1、Designation: C 786 96 (Reapproved 2003)Standard Test Method forFineness of Hydraulic Cement and Raw Materials by the300-m (No. 50), 150-m (No. 100), and 75-m (No. 200)Sieves by Wet Methods1This standard is issued under the fixed designation C 786; the number immediately following the designation ind
2、icates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers wet sieving tech
3、niques fordetermination of fineness of hydraulic cement and raw mate-rials by means of the 300-m (No. 50), the 150-m (No. 100),and the 75-m (No. 200) sieves.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if
4、 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:C 114 Test Methods for Chemical Analysis of Hydr
5、aulicCement2C 184 Test Method for Fineness of Hydraulic Cement bythe 150-m (No. 100) and 75-m (No. 200) Sieves3C 430 Test Method for Fineness of Hydraulic Cement bythe 45-m (No. 325) Sieve2E 11 Specification for Wire Cloth and Sieves for TestingPurposes43. Apparatus3.1 Wet Test SievesStandard 300-m
6、(No. 50), 150-m(No. 100), or 75-m (No. 200) sieve cloth conforming to therequirements of Specification E 11, for standard sieves shall bewoven from AISI Type 304 wire. The cloth shall be mounted inthe frame without distortion, looseness, or wrinkling. Sieveframes are designated as 76.2 or 101.6-mm (
7、3 or 4-in.)diameter type, as follows:Sieves76 mm(3-in.)mm (in.)102 mm(4-in.)mm (in.)Diameter of frame 76 6 6(3.0 6 0.25)102 6 6(4.0 6 0.25)Depth of sieve from top of frame 83 6 6(3.25 6 0.25)108 6 6(4.25 6 0.25)Overall height 102 6 6(4.0 6 0.25)127 6 6(5.0 6 0.25)3.1.1 For a sieve fabricated by sold
8、ering the cloth to theframe, the joint shall be made smooth to prevent material fromlodging in the joints between the sieve cloth and the frame.Two-piece sieves shall clamp tightly on the cloth to preventparticles from lodging in the joints between the sieve cloth andthe frame, and shall have legs o
9、f sufficient length, 19-mm(0.75-in.) minimum, to allow air circulation beneath the sievecloth.3.2 Spray Nozzleconforming to the requirements of TestMethod C 430. Nozzles having an alternative design areacceptable if the sieve test results agree with those performedusing a nozzle conforming to Test M
10、ethod C 430.3.3 Pressure Gageconforming to the requirements of TestMethod C 430.3.4 Balanceanalytical, accurate to within 0.005 g.3.5 WeightsThe weights used in fineness determinationsshall conform to the requirements of Test Methods C 114.3.6 BrushA nylon or pure bristle brush will be requiredfor u
11、se in cleaning the sieves. A 13-mm (0.5-in.) diameterround-style brush with a 229-mm (9-in.) handle is a convenientsize. (WarningDo not use brass or steel-bristle brushes forcleaning sieves due to the possibility that the stiff bristle willpart the wire weave, thereby altering the size of the openin
12、gsand rendering the sieve useless. A 13-mm (12-in.) hog bristlestencil brush is also satisfactory for brushing sieves.)3.7 Dry Test SievesThe standard samples for calibratingthe wet test sieves must be standardized on 203-mm (8-in.)diameter sieves meeting the requirements of Test MethodC 184. The 30
13、0-m (No. 50) sieve shall meet the samerequirements.1This test method is under the jurisdiction of ASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.25 on Fineness.Current edition approved June 10, 2003. Published August 2003. Originallyapproved in 1974. Last previous e
14、dition approved in 1996 as C 786 96.2Annual Book of ASTM Standards, Vol 04.01.3Discontinued. See 1993 Annual Book of ASTM Standards, Vol 4.01.4Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3
15、.8 NBS SRM No. 1004Glass Bead Standard.4. Dry Sieve Standardization4.1 Correction Factors:4.1.1 Correction of the residues obtained on the 203-mm(8-in.) diameter 300-m (No. 50) and 150-m (No. 100) drytesting sieves is not required.4.1.2 Where applicable, a correction factor for a 75-m (No.200) sieve
16、 shall be determined using the instructions given inAnnex A1. A correction factor should be determined whenaccuracy is desired in order to compare results betweenlaboratories.4.2 Standard SamplesEach laboratory must prepare itsown standard samples for wet-sieve tests for each of the sievesizes used.
