1、Designation: C917 05 (Reapproved 2011)C917/C917M 18Standard Test Method forEvaluation of Cement Strength Uniformity FromVariability ofCement from a Single Source Based on Strength1This standard is issued under the fixed designation C917;C917/C917M; the number immediately following the designation in
2、dicates theyear of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is intended for use in
3、instances in which the purchaser desires information on the strength uniformitycovers a procedure for determining the variability of a hydraulic cement produced at a single source. source using strength testsas the characteristic property. It is intended that this test method normally be used for th
4、e predominant cement manufactured ata cement plant. Guidelines for sampling, testing, presentation of results, and evaluation are given.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as the standard. The values inparentheses are for information only.stated
5、 in each system may not be exact equivalents; therefore each system shall be usedindependently of the other. Combining values from the two systems may result in non-conformance with the standard. One systemof units is used in the Figure and Tables in this standard to illustrate the calculation metho
6、ds that are applicable independent ofthe system of units.1.3 This standard does 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 safety, health, and healthenvironmental practices a
7、nd determine theapplicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommend
8、ations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C109/C109M Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or 50-mm Cube Specimens)C150 Specification for Portland CementC219 Terminology
9、Relating to Hydraulic CementC595 Specification for Blended Hydraulic CementsC1157 Performance Specification for Hydraulic CementC1451 Practice for Determining Variability of Ingredients of Concrete From a Single SourceE456 Terminology Relating to Quality and Statistics3. Terminology3.1 DefinitionsFo
10、r definitions of terms relating to this test method, refer to Practice C1451 and Terminologies C219 and E456.4. Significance and Use4.1 This test method is designed to present in a standardized format information on the variability of strength of cement froma single source over a period of time. It
11、can be applied to all hydraulic cements covered in Specifications C150, C595, and C1157.The results derived from this test method are intended for information only and are not requirements of any existing ASTMspecification. A specification may refer to this test method to obtain information on the v
12、ariability of cement from a single source.NOTE 1It should be recognized that concrete strength variability is influenced by other factors in addition to cement strength variability.1 This test method is under the jurisdiction of ASTM Committee C01 on Cement and is the direct responsibility of Subcom
13、mittee C01.27 on Strength.Current edition approved April 1, 2011Jan. 1, 2018. Published May 2011January 2018. Originally approved in 1979. Last previous edition approved in 20052011 asC917 05.C917 05 (2011). DOI: 10.1520/C0917-05R11.10.1520/C0917-18.2 For referencedASTM standards, visit theASTM webs
14、ite, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indicatio
15、n 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 current versionof the standard as published by ASTM is to be consid
16、ered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 The procedure is based on obtaining samples from locations during the delivery of cement to the user and is morerepresentative of the variability of cement
17、 used in concrete production than test data reported on mill test reports. Variationdetermined from the test results is corrected for testing error, therefore giving the user one indicator of the source variation of thecement.NOTE 1It should be recognized that concrete strength variability is influe
18、nced by other factors in addition to cement strength variability.4.3 This test method does not provide information on the relationship between the variability of cement and the variability ofconcrete properties. The user can, along with supplementary information or correlative testing of concrete pr
19、operties, developquantitative estimates of the effects.5. Sampling5.1 All sampling shall be performed by quality control or testing personnel or someone Establish a sampling plan that includesthe lot size, sampling frequency, location and procedure of sampling, and handling and retention of samples.
20、 Sampling shall beperformed by personnel specifically trained for this purpose.5.2 Take random grab samples from delivery units or during the loading or unloading process. Delivery units larger than 125tons (115 Mg)115 Mg 125 tons shall be sampled during loading or unloading. If samples are taken du
21、ring loading or unloading,the two or more portions that are to be composited to make a sample shall be taken during the transfer to no more than 125 tons(115 Mg) 115 Mg 125 tons of cement. Identify samples by the date on which the cement they represent was shipped or received.NOTE 2Standard statisti
22、cal procedures are recommended for ensuring that samples are selected by a random procedure. These procedures can be usedto select the days within a month or within a week that samples will be taken. Then the delivery unit or the time of day can be chosen randomly.5.3 If taken from a truck or rail c
23、ar, take at least two separate 5-lb (approximately 2.3-kg) grab samples grab samples ofapproximately equal size and thoroughly mix together to obtain a minimum 10-lb (4.5-kg)5-kg 10-lb test sample. Sample onlythrough hatches in the top of the unit. Remove approximately a 12-in. (300-mm)300-mm 12-in.
