ASTM C1356-07(2012)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: C1356 − 07 (Reapproved 2012)
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 C1356; 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* 3.1.2 voids, n—isolated or interconnected open areas in the
clinker, also called pores.
1.1 This test method covers a systematic procedure for
measuring the percentage volume of the phases in portland 3.2 Principal Clinker Phases:
cement clinker by microscopy.
3.2.1 alite, n—crystallinetricalciumsilicate(C S),modified
incompositionandcrystalstructurebyincorporationofforeign
1.2 This standard does not purport to address all of the
ions; the crystals are pseudo-hexagonal with well-defined
safety concerns, if any, associated with its use. It is the
faces, though less regular shapes commonly occur.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3.2.2 aluminate, n—tricalcium aluminate (C A) modified in
bility of regulatory limitations prior to use.
composition and crystal structure by incorporation of a sub-
1.3 The values stated in SI units are to be regarded as the
stantial proportion of foreign ions; aluminate forms cubic
standard.
crystals when relatively pure, and forms identifiable elongated
crystals commonly called “alkali aluminate” when in solid
2. Referenced Documents
solution with significant amounts of potassium or sodium, or
both.
2.1 ASTM Standards:
C150Specification for Portland Cement
3.2.3 belite, n—crystalline dicalcium silicate (C S), modi-
C219Terminology Relating to Hydraulic Cement
fied in composition and crystal structure by incorporation of
C670Practice for Preparing Precision and Bias Statements
foreign ions; belite usually occurs as rounded crystals marked
for Test Methods for Construction Materials
by striations formed by cross sections of lamellae, and may
D75Practice for Sampling Aggregates
occur as single crystals or in clusters.
D3665Practice for Random Sampling of Construction Ma-
3.2.4 ferrite, n—a solid solution of approximate composi-
terials
tion tetracalcium aluminoferrite (C AF) modified in composi-
tion by variation in theAl/Fe ratio and by substantial incorpo-
3. Terminology
ration of foreign ions; ferrite is characterized by high
3.1 Definitions:
reflectivity in polished sections and is normally the only
3.1.1 clinker phase, n—a physically and chemically distinct
strongly colored compound among the principal clinker
optically identifiable portion of the clinker sample, including
phases.
both principal phases (alite, belite, aluminate, and ferrite),
3.2.4.1 Discussion—Aluminate and ferrite form most of the
minor phases (for example, free lime, periclase, and alkali
interstitial material between the silicate crystals and, under
sulfates), and voids.
certain conditions of cooling, may not be easily identifiable or
3.1.1.1 Discussion—Voids, though not a phase in the sense
resolved by ordinary light microscopy.
of being a crystalline compound, are a distinct, identifiable
3.3 Minor Clinker Phases:
portion of a clinker microstructure.
3.3.1 alkali sulfates, n—sodium sulfate, potassium sulfate,
and double sulfates such as calcium langbeinite
(K SO –2CaSO ).
2 4 4
ThistestmethodisunderthejurisdictionofASTMCommitteeC01onCement
andisthedirectresponsibilityofSubcommitteeC01.23onCompositionalAnalysis.
3.3.2 free lime, n—calciumoxide(C)foundmostlyasround
Current edition approved Oct. 1, 2012. Published November 2012. Originally
crystals.
approved in 1996. Last previous edition approved in 2007 as C1356–07. DOI:
10.1520/C1356-07R12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
¯
Standards volume information, refer to the standard’s Document Summary page on 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
the ASTM website. K=K O in cement chemistry notation.
*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
C1356 − 07 (2012)
which typically form the ground mass in which the silicates occur.
3.3.3 periclase, n—crystalline form of free magnesium ox-
Reflected light objective lenses with magnification up to 100× designed
ide (M), that has not been taken up in solid solution with other
for use in oil-immersion are required.
phases.
6.4 Assorted eyepieces (5×, 10×, 20×) which when com-
3.4 For definitions of other terms relating to hydraulic
bined with the objectives described in 6.3 will provide magni-
cements, refer to Terminology C219.
fications up to 800×.
6.5 Eyepiece reticles (graticulae) with a linear grid pattern
4. Summary of Test Method
containing 9, 16, or 25 intersections.
