1、Designation: C 495 07Standard Test Method forCompressive Strength of Lightweight Insulating Concrete1This standard is issued under the fixed designation C 495; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the preparation of spe
3、cimensand the determination of the compressive strength of light-weight insulating concrete having an oven-dry density notexceeding 50 lb/ft3(800 kg/m3) as determined by the proce-dures described herein. This test method covers the preparationand testing of molded 3 by 6-in. (75 by 150-mm) cylinders
4、.1.2 The values stated in inch-pound units are to be regardedas the standard.1.3 This standard does not purport to address all of thesafety problems, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determ
5、ine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 39/C 39M Test Method for Compressive Strength of Cy-lindrical Concrete SpecimensC88 Test Method for Soundness of Aggregates by Use ofSodium Sulfate or Magnesium SulfateC 109/C 109M Test Method
6、for Compressive Strength ofHydraulic Cement Mortars(Using 2-in. or 50-mm CubeSpecimens)C 172 Practice for Sampling Freshly Mixed ConcreteC 617 Practice for Capping Cylindrical Concrete Speci-mensC 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction Materials3. S
7、ignificance and Use3.1 This test method provides standardized requirements forsampling, molding, curing, and testing lightweight insulatingconcretes for the purpose of determining compliance withcompressive strength and density specifications.4. Apparatus4.1 Testing MachineUse a testing machine as p
8、rescribedin Test Method C 39/C 39M.4.2 Scales and WeightsUse scales and weights in weigh-ing specimens that conform to those specified in the ApparatusSection of Test Method C 109/C 109M.4.3 Drying OvenUse an oven as specified in Test MethodC88.4.4 MoldsUse molds made of nonabsorbent materials orof
9、materials treated to reduce absorption, that are watertight,and not subject to distortion of more than116 in. (1.6 mm) inany dimension during molding and early curing of specimens.Coat all mold surfaces that will be in contact with concreteexcept single use plastic molds with wax or mineral oil, pri
10、orto use. Use molds having a diameter of 3 6116 in. (75 6 1.6mm) and a length of 6 618 in. (1506 3 mm).5. Sampling5.1 Sample fresh lightweight insulating concrete in accor-dance with applicable provisions of Practice C 172, with thefollowing exceptions:5.1.1 Sampling from Pump EquipmentFill a bucket
11、 ofapproximately 10-qt (9-dm3) capacity by passing through thedischarge stream of the concrete pump hose being used to placethe concrete, at the point of placement of the concrete. Exercisecare to ensure that the sample is representative of the pour,avoiding the beginning or ending of the discharge
12、from theequipment. Prepare the test specimens as described in Section1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.21 on Lightweight Aggregates and Concrete.Current edition approved July 15, 20
13、07. Published August 2007. Originallyapproved in 1962. Last previous edition approved in 1999 as C 495 99a.2For referenced 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 stand
14、ards 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.6, by filling them with a scoop of lightweight insulatingconcrete dipped
15、from the bucket.5.1.2 Remixing SampleDo not remix the sample.6. Test Specimens6.1 Size and ShapeUse cylindrical test specimens 3 6116in. (75 6 1.6 mm) in diameter and 6 618 in. (150 6 3 mm)in length, with the base of each specimen perpendicular to thelongitudinal axis within the limits prescribed in
16、 6.8.6.2 NumberObtain at least four test specimens for com-pressive strength tests from each sample of lightweight insu-lating concrete.6.3 MoldingIn molding the specimens, place the concretein two approximately equal layers. Tap the sides of the moldlightly with a rubber mallet after placing each l
17、ayer until thesurface of the layer has subsided approximately to a plane.Over fill the mold when placing the second layer. Do not rodthe concrete.6.4 Finishing SurfaceStrike off the specimens immedi-ately after filling the molds. Cover them in such a manner as toprevent evaporation without marring t
18、he surface (Note 1). Ifdesired, cover the filled mold with a glass or metal plate toobtain a surface that will be suitable for testing without cappingand with a minimum of grinding.NOTE 1It is desirable to place the filled mold in a moist room if oneis available. If this is done, protect the surface
19、 from dripping water.6.5 Removal from MoldsDo not remove specimens frommolds until danger of damage to the specimens is past. In anyevent, remove specimens from the molds within 7 days aftermolding.6.6 CuringFor the first 24 h after molding, maintain thespecimens at a temperature of 70 6 10 F (21.1
20、6 5.5 C).After 246 2 h, store the specimens in a moist condition (Note2) at a temperature of 73.4 6 3 F (23.0 6 1.7 C) (Note 3).Do not expose specimens to a stream of running water nor storein water, unless a saturated lime (calcium hydroxide) solutionis used.After 7 days, store the specimens at a t
21、emperature of 706 10 F and a relative humidity of 50 6 30 % for 18 days.Twenty-five days after molding, dry the specimens in an ovenat 140 6 5F(606 2.8 C) for 3 days (Note 4). Coolspecimens to room temperature and test for compressivestrength at an age of 28 days.NOTE 2A moist condition is that in w
22、hich free water is maintained onthe surfaces of the specimens at all times.NOTE 3The temperature within damp sand and under wet burlap orsimilar materials will always be lower than the temperature in thesurrounding atmosphere if evaporation takes place.NOTE 4Caution must be observed in loading the o
23、ven so that themoisture content of the specimen at time of test does not exceed 5 % of theoven-dry density determined in accordance with 9.1.6.7 Preparation for TestingCheck the surfaces of thespecimen that will be in contact with the bearing surfaces of thetesting machine within 0.02 in. (0.5 mm).
