ASTM C1356-96(2001)

Standard Test Method for Quantitative Determination of Phases in Portland Cement Clinker by Microscopical Point-Count Procedure

SCOPE
1.1 This test method covers a systematic procedure for measuring the percentage volume of the phases in portland cement clinker by microscopy.  
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use.  
1.3 The values stated in SI units are to be regarded as the standard.

General Information

• Status: Historical
• Publication Date: 09-Dec-1996
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: C01 - Cement
• Drafting Committee: C01.23 - Compositional Analysis

Relations

• Replaced By: ASTM C1356-07 - Standard Test Method for Quantitative Determination of Phases in Portland Cement Clinker by Microscopical Point-Count Procedure
• Effective Date: 01-Jun-2007
• Referred By: ASTM C1723-16(2022) - Standard Guide for Examination of Hardened Concrete Using Scanning Electron Microscopy
• Effective Date: 10-Dec-1996

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
Designation:C1356–96 (Reapproved 2001)
Standard Test Method for
Quantitative Determination of Phases in Portland Cement
Clinker by Microscopical Point-Count Procedure
This standard is issued under the fixed designation C 1356; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2.1 alite, n—crystallinetricalciumsilicate(C S),modified
incompositionandcrystalstructurebyincorporationofforeign
1.1 This test method covers a systematic procedure for
ions; the crystals are pseudo-hexagonal with well-defined
measuring the percentage volume of the phases in portland
faces, though less regular shapes commonly occur.
cement clinker by microscopy.
3.2.2 aluminate, n—tricalcium aluminate (C A) modified in
1.2 This standard does not purport to address all of the
composition and crystal structure by incorporation of a sub-
safety concerns, if any, associated with its use. It is the
stantial proportion of foreign ions; aluminate forms cubic
responsibility of the user of this standard to establish appro-
crystals when relatively pure, and forms identifiable elongated
priate safety and health practices and determine the applica-
crystals commonly called 88alkali aluminate” when in solid
bility of regulatory limitations prior to use.
solution with significant amounts of potassium or sodium, or
1.3 The values stated in SI units are to be regarded as the
both.
standard.
3.2.3 belite, n—crystalline dicalcium silicate (C S), modi-
2. Referenced Documents
fied in composition and crystal structure by incorporation of
foreign ions; belite usually occurs as rounded crystals marked
2.1 ASTM Standards:
by striations formed by cross sections of lamellae, and may
C 150 Specification for Portland Cement
occur as single crystals or in clusters.
C 670 Practice for Preparing Precision and Bias Statements
3.2.4 ferrite, n—a solid solution of approximate composi-
for Test Methods for Construction Materials
tion tetracalcium aluminoferrite (C AF) modified in composi-
D75 Practice for Sampling Aggregates
tion by variation in theAl/Fe ratio and by substantial incorpo-
D 3665 Practice for Random Sampling of Construction
ration of foreign ions; ferrite is characterized by high
Materials
reflectivity in polished sections and is normally the only
3. Terminology
strongly colored compound among the principal clinker
phases.
3.1 Definitions:
3.2.4.1 Discussion—Aluminate and ferrite form most of the
3.1.1 clinker phase, n—a physically and chemically distinct
interstitial material between the silicate crystals and, under
optically identifiable portion of the clinker sample, including
certain conditions of cooling, may not be easily identifiable or
both principal phases (alite, belite, aluminate, and ferrite),
resolved by ordinary light microscopy.
minor phases (for example, free lime, periclase, and alkali
3.3 Minor Clinker Phases:
sulfates), and voids.
3.3.1 alkali sulfates, n—sodium sulfate, potassium sulfate,
3.1.1.1 Discussion—Voids, though not a phase in the sense
and double sulfates such as calcium langbeinite
of being a crystalline compound, are a distinct, identifiable
(K SO –2CaSO ).
portion of a clinker microstructure. 2 4 4
3.3.2 free lime, n—calciumoxide(C)foundmostlyasround
3.1.2 voids, n—isolated or interconnected open areas in the
crystals.
clinker, also called pores.
3.3.3 periclase, n—crystalline form of free magnesium
3.2 Principal Clinker Phases:
oxide (M), that has not been taken up in solid solution with
other phases.
This test method is under the jurisdiction ofASTM Committee C01 on Cement
and is the direct responsibility of Subcommittee C01.23 on CompositionalAnalysis. 4. Summary of Test Method
Current edition approved Aug. 10, 2001. Published March 1997.
2 4.1 The test method consists of the preparation and micro-
Annual Book of ASTM Standards, Vol 04.01.
Annual Book of ASTM Standards, Vol 04.02. scopical examination of a specimen produced by encapsulating
Annual Book of ASTM Standards, Vol 04.03.
clinker in a mounting medium and sectioning the specimen so
¯