4.1 The test method consists of the preparation and micro-
6.6 Eyepiece micrometer for measuring dimensions of the
scopicalexaminationofaspecimenproducedbyencapsulating
object under investigation and calibrated for each magnifica-
clinker in a mounting medium and sectioning the specimen so
tion.
as to expose the interior of particles for visual examination.
Polishing the section surface and treating it with etchants to
6.7 Stage micrometer for the calibration of the eyepiece
highlight specific phases complete the preparation. During
micrometer.
microscopical examination phases are identified and their
6.8 Light source that provides uniform and consistent illu-
proportions determined by a point-count procedure. In this
mination of the field and light of constant intensity.
procedure, the specimen is moved in uniform increments on a
6.9 Counting (tallying) device capable of recording up to
microscope stage, and phases falling under the cross hairs of
ten categories of data.
the eyepiece are identified and counted (1-5).
6.10 Crushing device capable of reducing sample particle
5. Significance and Use
size to between 1 and 4 mm.
5.1 This test method provides a relatively simple and
6.11 Riffle sample splitter to reduce sample from initial
reliable microscopical means of measuring the phase abun-
volume to approximately 100 g.
danceofportlandcementclinker(Note1).Microscopicalpoint
6.12 Wireclothsieveswithopeningssuitableforsievingthe
counting provides a direct measure of the clinker phase
entire clinker sample to broadly define the model size class,
composition in contrast to the calculated Bogue phase compo-
and sieves with 1-mm and 4-mm square openings to concen-
sition (Note 2).
trate particles of recommended size for specimen preparation.
NOTE1—Thistestmethodutilizesareflectedlightmicroscope.Related
6.13 Vacuum impregnation device to force epoxy into
methods such as transmitted light microscopy, scanning electron
microscopy, and automated imaging techniques may also be used for clinker voids. (Vacuum bell jar or desiccator connected to a
clinker analysis but are not presently included in this test method.
vacuum pump.)
NOTE2—Thistestmethodallowsdirectdeterminationoftheproportion
6.14 Curing oven, hot plate, slide warmer, or ultraviolet
of each individual phase in portland-cement clinker. This test method is
intended to provide an alternative to the indirect estimation of phase light may be used to accelerate the epoxy hardening.
proportion using the equations in Specification C150 (footnote C inTable
6.15 Thin, diamond-rimmed wafering saw for sectioning
number 1 and footnote B in Table number 2).
the encapsulated clinker.
5.2 This test method assumes the operator is qualified to
6.16 Glassgrinding(lapping)plates(300mm×300mm×5
operate a reflected light microscope and the required
mm) required only if the mechanical system is not equipped to
accessories, is able to correctly prepare polished sections and
handle the final grinding with alumina powder.
use necessary etchants, and is able to correctly identify the
constituent phases.
6.17 Ultrasonic cleaning device (optional) to clean the
sample prior to, between, and after polishing steps.
5.3 Thistestmethodmaybeusedaspartofaqualitycontrol
program in cement manufacturing as well as a troubleshooting
7. Reagents and Materials
tool. Microscopic characterization of clinker phases may also
7.1 Consumable grinding (lapping) and polishing supplies.
aidincorrelatingcementpropertiesandcementperformancein
After the encapsulated specimen has been cut with the saw, all
concrete, to the extent that properties and performance are a
or most of the following grinding and polishing steps are
function of phase composition.
required: 120-, 320-, and 600-grit silicon carbide grinding
papers or equivalent and 5 µm, 0.3µ m, and 0.05 µm alumina
6. Apparatus
polishingpowdersortheirequivalent.Diamondgrindingdiscs,
6.1 Reflected light microscope.
siliconcarbidepaper,orpolishingclothsandaluminapolishing
6.2 Mechanical stage with stepping increments ranging
powder may be used.Various types of polishing cloths may be
from0.05to2.0mm(toenableanalysisofclinkersofdifferent
used to produce a nearly flat clinker surface or a relief surface
average crystal sizes) and vernier scales graduated in both X
to aid in identification of periclase (1).
and Y directions.
7.2 Sample cups (with volumes ranging from 10 to 20 mL)
6.3 Microscope objectives of magnification 5×, 10×, 20×,
to contain epoxy-clinker mix during hardening.
and 40× or other magnifications suitable for the task.
