1、Designation: C786/C786M 10Standard 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 C786/C786M; the number immediately following the designation indicates t
2、he yearof original adoption or, in the case of revision, 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.1. Scope*1.1 This test method covers wet sieving techniques f
3、ordetermination 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 either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact
4、 equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard. Values in SI units or inch-pound units shallbe obtained by measurement in SI units or inch-pound unitsor by appropriate conversion, using
5、 the Rules for Conversionand Rounding given in IEEE/ASTM SI 10 of measurementsmade in other units. Values are stated in SI units wheninch-pound units are not used in practice.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibi
6、lity 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:2C114 Test Methods for Chemical Analysis of HydraulicCementC184 Test Method for Fineness of Hydrau
7、lic Cement by the150-m (No. 100) and 75-m (No. 200) Sieves3C430 Test Method for Fineness of Hydraulic Cement by the45-m (No. 325) SieveE11 Specification for Woven Wire Test Sieve Cloth and TestSievesIEEE/ASTM SI 10 American National Standard for Use ofthe International System of Units (SI): The Mode
8、rn MetricSystem3. Apparatus3.1 Wet Test SievesStandard 300-m (No. 50), 150-m(No. 100), or 75-m (No. 200) sieve cloth conforming to therequirements of Specification E11, for standard sieves shall bewoven fromAISI Type 304 wire. The cloth shall be mounted inthe frame without distortion, looseness, or
9、wrinkling. Sieveframes are designated as 76.2 or 101.6-mm 3 or 4-in.diameter type, as follows:Sieves76 mm3-in.mm in.102 mm4-in.mm in.Diameter of frame 76 6 63.0 6 0.25102 6 64.0 6 0.25Depth of sieve from top of frame 83 6 63.25 6 0.25108 6 64.25 6 0.25Overall height 102 6 64.0 6 0.25127 6 65.0 6 0.2
10、53.1.1 For a sieve fabricated by soldering 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 clot
11、h andthe frame, and shall have legs of sufficient length, 19-mm0.75-in. minimum, to allow air circulation beneath the sievecloth.3.2 Spray Nozzleconforming to the requirements of TestMethod C430. Nozzles having an alternative design are accept-able if the sieve test results agree with those performe
12、d usinga nozzle conforming to Test Method C430.3.3 Pressure Gageconforming to the requirements of TestMethod C430.3.4 Balanceanalytical, accurate to within 0.005 g.3.5 WeightsThe weights used in fineness determinationsshall conform to the requirements of Test Methods C114.3.6 BrushA nylon or pure br
13、istle brush will be requiredfor use in cleaning the sieves. A 13-mm 0.5-in. diameterround-style brush with a 229-mm 9-in. handle is a convenient1This test method is under the jurisdiction ofASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.25 on Fineness.Current editio
14、n approved Feb. 1, 2010. Published March 2010. Originallyapproved in 1974. Last previous edition approved in 2003 as C786 96(2003). DOI:10.1520/C0786_C0786M-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of
15、 ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr
16、Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.size. (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 openingsand rendering the sieve useless. A 13-
17、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 MethodC184. The 300-m (No. 50) sieve shall meet the samerequire
18、ments.3.8 NBS SRM No. 1004Glass Bead Standard.4. Dry Sieve Standardization4.1 Correction Factors:4.1.1 Correction of the residues obtained on the 203-mm8-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)
19、sieve 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
20、used. 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 o
21、f the 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
22、 3.7, perform the dry sieving tests, following the proce-dure of Test Method C184. 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
23、 vialsas 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 a
24、pplicable 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 Secti
25、on 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 fa
26、ctor (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
27、 test sample, Rt=1.25gWeight 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
28、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
29、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 mo
30、tionin 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 from
31、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 tha
32、t 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 use
33、, 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! (3
34、)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,C786/C786M 102Rt= residue from the sample retained on the sieve, g, andC = sieve correction factor (determined in accordancewith Section
35、5, which may 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=1.42gCorrected residue,Rc= (1.42/25.10) 3 (100 + 10.2) = 6.2 %F =1006.2 =93.8
36、%8. 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 testmethod, no sta
37、tement 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-mm8-in. Diameter SievesA1.1.1 The particle size distribution curve of cement at the300-m (No. 50) and
38、 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 A75-m (No. 200) sieve may or may not need to bestandardized, depending on the accuracy required. For internallaboratory use where changes in f
39、ineness 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 E11. A correction factor should be establishedwhere accuracy is desired in order to compare results betweenlaboratories.A1.2.2 To de
40、termine 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 three sieves.NOTE A1.1
41、NBS 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.A1.2.3 Select a tes
42、t 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 the testmaterial on
43、 each of the three sieves, following the procedure ofTest Method C184. Plot the average percent residues versus theeffective opening. The percent residue at the nominal openingof the No. 200 sieve can be read off the plot and the differencebetween the actual obtained residue and the nominal residue
44、at75 m may be used algebraically as a sieve correction factorfor that sieve, only in the same general fineness 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 sieves being correc
45、ted: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 should if it were a 7
46、5-m opening, the correction, C,tobe applied to the residue in percent is 0.2%.C786/C786M 103SUMMARY OF CHANGESCommittee C01 has identified the location of selected changes to this test method since the last issue,C786 96(2003), that may impact the use of this test method. (Approved February 1, 2010)
47、(1) Revised the standard as a dual-units test method.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 the validity of any such patent ri
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