ASTM C917/C917M-18

Standard Test Method for Evaluation of Variability of Cement from a Single Source Based on Strength

SIGNIFICANCE AND USE
4.1 This test method is designed to present in a standardized format information on the variability of strength of cement from a single source over a period of time. It 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 ASTM specification. A specification may refer to this test method to obtain information on the variability of cement from a single source.  
4.2 The procedure is based on obtaining samples from locations during the delivery of cement to the user and is more representative of the variability of cement used in concrete production than test data reported on mill test reports. Variation determined from the test results is corrected for testing error, therefore giving the user one indicator of the source variation of the cement.
Note 1: It should be recognized that concrete strength variability is influenced 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 of concrete properties. The user can, along with supplementary information or correlative testing of concrete properties, develop quantitative estimates of the effects.
SCOPE
1.1 This test method covers a procedure for determining the variability of a hydraulic cement produced at a single source using strength tests as the characteristic property. It is intended that this test method normally be used for the predominant cement manufactured at a 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 stated in each system may not be exact equivalents; therefore each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. One system of units is used in the Figure and Tables in this standard to illustrate the calculation methods that are applicable independent of the 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 responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Dec-2017
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: C01 - Cement
• Drafting Committee: C01.27 - Strength

Relations

• Replaces: ASTM C917-05(2011) - Standard Test Method for Evaluation of Cement Strength Uniformity From a Single Source
• Effective Date: 01-Jan-2018
• Refers: ASTM C219-24 - Standard Terminology Relating to Hydraulic and Other Inorganic Cements
• Effective Date: 01-Apr-2024
• Refers: ASTM C109/C109M-23 - Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 50 mm [2 in.] Cube Specimens)
• Effective Date: 15-Dec-2023
• Refers: ASTM E456-13a(2022)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022
• Refers: ASTM C219-20a - Standard Terminology Relating to Hydraulic and Other Inorganic Cements
• Effective Date: 01-Aug-2020
• Refers: ASTM C219-20 - Standard Terminology Relating to Hydraulic and Other Inorganic Cements
• Effective Date: 01-Apr-2020
• Refers: ASTM C219-19a - Standard Terminology Relating to Hydraulic and Other Inorganic Cements
• Effective Date: 15-Nov-2019
• Refers: ASTM C219-19 - Standard Terminology Relating to Hydraulic Cement
• Effective Date: 01-Jun-2019
• Refers: ASTM E456-13A(2017)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Oct-2017
• Refers: ASTM E456-13A(2017)e3 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Oct-2017
• Refers: ASTM C219-14 - Standard Terminology Relating to Hydraulic Cement
• Effective Date: 01-Jul-2014
• Refers: ASTM E456-13a - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM E456-13ae1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM E456-13ae3 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM E456-13ae2 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013

Overview

ASTM C917/C917M-18 is the Standard Test Method for Evaluation of Variability of Cement from a Single Source Based on Strength. Developed by ASTM International, this standard enables concrete producers, quality control laboratories, and cement manufacturers to assess and monitor the variability in the strength of hydraulic cement from a single source over a period of time. The primary goal is to present standardized information regarding the consistency of cement, which is crucial for ensuring reliable performance in concrete production.

The method applies to all hydraulic cements covered by ASTM C150 (Portland Cement), ASTM C595 (Blended Hydraulic Cements), and ASTM C1157 (Performance Specifications for Hydraulic Cement). Results obtained using this test method are intended for informational purposes and do not constitute specification requirements, but can be referenced to understand and control the uniformity of cement supply.

Key Topics

• Strength Variability Assessment
  The test method focuses on evaluating the variability in compressive strength of cement by systematically sampling and testing cement delivered to users.

• Sampling and Testing Procedures
  Guidance is included for random sampling during delivery, ensuring results that reflect the actual variability encountered in practice, rather than relying solely on mill reports.

• Statistical Evaluation
  Calculation procedures include mean strength, standard deviation, coefficient of variation, and moving averages of both 7-day and 28-day compressive strengths.

• Correction for Testing Error
  The standard provides a process to distinguish true product variability from that introduced by laboratory testing, enabling a corrected assessment of cement uniformity.

