ASTM C642-2013 Standard Test Method for Density Absorption and Voids in Hardened Concrete《硬化混凝土的密度、吸收性及空隙度的标准试验方法》.pdf

1、Designation: C642 06C642 13Standard Test Method forDensity, Absorption, and Voids in Hardened Concrete1This standard is issued under the fixed designation C642; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis

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

3、of this test method references notes and footnotes which provide explanatory information. These notes andfootnotes (excluding those in tables and figures) shall not be considered as requirements of this standard.1.3 The values stated in SI units are to be regarded as the standard.1.4 This standard d

4、oes not purport to address all of the safety concerns, 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. Significance and Use2.1 This test

5、 method is useful in developing the data required for conversions between mass and volume for concrete. It canbe used to determine conformance with specifications for concrete and to show differences from place to place within a mass ofconcrete.3. Apparatus3.1 Balance, sensitive to 0.025 % of the ma

6、ss of the specimen.3.2 Container, suitable for immersing the specimen and suitable wire for suspending the specimen in water.4. Test Specimen4.1 Whenever possible, the sample shall consist of several individual portions of concrete, each to be tested separately. Theindividual portions may be pieces

7、of cylinders, cores, or beams of any desired shape or size, except that the volume of each portionshall be not less than 350 cm3 (or for normal weight concrete, approximately 800 g); and each portion shall be free from observablecracks, fissures, or shattered edges.5. Procedure5.1 Oven-Dry MassDeter

8、mine the mass of the portions, and dry in an oven at a temperature of 100 to 110110 6 5 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 a temperatureof 20 to 25 C and determine the mass. If the specimen was comparatively

9、 dry when its mass was first determined, and the secondmass closely agrees with the first, consider it dry. If the specimen was wet when its mass was first determined, place it in the ovenfor a second drying treatment of 24 h and again determine the mass. If the third value checks the second, consid

10、er the specimendry. In case of any doubt, redry the specimen for 24-h periods until check values of mass are obtained. If the difference betweenvalues obtained from two successive values of mass exceeds 0.5 % of the lesser value, return the specimens to the oven for anadditional 24-h drying period,

11、and repeat the procedure until the difference between any two successive values is less than 0.5 %of the lowest value obtained. Designate this last value A.5.2 Saturated Mass After ImmersionImmerse the specimen, after final drying, cooling, and determination of mass, in waterat approximately 21 C fo

12、r not less than 48 h and until two successive values of mass of the surface-dried sample at intervals of24 h show an increase in mass of less than 0.5 % of the larger value. Surface-dry the specimen by removing surface moisture witha towel, and determine the mass. Designate the final surface-dry mas

13、s after immersion B.1 This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregatesand is the direct responsibility of Subcommittee C09.66 onConcretes Resistance to Fluid Penetration.Current edition approved July 1, 2006Feb. 1, 2013. Published August 2006Februa

14、ry 2013. Originally approved in 1969. Last previous edition approved in 19972006 asC642 97.C642 06. DOI: 10.1520/C0642-06.10.1520/C0642-13.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous v

15、ersion. 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 by ASTM is to be considered the official document.*A Summary of Changes s

16、ection appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 Saturated Mass After BoilingPlace the specimen, processed as described in 5.2, in a suitable receptacle, covered with tapwater, and boil for

17、 5 h. Allow it to cool by natural loss of heat for not less than 14 h to a final temperature of 20 to 25 C. Removethe surface moisture with a towel and determine the mass of the specimen. Designate the soaked, boiled, surface-dried mass C.5.4 Immersed Apparent MassSuspend the specimen, after immersi

18、on and boiling, by a wire and determine the apparent massin water. Designate this apparent mass D.6. Calculation6.1 By using the values for mass determined in accordance with the procedures described in Section 5, make the followingcalculations:Absorption after immersion, %5B 2A!/A# 3100 (1)Absorpti

19、on after immersion and boiling, %5C 2A!/A# 3100 (2)Bulk density, dry5A/C 2D!#5g1 (3)Bulk density after immersion5B/C 2D!# (4)Bulk density after immersion and boiling5C/C 2D!# (5)Apparent density5A/A 2D!#5g2 (6)Volume of permeable pore space voids!, %5g22g1!/g23100 (7)or C 2A!/C 2D! 3100where:A = mas

