ASTM C495 C495M-2012 Standard Test Method for Compressive Strength of Lightweight Insulating Concrete《轻量级绝缘混凝土的压缩强度标准试验方法》.pdf

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1、Designation:C49507 Designation: C495/C495M 12Standard Test Method forCompressive Strength of Lightweight Insulating Concrete1This standard is issued under the fixed designation C495/C495M; the number immediately following the designation indicates the yearof original adoption or, in the case of revi

2、sion, 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1This1.1 This test m

3、ethod covers the preparation of specimens and the determination of the compressive strength oflightweight insulating concrete having an oven-dry density not exceeding 50 lb/ft800 kg/m3(800 kg/m50 lb/ft3) as determined bythe procedures described herein. This test method covers the preparation and tes

4、ting of molded 3 by 6-in. (75 by 150-mm)cylinders.1.2The values stated in inch-pound units are to be regarded as the standard. as determined by the procedures described herein.This test method covers the preparation and testing of molded 75 by 150-mm 3 by 6-in. cylinders.1.2 The values stated in eit

5、her SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.1.3 This sta

6、ndard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibilityof 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 AS

7、TM Standards:2C39/C39M Test Method for Compressive Strength of Cylindrical Concrete SpecimensC88 Test Method for Soundness of Aggregates by Use of Sodium Sulfate or Magnesium SulfateC109/C109M Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or 50-mm Cube Specimens)C172

8、Practice for Sampling Freshly Mixed ConcreteC617 Practice for Capping Cylindrical Concrete SpecimensC670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials3. Significance and Use3.1 This test method provides standardized requirements for sampling, moldin

9、g, curing, and testing lightweight insulatingconcretes for the purpose of determining compliance with compressive strength and density specifications.4. Apparatus4.1 Testing MachineUse a testing machine as prescribed in Test Method C39/C39M.4.2 Scales and WeightsUse scales and weights in weighing sp

10、ecimens that conform to those specified in theApparatus Sectionof Test Method C109/C109M.4.3 Drying OvenUse an oven as specified in Test Method C88.4.4 MoldsUse molds made of nonabsorbent materials or of materials treated to reduce absorption, that are watertight, and notsubject to distortion of mor

11、e than in. (1.6 mm)2 mm 116 in. in any dimension during molding and early curing of specimens. Coatall mold surfaces that will be in contact with concrete except single use plastic molds with wax or mineral oil, prior to use. Usemolds having a diameter of 375 6 in. (752 mm 3 6 1.6 mm)116 in. and a l

12、ength of 6150 6 in. (1506 3mm).3mm6618in.1This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.21 onLightweight Aggregates and Concrete.Current edition approved July 15, 2007. Published August 2007.

13、Originally approved in 1962. Last previous edition approved in 1999 as C49599a. DOI:10.1520/C0495-07.Current edition approved April 1, 2012. Published April 2012. Originally approved in 1962. Last previous edition approved in 2007 as C49507. DOI:10.1520/C0495_C0495M-12.2For referenced ASTM standards

14、, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide the user of an AST

15、M 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 all cases only the current versionof the standard as published

16、by ASTM is to be considered the official document.*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. Sampling5.1 Sample fresh lightweight insulating concrete in accorda

17、nce with applicable provisions of Practice C172, with the followingexceptions:5.1.1 Sampling from Pump EquipmentFill a bucket of approximately 10-qt (9-dm3)9-L 10-qt capacity by passing throughthe discharge stream of the concrete pump hose being used to place the concrete, at the point of placement

18、of the concrete. Exercisecare to ensure that the sample is representative of the pour, avoiding the beginning or ending of the discharge from the equipment.Prepare the test specimens as described in Section 6, by filling them with a scoop of lightweight insulating concrete dipped fromthe bucket.5.1.

