimate 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 ate
41、mperature of 60 to 80F (16 to 27C).8.2 Cyclical Testing:8.2.1 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
42、.(2 mm). During the freezing cycle, maintain the air temperaturein 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, a
43、t the end ofa freezing cycle, open the containers and visually 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
44、to monitor the airtemperature throughout the chamber. If 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, c
45、onstanttemperature monitoring is not necessary, but it should 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 w
46、ith thawing cycle requirements in 8.2.6.8.2.2 After the freezing 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
47、the time required for the air temperaturearound the specimens 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 l
48、aid out in a single layer without stacking in thevertical 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.
49、3 One freezingandthawing cycle is defined as a com-pleted 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 inspect 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 result