• Reporting Requirements
  Detailed instructions are given for reporting data, including manufacturer information, sample identification, test results, and statistical metrics over specified time frames.

Applications

ASTM C917/C917M-18 is widely used in several practical contexts:

• Quality Control for Cement Plants
  Regular evaluation of strength variability supports internal quality monitoring and continuous process improvement in cement manufacture.

• Concrete Producers
  By analyzing the uniformity of cement strength, concrete producers can make informed decisions related to mix designs and risk management, ensuring consistent concrete performance.

• Specification and Procurement
  Purchasers and project specifiers may reference this method in procurement documents to request uniformity reports, supporting supplier evaluation and compliance.

• Research and Troubleshooting
  The statistically rigorous data provided under this standard aids in diagnosing supply issues, identifying trends, and correlating cement performance with other variables affecting concrete strength.

• Regulatory and Certification Requirements
  While not itself a compliance standard, the use of ASTM C917/C917M-18 can support broader conformance to quality management and traceability in accordance with industry best practices.

Related Standards

To fully implement and interpret ASTM C917/C917M-18, several related ASTM standards are commonly referenced:

• ASTM C109/C109M – Test Method for Compressive Strength of Hydraulic Cement Mortars
• ASTM C150 – Specification for Portland Cement
• ASTM C595 – Specification for Blended Hydraulic Cements
• ASTM C1157 – Performance Specification for Hydraulic Cement
• ASTM C1451 – Practice for Determining Variability of Ingredients of Concrete From a Single Source
• ASTM C219 – Terminology Relating to Hydraulic Cement
• ASTM E456 – Terminology Relating to Quality and Statistics

By employing ASTM C917/C917M-18 alongside these standards, organizations can effectively manage and communicate the variability of cement strength from single sources, thereby supporting higher quality and reliability in concrete construction projects.