24、 layer of cement. Make a holebefore obtaining a sample to avoid collecting dust collector material that may be discharged into the delivery unit after the cementflow ceases.5.4 If taken from another point in the loading or unloading process, the sample shall consist of a minimum of two separate 5-lb
25、(approximately 2.3-kg) grab samples a minimum 5-kg 10-lb sample shall be obtained as two separate grab samples ofapproximately equal size and thoroughly mixed together or at least 10 lb (4.5 kg) as accumulated by a continuous sampler. Takecare to avoid segregation and contamination of samples taken
26、from screws, pneumatic systems, or air slides.5.5 When samples are taken at the cement plant and shipments or rate of production of the cement exceeds 25 000 tons (23 000Mg) 23 000 Mg 25 000 tons per month, take samples at a rate of at least ten per month and at least two per week. When shipmentor r
27、ate of production of the cement is less than 25 000 tons (23 000 Mg) 23 000 Mg 25 000 tons per month, take samples at arate of at least one per 2500 tons (2300 Mg). 2300 Mg 2500 tons. When samples are taken at the cement plant, in no instanceshall samples be taken more frequently than one per 200 to
28、ns (180 Mg) 180 Mg 200 tons of cement shipped or received, exceptthat sampling of consecutive shipments is permitted when they result from randomization.6. Procedure6.1 Total VariationTest all samples for 7- and 28-day compressive strength in accordance with Test Method C109/C109Musing three specime
29、ns for each test age. To be comparable, all tests used in a single evaluation must be made in a single laboratoryand preferably by the same laboratory operator. Calculate the total variation among the samples as directed in 7.1.3. Whenduplicate tests are made on a sample in accordance with 6.2, incl
30、ude only the first test result to calculate the total variation. Thetotal variation includes the component of testing error.NOTE 3When separate evaluations of a single source are made by two or more laboratories, additional tests of a standard cement or exchange ofportions of the same sample of ceme
31、nt may be necessary to determine differences in testing that are likely to be obtained in the different laboratories.Five or more batches may be necessary to obtain a valid comparison between laboratories. Statistical techniques must be used to assess the validity ofdifferences that might be obtaine
32、d. Participation in the Cement Proficiency Sample Program of the CCRLby both laboratories will be helpful in resolvingdifferences that are found.6.1.1 When two laboratories exchange portions of the same sample and prepare single batches, results from the two laboratoriesshall not differ by more than
33、 18.7 % of the average of the two laboratories (see Test Method C109/C109M multilaboratory d2s).If a larger number of samples are exchanged the difference in average strength shall not exceed 18.7/=n % of the overall averagestrength, where n is the number of samples exchanged and tested by each labo
34、ratory. A more precise calculation is outlined inAppendix X1.6.2 Testing ErrorMix duplicate batches of mortar to determine the effect of testing variations on the uniformity of resultsmade in a single laboratory. from the same sample to estimate the within-laboratory testing error. Make duplicate ba
35、tches on a daydifferent from the original batch of mortar.6.2.1 When a uniformity testing program is started on shipments from a single source, make duplicate batches of mortar fromevery third cement sample. When duplicate tests have been made from a minimum of five cement samples, calculate the ave
36、rageC917/C917M 182range, within-laboratory R , for the available duplicates, then calculate standard deviation and coefficient of variation for testingtesting error according to 7.1.3 and 7.1.4, respectively. . Increase the number of duplicate batches used in the calculation until theresults of ten
