ASTM C1365-18

Standard Test Method for Determination of the Proportion of Phases in Portland Cement and Portland-Cement Clinker Using X-Ray Powder Diffraction Analysis

SIGNIFICANCE AND USE
6.1 This test method allows direct determination of the proportion of some individual phases in cement or portland-cement clinker. Thus it provides an alternative to the indirect estimation of phase proportion using the equations in Specification C150/C150M (Annex A1).  
6.2 This test method assumes that the operator is qualified to operate an X-ray diffractometer and to interpret X-ray diffraction spectra.  
6.3 This test method may be used as part of a quality control program in cement manufacturing.  
6.4 This test method may be used in predicting properties and performance of hydrated cement and concrete that are a function of phase composition.  
6.5 QXRD provides a bulk analysis (that is, the weighted average composition of several grams of material). Therefore, results may not agree precisely with results of microscopical methods.
SCOPE
1.1 This test method covers direct determination of the proportion by mass of individual phases in portland cement or portland-cement clinker using quantitative X-ray (QXRD) analysis. The following phases are covered by this standard: alite (tricalcium silicate), belite (dicalcium silicate), aluminate (tricalcium aluminate), ferrite (tetracalcium aluminoferrite), periclase (magnesium oxide), gypsum (calcium sulfate dihydrate), bassanite (calcium sulfate hemihydrate), anhydrite (calcium sulfate), and calcite (calcium carbonate).  
1.2 This test method specifies certain general aspects of the analytical procedure, but does not specify detailed aspects. Recommended procedures are described, but not specified. Regardless of the procedure selected, the user shall demonstrate by analysis of certified reference materials (CRM's) that the particular analytical procedure selected for this purpose qualifies (that is, provides acceptable precision and bias) (see Note 1). The recommended procedures are ones used in the round-robin analyses to determine the precision levels of this test method.  
Note 1: A similar approach was used in the performance requirements for alternative methods for chemical analysis in Test Methods C114.  
1.3 The values stated in SI units shall be regarded as the standard.  
1.4 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. For specific hazards, see Section 9.  
1.5 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: 28-Feb-2018
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: C01 - Cement
• Drafting Committee: C01.23 - Compositional Analysis

Relations

• Replaces: ASTM C1365-06(2011) - Standard Test Method for Determination of the Proportion of Phases in Portland Cement and Portland-Cement Clinker Using X-Ray Powder Diffraction Analysis
• Effective Date: 01-Mar-2018
• Refers: ASTM C219-24 - Standard Terminology Relating to Hydraulic and Other Inorganic Cements
• Effective Date: 01-Apr-2024
• Refers: ASTM C670-24a - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Feb-2024
• Refers: ASTM C670-24 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM C114-23 - Standard Test Methods for Chemical Analysis of Hydraulic Cement
• Effective Date: 01-Oct-2023
• 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 C150/C150M-19 - Standard Specification for Portland Cement
• Effective Date: 01-Apr-2019
• Refers: ASTM C150/C150M-16 - Standard Specification for Portland Cement
• Effective Date: 15-Mar-2016
• Refers: ASTM C150/C150M-15 - Standard Specification for Portland Cement
• Effective Date: 01-Jul-2015
• Refers: ASTM C219-14 - Standard Terminology Relating to Hydraulic Cement
• Effective Date: 01-Jul-2014
• Refers: ASTM C114-13 - Standard Test Methods for Chemical Analysis of Hydraulic Cement
• Effective Date: 01-Oct-2013
• Refers: ASTM C219-13a - Standard Terminology Relating to Hydraulic Cement
• Effective Date: 01-Aug-2013

Overview

ASTM C1365-18 is the Standard Test Method for Determination of the Proportion of Phases in Portland Cement and Portland-Cement Clinker Using X-Ray Powder Diffraction Analysis (QXRD). Issued by ASTM International, this standard provides a direct analytical method to accurately quantify the mass proportions of individual mineralogical phases present in portland cement and portland-cement clinker. By leveraging X-ray powder diffraction (XRD or QXRD), users can achieve precise phase identification and quantification, supporting both quality control and product performance assessment in cement manufacturing and related industries.

Key Topics

• Direct Phase Determination: Unlike traditional chemical or equation-based estimations (e.g., Bogue calculations), this test method enables direct measurement of key phases such as alite (tricalcium silicate), belite (dicalcium silicate), aluminate (tricalcium aluminate), ferrite (tetracalcium aluminoferrite), periclase (magnesium oxide), gypsum, bassanite, anhydrite, and calcite.
• Scope of Materials: The method applies to portland cement and portland-cement clinker, with relevance for various cement types and compositions.
• Operator Qualification: Proper use of QXRD and accurate interpretation of diffraction spectra require that operators be trained and qualified in XRD analysis.
• Bulk Analysis Capability: QXRD evaluates the weighted average composition from several grams of material, allowing for representative bulk analysis.
• Quality Assurance: QXRD-based phase analysis supports quality control, compliance with specifications, and consistency in production.
• Predicting Performance: Understanding phase proportions is critical for predicting cement and concrete properties, such as setting time, strength development, and durability.

Applications

• Cement Manufacturing Quality Control: Producers of portland cement and clinker use this standard to monitor and control phase composition during production, ensuring products meet performance and regulatory requirements.
• Product Certification and Specification Compliance: Results from this test method support compliance with ASTM C150/C150M and other standards specifying phase composition or performance.
• Research and Development: Laboratories and R&D teams utilize QXRD to investigate the effects of raw materials, processing conditions, and additives on the mineralogical makeup of cement products.
• Performance Prediction: Accurate phase quantification aids in predicting key characteristics of the final cement or concrete, such as strength, setting behavior, sulfate resistance, and heat of hydration.
• Comparative Analysis: QXRD provides a valuable alternative or supplement to microscopic analysis and chemical estimation methods, facilitating the verification of phase proportions and troubleshooting of inconsistencies.

Related Standards

For comprehensive quality and testing workflows, the following ASTM standards are commonly referenced alongside ASTM C1365-18:

• ASTM C114: Test Methods for Chemical Analysis of Hydraulic Cement
• ASTM C150/C150M: Specification for Portland Cement
• ASTM C183/C183M: Practice for Sampling and the Amount of Testing of Hydraulic Cement
• ASTM C219: Terminology Relating to Hydraulic Cement
• ASTM C670: Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• ASTM E29: Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

Summary

Employing ASTM C1365-18 for quantitative phase analysis using X-ray powder diffraction ensures high accuracy in determining the mineralogical composition of portland cement and clinker. This enhances quality control, supports compliance with international specifications, and underpins technical innovation and performance assurance across the cement and concrete industry. By integrating QXRD methodology into analytical and production processes, stakeholders gain a robust tool for reliable and actionable materials characterization.

