ASTM C642-2006 Standard Test Method for Density Absorption and Voids in Hardened Concrete《硬化混凝土的比重、吸收性及空隙度的标准试验方法》.pdf

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1、Designation: C 642 06Standard Test Method forDensity, Absorption, and Voids in Hardened Concrete1This standard is issued under the fixed designation C 642; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.

2、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 determinations of denisty,percent absorption, and percent voids in hardened concrete.1.2 The text of th

3、is test method references notes andfootnotes which provide explanatory information. These notesand footnotes (excluding those in tables and figures) shall notbe considered as requirements of this standard.1.3 The values stated in SI units are to be regarded as thestandard.2. Significance and Use2.1

4、This test method is useful in developing the datarequired for conversions between mass and volume for con-crete. It can be used to determine conformance with specifica-tions for concrete and to show differences from place to placewithin a mass of concrete.3. Apparatus3.1 Balance, sensitive to 0.025

5、% of the mass of thespecimen.3.2 Container, suitable for immersing the specimen andsuitable wire for suspending the specimen in water.4. Test Specimen4.1 Whenever possible, the sample shall consist of severalindividual portions of concrete, each to be tested separately.The individual portions may be

6、 pieces of cylinders, cores, orbeams of any desired shape or size, except that the volume ofeach portion shall be not less than 350 cm3(or for normalweight concrete, approximately 800 g); and each portion shallbe free from observable cracks, fissures, or shattered edges.5. Procedure5.1 Oven-Dry Mass

7、Determine the mass of the portions,and dry in an oven at a temperature of 100 to 110 C for notless than 24 h. After removing each specimen from the oven,allow it to cool in dry air (preferably in a desiccator) to atemperature of 20 to 25 C and determine the mass. If thespecimen was comparatively dry

8、 when its mass was firstdetermined, and the second mass closely agrees with the first,consider it dry. If the specimen was wet when its mass was firstdetermined, place it in the oven for a second drying treatmentof 24 h and again determine the mass. If the third value checksthe second, consider the

9、specimen dry. In case of any doubt,redry the specimen for 24-h periods until check values of massare obtained. If the difference between values obtained fromtwo successive values of mass exceeds 0.5 % of the lesservalue, return the specimens to the oven for an additional 24-hdrying period, and repea

10、t the procedure until the differencebetween any two successive values is less than 0.5 % of thelowest value obtained. Designate this last value A.5.2 Saturated Mass After ImmersionImmerse the speci-men, after final drying, cooling, and determination of mass, inwater at approximately 21 C for not les

11、s than 48 h and untiltwo successive values of mass of the surface-dried sample atintervals of 24 h show an increase in mass of less than 0.5 %of the larger value. Surface-dry the specimen by removingsurface moisture with a towel, and determine the mass.Designate the final surface-dry mass after imme

12、rsion B.5.3 Saturated Mass After BoilingPlace the specimen,processed as described in 5.2, in a suitable receptacle, coveredwith tap water, and boil for 5 h.Allow it to cool by natural lossof heat for not less than 14 h to a final temperature of 20 to 25C. Remove the surface moisture with a towel and

13、 determinethe mass of the specimen. Designate the soaked, boiled,surface-dried mass C.5.4 Immersed Apparent MassSuspend the specimen, afterimmersion and boiling, by a wire and determine the apparentmass in water. Designate this apparent mass D.6. Calculation6.1 By using the values for mass determine

14、d in accordancewith the procedures described in Section 5, make the followingcalculations:Absorption after immersion, % 5 B A!/A 3 100 (1)Absorption after immersion and boiling, % 5 C A!/A 3 100(2)Bulk density, dry 5 A/C 2 D!#r5g1(3)Bulk density after immersion 5 B/C D!#r (4)1This test method is und

15、er the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.69 on Miscellaneous Tests.Current edition approved July 1, 2006. Published August 2006. Originallyapproved in 1969. Last previous edition approved in 1997 as C 642 97.1*A

16、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.Bulk density after immersion and boiling 5 C/C D!#r (5)Apparent density 5 A/A D!#r5g2(6)Volume of permeable pore space void

17、s!,%5 g2 g1!/g23 100(7)or C A!/C D! 3 100where:A = mass of oven-dried sample in air, gB = mass of surface-dry sample in air after immersion, gC = mass of surface-dry sample in air after immersion andboiling, gD = apparent mass of sample in water after immersionand boiling, gg1= bulk density, dry, Mg