37、cement samples are used in the calculation. After that time, use only the ten most recent results of duplicate testingin the calculation of the standard deviation and coefficient of variation for testing. testing error. See Table 1.6.2.2 When at least ten sets of duplicate batches have been made and
38、 the coefficient of variation for testing error is less than4.0 %, the frequency of testing duplicate batches can be reduced to one out of in ten consecutive cement samples. Resume afrequency of testing one sample out of three in three samples if the coefficient of variation later for testing error
39、exceeds 4.0 %.If the coefficient of variation for testing error exceeds 5.5 %, the data are of questionable precision, and laboratory procedures andequipment should be thoroughly examined.6.2.3 Use the results of duplicate tests indicating acceptable precision to estimate the single-laboratorywithin
40、-laboratory testingvariationerror for all other types of cement tested in that laboratory during the same period of time, provided that duplicate testshave been made on at least one sample per month.7. Calculation7.1 The calculations shall include the following:7.1.1 Average Strength: StrengthCalcul
41、ate the average strength of all test results during the reporting period. Use only the firsttest result from each sample that was tested in duplicate.X5X11X21.1Xnn (1)where:where:X = average strength,X = average strength, MPa psi,X1, X2, . . ., Xn = strength of individual tests, each of which is com
42、posed of the average of cubes in accordance with TestMethod C109/C109M, andX1, X2, . . ., Xn = individual strength test results, each of which the average of cubes in accordance with Test MethodC109/C109M, andn = number of individual samples.7.1.2 Moving AverageAfter five test results are obtained,
43、calculate the moving average of strength of the five most recentresults.X5 5Xi241Xi231Xi221Xi211Xi5 (2)where:X5 = Moving average of five consecutive strength results, MPa psi, andXi = The most recent of five consecutive strength results, MPa psi.7.1.3 Total Standard Deviation:St5X12X!21X22X!21.1Xn2X
44、!2n21! (3)TABLE 1 Example Illustrating Calculation of Testing ErrorADate SampleNumber 7-day Strength, MPa d2 k Se, MPaB Xd, MPa Ve, %CTest A Test B Average01/06 3 33.7 34.2 34.0 0.2501/16 6 31.5 32.2 31.9 0.4901/30 9 32.0 33.4 32.7 1.9602/05 12 30.3 31.1 30.7 0.6402/13 15 30.2 29.6 29.9 0.36 5 0.61
45、32.1 1.91 %02/21 18 32.4 32.8 32.6 0.16 6 0.57 32.2 1.78 %03/04 21 30.8 31.7 31.3 0.81 7 0.58 32.1 1.81 %03/14 24 27.7 27.3 27.5 0.16 8 0.55 31.5 1.76 %03/19 27 34.2 33.2 33.7 1.00 9 0.57 31.7 1.80 %03/27 30 31.3 31.2 31.3 0.01 10 0.54 31.7 1.71 %04/30 40 32.7 33.9 33.3 1.44 10 0.59 31.6 1.88 %05/31
46、 50 34.6 33.2 33.9 1.96 10 0.65 31.7 2.06 %06/29 60 33.3 32.5 32.9 0.64 10 0.60 31.7 1.89 %A This example is in SI units. The same concept applies in inch-pound units. The same calculations should be performed for 28-day strength.B Determined in accordance with 7.1.4.1.C Determined in accordance wit
47、h 7.1.4.2.C917/C917M 183St5X12X!21X22X!21.1Xn2X!2n21! (3)where:where:St = standard deviation, psi.St = total standard deviation, MPa psi.7.1.3 Standard Deviation For Testing:Se50.862RSe = standard deviation estimated from tests of duplicate batches mixed in a single laboratory,R = range, the differe
48、nce between the strengths of the duplicate batches from a single sample (all numbers are positive),R = average of the individual ranges, R, for the preceding ten tests of duplicate batches. See 6.2.1 if fewer than ten rangesare available, and0.862 = range coefficient for duplicate tests of the same
49、sample of cement.7.1.4 Coeffcient of Variation for Testing: Testing Error:Ve 5100Se/Xwhere:Ve = coefficients of variation estimated from tests of duplicate batches mixed in a single laboratory, andX = average of the strengths of the duplicate batches from which R is calculated.7.1.4.1 Calculate the standard deviation for testing error as follows:Se 5d22k (4)where:Se = standard deviation for testing error estimated from tests of duplicate batches mixed in a single laboratory from differentsamples, MPa psi,d =
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