Keywords: ASTM C1365-18, X-ray powder diffraction, QXRD, portland cement, cement clinker, phase analysis, quality control, cement manufacturing, mineralogical composition, clinker phases, alite, belite, Rietveld analysis, cement performance, ASTM standards.

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: C1365 − 18
Standard Test Method for
Determination of the Proportion of Phases in Portland
Cement and Portland-Cement Clinker Using X-Ray Powder
Diffraction Analysis
This standard is issued under the fixed designation C1365; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method covers direct determination of the
proportion by mass of individual phases in portland cement or
2. Referenced Documents
portland-cement clinker using quantitative X-ray (QXRD)
2.1 ASTM Standards:
analysis. The following phases are covered by this standard:
C114 Test Methods for Chemical Analysis of Hydraulic
alite (tricalcium silicate), belite (dicalcium silicate), aluminate
Cement
(tricalcium aluminate), ferrite (tetracalcium aluminoferrite),
C150/C150M Specification for Portland Cement
periclase (magnesium oxide), gypsum (calcium sulfate
C183/C183M Practice for Sampling and the Amount of
dihydrate), bassanite (calcium sulfate hemihydrate), anhydrite
Testing of Hydraulic Cement
(calcium sulfate), and calcite (calcium carbonate).
C219 Terminology Relating to Hydraulic Cement
1.2 This test method specifies certain general aspects of the
C670 Practice for Preparing Precision and Bias Statements
analytical procedure, but does not specify detailed aspects.
for Test Methods for Construction Materials
Recommended procedures are described, but not specified.
E29 Practice for Using Significant Digits in Test Data to
Regardless of the procedure selected, the user shall demon-
Determine Conformance with Specifications
strate by analysis of certified reference materials (CRM’s) that
E691 Practice for Conducting an Interlaboratory Study to
the particular analytical procedure selected for this purpose
Determine the Precision of a Test Method
qualifies (that is, provides acceptable precision and bias) (see
Note 1). The recommended procedures are ones used in the
3. Terminology
round-robin analyses to determine the precision levels of this
3.1 Definitions: Definitions are in accordance with Termi-
test method.
nology C219.
NOTE 1—Asimilar approach was used in the performance requirements
3.2 Phases (1):
for alternative methods for chemical analysis in Test Methods C114.
3.2.1 alite, n—tricalcium silicate (C S) modified in com-
1.3 The values stated in SI units shall be regarded as the
position and crystal structure by incorporation of foreign ions;
standard.
occurs typically between 30 to 70 % (by mass) of the portland-
1.4 This standard does not purport to address all of the
cement clinker; and is normally either the M or M crystal
1 3
safety concerns, if any, associated with its use. It is the polymorph, each of which is monoclinic.
responsibility of the user of this standard to establish appro-
3.2.2 alkali sulfates, n—arcanite (K SO ) may accommo-
2 4
+ +
priate safety, health, and environmental practices and deter-
date Na , Ca2 , and CO in solid solution, aphthitalite (K ,
3 4-x
mine the applicability of regulatory limitations prior to use.
Na )SO with x usually 1 but up to 3), calcium langbeinite
x 4
For specific hazards, see Section 9.
(K Ca [SO ] ) may occur in clinkers high in K O, and
2 2 4 3 2
1.5 This international standard was developed in accor-
thenardite (Na SO ) in clinkers with high Na/K ratios (1).
2 4
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
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
1 the ASTM website.
This test method is under the jurisdiction ofASTM Committee C01 on Cement
The boldface numbers in parentheses refer to the list of references at the end of
and is the direct responsibility of Subcommittee C01.23 on CompositionalAnalysis.
this standard.
Current edition approved March 1, 2018. Published April 2018. Originally
Whenexpressingchemicalformulae,C=CaO,S=SiO ,A=Al O ,F=Fe O ,
2 2 3 2 3
approved in 1998. Last previous edition approved in 2011 as C1365 – 06 (2011).
¯
DOI: 10.1520/C1365-18. M = MgO, S =SO,andH=H O.
3 2
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1365 − 18
3.2.3 aluminate, n—tricalcium aluminate (C A) modified in 3.3.3 phase, n—a homogeneous, physically distinct, and
composition and sometimes in crystal structure by incorpora- mechanically separable portion of a material, identifiable by its
tion of a substantial proportion of foreign ions; occurs as 2 to chemical composition and crystal structure.
15 % (by mass) of the portland-cement clinker; is normally
3.3.3.1 Discussion—Phases in portland-cement clinker and
cubic when relatively pure and orthorhombic or monoclinic
cements that are included in this test method are four major
when in solid solution with significant amounts of sodium (2).
phases (alite, belite, aluminate, and ferrite) and one minor
¯ phase (periclase).
3.2.4 anhydrite, n—calcium sulfate ~CS! and is orthorhom-
3.3.3.2 Discussion—Precision values are provided for addi-
bic (see Note 2).
tional phases (gypsum, bassanite, anhydrite, arcanite, and
NOTE 2—Calcium sulfate is added to the clinker during grinding to
control setting time, strength development, and volume stability. Several
calcite). Values for these constituents may be provided using
phases may form as a result of dehydration of gypsum. The first 1.5
this method but are considered informational until suitable
molecules of water are lost between 0 and 65°C with minor changes in
certified reference materials for qualification are available.
structure; and, above 95°C, the remaining 0.5 molecules of water are lost
transforming the structure to the metastable γ polymorph of anhydrite
3.3.4 qualification,n—processbywhichaQXRDprocedure
(sometimes referred to as ‘soluble anhydrite’) and subsequently the
is shown to be valid.
orthorhombic form (3).
3.3.5 Rietveld analysis, n—process of refining crystallo-
¯
~ !
3.2.5 bassanite, n—calcium sulfate hemihydrate CSH
1/2
graphic and instrument variables to minimize differences
and is monoclinic.
between observed and calculated X-ray powder diffraction
3.2.6 belite, n—dicalcium silicate (C S) modified in com-
patterns for one or more phases, estimating their relative
position and crystal structure by incorporation of foreign ions;