Keywords: ASTM C917, cement strength variability, hydraulic cement, compressive strength testing, sampling, statistical analysis, quality control, concrete production, standardization.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C917/C917M − 18
Standard Test Method for
Evaluation of Variability of Cement from a Single Source
Based on Strength
This standard is issued under the fixed designation C917/C917M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope C150Specification for Portland Cement
C219Terminology Relating to Hydraulic Cement
1.1 Thistestmethodcoversaprocedurefordeterminingthe
C595Specification for Blended Hydraulic Cements
variability of a hydraulic cement produced at a single source
C1157Performance Specification for Hydraulic Cement
using strength tests as the characteristic property. It is intended
C1451PracticeforDeterminingVariabilityofIngredientsof
that this test method normally be used for the predominant
Concrete From a Single Source
cement manufactured at a cement plant. Guidelines for
E456Terminology Relating to Quality and Statistics
sampling, testing, presentation of results, and evaluation are
given.
3. Terminology
1.2 The values stated in either SI units or inch-pound units
3.1 Definitions—For definitions of terms relating to this test
aretoberegardedseparatelyasthestandard.Thevaluesstated
method, refer to Practice C1451 and Terminologies C219 and
in each system may not be exact equivalents; therefore each
E456.
system shall be used independently of the other. Combining
values from the two systems may result in non-conformance
4. Significance and Use
withthestandard.OnesystemofunitsisusedintheFigureand
Tablesinthisstandardtoillustratethecalculationmethodsthat
4.1 Thistestmethodisdesignedtopresentinastandardized
are applicable independent of the system of units.
format information on the variability of strength of cement
from a single source over a period of time. It can be applied to
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the all hydraulic cements covered in Specifications C150, C595,
and C1157. The results derived from this test method are
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- intended for information only and are not requirements of any
mine the applicability of regulatory limitations prior to use. existingASTM specification.Aspecification may refer to this
1.4 This international standard was developed in accor- test method to obtain information on the variability of cement
dance with internationally recognized principles on standard- from a single source.
ization established in the Decision on Principles for the
4.2 The procedure is based on obtaining samples from
Development of International Standards, Guides and Recom-
locations during the delivery of cement to the user and is more
mendations issued by the World Trade Organization Technical
representative of the variability of cement used in concrete
Barriers to Trade (TBT) Committee.
productionthantestdatareportedonmilltestreports.Variation
determined from the test results is corrected for testing error,
2. Referenced Documents
therefore giving the user one indicator of the source variation
2.1 ASTM Standards:
of the cement.
C109/C109MTest Method for Compressive Strength of
NOTE 1—It should be recognized that concrete strength variability is
Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube
influenced by other factors in addition to cement strength variability.
Specimens)
4.3 This test method does not provide information on the
relationshipbetweenthevariabilityofcementandthevariabil-
1 ityofconcreteproperties.Theusercan,alongwithsupplemen-
ThistestmethodisunderthejurisdictionofASTMCommitteeC01onCement
and is the direct responsibility of Subcommittee C01.27 on Strength.
tary information or correlative testing of concrete properties,
Current edition approved Jan. 1, 2018. Published January 2018. Originally
develop quantitative estimates of the effects.
approved in 1979. Last previous edition approved in 2011 as C917–05(2011).
DOI: 10.1520/C0917-18.
5. Sampling
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
5.1 Establish a sampling plan that includes the lot size,
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. sampling frequency, location and procedure of sampling, and
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C917/C917M − 18
handling and retention of samples. Sampling shall be per- 6. Procedure
formed by personnel specifically trained for this purpose.
6.1 Total Variation—Test all samples for 7- and 28-day
5.2 Takerandomgrabsamplesfromdeliveryunitsorduring
compressive strength in accordance with Test Method C109/
the loading or unloading process. Delivery units larger than
C109M using three specimens for each test age. To be
115 Mg [125 tons] shall be sampled during loading or
comparable, all tests used in a single evaluation must be made
unloading. If samples are taken during loading or unloading,
in a single laboratory and preferably by the same laboratory
the two or more portions that are to be composited to make a
operator. Calculate the total variation among the samples as
sample shall be taken during the transfer to no more than
directedin7.1.3.Whenduplicatetestsaremadeonasamplein
115Mg [125 tons] of cement. Identify samples by the date on
accordance with 6.2, include only the first test result to
which the cement they represent was shipped or received.