C = CaO, S = SiO ,A=Al O ,F=Fe O,S=SO , M = MgO, N = Na O, and
2 2 3 2 3 3 2
as to expose the interior of particles for visual examination.
K=K O in cement chemistry notation.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
C1356–96 (2001)
Polishing the section surface and treating it with etchants to 6.8 Light source that provides uniform and consistent illu-
highlight specific phases complete the preparation. During mination of the field and light of constant intensity.
microscopical examination phases are identified and their 6.9 Counting (tallying) device capable of recording up to
proportions determined by a point-count procedure. In this ten categories of data.
procedure, the specimen is moved in uniform increments on a 6.10 Crushing device capable of reducing sample particle
microscope stage, and phases falling under the cross hairs of size to between 1 and 4 mm.
the eyepiece are identified and counted (1-5). 6.11 Riffle sample splitter to reduce sample from initial
volume to approximately 100 g.
5. Significance and Use
6.12 Wireclothsieveswithopeningssuitableforsievingthe
5.1 This test method provides a relatively simple and
entire clinker sample to broadly define the model size class,
reliable microscopical means of measuring the phase abun- and sieves with 1-mm and 4-mm square openings to concen-
danceofportlandcementclinker(Note1).Microscopicalpoint
trate particles of recommended size for specimen preparation.
counting provides a direct measure of the clinker phase 6.13 Vacuum impregnation device to force epoxy into
composition in contrast to the calculated Bogue phase compo-
clinker voids. (Vacuum bell jar or desiccator connected to a
sition (Note 2). vacuum pump.)
6.14 Curing oven, hot plate, slide warmer, or ultraviolet
NOTE 1—This test method utilizes a reflected light microscope. Related
light may be used to accelerate the epoxy hardening.
methods such as transmitted light microscopy, scanning electron micros-
6.15 Thin, diamond-rimmed wafering saw for sectioning
copy, and automated imaging techniques may also be used for clinker
analysis but are not presently included in this test method. the encapsulated clinker.
NOTE 2—Thistestmethodallowsdirectdeterminationoftheproportion
6.16 Glass grinding (lapping) plates (300 mm 3 300
of each individual phase in portland-cement clinker. This test method is
mm 3 5 mm) required only if the mechanical system is not
intended to provide an alternative to the indirect estimation of phase
equipped to handle the final grinding with alumina powder.
proportion using the equations in Specification C 150 (footnote C inTable
6.17 Ultrasonic cleaning device (optional) to clean the
number 1 and footnote B in Table number 2).
sample prior to, between, and after polishing steps.
5.2 This test method assumes the operator is qualified to
operate a reflected light microscope and the required accesso-
7. Reagents and Materials
ries, is able to correctly prepare polished sections and use
7.1 Consumable grinding (lapping) and polishing supplies.
necessary etchants, and is able to correctly identify the con-
After the encapsulated specimen has been cut with the saw, all
stituent phases.
or most of the following grinding and polishing steps are
5.3 Thistestmethodmaybeusedaspartofaqualitycontrol
required: 120-, 320-, and 600-grit silicon carbide grinding
program in cement manufacturing as well as a troubleshooting
papers or equivalent and 5 µm, 0.3µ m, and 0.05 µm alumina
tool. Microscopic characterization of clinker phases may also
polishingpowdersortheirequivalent.Diamondgrindingdiscs,
aidincorrelatingcementpropertiesandcementperformancein
siliconcarbidepaper,orpolishingclothsandaluminapolishing
concrete, to the extent that properties and performance are a
powder may be used. Various types of polishing cloths may be
function of phase composition.
used to produce a nearly flat clinker surface or a relief surface
to aid in identification of periclase (1).
6. Apparatus
7.2 Sample cups (with volumes ranging from 10 to 20 mL)
6.1 Reflected light microscope.
to contain epoxy-clinker mix during hardening.
6.2 Mechanical stage with stepping increments ranging
7.3 Epoxy resin and hardener for encapsulation of the
from 0.05 to 2.0 mm (to enable analysis of clinkers of different
clinker. Low viscosity resin will facilitate penetration into
average crystal sizes) and vernier scales graduated in both X
clinker voids. When hardened it should have an abrasive
and Y directions.
resistance close to that of the clinker to minimize relief during
6.3 Microscope objectives of magnification 53,103,203,
polishing. It should be resistant to substances used for washing
and 403 or other magnifications suitable for the task.
and etching.
NOTE 3—The use of reflected light with oil immersion is optional. It is 7.4 Isopropyl alcohol (2-propanol) for washing the speci-
highly recommended for study of finely crystalline aluminate and ferrite
men and for use in the ultrasonic cleaner. Propylene glycol is
which typically form the ground mass in which the silicates occur.
