1、Designation: C786/C786M 10 (Reapproved 2016)C786/C786M 17Standard 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 follow
2、ing the designation indicates the 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
3、covers wet sieving techniques for determination of fineness of hydraulic cement and raw materials bymeans 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 units are to be regarded separately as standard. The values state
4、d 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. Values in SI units or inch-pound units shall be obtained bymeasurement in SI units or inch-pound units
5、or by appropriate conversion, using the Rules for Conversion and Rounding givenin IEEE/ASTM SI 10 of measurements made in other units. Values are stated in SI units when inch-pound units are not used inpractice.1.3 This standard does not purport to address all of the safety concerns, if any, associa
6、ted with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationa
7、lly recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C114 Test Meth
8、ods for Chemical Analysis of Hydraulic CementC125 Terminology Relating to Concrete and Concrete AggregatesC184 Test Method for Fineness of Hydraulic Cement by the 150-m (No. 100) and 75-m (No. 200) Sieves (Withdrawn 2002)3C219 Terminology Relating to Hydraulic CementC430 Test Method for Fineness of
9、Hydraulic Cement by the 45-m (No. 325) SieveE11 Specification for Woven Wire Test Sieve Cloth and Test SievesIEEE/ASTM SI 10 American National Standard for Use of the International System of Units (SI): The Modern Metric System3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this
10、 test method, refer to Terminology C125 and C219.4. Apparatus4.1 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 be woven from AISI Type 304 wire. The cloth shall be mounted inthe fra
11、me without distortion, looseness, or wrinkling. Sieve frames are designated as 76.2 or 101.6-mm 3 or 4-in. diameter type,as follows:1 This test method is under the jurisdiction of ASTM Committee C01 on Cement and is the direct responsibility of Subcommittee C01.25 on Fineness.Current edition approve
12、d April 1, 2016Dec. 1, 2017. Published April 2016December 2017. Originally approved in 1974. Last previous edition approved in 20102016 asC786/C786M 10.C786/C786M 10 (2016). DOI: 10.1520/C0786_C0786M-10R16.10.1520/C0786_C0786M-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, o
13、r contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is
14、intended only to provide the user of an ASTM 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 c
15、urrent versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Sieves76 mm3-in.mm in.102 mm
16、4-in.mm in.Diameter of frame 76 63.0 0.25102 64.0 0.25Depth of sieve from top of frame 83 63.25 0.25108 64.25 0.25Overall height 102 64.0 0.25127 65.0 0.254.1.1 For a sieve fabricated by soldering the cloth to the frame, the joint shall be made smooth to prevent material from lodgingin the joints be
17、tween the sieve cloth and the frame. Two-piece sieves shall clamp tightly on the cloth to prevent particles fromlodging in the joints between the sieve cloth and the frame, and shall have legs of sufficient length, 19-mm 0.75-in. minimum,to allow air circulation beneath the sieve cloth.4.2 Spray Noz
18、zleconforming to the requirements of Test Method C430. Nozzles having an alternative design are acceptableif the sieve test results agree with those performed using a nozzle conforming to Test Method C430.4.3 Pressure Gageconforming to the requirements of Test Method C430.4.4 Balanceanalytical, accu
19、rate to within 0.005 g.4.5 WeightsThe weights used in fineness determinations shall conform to the requirements of Test Methods C114.4.6 BrushAnylon or pure bristle brush will be required for use in cleaning the sieves.A13-mm 0.5-in. diameter round-stylebrush with a 229-mm 9-in. handle is a convenie
20、nt size. (WarningDo not use brass or steel-bristle brushes for cleaning sievesdue to the possibility that the stiff bristle will part the wire weave, thereby altering the size of the openings and rendering the sieveuseless. A 13-mm 12-in. hog bristle stencil brush is also satisfactory for brushing s