calculate the total variation. The total variation includes the
component of testing error.
NOTE2—Standardstatisticalproceduresarerecommendedforensuring
thatsamplesareselectedbyarandomprocedure.Theseprocedurescanbe
NOTE3—Whenseparateevaluationsofasinglesourcearemadebytwo
used to select the days within a month or within a week that samples will
or more laboratories, additional tests of a standard cement or exchange of
be taken. Then the delivery unit or the time of day can be chosen
portions of the same sample of cement may be necessary to determine
randomly.
differences in testing that are likely to be obtained in the different
5.3 If taken from a truck or rail car, take at least two
laboratories. Five or more batches may be necessary to obtain a valid
comparison between laboratories. Statistical techniques must be used to
separate grab samples of approximately equal size and thor-
assess the validity of differences that might be obtained. Participation in
oughly mix together to obtain a minimum 5-kg [10-lb] test
the Cement Proficiency Sample Program of the CCRL by both laborato-
sample. Sample only through hatches in the top of the unit.
ries will be helpful in resolving differences that are found.
Remove approximately a 300-mm [12-in.] layer of cement.
6.1.1 When two laboratories exchange portions of the same
Makeaholebeforeobtainingasampletoavoidcollectingdust
sample and prepare single batches, results from the two
collectormaterialthatmaybedischargedintothedeliveryunit
laboratoriesshallnotdifferbymorethan18.7%oftheaverage
after the cement flow ceases.
of the two laboratories (see Test Method C109/C109M multi-
5.4 If taken from another point in the loading or unloading
laboratory d2s). If a larger number of samples are exchanged
process, a minimum 5-kg [10-lb] sample shall be obtained as
the difference in average strength shall not exceed 18.7/=n%
two separate grab samples of approximately equal size and
of the overall average strength, where n is the number of
thoroughly mixed together or as accumulated by a continuous
samples exchanged and tested by each laboratory. A more
sampler. Take care to avoid segregation and contamination of
precise calculation is outlined in Appendix X1.
samples taken from screws, pneumatic systems, or air slides.
6.2 Testing Error—Mix duplicate batches of mortar from
5.5 When samples are taken at the cement plant and
thesamesampletoestimatethewithin-laboratorytestingerror.
shipments or rate of production of the cement exceeds
Make duplicate batches on a day different from the original
23000Mg[25000tons]permonth,takesamplesatarateofat
batch of mortar.
least ten per month and at least two per week. When shipment
or rate of production of the cement is less than 23000Mg 6.2.1 When a testing program is started on shipments from
[25000tons] per month, take samples at a rate of at least one a single source, make duplicate batches of mortar from every
per 2300Mg [2500tons]. When samples are taken at the third cement sample. When duplicate tests have been made
cement plant, in no instance shall samples be taken more from a minimum of five cement samples, calculate the within-
frequently than one per 180Mg [200 tons] of cement shipped laboratorytestingerroraccordingto7.1.4.Increasethenumber
or received, except that sampling of consecutive shipments is of duplicate batches used in the calculation until the results of
permitted when they result from randomization. tencementsamplesareusedinthecalculation.Afterthattime,
A
TABLE 1 Example Illustrating Calculation of Testing Error
Sample 7-day Strength, MPa
2 B C
¯
Date d kS , MPa X , MPa V ,%
e d e
Number Test A Test B Average
01/06 3 33.7 34.2 34.0 0.25
01/16 6 31.5 32.2 31.9 0.49
01/30 9 32.0 33.4 32.7 1.96
02/05 12 30.3 31.1 30.7 0.64
02/13 15 30.2 29.6 29.9 0.36 5 0.61 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 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 with 7.1.4.2.
C917/C917M − 18
use only the ten most recent results of duplicate testing in the where:
calculation of the testing error. See Table 1.
S = standard deviation for testing error estimated from tests
e
6.2.2 When at least ten sets of duplicate batches have been
of duplicate batches mixed in a single laboratory from
made and the coefficient of variation for testing error is less
different samples, MPa [psi],
than 4.0%, the frequency of testing duplicate batches can be d = difference between duplicate determinations for each
reduced to one in ten consecutive cement samples. Resume a sample, and
frequency of testing one in three samples if the coefficient of k = number of sets of duplicate batches tested.
variation for testing error exceeds 4.0%. If the coefficient of
7.1.4.2 Calculatethecoefficientofvariationfortestingerror
variation for testing error exceeds 5.5%, the data are of
as follows:
questionable precision, and laboratory procedures and equip-
S
e
ment should be thoroughly examined.
V 5 3100 (5)
e
¯
X
6.2.3 Use the results of duplicate tests indicating acceptable d
precision to estimate the within-laboratory testing error for all
where:
other types of cement tested in that laboratory during the same
V = coefficientofvariationestimatedfromtestsofduplicate
e
periodoftime,providedthatduplicatetestshavebeenmadeon
batches mixed in a single laboratory from different
at least one sample per month.
samples, and
¯
X = Overall average of duplicate tests, M
...