abundance.
occurs typically as 15 to 45 % (by mass) of the portland-
3.3.6 standardization, n—process of determining the rela-
cement clinker as normally the β polymorph, which is mono-
tionship between XRD intensity and phase proportion for one
clinic. In lesser amounts, other polymorphs can be present.
or more phases (see Note 5).
3.2.7 calcite, n—calcium carbonate is trigonal and may be
NOTE 5—In the literature of X-ray powder diffraction analysis, the
present in a cement as an addition or from carbonation of free
standardization process has been commonly referred to as calibration;
lime.
however,wehavedeterminedthatstandardizationisamoreaccurateterm.
3.2.8 ferrite, n—tetracalcium aluminoferrite solid solution
3.3.6.1 Discussion—Rietveld analysis uses crystal structure
of approximate composition C (A,F) modified in composition
models to calculate powder diffraction patterns of phases that
by variation in theAl/Fe ratio and by substantial incorporation
serve as the reference patterns. The pattern-fitting step seeks
of foreign ions as C A F where0 4 X 2-X
the best-fit combination of selected pattern intensities to the
to 15 % (by mass) of a portland-cement clinker; and is
raw data. The relative pattern intensities along with the
orthorhombic.
crystallographic attributes of each phase are used to calculate
3.2.9 free lime, n—free calcium oxide (C); cubic (see Note
relative abundance. The standardization approach uses pow-
3).
deredsamplesofpurephasestoassesstherelationshipbetween
NOTE 3—Free lime (CaO) may be present in clinker and cement but diffraction intensity ratios and mass fraction ratios of two or
readilyhydratestoformportlandite(Ca(OH) ).Portlanditemaycarbonate
2 more constituents; and is referred to here as the traditional
to form calcium carbonate, generally as calcite. Heat-treating a freshly-
method.
ground sample to 600°C is useful to convert any portlandite back to free
lime but will also dehydrate the hydrous calcium sulfate phases (gypsum
3.3.7 X-ray diffraction (XRD), n—the process by which
and bassanite) to anhydrite.
X-rays are coherently scattered by electrons in a crystalline
¯
3.2.10 gypsum, n—calcium sulfate dihydrate ~CSH ! and is material.
monoclinic .
4. Background
3.2.11 periclase, n—free magnesium oxide (M); cubic.
4.1 This test method assumes general knowledge concern-
3.3 Definitions of Terms Specific to This Standard:
ing the composition of cement and portland-cement clinker.
3.3.1 Certified Reference Material (CRM), n—a material
Necessary background information may be obtained from a
whose properties (in this case phase abundance, XRD peak
number of references (1, 4).
positionorintensity,orboth)areknownandcertified(seeNote
4).
4.2 This test method also assumes general expertise in XRD
and QXRD analysis. Important background information may
NOTE 4—NIST Standard Reference Material (SRM®) Clinkers 2686,
be obtained from a number of references (5-10).
2687, and 2688 are suitable CRMs for qualification.
3.3.2 diffractometer, n—the instrument, an X-ray powder
5. Summary
diffractometer, for determining the X-ray diffraction pattern of
a crystalline powder.
5.1 This test method covers direct determination of the
proportion by mass of individual phases in cement or portland-
cement clinker using quantitative X-ray powder diffraction
analysis. The following phases are covered by this standard:
Portland cement clinker SRM’s® from the Standard Reference Material
Program, National Institute of Standards and Technology. alite (tricalcium silicate, C S), belite (dicalcium silicate, C S),
3 2
C1365 − 18
aluminate (tricalcium aluminate, C A), ferrite (tetracalcium 8. Materials
aluminoferrite,C AF),periclase(magnesiumoxide,M),arcan-
8.1 Standardization Phases—The use of standardization
¯
ite (potassium sulfate, KS), gypsum (calcium sulfate dihydrate,
phases is recommended for establishing the intensity ratio/
¯ ¯
CSH ), bassanite (calcium sulfate hemihydrate, CSH1), anhy-
2 mass ratio relationships when using the traditional quantitative
¯
drite (calcium sulfate, CS), and calcite (calcium carbonate, method. These phases must usually be synthesized (11, 12).
CaCO ).
8.2 CRM Clinker—The use of three CRM clinkers is re-
quired to qualify the QXRD procedure.
A QXRD test procedure includes some or all of the follow-
ing: (a) specimen preparation; (b) data collection and phase
8.3 Internal Standard—The use of an internal standard is
identification; (c) standardization (for the standardization ap-
recommended for the standardization approach. Suitable ma-
proach); (d) collecting a set of crystal structure models for
terials include chemical reagents (see 8.4) or CRM’s (see
refinement (for the Rietveld approach); (e) use of an internal or
Appendix X2).
external standard (to correct for various effects on intensity
8.4 Reagent Chemicals—Reagent grade chemicals, if used
besides phase proportion); (f) analysis of the sample (in which
either as an internal standard or during chemical extraction of
the powder diffraction pattern is measured and/or the intensity
certain phases, shall meet the specifications of the Committee
of selected XRD peaks or patterns are measured); and (g)
on Analytical Reagents of the American Chemical Society
calculation of the proportion of each phase.
where such specifications are available. Other grades may be
5.2 This test method does not specify details of the QXRD used, provided it is first ascertained that the chemical is
sufficiently pure to permit its use without lessening the accu-
test procedure. The user must demonstrate by analysis of
certified reference materials that the particular analytical pro- racy of the determination.
cedure selected for this purpose provides acceptable levels of
9. Hazards
precision and bias. Two recommended procedures (the Riet-
veld approach and the traditional approach used to determine
9.1 The importance of careful and safe operation of an
the acceptable levels of precision and bias) are given in
X-ray diffractometer cannot be overemphasized. X-rays are
Appendix X2 and Appendix X3.
particularly hazardous. An X-ray diffractometer must be oper-
ated safely to avoid serious injury or death. The X-rays are
6. Significance and Use generated by high voltages, perhaps as high as 55 kV peak,
requiring care to avoid serious electric shock. Klug and
6.1 This test method allows direct determination of the