19、2 Remixing SampleDo not remix the sample.6. Test Specimens6.1 Size and ShapeUse cylindrical test specimens 375 6 in. (752 mm 3 6 1.6 mm)116 in. in diameter and 6150 6 in. (1503mm 6 6 3 mm)18 in. in length, with the base of each specimen perpendicular to the longitudinal axis within the limits prescr

20、ibedin 6.8.6.2 NumberObtain at least four test specimens for compressive strength tests from each sample of lightweight insulatingconcrete.6.3The compressive strength of the sample shall be based on the average strength of four cylinders. Obtain at least four testcylinders for compressive strength t

21、ests from each sample of lightweight insulating concrete.6.3 MoldingIn molding the specimens, place the concrete in two approximately equal layers. Tap the sidesoutside of the moldlightly 10 to 15 times with a rubber malletan open hand after placing each layer until the surface of the layer has subs

22、idedapproximately to a plane.to close voids and release entrapped air. Over fill the mold when placing the second layer. Do not rodthe concrete.6.4 Finishing SurfaceStrike off the specimens immediately after filling the molds. Cover them in such a manner as to preventevaporation without marring the

23、surface (Note 1). If desired, cover the filled mold with a glass or metal plate to obtain a surfacethat will be suitable for testing without capping and with a minimum of grinding.NOTE 1It is desirable to place the filled mold in a moist room if one is available. If this is done, protect the surface

24、 from dripping water.6.5 Removal from MoldsDo not remove specimens from molds until danger of damage to the specimens is past. In any event,remove specimens from the molds within 7 days after molding.6.6 CuringFor the first 24 h after molding, maintain the specimens at a temperature of 7021 6 10 F (

25、21.16 C 70 6 5.5C).10 F. After 246 2 h, store the specimens in a moist condition (Note 2) at a temperature of 73.4 6 3 F (23.0 6 1.7 C) ()at a temperature of 23.0 6 2.0 C 73.5 6 3.5 F (Note 3). Do not expose specimens to a stream of running water nor store inwater, unless a saturated lime (calcium h

26、ydroxide) solution is used. After 7 days, store the specimens at a temperature of 7021 66C706 10 F and a relative humidity of 50 6 30 % for 18 days. Twenty-five days after molding, dry the specimens in anoven at 14060 6 5 F (603 C 140 6 2.8 C)5 F for 3 days (Note 4). Cool specimens to room temperatu

27、re and test forcompressive strength at an age of 28 days. ). Cool specimens to room temperature and test for compressive strength at an age of28 days. If cellular concrete made using preformed foam is being tested, moist cure the cylinders from day 2 to day 25. At day25 air dry the cylinders for 3 d

28、ays at a temperature of 21 6 6C706 10 F and a relative humidity of 50 6 10 %. Do not ovendry the specimens prior to load testing.NOTE 2A moist condition is that in which free water is maintained on the surfaces of the specimens at all times.NOTE 3The temperature within damp sand and under wet burlap

29、 or similar materials will always be lower than the temperature in the surroundingatmosphere if evaporation takes place.NOTE 4Caution must be observed in loading the oven so that the moisture content of the specimen at time of test does not exceed 5 % of the oven-drydensity determined in accordance

30、with 9.1.6.7 Preparation for TestingCheck whether the surfaces of the specimen that will be in contact with the bearing surfaces ofthe testing machine are within 0.02 in. (0.5 mm).0.5 mm 0.02 in. If the bearing surfaces depart from a plane more than 0.02 in.(0.5 mm),0.5 mm 0.02 in., grind them to co

31、nform to this tolerance or cap in accordance with Practice C617. Cap surfaces to beplane within 0.002 in. (0.05 mm).0.05 mm 0.002 in. Check the planeness of the bearing surface of the specimen by means ofa straightedge and feeler gage, making a minimum of three measurements on different diameters of

32、 the specimen. Make sure thesurface of the specimen in contact with the lower bearing block of the testing machine does not depart from perpendicularity withthe longitudinal axis of the cylinder by more than 1 (approximately equivalent to 0.1 in.2.5 mm in 6 in. (2.5 mm150 mm 0.1in. in 150 mm)6 in.)