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 version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: C917 − 05 (Reapproved 2011) C917/C917M − 18
Standard Test Method for
Evaluation of Cement Strength Uniformity FromVariability of
Cement from a Single Source Based on Strength
This standard is issued under the fixed designation C917;C917/C917M; the number immediately following the designation indicates the
year of 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 is intended for use in instances in which the purchaser desires information on the strength uniformity
covers a procedure for determining the variability of a hydraulic cement produced at a single source. source using strength tests
as the characteristic property. It is intended that this test method normally be used for the predominant cement manufactured at
a 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 in
parentheses are for information only.stated in each system may not be exact equivalents; therefore each system shall be used
independently of the other. Combining values from the two systems may result in non-conformance with the standard. One system
of units is used in the Figure and Tables in this standard to illustrate the calculation methods that are applicable independent of
the 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 responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C109/C109M Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube Specimens)
C150 Specification for Portland Cement
C219 Terminology Relating to Hydraulic Cement
C595 Specification for Blended Hydraulic Cements
C1157 Performance Specification for Hydraulic Cement
C1451 Practice for Determining Variability of Ingredients of Concrete From a Single Source
E456 Terminology Relating to Quality and Statistics
3. Terminology
3.1 Definitions—For definitions of terms relating to this test method, refer to Practice C1451 and Terminologies C219 and E456.
4. Significance and Use
4.1 This test method is designed to present in a standardized format information on the variability of strength of cement from
a single source over a period of time. It 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 ASTM
specification. A specification may refer to this test method to obtain information on the variability of cement from a single source.
NOTE 1—It should be recognized that concrete strength variability is influenced by other factors in addition to cement strength variability.
This test method is under the jurisdiction of ASTM Committee C01 on Cement and is the direct responsibility of Subcommittee 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 as
C917 – 05.C917 – 05 (2011). DOI: 10.1520/C0917-05R11.10.1520/C0917-18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C917/C917M − 18
4.2 The procedure is based on obtaining samples from locations during the delivery of cement to the user and is more
representative of the variability of cement used in concrete production than test data reported on mill test reports. Variation
determined from the test results is corrected for testing error, therefore giving the user one indicator of the source variation of the
cement.
NOTE 1—It should be recognized that concrete strength variability is influenced 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 of
concrete properties. The user can, along with supplementary information or correlative testing of concrete properties, develop
quantitative estimates of the effects.
5. Sampling
5.1 All sampling shall be performed by quality control or testing personnel or someone Establish a sampling plan that includes
the lot size, sampling frequency, location and procedure of sampling, and handling and retention of samples. Sampling shall be
performed 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 125
tons (115 Mg)115 Mg [125 tons] shall be sampled during loading or unloading. If samples are taken during 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 2—Standard statistical procedures are recommended for ensuring that samples are selected by a random procedure. These procedures can be used
to 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 car, take at least two separate 5-lb (approximately 2.3-kg) grab samples grab samples of