Alexander (6) (pp. 58–60) state, “The responsibility for safe
proportion of some individual phases in cement or portland-
operation rests directly on the individual operator” (italics are
cement clinker. Thus it provides an alternative to the indirect
theirs).
estimation of phase proportion using the equations in Specifi-
cation C150/C150M (Annex A1).
10. Sampling and Sample Preparation
6.2 Thistestmethodassumesthattheoperatorisqualifiedto
10.1 Take samples of cement in accordance with the appli-
operate an X-ray diffractometer and to interpret X-ray diffrac-
cable provisions of Practice C183/C183M. Take samples of
tion spectra.
portland-cement clinker so as to be representative of the
material being tested.
6.3 Thistestmethodmaybeusedaspartofaqualitycontrol
10.2 Prepare samples as required for the specific analytical
program in cement manufacturing.
procedure (see Appendix X3).
6.4 This test method may be used in predicting properties
and performance of hydrated cement and concrete that are a
11. Qualification and Assessment
function of phase composition.
11.1 Qualification of Test Procedure:
6.5 QXRD provides a bulk analysis (that is, the weighted 11.1.1 When analytical data obtained in accordance with
average composition of several grams of material). Therefore, this test method are required, any QXRD test procedure that
meets the requirements described in this section may be used.
results may not agree precisely with results of microscopical
methods. 11.1.2 Prior to use for analysis of cement or portland-
cement clinker, qualify the QXRD test procedure for the
analysis. Maintain records that include a description of the
7. Apparatus
QXRD procedure and the qualification data (or, if applicable,
7.1 X-Ray Diffractometer—The X-ray diffractometer allows
re-qualification data). Make these records available to the
measurement of the X-ray diffraction pattern from which the
purchaser if requested in the contract or order.
crystalline phases within the sample may be qualitatively
identified and the proportion of each phase may be quantita-
tively determined. X-ray diffractometers are manufactured
Reagent Chemicals, American Chemical Society Specifications , American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
commercially and a number of instruments are available. The
listed by the American Chemical Society, see Analar Standards for Laboratory
suitability of the diffractometer for this test method shall be
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
established using the qualification procedure outlined in this
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
test method. MD.
C1365 − 18
TABLE 2 Permissible Maximum Difference Between Mean Value
11.1.3 If more than one X-ray diffractometer is used in a
and Known Value (Mass percent) Expressed at a 95 %
specific laboratory for the same analysis, even if the instru-
Confidence Level for the Mean of a Selected Number of
ments are substantially identical, qualify each separately.
A
Replicates (k) = 2, 3, 4
11.1.4 If more than one procedure is used to mount speci-
Phase 2 replicates 3 replicates 4 replicates
mens for QXRD, the use of each procedure shall constitute a
alite 5.93 4.91 4.31
separate test procedure and each procedure shall be qualified
belite 3.70 3.06 2.69
aluminate 2.14 1.77 1.55
separately.
ferrite 2.46 2.04 1.79
11.1.5 Qualificationshallconsistofreplicatedeterminations
periclase 0.77 0.64 0.56
of the three SRM® clinkers, re-mounting the specimen for
arcanite 0.85 0.70 0.61
gypsum 1.55 1.28 1.12
each analysis, (see Note 6) for the proportions of C S, C S,
3 2
bassanite 1.52 1.26 1.11
C A(cubic and orthorhombic), C AF, and M using the desired
3 4
anhydrite 1.67 1.38 1.21
QXRD procedure (see Note 7). calcite 0.68 0.56 0.49
A
Computed from within-laboratory standard deviation using 95 % confidence
NOTE 6—Prior to qualification, it may be convenient to carry out a
interval and 30 df.
preliminaryassessmentinwhichoneormoremixturesofsyntheticphases
areanalyzed.Suchapreliminaryassessmentshouldproducenomorethan
the permissible variation described in 11.2.
NOTE 7—It is recommended that at least two replicate analyses be
carried out, but three determinations may be used for assessing permis- 11.3.1 QXRD procedures that provide acceptable results for
sible variation.
some phases but not for others shall be used only for those
phasesforwhichacceptableresultsareobtained.However,itis
11.2 Permissible Variation:
notexpectedthataQXRDprocedurewouldprovideacceptable
11.2.1 The values of permissible variation were computed
results for some phases and not for others, and such a result
from the within-laboratory standard deviation values obtained
may indicate that the procedure is not, in fact, valid.
in round robin analyses of mixtures of SRM® clinkers and
synthetic phases (see 14.2).
11.4 Assessing the Diffractometer:
11.2.2 Replicate analyses shall differ from each other by no
11.4.1 The procedures described in theAnnex shall be used
more than the within-lab repeatability value shown in Table 1.
to assess the diffractometer. Note that assessment is different
11.2.3 Atestresultshallbejudgednotequivalentifitdiffers
from qualification or re-qualification.
from that of another laboratory by more than the between-lab
11.4.2 The diffractometer shall be assessed each month that
reproducibility value shown in Table 1.
this test method is used.
11.2.4 The mean result shall differ from the known value by
11.4.3 The diffractometer shall be assessed after any sub-
no more than the value shown in Table 2 for the particular
stantial modification in the instrument (see Note 8).
number of replicates.
NOTE 8—Substantial modification of the diffractometer includes chang-
11.2.4.1 Discussion—Qualification limits in Table 2 are
ing the X-ray tube, changing a detector, adding or removing a
prediction intervals (95 %) for a future mean and are designed
monochromator, and realignment.
to bracket values of a mean of k (=2,3,4) future measurements
11.4.4 QXRD procedure shall be assessed upon receipt of
of the relevant phases. The intervals are based upon the
evidence that the test procedure is not providing data in
performance of the eleven round robin participants.
accordance with the permissible variation.
11.2.5 Known Values—The known values of each phase in
11.5 Re-qualification of QXRD Procedure:
the SRM® clinkers provided by NIST was determined using