21、ieves.)4.7 Dry Test SievesThe standard samples for calibrating the wet test sieves must be standardized on 203-mm 8-in. diametersieves meeting the requirements of Test Method C184. The 300-m (No. 50) sieve shall meet the same requirements.4.8 NBS SRM No. 1004Glass Bead Standard.5. Dry Sieve Standard
22、ization5.1 Correction Factors:5.1.1 Correction of the residues obtained on the 203-mm 8-in. diameter 300-m (No. 50) and 150-m (No. 100) dry testingsieves is not required.5.1.2 Where applicable, a correction factor for a 75-m (No. 200) sieve shall be determined using the instructions given inAnnex A1
23、. A correction factor should be determined when accuracy is desired in order to compare results between laboratories.5.2 Standard SamplesEach laboratory must prepare its own standard samples for wet-sieve tests for each of the sieve sizesused. Select standard samples at a level of fineness in the sa
24、me range as that used in routine work. After the selected material isreserved, uniformly mix the gross sample by placing it on a sheet of rubber, oil cloth, or heavy wrapping paper, depending on thesample size, and raising first one corner of the sheet and then the other so as to roll the sample ove
25、r and over at least 100 times.Temporarily seal the prepared standard material in airtight containers during the standardization procedure prior to sealing smallportions as standard samples in vials. Using the 203-mm 8-in. diameter sieves from 3.74.7, perform the dry sieving tests,following the proce
26、dure of Test Method C184. Repeat the test three times and use the average of the amounts passing, expressedas percent, as the standard value of the sample. Use this standard sample to calibrate the wet sieves. Place the entire sample inairtight vials as soon as possible to prevent changes due to hum
27、idity. Vials shall be prepared in denominations such as to containapproximately 50 g for standardizing the 300-m (No. 50); 25 g for the 150-m (No. 100); or 10 g for the 75-m (No. 200) sieve.6. Wet Sieve Calibration6.1 Weigh the contents of the applicable size standard sample vial for the desired sie
28、ve determination on a balance ofappropriate sensitivity to the nearest 0.01 g. Record the weight and transfer the sample quantitatively to a clean dry wet test 300-m(No. 50), 150-m (No. 100), or 75-m (No. 200) sieve and proceed as directed in Section 67. The sieve correction factor is thedifference
29、between the test residue obtained and the residue value indicated by the standardization tests of Section 45, expressedas a percentage of the test residue. This factor is expressed as follows:C 5Rs3Wt/100!2RtRt 3100 (1)where:C = sieve correction factor (which may be either plus or minus), %,C786/C78
30、6M 172Rt = test residue from sample retained on sieve, g,Rs = standard residue retained on sieve, %, andWt = weight of test sample, g.6.1.1 Example of Determination of Wet Sieve Calibration:% Residue on 150-m (No. 100) sieve forstandard sample, Rs= 5.40%Residue from test sample, Rt = 1.25 gWeight of
31、 sample, Wt = 25.5 gCorrection factor,C,%55.40325.5/100!21.251.25 (2)31005610.2NOTE 1The sieve correction is specified as a factor to be multiplied by the residue obtained, and therefore the amount to be added to or subtractedfrom the test residue in any given instance is proportional to the amount
32、of the residue.7. Procedure for Wet Sieving7.1 Weigh the sample to the nearest 0.01 g using approximately 50 g for a 300-m (No. 50), 25 g for a 150-m (No. 100), or10 g for a 75-m (No. 200) determination. Record the weight and transfer the sample quantitatively to a clean dry sieve. Wet thesample tho
33、roughly with a gentle stream of water. Remove the sieve from under the nozzle and adjust the pressure on the spraynozzle to 69 6 4 kPa 10 6 0.5 psi. Return the sieve to its position under the nozzle and wash for 112 min, moving the sievein the spray with a circular motion in a horizontal plane at th
34、e rate of one motion per second. Every portion of the screen shouldbe sprayed during each circular motion of the sieve. Hold the sieve so that the bottom of the spray nozzle extends 13 mm 0.5 in.below the top of the sieve frame. Immediately after removing the sieve from the spray, rinse once with ab