approximately equal size and thoroughly mix together to obtain a minimum 10-lb (4.5-kg)5-kg [10-lb] test sample. Sample only
through hatches in the top of the unit. Remove approximately a 12-in. (300-mm)300-mm [12-in.] layer of cement. Make a hole
before obtaining a sample to avoid collecting dust collector material that may be discharged into the delivery unit after the cement
flow 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
(approximately 2.3-kg) grab samples a minimum 5-kg [10-lb] sample shall be obtained as two separate grab samples of
approximately equal size and thoroughly mixed together or at least 10 lb (4.5 kg) as accumulated by a continuous sampler. Take
care to avoid segregation and contamination of samples taken 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 (23 000
Mg) 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 shipment
or rate 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 a
rate of at least one per 2500 tons (2300 Mg). 2300 Mg [2500 tons]. When samples are taken at the cement plant, in no instance
shall samples be taken more frequently than one per 200 tons (180 Mg) 180 Mg [200 tons] of cement shipped or received, except
that sampling of consecutive shipments is permitted when they result from randomization.
6. Procedure
6.1 Total Variation—Test all samples for 7- and 28-day compressive strength in accordance with Test Method C109/C109M
using three specimens for each test age. To be comparable, all tests used in a single evaluation must be made in a single laboratory
and preferably by the same laboratory operator. Calculate the total variation among the samples as directed in 7.1.3. When
duplicate tests are made on a sample in accordance with 6.2, include only the first test result to calculate the total variation. The
total variation includes the component of testing error.
NOTE 3—When separate evaluations of a single source are made by two or more laboratories, additional tests of a standard cement or exchange of
portions of the same sample of cement 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 of
differences that might be obtained. Participation in the Cement Proficiency Sample Program of the CCRL by both laboratories will be helpful in resolving
differences that are found.
6.1.1 When two laboratories exchange portions of the same sample and prepare single batches, results from the two laboratories
shall not differ by more than 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 average
strength, where n is the number of samples exchanged and tested by each laboratory. A more precise calculation is outlined in
Appendix X1.
6.2 Testing Error—Mix duplicate batches of mortar to determine the effect of testing variations on the uniformity of results
made in a single laboratory. from the same sample to estimate the within-laboratory testing error. Make duplicate batches on a day
different 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 from
every third cement sample. When duplicate tests have been made from a minimum of five cement samples, calculate the average
C917/C917M − 18
¯
range, within-laboratory R , for the available duplicates, then calculate standard deviation and coefficient of variation for testing
testing error according to 7.1.3 and 7.1.4, respectively. . Increase the number of duplicate batches used in the calculation until the
results of ten cement samples are used in the calculation. After that time, use only the ten most recent results of duplicate testing
in 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 the coefficient of variation for testing error is less than
4.0 %, the frequency of testing duplicate batches can be reduced to one out of in ten consecutive cement samples. Resume a
frequency of testing one sample out of three in three samples if the coefficient of variation later for testing error exceeds 4.0 %.
If the coefficient of variation for testing error exceeds 5.5 %, the data are of questionable precision, and laboratory procedures and
equipment should be thoroughly examined.
6.2.3 Use the results of duplicate tests indicating acceptable precision to estimate the single-laboratorywithin-laboratory testing