suitable as a lubricant for the saw blade.
Reflected light objective lenses with magnification up to 1003 designed
7.5 Immersion oil with an index of refraction of 1.51 if
for use in oil-immersion are required.
reflected light immersion-oil technique is used.
6.4 Assorted eyepieces (53,103,203) which when com-
7.6 Etching material to highlight different phases for count-
bined with the objectives described in 6.3 will provide magni-
ing. (See Appendix X3.)
fications up to 8003.
6.5 Eyepiece reticles (graticulae) with a linear grid pattern 8. Sampling
containing 9, 16, or 25 intersections.
8.1 Take samples of portland-cement clinker in accordance
6.6 Eyepiece micrometer for measuring dimensions of the
with the applicable provisions of Practices D 75 and D 3665 so
object under investigation and calibrated for each magnifica-
tion.
6.7 Stage micrometer for the calibration of the eyepiece
The boldface numbers in parentheses refer to the list of references at the end of
micrometer. this standard.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
C1356–96 (2001)
as to be representative of the quantity of material with which in the chosen X or Y direction to bring another field into view.
testing is concerned (see Appendix X1). The phases under the grid points are identified, counted, and
8.2 Sieve the initial sample to obtain clinker particles
the mechanical stage advanced one stepping interval to an
representing approximately 70 % of the clinker particle size
adjacentfieldofview.Thisprocedureiscontinueduntilarange
distribution, centered about the mode. This particle size inter-
of 3000-4000 points are recorded.
val represents a size range of approximately two standard
At the clinker periphery, some of the reticle points may fall
deviations, one on each side of the mode, and is herein defined
on the encapsulating epoxy that surrounds the clinker particle.
as the “bulk mode” (M ), the combined material between the
b
Count only points within the clinker, and disregard the reticle
extremes of the particle size distribution. State the sieve sizes
points over epoxy at the clinker periphery. Thus, the clinker
used. If either extreme of the particle size distribution is to be
voidspace(porosity),ifdeterminedinthepointcount,doesnot
studied, the selected portion shall be identified as non-modal,
include cavities on the surface of the clinker particle. As one
andthepercentagesretainedorpassingstandardsievesshallbe
stepsoverirrelevantareas(suchasepoxyexteriortotheclinker
stated. The recommended size fraction for microscopical
or severally damaged portions of the polished surface that
analysis is 2 to 4 mm. Therefore, that portion of the initial
obscure the phase identification) the count is temporarily
clinker sample representing the bulk mode shall be crushed,
suspended until a suitable clinker surface again falls under the
sieved, and riffled to provide approximately 100 g. Whole
reticle grid points. Artifacts (for example, blot marks, residual
clinkers may be encapsulated to study the phase distribution
liquids) on the section surface are not to be counted. If the
within clinker nodules.
identity of the phase is obscured by the area formed by the grid
intersection, one should consistently use a specified corner of
9. Preparation of Sample Specimen
the intersection where the phase can be clearly observed.
9.1 Polished sections shall be polished to a fineness such
When the edge of the mount is reached at the end of a line
that grinding pits and scratches have been eliminated (see
Appendix X1). of traverse, the mount is translated one stepping interval
9.2 Etching of the clinker surface may be used to facilitate perpendicular to that line and counting continues in the
identification of clinker phases (1); additional information may oppositedirection,orthemountisrepositionedtoapointatthe
be found in the Appendix X1.
original starting boundary to keep the same direction of travel.
As one progresses along the lines of traverse the data are
10. Counting Procedure
accumulated until 3000–4000 points (N) are recorded.
10.1 Choose the microscope magnification such that adja-
cent reticle grid points do not fall on the same crystal, except
11. Calculation of Results
for a few unusually large crystals. Magnification from 2003 to
11.1 Calculate the volume fraction of each phase in the
5003 will accommodate most clinkers. Reticles with multiple
samplebydividingthenumberofpointscountedforthatphase
grid points are recommended. Single crosshair reticles are not
by the total number of points counted. This number multiplied
suitable.
by 100 yields the phase content in volume per cent.
10.2 Choose the stepping interval such that an entirely
different field of view is observed after each step. 11.2 The number of points to be counted is to be between
10.3 Attach a mechanical stage to the microscope. The 3000 and 4000 (2). The absolute error at the 96 % confidence
mechanical stage may be an electrically driven specimen interval has been shown to be:
carriage connected to an automatic electro
...