35、out 50 cm3 of distilledor deionized water using caution not to lose any of the residue. Gently blot the lower surface of the screen cloth with a damp, cleancloth. Dry the sieve and residue in an oven or over a hot plate (see Note 2), supporting the sieve in such a manner that air maypass freely bene
36、ath it. Cool the sieve; then brush the residue from the sieve, and weigh on a balance to the nearest 0.01 g (see Note3).NOTE 2Care should be taken when heating the sieve, so that any solder that may have been used in assembling the sieve does not soften.NOTE 3Prior to each use, dip the sieve in dilu
37、te acetic acid (1+6) or dilute HCl (1+10) and immediately rinse it with distilled or deionized water toremove particles lodged in the meshes. Recalibrate the sieve after 25 determinations.8. Calculation8.1 Calculate the fineness of the material as follows:Rc 5Rt /W!31001C! (3)F 51002Rc (4)where:F =
38、fineness expressed as the corrected percentage of sample 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 accordance with Section 5, which may be either plus or minus
39、), %.C = sieve correction factor (determined in accordance with Section 6, which may be either plus or minus), %.8.1.1 Example for 150-m (No. 100) Sieve Determination:Sieve correction factor, C = 10.2 %Exact weight of sample used for test, W = 25.10 gResidue from sample retained on sieve, Rt = 1.42
40、gCorrected residue,Rc = (1.42 25.10) (100 + 10.2) = 6.2 %F = 100 6.2 = 93.8 %9. Precision and Bias9.1 No precision data are available due to the limited use of this method. Therefore, users are advised to develop their ownlaboratory precision.9.2 Since there is no accepted reference material suitabl
41、e for determining any bias that may be associated with this test method,no statement on bias is being made.10. Keywords10.1 fineness; hydraulic cement and raw materials; sieveC786/C786M 173ANNEX(Mandatory Information)A1. DRY SIEVE CORRECTION FACTORSA1.1 300-m (No. 50) and 150-m (No. 100) 203-mm 8-in
42、. Diameter SievesA1.1.1 The particle size distribution curve of cement at the 300-m (No. 50) and 150-m (No. 100) is level in this region, andtherefore 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 b
43、e standardized, depending on the accuracy required. For internallaboratory use where changes in fineness are of more importance than the absolute value, it is not necessary to standardize the drysieve. The sieve cloth, as a minimum, should conform to Specification E11. A correction factor should be
44、established whereaccuracy is desired in order to compare results between laboratories.A1.2.2 To determine the percentage of test material passing through a nominal 75-m (No. 200) sieve, two additional sieves areneeded: a 90-m (No. 170) and a 63-m (No. 230) sieve. Using NBS SRM No 1004 (No. 140-No. 4
45、00 sieve), Glass Bead Standard,determine the effective openings of each of the three sieves.NOTE A1.1NBS SRM No. 1004 tends to blind the screen during use and the beads lodged in the meshes are difficult to remove. Tapping the frame ofthe sieve and gentle brushing of the cloth from the underside wil
46、l aid in recovering all the beads and keep the bead loss down to approximately 50 mg.A1.2.3 Select a test material. It is important that the sample for calibration be of the same typical fineness as the range in whichthe sieve is to be used. The use of the same test material selected for the 75-m (N
47、o. 200) dry sieve calibration is encouraged (see4.25.2). Determine the percent residue of the test material on each of the three sieves, following the procedure of Test MethodC184. Plot the average percent residues versus the effective opening. The percent residue at the nominal opening of the No. 2
48、00sieve can be read off the plot and the difference between the actual obtained residue and the nominal residue at 75 m may be usedalgebraically as a sieve correction factor for that sieve, only in the same general fineness area.A1.3 ExampleDetermination Ofof Sieve Correction factorFactor for 75-m (
49、No. 200) SieveA1.3.1 Using the SRM 1004, the following was determined:(a) Effective opening of nominal 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 752m52.1% (A1.1)A1.3.2 Since the sieve is woven too tightly and retains more than it should if it were a 75-m opening,