variationerror for all other types of cement tested in that laboratory during the same period of time, provided that duplicate tests
have been made on at least one sample per month.
7. Calculation
7.1 The calculations shall include the following:
7.1.1 Average Strength: Strength—Calculate the average strength of all test results during the reporting period. Use only the first
test result from each sample that was tested in duplicate.
X 1X 1.1X
1 2 n
¯
X 5 (1)
n
where:
where:
¯
= average strength,
X
X¯ = average strength, MPa [psi],
X , X , . . ., X = strength of individual tests, each of which is composed of the average of cubes in accordance with Test
1 2 n
Method C109/C109M, and
X , X , . . ., X = individual strength test results, each of which the average of cubes in accordance with Test Method
1 2 n
C109/C109M, and
n = number of individual samples.
7.1.2 Moving Average—After five test results are obtained, calculate the moving average of strength of the five most recent
results.
X 1X 1X 1X 1X
i24 i23 i22 i21 i
¯
X 5 (2)
where:
X¯ = Moving average of five consecutive strength results, MPa [psi], and
X = The most recent of five consecutive strength results, MPa [psi].
i
7.1.3 Total Standard Deviation:
2 2 2
¯ ¯ ¯
~X 2 X! 1~X 2 X! 1.1~X 2 X!
1 2 n
S 5Π(3)
t
n2 1
~ !
A
TABLE 1 Example Illustrating Calculation of Testing Error
Sample 7-day Strength, MPa
2 B C
Date d k S , MPa X¯ , MPa V , %
e d e
Number Test A Test B Average
01/06 3 33.7 34.2 34.0 0.25
01/16 6 31.5 32.2 31.9 0.49
01/30 9 32.0 33.4 32.7 1.96
02/05 12 30.3 31.1 30.7 0.64
02/13 15 30.2 29.6 29.9 0.36 5 0.61 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 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 with 7.1.4.2.
C917/C917M − 18
2 2 2
¯ ¯ ¯
~X 2 X! 1~X 2 X! 1.1~X 2 X!
1 2 n
Œ
S 5 (3)
t
~n2 1!
where:
where:
S = standard deviation, psi.
t
S = total standard deviation, MPa [psi].
t
7.1.3 Standard Deviation For Testing:
¯
S 5 0.862R
e
S = standard deviation estimated from tests of duplicate batches mixed in a single laboratory,
e
R = range, the difference between the strengths of the duplicate batches from a single sample (all numbers are positive),
¯
= average of the individual ranges, R, for the preceding ten tests of duplicate batches. See 6.2.1 if fewer than ten ranges
R
are available, and
0.862 = range coefficient for duplicate tests of the same sample of cement.
7.1.4 Coeffıcient of Variation for Testing: Testing Error:
¯
V 5 100 S /X
e e
where:
V = coefficients of variation estimated from tests of duplicate batches mixed in a single laboratory, and
e
¯ ¯
=
X 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:
Σd
S 5 (4)
Œ
e
2k
where:
S = standard deviation for testing error estimated from tests of duplicate batches mixed in a single laboratory from different
e
samples, MPa [psi],
d = difference between duplicate determinations for each sample, and
k = number of sets of duplicate batches tested.
7.1.4.2 Calculate the coefficient of variation for testing error as follows:
S
e
V 5 3100 (5)
e
¯
X
d
where:
V = coefficient of variation estimated from tests of duplicate batches mixed in a single laboratory from different samples, and
e
X¯ = Overall average of duplicate tests, MPa [psi].
d
7.1.5 Standard Deviation Corrected For Testing Variations: Single-source Variation:
2 2
S 5=S 2 S (3)
c t e
where:
S = net standard deviation of cement corrected for testing error,
c
S = total standard deviations for all tests included in the calculation, and
t
S = standard deviation of duplicate tests run on split sample to evaluate testing error.
e
7.1.5.1 Variation of cement from a single source, expressed in terms of standard deviation, corrected for testing error, is
calculated as follows:
2 2
=
S 5 S 2 S (6)
c t e
where:
S = single-source standard deviation corrected for testing error, MPa [psi].
c
The addition of the subscript 28 or 7 indicates the type of strength data used in the calculation.
C917/C917M − 18
NOTE 4—Values for averages and standard deviations can be calculated by other methods that are available in ASTM STP 15 D. Electronic calculators
are available for obtaining these statistics directly.
The addition of the subscript 28 or 7 indicates the type of strength data used in the calculation.