11.5.1 If assessment shows that the X-ray diffractometer is
quantitative X-ray powder diffraction and optical microscopy
not properly aligned (as discussed in Annex A1), it shall be
(13).
realigned following the manufacturer’s instructions. When
11.3 Partial Results:
subsequent assessment shows that the X-ray diffractometer is
properly aligned (or was not properly aligned when the QXRD
procedure was previously qualified), qualification of the
TABLE 1 Permissible Maximum Difference Between Replicate
A QXRD procedure shall be repeated.
Values (Percent of Clinker or Cement)
Repeatability Reproducibility
12. Recommended Procedure
Within-Lab Between-Lab
d2s-
12.1 For required analytical data see Section 11 and the
s-within d2s-within s-between
between
recommended QXRD procedures described in Appendix X2.
alite 0.74 2.04 2.27 6.30
belite 0.64 1.77 1.40 3.87
13. Report
aluminate 0.47 1.31 0.79 2.19
ferrite 0.49 1.36 0.89 2.47
13.1 Report the following information:
periclase 0.23 0.63 0.50 1.39
13.1.1 The phase and its proportion, and which method
arcanite 0.22 0.60 0.34 0.94
gypsum 0.21 0.59 0.59 1.65
(Rietveld or standardization) was used. Round figures to the
bassanite 0.39 1.08 0.58 1.60
number of significant places required in the report only after
anhydrite 0.27 0.74 0.64 1.77
calculations are completed, in order to keep the final results
calcite 0.99 2.73 0.50 1.50
A substantially free of calculation errors. Follow the rounding
As described in Practice C670.
procedure outlined in Practice E29.
C1365 − 18
14. Precision and Bias conducted tests on the same clinker or cement by two different
laboratories should not differ from each other by more than
14.1 Analysis—A round-robin analysis by Rietveld refine-
d2s-between in 95 % of comparisons, where d2s-between
ment of the SRM® clinkers with calcium sulfate and calcium
=1.96·√2· .
sbetween
carbonate additions has been carried out following experimen-
tal procedures described in Appendix X2. An earlier coopera-
14.3 Bias—The difference between the estimate of true
tive standardization of mixtures of synthetic phases and a
mean phase concentration and the accepted reference values.
round-robin analysis of the RM clinkers have been carried out
14.4 Discussion—Eleven laboratories participated in a co-
(11, 12) following the experimental procedures described in
operative round-robin analysis of mixtures of four separate
Appendix X3 (see Note 9). Results were analyzed statistically
reference materials. Reference values were that of the SRM®
according to Practices E691 and C670 to determine precision
clinkers adjusted for the known amounts of added calcium
levels.
sulfates and calcite. Taylor (1) concluded that the four major
NOTE 9—Analysis of clinker is likely to include variance in addition to
phases in portland-cement clinker may be determined using
that found in analysis of mixtures of synthetic phases.
QXRD with an absolute accuracy of 2 to 5 percentage points
14.1.1 The precision values are all expressed as percentage
(by mass) for alite and belite and 1 to 2 percentage points (by
points by mass relative to the total clinker or cement.
mass) for aluminate and ferrite. The SRM® clinkers do not
contain gypsum, bassanite, anhydrite or calcite so these data
14.2 Precision—The within-laboratory standard deviation
are provided for informational purposes. The qualification
and the between-laboratory standard deviation for all phases
requires assessment of certified phases in the clinker SRMs®
are given in Table 1, representing pooled results from the four
only. As new SRMs® become available, additional phase
test mixtures. The within-laboratory standard deviation for
qualifications will be added to the test method. There is
each phase is reported as ‘s-within.’ Results of two properly
insufficient data to estimate method bias at this time.
conductedtestsbythesameoperatorshouldnotvarymorethan
d2s-within in 95 % of comparisons, where d2s-within =
15. Keywords
1.96·√2· . The multi-laboratory standard deviation for
swithin
each phase is reported as ‘s-between.’Results of two properly
15.1 alite; alkali sulfate; aluminate; belite; cement; clinker;
diffractometer; ferrite; periclase; phase analysis; quantitative
X-ray powder diffraction analysis; QXRD; Rietveld analysis;
SRM’s from the Standard Reference Material Program, National Institute of
Standards and Technology are Certified Reference Materials. X-ray powder diffraction; XRD
ANNEX
(Mandatory Information)
A1. ASSESSING THE X-RAY DIFFRACTOMETER
A1.1 Introduction—This Annex provides a procedure for indefinite period of time, even after changes in the diffracto-
assessingthediffractometertoassurethevalidityoftheQXRD meter such as realignment and replacement of the X-ray tube,
procedure over a long period of time (several years or longer). and transferable from one diffractometer to another).
A QXRD analysis of portland cement and portland-cement
A1.2.2 The requirements for the QXRD standardization to
clinker is made particularly difficult by the fact that individual
be universal are: (1) specimens are free from preferred
clinker phases used for standardization are not stable over long
orientation, primary extinction, and microabsorption, (2) the
periods of time, because they hydrate easily, and are not easily
irradiated volume of the specimen is constant and independent
synthesized. Thus it is difficult to assess standardizations
of scattering angle, (3) monochromator polarization effects are
directly by reanalysis of one or more standardization speci-
corrected, (4) integrated peak intensity is used, (5) when using
mens. In addition, it is not desirable to repeat the standardiza-
an internal standard, standardization and analyses are carried
tion unless absolutely necessary.Amore reasonable strategy is
out with an internal standard from the same lot because
to use an external standard to assess the diffractometer and to
differences in the particle size distribution between lots of the
decidewhenitisnecessarytore-qualifyaparticularprocedure.
samematerialcancausesignificantdifferenceinpeakintensity,
This Annex provides a procedure for assessing the diffracto-
and (6) standardization and analyses are carried out with the
metertoassurethevalidityoftheQXRDprocedureoveralong
diffractometer in proper geometric alignment.
period of time (several years or longer).
A1.2.3 If analy
...