20、s 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 and boiling, gD = apparent mass of sample in water after immersion and boiling, gg1 = bulk density, dry, Mg/m3 andg2 = apparent density, Mg/m3 = density of wa

21、ter = 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, “permeable” voids, and “impermeable” voids) = 600 cm3.7.1.3 Absolute density of solid part of specimen =

22、2.0 Mg/m3.7.1.4 Void space in specimen contains initially only air (no water).7.2 Then, it follows that there are 500 cm3 of solids and 100 cm3 of voids making up the specimen, and the void content is 16= 16.67 %.7.3 Assume that on immersion 90 mL of water is absorbed.7.4 Assume that after immersion

23、 and boiling 95 mL of water is absorbed.7.5 Based on the assumptions given in 7.1-7.4 above, the data that would be developed from the procedures given in Section5 would be as follows:7.5.1 Oven-dry mass, A = 1000 g.7.5.2 Mass in air after immersion, B = 1090 g.7.5.3 Mass in air after immersion and

24、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 displaced water, and volume of specimen = 600 cm3, mass of specimen in water afterimmersion and boiling is 1095 600 = 495 g.7.6 By using the data given above

25、to perform the calculations described in Section 6, the following results will be obtained(Note 2):Absorption after immersion, %5B 2A!/A#31005109021000!/1000#310059.0 (8)Absorption after immersion, %5B 2A/A# 31005109021000!/1000#310059.0 (8)Absorption after immersion and boiling, %5C 2A!/A# 31005109

26、521000!/1000#310059.5 (9)Bulk density, dry5A/C 2D!#51000/10952495!#3151.67 Mg/m35g1 (10)Bulk density after immersion5B/C 2D!#51090/10952495!#3151.82 (11)Bulk density after immersion and boiling5C/C 2D!# 51095/10952495!#3151.83 Mg/m3 (12)C642 132Apparent density5A/A 2D!# 51000/10002495!#3151.98 Mg/m3

27、 5g2 (13)Volume of permeable voids, % (14)5g22g1!/g2#310051.9821.67!/1.98#3100515.8, or C 2A!/C 2D!# 31005109521000!/10952495!#3100515.7NOTE 2This test method does not involve a determination of absolute density. Hence, such pore space as may be present in the specimen that is notemptied during the

28、specified drying or is not filled with water during the specified immersion and boiling or both is considered “impermeable” and isnot differentiated from the solid portion of the specimen for the calculations, especially those for percent voids. In the example discussed it was assumedthat the absolu

29、te density of the solid portion of the specimen was 2.0 Mg/m3, the total void space was 16.67 %, and the impermeable void space was5 cm3. The operations, if performed, and the calculations, if performed as described, have the effect of assuming that there are 95 cm3 of pore space and505 cm3 of solid

30、s, and indicate that the solid material, therefore, has an apparent density of 1.98 rather than the absolute density of 2.00 Mg/m3 and thespecimen has a percentage of voids of 15.8 rather than 16.67.Depending on the pore size distribution and the pore entry radii of the concrete and on the purposes

31、for which the test results are desired, the proceduresof this test method may be adequate, or they may be insufficiently rigorous. In the event that it is desired to fill more of the pores than will be filled byimmersion and boiling, various techniques involving the use of vacuum treatment or increa

32、sed pressures may be used. If a rigorous measure of total porespace is desired, this can only be obtained by determining absolute density by first reducing the sample to discrete particles, each of which is sufficientlysmall so that no impermeable pore space can exist within any of the particles. If

33、 the absolute density were determined and designated g3, then:Total void volume, %5g32g1!/g33100 (15)52.0021.67!/2.003100516.58. Precision and Bias8.1 PrecisionAt present there are insufficient data available to justify attempting to develop a precision statement for this testmethod.8.2 BiasBias for

34、 this test method cannot be determined since there is no reference standard available for comparison.9. Keywords9.1 absorption; concrete-hardened; density; voidsSUMMARY OF CHANGESCommittee C09 has identified the location of selected changes to this test method since the last issue,C642 97C642 06, th

35、at may impact the use of this test method. (Approved JulyFebruary 1, 2006)2013)(1) Added new 1.31.4.(2) Modified 5.1.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

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37、her 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 attend.

38、 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. Indi

39、vidual 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).C642 133