17、 Select standard samples at a level of fineness in thesame range as that used in routine work. After the selectedmaterial is reserved, uniformly mix the gross sample byplacing it on a sheet of rubber, oil cloth, or heavy wrappingpaper, depending on the sample size, and raising first onecorner of the
18、 sheet and then the other so as to roll the sampleover and over at least 100 times. Temporarily seal the preparedstandard material in airtight containers during the standardiza-tion procedure prior to sealing small portions as standardsamples in vials. Using the 203-mm (8-in.) diameter sievesfrom 3.
19、7, perform the dry sieving tests, following the proce-dure of Test Method C 184. Repeat the test three times and usethe average of the amounts passing, expressed as percent, asthe standard value of the sample. Use this standard sample tocalibrate the wet sieves. Place the entire sample in airtight v
20、ialsas soon as possible to prevent changes due to humidity. Vialsshall be prepared in denominations such as to contain approxi-mately 50 g for standardizing the 300-m (No. 50); 25 g for the150-m (No. 100); or 10 g for the 75-m (No. 200) sieve.5. Wet Sieve Calibration5.1 Weigh the contents of the app
21、licable size standardsample vial for the desired sieve determination on a balance ofappropriate sensitivity to the nearest 0.01 g. Record the weightand transfer the sample quantitatively to a clean dry wet test300-m (No. 50), 150-m (No. 100), or 75-m (No. 200) sieveand proceed as directed in Section
22、 6. The sieve correctionfactor is the difference between the test residue obtained andthe residue value indicated by the standardization tests ofSection 4, expressed as a percentage of the test residue. Thisfactor is expressed as follows:C 5Rs 3 Wt/100! 2 RtRt3 100 (1)where:C = sieve correction fact
23、or (which may be either plus orminus), %,Rt= test residue from sample retained on sieve, g,Rs= standard residue retained on sieve, %, andWt= weight of test sample, g.5.1.1 Example of Determination of Wet Sieve Calibration:% Residue on 150-m (No. 100) sieve forstandard sample, Rs= 5.40%Residue from t
24、est sample, Rt= 1.25 gWeight of sample, Wt= 25.5 gCorrection factor, C,%55.40 3 25.5/100! 2 1.251.25(2)3 100 5610.2NOTE 1The sieve correction is specified as a factor to be multipliedby the residue obtained, and therefore the amount to be added to orsubtracted from the test residue in any given inst
25、ance is proportional to theamount of the residue.6. Procedure for Wet Sieving6.1 Weigh the sample to the nearest 0.01 g using approxi-mately 50 g for a 300-m (No. 50), 25 g for a 150-m (No.100), or 10 g for a 75-m (No. 200) determination. Record theweight and transfer the sample quantitatively to a
26、clean drysieve. Wet the sample thoroughly with a gentle stream of water.Remove the sieve from under the nozzle and adjust thepressure on the spray nozzle to 69 6 4 kPa (10 6 0.5 psi).Return the sieve to its position under the nozzle and wash for112 min, moving the sieve in the spray with a circular
27、motionin a horizontal plane at the rate of one motion per second.Every portion of the screen should be sprayed during eachcircular motion of the sieve. Hold the sieve so that the bottomof the spray nozzle extends 13 mm (0.5 in.) below the top ofthe sieve frame. Immediately after removing the sieve f
28、rom thespray, rinse once with about 50 cm3of distilled or deionizedwater using caution not to lose any of the residue. Gently blotthe lower surface of the screen cloth with a damp, clean cloth.Dry the sieve and residue in an oven or over a hot plate (seeNote 2), supporting the sieve in such a manner
29、 that air maypass freely beneath it. Cool the sieve; then brush the residuefrom the sieve, and weigh on a balance to the nearest 0.01 g(see Note 3).NOTE 2Care should be taken when heating the sieve, so that anysolder that may have been used in assembling the sieve does not soften.NOTE 3Prior to each
30、 use, dip the sieve in dilute acetic acid (1+6) ordilute HCl (1+10) and immediately rinse it with distilled or deionizedwater to remove particles lodged in the meshes. Recalibrate the sieve after25 determinations.7. Calculation7.1 Calculate the fineness of the material as follows:Rc5 Rt/W! 3 100 1 C