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: C1365 − 06 (Reapproved 2011) C1365 − 18
Standard Test Method for
Determination of the Proportion of Phases in Portland
Cement and Portland-Cement Clinker Using X-Ray Powder
Diffraction Analysis
This standard is issued under the fixed designation C1365; 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*Scope
1.1 This test method covers direct determination of the proportion by mass of individual phases in portland cement or
portland-cement clinker using quantitative X-ray (QXRD) analysis. The following phases are covered by this standard: alite
(tricalcium silicate), belite (dicalcium silicate), aluminate (tricalcium aluminate), ferrite (tetracalcium aluminoferrite), periclase
(magnesium oxide), gypsum (calcium sulfate dihydrate), bassanite (calcium sulfate hemihydrate), anhydrite (calcium sulfate), and
calcite (calcium carbonate).
1.2 This test method specifies certain general aspects of the analytical procedure, but does not specify detailed aspects.
Recommended procedures are described, but not specified. Regardless of the procedure selected, the user shall demonstrate by
analysis of certified reference materials (CRM’s) that the particular analytical procedure selected for this purpose qualifies (that
is, provides acceptable precision and bias) (see Note 1). The recommended procedures are ones used in the round-robin analyses
to determine the precision levels of this test method.
NOTE 1—A similar approach was used in the performance requirements for alternative methods for chemical analysis in Test Methods C114.
1.3 The values stated in SI units shall be regarded as the standard.
1.4 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. For specific hazards, see Section 9.
1.5 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:
C114 Test Methods for Chemical Analysis of Hydraulic Cement
C150C150/C150M Specification for Portland Cement
C183C183/C183M Practice for Sampling and the Amount of Testing of Hydraulic Cement
C219 Terminology Relating to Hydraulic Cement
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions: Definitions are in accordance with Terminology C219.
3.2 Phases (1):
This test method is under the jurisdiction of ASTM Committee C01 on Cement and is the direct responsibility of Subcommittee C01.23 on Compositional Analysis.
Current edition approved Dec. 1, 2011March 1, 2018. Published May 2012April 2018. Originally approved in 1998. Last previous edition approved in 20062011 as
C1365 - 98 (2006).C1365 – 06 (2011). DOI: 10.1520/C1365-06R11.10.1520/C1365-18.
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.
The boldface numbers in parentheses refer to the list of references at the end of this standard.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1365 − 18
3.2.1 alite, n—tricalcium silicate (C S) modified in composition and crystal structure by incorporation of foreign ions; occurs
typically between 30 to 70 % (by mass) of the portland-cement clinker; and is normally either the M or M crystal polymorph,
1 3
each of which is monoclinic.
+ +
3.2.2 alkali sulfates, n—arcanite (K SO ) may accommodate Na , Ca2 , and CO in solid solution, aphthitalite (K ,Na )SO
2 4 3 4-x x 4
with x usually 1 but up to 3), calcium langbeinite (K Ca [SO ] ) may occur in clinkers high in K O, and thenardite (Na SO ) in
2 2 4 3 2 2 4
clinkers with high Na/K ratios (1).
3.2.3 aluminate, n—tricalcium aluminate (C A) modified in composition and sometimes in crystal structure by incorporation of
a substantial proportion of foreign ions; occurs as 2 to 15 % (by mass) of the portland-cement clinker; is normally cubic when
relatively pure and orthorhombic or monoclinic when in solid solution with significant amounts of sodium (2).
¯
3.2.4 anhydrite, n—calcium sulfate ~CS! and is orthorhombic (see Note 2).
NOTE 2—Calcium sulfate is added to the clinker during grinding to control setting time, strength development, and volume stability. Several phases
may form as a result of dehydration of gypsum. The first 1.5 molecules of water are lost between 0 and 65 °C 65°C with minor changes in structure;
and, above 95 °C, 95°C, the remaining 0.5 molecules of water are lost transforming the structure to the metastable γ polymorph of anhydrite (sometimes
referred to as ‘soluble anhydrite’) and subsequently the orthorhombic form (3).
¯
3.2.5 bassanite, n—calcium sulfate hemihydrate ~CSH ! and is monoclinic.
1/2
3.2.6 belite, n—dicalcium silicate (C S) modified in composition and crystal structure by incorporation of foreign ions; occurs
typically as 15 to 45 % (by mass) of the portland-cement clinker as normally the β polymorph, which is monoclinic. In lesser
amounts, other polymorphs can be present.
3.2.7 calcite, n—calcium carbonate is trigonal and may be present in a cement as an addition or from carbonation of free lime.
3.2.8 ferrite, n—tetracalcium aluminoferrite solid solution of approximate composition C (A,F) modified in composition by
variation in the Al/Fe ratio and by substantial incorporation of foreign ions as C A F where 0 < x < 1.4; constituting 5 to 15 %
4 X 2-X
(by mass) of a portland-cement clinker; and is orthorhombic.
3.2.9 free lime, n—free calcium oxide (C); cubic (see Note 3).
NOTE 3—Free lime (CaO) may be present in clinker and cement but readily hydrates to form portlandite (Ca(OH) ). Portlandite may carbonate to form
calcium carbonate, generally as calcite. Heat-treating a freshly-ground sample to 600 °C 600°C is useful to convert any portlandite back to free lime but
will also dehydrate the hydrous calcium sulfate phases (gypsum and bassanite) to anhydrite.
¯
3.2.10 gypsum, n—calcium sulfate dihydrate ~CSH ! and is monoclinic .
3.2.11 periclase, n—free magnesium oxide (M); cubic.
3.3 Definitions of Terms Specific to This Standard:
3.3.1 Certified Reference Material (CRM), n—a material whose properties (in this case phase abundance, XRD peak position
or intensity, or both) are known and certified (see Note 4).
NOTE 4—NIST Standard Reference Material (SRM®) Clinkers 2686, 2687, and 2688 are suitable CRMs for qualification.
3.3.2 diffractometer, n—the instrument, an X-ray powder diffractometer, for determining the X-ray diffraction pattern of a
crystalline powder.
3.3.3 phase, n—a homogeneous, physically distinct, and mechanically separable portion of a material, identifiable by its
chemical composition and crystal structure.
3.3.3.1 Discussion—
Phases in portland-cement clinker and cements that are included in this test method are four major phases (alite, belite, aluminate,
and ferrite) and one minor phase (periclase).
3.3.3.2 Discussion—
Precision values are provided for additional phases (gypsum, bassanite, anhydrite, arcanite, and calcite). Values for these
constituents may be provided using this method but are considered informational until suitable certified reference materials for
qualification are available.
3.3.4 qualification, n—process by which a QXRD procedure is shown to be valid.
3.3.5 Rietveld analysis, n—process of refining crystallographic and instrument variables to minimize differences between
observed and calculated X-ray powder diffraction patterns for one or more phases, estimating their relative abundance.
4 ¯
When expressing chemical formulae, C = CaO, S = SiO , A = Al O , F = Fe O , M = MgO, S = SO , and H = H O.
2 2 3 2 3 3 2
Portland cement clinker SRM’s® from the Standard Reference Material Program, National Institute of Standards and Technology.
C1365 − 18
3.3.6 standardization, n—process of determining the relationship between XRD intensity and phase proportion for one or more
phases (see Note 5).
NOTE 5—In the literature of X-ray powder diffraction analysis, the standardization process has been commonly referred to as calibration; however, we
have determined that standardization is a more accurate term.
3.3.6.1 Discussion—
Rietveld analysis uses crystal structure models to calculate powder diffraction patterns of phases that serve as the reference
patterns. The pattern-fitting step seeks the best-fit combination of selected pattern intensities to the raw data. The relative pattern
intensities along with the crystallographic attributes of each phase are used to calculate relative abundance. The standardization
approach uses powdered samples of pure phases to assess the relationship between diffraction intensity ratios and mass fraction