33、or the combined departure of the two bearing surfaces from perpendicularity by more than 3.6.8 Measurement of SpecimenDetermine the diameter of the specimens to the nearest 0.01 in. (0.3 mm) by averaging twodiameters measured at right angles to each other at about midheight of the specimen. Use thes

34、e dimensions in computing thecross-sectional areas. Determine the height of the specimen to the nearest 0.01 in. Determine the diameter of the specimens tothe nearest 0.2 mm 0.01 in. by averaging two diameters measured at right angles to each other at about midheight of thespecimen. Use these dimens

35、ions in computing the cross-sectional areas. Determine the height of the specimen to the nearest 0.2mm 0.01 in. Weigh the cylinders before capping and calculate the density from the measured dimensions. Record the densityto the nearest 10 kg/m30.5 lb/ft3.C495/C495M 1227. Procedure7.1 Placing of Spec

36、imenWipe clean the bearing faces of the upper and lower bearing blocks of the compression test machineand of the test specimen and place the test specimen on the lower bearing block. Carefully align the axis of the specimen with thecenter of thrust of the spherically seated block. As the spherically

37、 seated block is brought to bear on the specimen, gently rotateits movable portion by hand so that uniform seating is obtained.7.2 Rate of LoadingContinuously apply the load without shock at a constant rate such that the maximum load will be reachedin 65 6 15 s. Record the maximum load sustained by

38、the specimen. Note the type of failure and the appearance of the concrete.8. Calculation8.1Calculate8.1 Calculate the unit compressive strength of the concrete by dividing the maximum load by the averagecross-sectional area and record to the nearest 10 psi (69 kPa).0.1 MPa 10 psi.9. Oven-Dry Density

39、9.1 When the oven-dry unit density is desired, mold two companion specimens for this purpose at the same time as thecompressive strength specimens. Cure the companion specimens the same as the compressive strength specimens, except dry thecompanion specimens at the age of 28 days in an oven at 23011

40、0 6 18 F (1105 C 230 6 10 C)F and weigh at 24-h intervalsuntil the loss in weight does not exceed 1 % in a 24-h period. Determine the mass and dimensions of the oven-dry specimens andcalculate the density from the average data obtained.10. Report10.1 For each specimen tested report the following inf

41、ormation where applicable:10.1.1 Identification number,10.1.2Dimensions of test specimen, in inches (millimetres),10.1.3The cross-sectional area in square inches (square centimetres),10.1.4Type of cap,10.1.5Maximum load, in pounds-force (or kilonewtons),10.1.6Unit compressive strength in pounds-forc

42、e per square inch (or kilopascals),10.1.7Type of fracture and appearance of the concrete following determination of compressive strength,10.1.8Defects in either specimen or caps,10.1.9Age of specimen, in days,10.1.10Calculated oven-dry density, if determined,10.1.11Average ambient temperature and av

43、erage relative humidity at which specimens were stored during the 18-day curingperiod, and10.1.12Summation of tests of specimens from same sample with average of test results. This summation shall be shown on thereport of the last specimen tested and should be referenced in reports of other specimen

44、s.10.1.2 Cylinder density reported to nearest 10 kg/m30.5 lb/ft3.10.1.3 Dimensions of test specimen, in mm in.,10.1.4 The cross-sectional area in mm2in.2,10.1.5 Type of cap,10.1.6 Maximum load, in kN lb,10.1.7 Unit compressive strength shall be reported as the average of testing four cylinders from

45、the same batch of lightweightinsulating concrete defined in 6.2, in MPa psi,10.1.8 Type of fracture and appearance of the concrete following determination of compressive strength,10.1.9 Defects in either specimen or caps,10.1.10 Age of specimen, in days,10.1.11 Calculated oven-dry density, if determ

46、ined,10.1.12 Average ambient temperature and average relative humidity at which specimens were stored during the 18-day curingperiod, and10.1.13 Summation of tests of specimens from same sample with average of test results. This summation shall be shown on thereport of the last specimen tested and s

47、hould be referenced in reports of other specimens.11. Precision and Bias11.1 Precision:11.1.1The single operator standard deviation for a test result (where a test result is, as defined in this test method, the averageof four separate compressive strength measurements) has been found to be 21 psi (N

48、ote 5). Therefore, results of two properlyconducted tests (each consisting of the average of four individual measurements) by the same operator on concrete samples fromthe same batch should not differ by more than 59 psi (Note 5). The range (difference between highest and lowest) of the fourindividu

49、al measurements used in calculating the average should not exceed 155 psi (11.1.1 The single operator standard deviation for a test result (where a test result is, as defined in this test method, the averageC495/C495M 123of four separate compressive strength measurements) has been found to be 0.14 MPa 21 psi (Notes 5 and 6). Therefore, resultsof two properly conducted tests (each consisting of the average of four individual measurements) by the same operator on concret