31、! (3)F 5 100 2 Rc(4)where:F = fineness expressed as the corrected percentage ofsample passing the sieve,Rc= corrected residue, %,W = weight of sample used for test, g,Rt= residue from the sample retained on the sieve, g, andC = sieve correction factor (determined in accordancewith Section 5, which m
32、ay be either plus or mi-nus), %.7.1.1 Example for 150-m (No. 100) Sieve Determination:Sieve correction factor, C = 610.2 %Exact weight of sample used for test, W = 25.10 gResidue from sample retained on sieve, Rt= 1.42 gCorrected residue,Rc= (1.42/25.10) 3 (100 + 10.2) = 6.2 %F = 100 6.2 = 93.8 %C 7
33、86 96 (2003)28. Precision and Bias8.1 No precision data are available due to the limited use ofthis method. Therefore, users are advised to develop their ownlaboratory precision.8.2 Since there is no accepted reference material suitable fordetermining any bias that may be associated with this testme
34、thod, no statement on bias is being made.9. Keywords9.1 fineness; hydraulic cement and raw materials; sieveANNEX(Mandatory Information)A1. DRY SIEVE CORRECTION FACTORSA1.1 300-m (No. 50) and 150-m (No. 100) 203-mm (8-in.) Diameter SievesA1.1.1 The particle size distribution curve of cement at the300
35、-m (No. 50) and 150-m (No. 100) is level in this region,and therefore it is felt that no sieve correction is necessary.A1.2 75-m (No. 200) 203-mm (8-in.) Diameter SieveA1.2.1 A 75-m (No. 200) sieve may or may not need to bestandardized, depending on the accuracy required. For internallaboratory use
36、where changes in fineness are of more impor-tance than the absolute value, it is not necessary to standardizethe dry sieve. The sieve cloth, as a minimum, should conformto Specification E 11. A correction factor should be establishedwhere accuracy is desired in order to compare results betweenlabora
37、tories.A1.2.2 To determine the percentage of test material passingthrough a nominal 75-m (No. 200) sieve, two additionalsieves are needed: a 90-m (No. 170) and a 63-m (No. 230)sieve. Using NBS SRM No 1004 (No. 140-No. 400 sieve),Glass Bead Standard, determine the effective openings of eachof the thr
38、ee sieves.NOTE A1.1NBS SRM No. 1004 tends to blind the screen during useand the beads lodged in the meshes are difficult to remove. Tapping theframe of the sieve and gentle brushing of the cloth from the underside willaid in recovering all the beads and keep the bead loss down toapproximately 50 mg.
39、A1.2.3 Select a test material. It is important that the samplefor calibration be of the same typical fineness as the range inwhich the sieve is to be used. The use of the same test materialselected for the 75-m (No. 200) dry sieve calibration isencouraged (see 4.2). Determine the percent residue of
40、the testmaterial on each of the three sieves, following the procedure ofTest Method C 184. Plot the average percent residues versusthe effective opening. The percent residue at the nominalopening of the No. 200 sieve can be read off the plot and thedifference between the actual obtained residue and
41、the nominalresidue at 75 m may be used algebraically as a sievecorrection factor for that sieve, only in the same generalfineness area.A1.3 ExampleDetermination Of Sieve Correctionfactor for 75-m (No. 200) SieveA1.3.1 Using the SRM 1004, the following was determined:(a) Effective opening of nominal
42、sieves being corrected:75-m (No. 200) 72 m90-m (No. 170) 90 m63-m (No. 230) 65 m(b) Test sample residue, % (to be plotted on graph paper):at 90 m 1.1 %at 72 m 2.3 %at 65 m 2.8 %(c) From the above plot:Residue at 752m 5 2.1% (A1.1)A1.3.2 Since the sieve is woven too tightly and retains morethan it sh
43、ould if it were a 75-m opening, the correction, C,tobe applied to the residue in percent is 0.2%.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 determi
44、nation 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, either reapproved or wi
45、thdrawn. 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. If you feel that y
46、our 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).C 786 96 (2003)3