ratios of two or more constituents; and is referred to here as the traditional method.
3.3.7 X-ray diffraction (XRD), n—the process by which X-rays are coherently scattered by electrons in a crystalline material.
4. Background
4.1 This test method assumes general knowledge concerning the composition of cement and portland-cement clinker. Necessary
background information may be obtained from a number of references (1, 4).
4.2 This test method also assumes general expertise in XRD and QXRD analysis. Important background information may be
obtained from a number of references (5-10).
5. Summary
5.1 This test method covers direct determination of the proportion by mass of individual phases in cement or portland-cement
clinker using quantitative X-ray powder diffraction analysis. The following phases are covered by this standard: alite (tricalcium
silicate, C S), belite (dicalcium silicate, C S), aluminate (tricalcium aluminate, C A), ferrite (tetracalcium aluminoferrite, C AF),
3 2 3 4
¯ ¯
periclase (magnesium oxide, M), arcanite (potassium sulfate, KS), gypsum (calcium sulfate dihydrate, CSH ), bassanite (calcium
¯ ¯
sulfate hemihydrate, CSH ), anhydrite (calcium sulfate, CS), and calcite (calcium carbonate, CaCO ).
A QXRD test procedure includes some or all of the following: (a) specimen preparation; (b) data collection and phase
identification; (c) standardization (for the standardization approach); (d) collecting a set of crystal structure models for refinement
(for the Rietveld approach); (e) use of an internal or external standard (to correct for various effects on intensity besides phase
proportion); (f) analysis of the sample (in which the powder diffraction pattern is measured and/or the intensity of selected XRD
peaks or patterns are measured); and (g) calculation of the proportion of each phase.
5.2 This test method does not specify details of the QXRD test procedure. The user must demonstrate by analysis of certified
reference materials that the particular analytical procedure selected for this purpose provides acceptable levels of precision and
bias. Two recommended procedures (the Rietveld approach and the traditional approach used to determine the acceptable levels
of precision and bias) are given in Appendix X1X2 and Appendix X2X3.
6. Significance and Use
6.1 This test method allows direct determination of the proportion of some individual phases in cement or portland-cement
clinker. Thus it provides an alternative to the indirect estimation of phase proportion using the equations in Specification
C150C150/C150M (Annex A1).
6.2 This test method assumes that the operator is qualified to operate an X-ray diffractometer and to interpret X-ray diffraction
spectra.
6.3 This test method may be used as part of a quality control program in cement manufacturing.
6.4 This test method may be used in predicting properties and performance of hydrated cement and concrete that are a function
of phase composition.
6.5 QXRD provides a bulk analysis (that is, the weighted average composition of several grams of material). Therefore, results
may not agree precisely with results of microscopical methods.
7. Apparatus
7.1 X-Ray Diffractometer—The X-ray diffractometer allows measurement of the X-ray diffraction pattern from which the
crystalline phases within the sample may be qualitatively identified and the proportion of each phase may be quantitatively
determined. X-ray diffractometers are manufactured commercially and a number of instruments are available. The suitability of
the diffractometer for this test method shall be established using the qualification procedure outlined in this test method.
C1365 − 18
8. Materials
8.1 Standardization Phases—The use of standardization phases is recommended for establishing the intensity ratio/mass ratio
relationships when using the traditional quantitative method. These phases must usually be synthesized (11, 12).
8.2 CRM Clinker—The use of three CRM clinkers is required to qualify the QXRD procedure.
8.3 Internal Standard—The use of an internal standard is recommended for the standardization approach. Suitable materials
include chemical reagents (see 8.4) or CRM’s (see Appendix X1X2).
8.4 Reagent Chemicals—Reagent grade chemicals, if used either as an internal standard or during chemical extraction of certain
phases, shall meet the specifications of the Committee on Analytical Reagents of the American Chemical Society where such
specifications are available. Other grades may be used, provided it is first ascertained that the chemical is sufficiently pure to
permit its use without lessening the accuracy of the determination.
9. Hazards
9.1 The importance of careful and safe operation of an X-ray diffractometer cannot be overemphasized. X-rays are particularly
hazardous. An X-ray diffractometer must be operated safely to avoid serious injury or death. The X-rays are generated by high
voltages, perhaps as high as 55 kV peak, requiring care to avoid serious electric shock. Klug and Alexander (6) (pp. 58–60) state,
“The responsibility for safe operation rests directly on the individual operator” (italics are theirs).
10. Sampling and Sample Preparation
10.1 Take samples of cement in accordance with the applicable provisions of Practice C183C183/C183M. Take samples of
portland-cement clinker so as to be representative of the material being tested.
10.2 Prepare samples as required for the specific analytical procedure (see Appendix X2X3).
11. Qualification and Assessment
11.1 Qualification of Test Procedure:
11.1.1 When analytical data obtained in accordance with this test method are required, any QXRD test procedure that meets the
requirements described in this section may be used.
11.1.2 Prior to use for analysis of cement or portland-cement clinker, qualify the QXRD test procedure for the analysis. Maintain
records that include a description of the QXRD procedure and the qualification data (or, if applicable, re-qualification data). Make
these records available to the purchaser if requested in the contract or order.
11.1.3 If more than one X-ray diffractometer is used in a specific laboratory for the same analysis, even if the instruments are
substantially identical, qualify each separately.
11.1.4 If more than one procedure is used to mount specimens for QXRD, the use of each procedure shall constitute a separate
test procedure and each procedure shall be qualified separately.
11.1.5 Qualification shall consist of replicate determinations of the three SRM® clinkers, re-mounting the specimen for each
analysis, (see Note 6) for the proportions of C S, C S, C A (cubic and orthorhombic), C AF, and M using the desired QXRD
3 2 3 4
procedure (see Note 7).
NOTE 6—Prior to qualification, it may be convenient to carry out a preliminary assessment in which one or more mixtures of synthetic phases are
analyzed. Such a preliminary assessment should produce no more than the permissible variation described in 11.2.
NOTE 7—It is recommended that at least two replicate analyses be carried out, but three determinations may be used for assessing permissible variation.
11.2 Permissible Variation:
11.2.1 The values of permissible variation were computed from the within-laboratory standard deviation values obtained in
round robin analyses of mixtures of SRM® clinkers and synthetic phases (see 14.2).
11.2.1.1 Discussion—Qualification limits in Table 2 are prediction intervals (95 %) for a future mean and are designed to
bracket values of a mean of k (=2,3,4) future measurements of the relevant phases. The intervals are based upon the performance
of the 11 round robin participants.
11.2.2 Replicate analyses shall differ from each other by no more than the within-lab repeatability value shown in Table 1.
11.2.3 A test result shall be judged not equivalent if it differs from that of another laboratory by more than the between-lab
reproducibility value shown in Table 1.
11.2.4 The mean result shall differ from the known value by no more than the value shown in Table 2 for the particular number
of replicates.
11.2.4.1 Discussion—Qualification limits in Table 2 are prediction intervals (95 %) for a future mean and are designed to
bracket values of a mean of k (=2,3,4) future measurements of the relevant phases. The intervals are based upon the performance
of the eleven round robin participants.