18、/m3andg2= apparent density, Mg/m3r = density of water = 1 Mg/m3= 1 g/cm3.7. Example7.1 Assume a sample having the following characteristics:7.1.1 Mass of the solid part of the specimen = 1000 g.7.1.2 Total volume of specimen (including solids, “perme-able” voids, and “impermeable” voids) = 600 cm3.7

19、.1.3 Absolute density of solid part of specimen = 2.0 Mg/m3.7.1.4 Void space in specimen contains initially only air (nowater).7.2 Then, it follows that there are 500 cm3of solids and 100cm3of voids making up the specimen, and the void content is16 = 16.67 %.7.3 Assume that on immersion 90 mL of wat

20、er is absorbed.7.4 Assume that after immersion and boiling 95 mLof wateris absorbed.7.5 Based on the assumptions given in 7.1-7.4 above, thedata that would be developed from the procedures given inSection 5 would be as follows:7.5.1 Oven-dry mass, A = 1000 g.7.5.2 Mass in air after immersion, B = 10

21、90 g.7.5.3 Mass in air after immersion and boiling, C = 1095 g.7.5.4 Apparent mass in water after immersion and boiling,D = 495 g.NOTE 1Since loss of mass in water is equal to mass of displacedwater, and volume of specimen = 600 cm3, mass of specimen in waterafter immersion and boiling is 1095 600 =

22、 495 g.7.6 By using the data given above to perform the calcula-tions described in Section 6, the following results will beobtained (Note 2):Absorption after immersion, % 5 B 2 A/A 3 1005 1090 2 1000!/1000 3 1005 9.0 (8)Absorption after immersion and boiling, % 5 C 2 A!/A 3 1005 1095 2 1000!/1000 3

23、1005 9.5 (9)Bulk density, dry 5 A/C 2 D!#r5 1000/1095 2 495!# 3 15 1.67 Mg/m35 g1(10)Bulk density after immersion 5 B/C 2 D!#r5 1090/1095 2 495!# 3 15 1.82 (11)Bulk density after immersion and boiling 5 C/C 2 D!# r5 1095/1095 2 495!# 3 15 1.83 Mg/m3(12)Apparent density 5 A/A 2 D!# r5 1000/1000 2 495

24、!# 3 15 1.98 Mg/m35 g2(13)Volume of permeable voids, % (14)5 g22 g1!/g2# 3 100 5 1.98 2 1.67!/1.98 3 1005 15.8, or C 2 A!/C 2 D!# 3 1005 1095 2 1000!/1095 2 495!# 3 100 5 15.7NOTE 2This test method does not involve a determination of absolutedensity. Hence, such pore space as may be present in the s

25、pecimen that isnot emptied during the specified drying or is not filled with water duringthe specified immersion and boiling or both is considered “impermeable”and is not differentiated from the solid portion of the specimen for thecalculations, especially those for percent voids. In the example dis

26、cussedit was assumed that the absolute density of the solid portion of thespecimen was 2.0 Mg/m3, the total void space was 16.67 %, and theimpermeable void space was 5 cm3. The operations, if performed, and thecalculations, if performed as described, have the effect of assuming thatthere are 95 cm3o

27、f pore space and 505 cm3of solids, and indicate that thesolid material, therefore, has an apparent density of 1.98 rather than theabsolute density of 2.00 Mg/m3and the specimen has a percentage ofvoids of 15.8 rather than 16.67.Depending on the pore size distribution and the pore entry radii of thec

28、oncrete and on the purposes for which the test results are desired, theprocedures of this test method may be adequate, or they may beinsufficiently rigorous. In the event that it is desired to fill more of thepores than will be filled by immersion and boiling, various techniquesinvolving the use of

29、vacuum treatment or increased pressures may beused. If a rigorous measure of total pore space is desired, this can only beobtained by determining absolute density by first reducing the sample todiscrete particles, each of which is sufficiently small so that no imperme-able pore space can exist withi

30、n any of the particles. If the absolute densitywere determined and designated g3, then:Total void volume, % 5 g32 g1!/g33 100 (15)5 2.00 2 1.67!/2.00 3 100 5 16.58. Precision and Bias8.1 PrecisionAt present there are insufficient data avail-able to justify attempting to develop a precision statement

31、 forthis test method.8.2 BiasBias for this test method cannot be determinedsince there is no reference standard available for comparison.9. Keywords9.1 absorption; concrete-hardened; density; voidsC642062SUMMARY OF CHANGESCommittee C09 has identified the location of selected changes to this test met

32、hod since the last issue,C 642 97, that may impact the use of this test method. (Approved July 1, 2006)(1) Added new 1.3.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 expres

33、sly advised that determination of 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,

34、 either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may at

35、tend. If you feel that your comments 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).C642063