24、If the bearingsurfaces depart from a plane more than 0.02 in. (0.5 mm), grindthem to conform to this tolerance or cap in accordance withPractice C 617. Cap surfaces to be plane within 0.002 in. (0.05mm). Check the planeness of the bearing surface of thespecimen by means of a straightedge and feeler
25、gage, makinga minimum of three measurements on different diameters of thespecimen. Make sure the surface of the specimen in contactwith the lower bearing block of the testing machine does notdepart from perpendicularity with the longitudinal axis of thecylinder by more than 1 (approximately equivale
26、nt to 0.1 in.in 6 in. (2.5 mm in 150 mm) or the combined departure of thetwo bearing surfaces from perpendicularity by more than 3.6.8 Measurement of SpecimenDetermine the diameter ofthe specimens to the nearest 0.01 in. (0.3 mm) by averagingtwo diameters measured at right angles to each other at ab
27、outmidheight of the specimen. Use these dimensions in computingthe cross-sectional areas. Determine the height of the specimento the nearest 0.01 in.7. Procedure7.1 Placing of SpecimenWipe clean the bearing faces ofthe upper and lower bearing blocks of the compression testmachine and of the test spe
28、cimen and place the test specimenon the lower bearing block. Carefully align the axis of thespecimen with the center of thrust of the spherically seatedblock. As the spherically seated block is brought to bear on thespecimen, gently rotate its movable portion by hand so thatuniform seating is obtain
29、ed.7.2 Rate of LoadingContinuously apply the load withoutshock at a constant rate such that the maximum load will bereached in 65 6 15 s. Record the maximum load sustained bythe specimen. Note the type of failure and the appearance ofthe concrete.8. Calculation8.1 Calculate the unit compressive stre
30、ngth of the concreteby dividing the maximum load by the average cross-sectionalarea and record to the nearest 10 psi (69 kPa).9. Oven-Dry Density9.1 When the oven-dry unit density is desired, mold twocompanion specimens for this purpose at the same time as thecompressive strength specimens. Cure the
31、 companion speci-mens the same as the compressive strength specimens, exceptdry the companion specimens at the age of 28 days in an ovenat 230 6 18 F (110 6 10 C) and weigh at 24-h intervals untilthe loss in weight does not exceed 1 % in a 24-h period.Determine the mass and dimensions of the oven-dr
32、y specimensand calculate the density from the average data obtained.10. Report10.1 For each specimen tested report the following infor-mation where applicable:10.1.1 Identification number,10.1.2 Dimensions of test specimen, in inches (millimetres),10.1.3 The cross-sectional area in square inches (sq
33、uarecentimetres),10.1.4 Type of cap,10.1.5 Maximum load, in pounds-force (or kilonewtons),10.1.6 Unit compressive strength in pounds-force persquare inch (or kilopascals),10.1.7 Type of fracture and appearance of the concretefollowing determination of compressive strength,10.1.8 Defects in either sp
34、ecimen or caps,C49507210.1.9 Age of specimen, in days,10.1.10 Calculated oven-dry density, if determined,10.1.11 Average ambient temperature and average relativehumidity at which specimens were stored during the 18-daycuring period, and10.1.12 Summation of tests of specimens from same samplewith ave
35、rage of test results. This summation shall be shown onthe report of the last specimen tested and should be referencedin reports of other specimens.11. Precision and Bias11.1 Precision:11.1.1 The single operator standard deviation for a testresult (where a test result is, as defined in this test meth
36、od, theaverage of four separate compressive strength measurements)has been found to be 21 psi (Note 5). Therefore, results of twoproperly conducted tests (each consisting of the average of fourindividual measurements) by the same operator on concretesamples from the same batch should not differ by m
37、ore than 59psi (Note 5). The range (difference between highest and lowest)of the four individual measurements used in calculating theaverage should not exceed 155 psi (Note 6).11.1.2 The multilaboratory standard deviation for a testresult has been found to be 29 psi (Note 5). Therefore, resultsof tw
38、o properly conducted tests (each consisting of the averageof four individual measurements) by two different laboratorieson concrete samples from the same batch should not differ bymore than 83 psi (Note 5).NOTE 5These numbers represent, respectively, the (1s) and (d2s)limits as described in Practice
39、 C 670.NOTE 6Calculated as described in 3.4.3 of Practice C 670.11.2 BiasThe bias of this test method cannot be deter-mined because compressive strength can only be defined interms of this test method.12. Keywords12.1 compressive strength; density; lightweight insulatingconcrete; oven-dry densitySUM
40、MARY OF CHANGESCommittee C09 has identified the location of selected changes to this test method since the last issue,C 495 99a, that may impact the use of this test method. (Approved July 15, 2007)(1) Replaced “weight” with “density” in 1.1, Note 4, the title ofSection 9, 9.1, and Section 12.(2) Re
41、placed “weight” with “mass” in 9.1, and corrected thecitation in Note 4 from 8.1 to 9.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of
42、 the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn.
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44、nts have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C495073