Reagent Chemicals, American Chemical Society Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
C1365 − 18
TABLE 1 Permissible Maximum Difference Between Replicate
A
Values (percent(Percent of clinkerClinker or cement)Cement)
Repeatability Reproducibility
Within-Lab Between-Lab
d2s-
s-within d2s-within s-between
between
alite 0.74 2.04 2.27 6.30
belite 0.64 1.77 1.40 3.87
aluminate 0.47 1.31 0.79 2.19
ferrite 0.49 1.36 0.89 2.47
periclase 0.23 0.63 0.50 1.39
arcanite 0.22 0.60 0.34 0.94
gypsum 0.21 0.59 0.59 1.65
bassanite 0.39 1.08 0.58 1.60
anhydrite 0.27 0.74 0.64 1.77
calcite 0.99 2.73 0.50 1.50
A
As described in Practice C670.
TABLE 2 Permissible Maximum Difference Between Mean Value
and Known Value (Mass percent) Expressed at a 95 %
Confidence Level for the Mean of a Selected Number of
A
Replicates (k) = 2, 3, 4
Phase 2 replicates 3 replicates 4 replicates
alite 5.93 4.91 4.31
belite 3.70 3.06 2.69
aluminate 2.14 1.77 1.55
ferrite 2.46 2.04 1.79
periclase 0.77 0.64 0.56
arcanite 0.85 0.70 0.61
gypsum 1.55 1.28 1.12
bassanite 1.52 1.26 1.11
anhydrite 1.67 1.38 1.21
calcite 0.68 0.56 0.49
A
Computed from within-laboratory standard deviation using 95 % confidence
interval and 30 df.
11.2.5 Known Values—The known values of each phase in the SRM® clinkers provided by NIST was determined using
quantitative X-ray powder diffraction and optical microscopy (13).
11.3 Partial Results:
11.3.1 QXRD procedures that provide acceptable results for some phases but not for others shall be used only for those phases
for which acceptable results are obtained. However, it is not expected that a QXRD procedure would provide acceptable results
for some phases and not for others, and such a result may indicate that the procedure is not, in fact, valid.
11.4 Assessing the Diffractometer:
11.4.1 The procedures described in the Annex shall be used to assess the diffractometer. Note that assessment is different from
qualification or re-qualification.
11.4.2 The diffractometer shall be assessed each month that this test method is used.
11.4.3 The diffractometer shall be assessed after any substantial modification in the instrument (see Note 8).
NOTE 8—Substantial modification of the diffractometer includes changing the X-ray tube, changing a detector, adding or removing a monochromator,
and realignment.
11.4.4 QXRD procedure shall be assessed upon receipt of evidence that the test procedure is not providing data in accordance
with the permissible variation.
11.5 Re-qualification of QXRD Procedure:
11.5.1 If assessment shows that the X-ray diffractometer is not properly aligned (as discussed in Annex A1), it shall be realigned
following the manufacturer’s instructions. When subsequent assessment shows that the X-ray diffractometer is properly aligned
(or was not properly aligned when the QXRD procedure was previously qualified), qualification of the QXRD procedure shall be
repeated.
12. Recommended Procedure
12.1 For required analytical data see Section 11 and the recommended QXRD procedures described in Appendix X1X2.
13. Report
13.1 Report the following information:
C1365 − 18
13.1.1 The phase and its proportion, and which method (Rietveld or standardization) was used. Round figures to the number
of significant places required in the report only after calculations are completed, in order to keep the final results substantially free
of calculation errors. Follow the rounding procedure outlined in Practice E29.
14. Precision and Bias
14.1 Analysis—A round-robin analysis by Rietveld refinement of the SRM® clinkers with calcium sulfate and calcium
carbonate additions has been carried out following experimental procedures described in Appendix X1X2. An earlier cooperative
standardization of mixtures of synthetic phases and a round-robin analysis of the RM clinkers have been carried out (11, 12)
following the experimental procedures described in Appendix X2X3 (see Note 9). Results were analyzed statistically according
to Practices E691 and C670 to determine precision levels.
NOTE 9—Analysis of clinker is likely to include variance in addition to that found in analysis of mixtures of synthetic phases.
14.1.1 The precision values are all expressed as percentage points by mass relative to the total clinker or cement.
14.2 Precision—The within-laboratory standard deviation and the between-laboratory standard deviation for all phases are
given in Table 1, representing pooled results from the four test mixtures. The within-laboratory standard deviation for each phase
is reported as ‘s-within.’ Results of two properly conducted tests by the same operator should not vary more than d2s-within in
95 % of comparisons, where d2s-within = 1.96·√2· . The multi-laboratory standard deviation for each phase is reported as
swithin
‘s-between.’ Results of two properly conducted tests on the same clinker or cement by two different laboratories should not differ
from each other by more than d2s-between in 95 % of comparisons, where d2s-between =1.96·√2· .
sbetween
14.3 Bias—The difference between the estimate of true mean phase concentration and the accepted reference values.
14.4 Discussion—Eleven laboratories participated in a cooperative round-robin analysis of mixtures of four separate reference
materials. Reference values were that of the SRM® clinkers adjusted for the known amounts of added calcium sulfates and calcite.
Taylor (1) concluded that the four major phases in portland-cement clinker may be determined using QXRD with an absolute
accuracy of 2 to 5 percentage points (by mass) for alite and belite and 1 to 2 percentage points (by mass) for aluminate and ferrite.
The SRM® clinkers do not contain gypsum, bassanite, anhydrite or calcite so these data are provided for informational purposes.
The qualification requires assessment of certified phases in the clinker SRMs® only. As new SRMs® become available, additional
phase qualifications will be added to the test method. There is insufficient data to estimate method bias at this time.
15. Keywords
15.1 alite; alkali sulfate; aluminate; belite; cement; clinker; diffractometer; ferrite; periclase; phase analysis; quantitative X-ray
powder diffraction analysis; QXRD; Rietveld analysis; X-ray powder diffraction; XRD
ANNEX
(Mandatory Information)
A1. ASSESSING THE X-RAY DIFFRACTOMETER
A1.1 Introduction—This Annex provides a procedure for assessing the diffractometer to assure the validity of the QXRD
procedure over a long period of time (several years or longer). A QXRD analysis of portland cement and portland-cement clinker
is made particularly difficult by the fact that individual clinker phases used for standardization are not stable over long periods of
time, because they hydrate easily, and are not easily synthesized. Thus it is difficult to assess standardizations directly by reanalysis
of one or more standardization specimens. In addition, it is not desirable to repeat the standardization unless absolutely necessary.
A more reasonable strategy is to use an external standard to assess the diffractometer and to decide when it is necessary to
re-qualify a particular procedure. This Annex provides a procedure for assessing the diffractometer to assure the validity of the
QXRD procedure over a long period of time (several years or longer).
A1.2 Overview:
A1.2.1 As long as certain aspects of the procedure are not changed, the relationship between peak intensity ratio and mass ratio
is assumed to be universal (that is, valid over an indefinite period of time, even after changes in the diffractometer such as
realignment and replacement of the X-ray tube, and transferable from one diffractometer to another).
SRM’s from the Standard Reference Material Program, National Institute of Standards and Technology are Certified Reference Materials.
C1365 − 18
A1.2.2 The requirements for the QXRD standardization to be universal are: (1) specimens are free from preferred orientation,
primary extinction, and microabsorption, (2) the irradiated volume of the specimen is constant and independent of scattering angle,
(3) monochromator polarization effects are corrected, (4) integrated peak intensity is used, (5) when using an internal standard,
standardization and analyses are carried out with an internal standard from the same lot because differences in the particle size
distribution between lots of the same materi
...