7.1.5.2 Variation of cement from a single source, expressed in terms of coefficient of variation, corrected for testing error, is
calculated as follows:
S
c
V 5 3100 (7)
c
¯
X
where:
V = Single source coefficient of variation corrected for testing error, %.
c
NOTE 4—Values for averages and standard deviations can be calculated by other methods that are available in ASTM STP 15 D. Electronic calculators
are available for obtaining these statistics directly.
7.1.5.3 If data are collected from two laboratories, calculate the single source variation of each laboratory using Eq. 6. Calculate
the pooled single-source standard deviation as follows:
2 2
n 2 1 S 1 n 2 1 S
~ ! ~ !
1 c1 2 c2
¯
S 5Π(8)
c
n 1n 2 2
1 2
where:
S¯ = pooled estimate of single-source standard deviation, MPa [psi],
c
S and S = standard deviation corrected for testing error from laboratory 1 and laboratory 2, respectively, and
c1 c2
n and n = number of tests in laboratory 1 and laboratory 2, respectively.
1 2
TABLE 1 Calculation of Standard Deviation for Testing
A
7-Day Data Average
B C D
Range ¯ S
Sample R e
E
Date Test A Test B V Note
e
Number
psi (MPa) psi (MPa) psi (MPa) psi (MPa) psi (MPa) psi (MPa)
01 /06 3 4900 (33.7) 4960 (34.2) 4930 (34.0) 60 (0.41) . . . . . . . . . . . . . . . . . .
01 /16 6 4580 (31.5) 4670 (32.2) 4625 (31.8) 90 (0.62) . . . . . . . . . . . . . . . . . .
01 /30 9 4650 (32.0) 4850 (33.4) 4750 (32.7) 200 (1.37) . . . . . . . . . . . . . . . . . .
02 /05 12 4400 (30.3) 4510 (31.1) 4455 (30.7) 110 (0.75) . . . . . . . . . . . . . . . . . .
02 /13 15 4380 (30.2) 4300 (29.6) 4340 (29.9) 80 (0.55) 108 (0.74) 93 (0.64) 2.02 % Av. 5
02 /21 18 4700 (32.4) 4770 (32.8) 4735 (32.6) 70 (0.48) 102 (0.70) 88 (0.60) 1.89 % Av. 6
03 /04 21 4470 (30.8) 4610 (31.7) 4540 (31.3) 140 (0.96) 107 (0.73) 92 (0.64) 2.00 % Av. 7
03 /14 24 4030 (27.7) 3970 (27.3) 4000 (27.5) 60 (0.41) 101 (0.69) 87 (0.60) 1.92 % Av. 8
03 /19 27 4970 (34.2) 4820 (33.2) 4895 (33.7) 150 (1.03) 107 (0.73) 92 (0.63) 2.01 % Av. 9
03 /27 30 4550 (31.3) 4530 (31.2) 4540 (31.3) 20 (0.13) 96 (0.67) 84 (0.58) 1.84 % Av. 10 (6)
04 /30 40 4750 (32.7) 4920 (33.9) 4835 (33.3) 170 (1.17) 109 (0.75) 94 (0.65) 2.06 % Av. last 10
05 /31 50 5030 (34.6) 4820 (33.2) 4925 (33.9) 210 (1.44) 121 (0.83) 104 (0.72) 2.27 % Av. last 10
06 /29 60 4830 (33.3) 4720 (32.5) 4775 (32.9) 110 (0.75) 112 (0.77) 97 (0.67) 2.10 % Av. last 10
07 /28 70 4400 (30.3) 4460 (30.7) 4430 (30.5) 60 (0.41) 107 (0.73) 92 (0.64) 2.00 % Av. last 10
08 /30 80 4550 (31.3) 4460 (30.7) 4505 (31.0) 90 (0.62) 108 (0.74) 93 (0.64) 2.02 % Av. last 10
09 /25 90 4930 (34.0) 5000 (34.4) 4965 (34.2) 70 (0.48) 108 (0.74) 93 (0.64) 2.01 % Av. last 10
10 /26 100 4950 (34.1) 4820 (33.2) 4885 (33.6) 130 (0.89) 107 (0.73) 92 (0.64) 1.97 % Av. last 10
11 /25 110 4670 (32.2) 4720 (32.5) 4695 (32.3) 50 (0.34) 106 (0.73) 91 (0.63) 1.93 % Av. last 10
12 /21 120 4450 (30.6) 4520 (31.1) 4485 (30.9) 70 (0.48) 96 (0.67) 84 (0.58) 1.80 % Av. last 10
28-Day Data
A B D
C
¯
Average Range S
Sample R e
E
Date Test A Test B V Note
e
Number
psi (MPa) psi (MPa) psi (MPa) psi (MPa) psi (MPa) psi (MPa)
01 /06 3 6370 (43.9) 6620 (45.6) 6495 (44.7) 250 (1.72) . . . . . . . . . . . . . . . . . .
01 /16 6 6250 (43.1) 6020 (41.5) 6135 (42.3) 230 (1.58) . . . . . . . . . . . . . . . . . .
01 /30 9 6050 (41.7) 6120 (42.2) 6085 (41.9) 70 (0.48) . . . . . . . . . . . . . . . . . .
02 /05 12 6020 (41.5) 6230 (42.9) 6125 (42.2) 210 (1.44) . . . . . . . . . . . . . . . . . .
02 /13 15 5600 (38.6) 5420 (37.3) 5510 (38.0) 180 (1.24) 188 (1.29) 162 (1.12) 2.67 % Av. 5
02 /21 18 5500 (37.9) 5530 (38.1) 5515 (38.0) 30 (0.20) 162 (1.11) 139 (0.96) 2.33 % Av. 6
03 /04 21 6320 (43.5) 6280 (43.3) 6300 (43.4) 40 (0.27) 144 (0.99) 124 (0.86) 2.06 % Av. 7
03 /14 24 5920 (40.8) 6010 (41.4) 5965 (41.1) 90 (0.62) 138 (0.94) 119 (0.82) 1.97 % Av. 8
03 /19 27 6300 (43.4) 6050 (41.7) 6175 (42.5) 250 (1.72) 150 (1.03) 129 (0.89) 2.14 % Av. 9
03 /27 30 6350 (43.7) 6410 (44.2) 6380 (44.0) 60 (0.41) 141 (0.97) 122 (0.84) 2.00 % Av. 10 (6)
04 /30 40 6050 (41.7) 5940 (40.9) 5995 (41.3) 110 (0.75) 127 (0.87) 109 (0.75) 1.82 % Av. last 10
05 /31 50 6670 (46.0) 6530 (45.0) 6600 (45.5) 140 (0.96) 118 (0.81) 102 (0.70) 1.68 % Av. last 10
06 /29 60 6350
...