NOTE 3—The use of reflected light with oil immersion is optional. It is Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
highly recommended for study of finely crystalline aluminate and ferrite this standard.
C1356 − 07 (2012)
7.3 Epoxy resin and hardener for encapsulation of the simple hand-operated carriage and counter. Place a small
clinker. Low viscosity resin will facilitate penetration into amountofsoftmodelingclayonastandard,petrographicglass
clinker voids. When hardened it should have an abrasive
slide (27 mm×46 mm) and level the sample thereon. Either
resistance close to that of the clinker to minimize relief during use a commercial leveling device or use a small spirit level to
polishing.Itshouldberesistanttosubstancesusedforwashing
adjust the mount while pressing it firmly into the clay.Atissue
and etching.
paper between the polished section and the leveling device or
spirit level prevents surface scratches. Place the glass slide
7.4 Isopropyl alcohol (2-propanol) for washing the speci-
with attached clay and leveled mount on the mechanical stage.
men and for use in the ultrasonic cleaner. Propylene glycol is
Check the accuracy of leveling by observing the focus at
suitable as a lubricant for the saw blade.
severalpointsonthepolishedsurface.Movetoastartingpoint
7.5 Immersion oil with an index of refraction of 1.51 if
(the initial field of view from which data will be taken) at the
reflected light immersion-oil technique is used.
edge of the mount and record the position in the X-Y
7.6 Etching material to highlight different phases for count-
coordinate system, using the graduated scales on the mechani-
ing. (See Appendix X3.)
cal stage.
8. Sampling 10.4 Use a tally sheet or a counting device to record the
phasesasrequired.Theobservershouldnotkeepamentaltally
8.1 Take samples of portland-cement clinker in accordance
of any data because of possible bias. Identify and record each
with the applicable provisions of Practices D75 and D3665 so
phaseunderthegridintersections.Insomecases,thealuminate
as to be representative of the quantity of material with which
and ferrite quantities may be combined and labeled “matrix”.
testing is concerned (see Appendix X1).
Move the mechanical stage a distance of one stepping interval
8.2 Sieve the initial sample to obtain clinker particles
in the chosen X orYdirection to bring another field into view.
representing approximately 70% of the clinker particle size
The phases under the grid points are identified, counted, and
distribution, centered about the mode. This particle size inter-
the mechanical stage advanced one stepping interval to an
val represents a size range of approximately two standard
adjacentfieldofview.Thisprocedureiscontinueduntilarange
deviations,oneoneachsideofthemode,andishereindefined
of 3000-4000 points are recorded.
as the “bulk mode” (M ), the combined material between the
b
At the clinker periphery, some of the reticle points may fall
extremes of the particle size distribution. State the sieve sizes
on the encapsulating epoxy that surrounds the clinker particle.
used. If either extreme of the particle size distribution is to be
Count only points within the clinker, and disregard the reticle
studied, the selected portion shall be identified as non-modal,
points over epoxy at the clinker periphery. Thus, the clinker
andthepercentagesretainedorpassingstandardsievesshallbe
voidspace(porosity),ifdeterminedinthepointcount,doesnot
stated. The recommended size fraction for microscopical
include cavities on the surface of the clinker particle. As one
analysis is 2 to 4 mm. Therefore, that portion of the initial
stepsoverirrelevantareas(suchasepoxyexteriortotheclinker
clinker sample representing the bulk mode shall be crushed,
or severally damaged portions of the polished surface that
sieved, and riffled to provide approximately 100 g. Whole
obscure the phase identification) the count is temporarily
clinkers may be encapsulated to study the phase distribution
suspended until a suitable clinker surface again falls under the
within clinker nodules.
reticle grid points.Artifacts (for example, blot marks, residual
9. Preparation of Sample Specimen
liquids) on the section surface are not to be counted. If the
identityofthephaseisobscuredbytheareaformedbythegrid
9.1 Polished sections shall be polished to a fineness such
intersection, one should consistently use a specified corner of
that grinding pits and scratches have been eliminated (see
the intersection where the phase can be clearly observed.
Appendix X1).
When the edge of the mount is reached at the end of a line
9.2 Etching of the clinker surface may be used to facilitate
of traverse, the mount is translated one stepping interval
identificationofclinkerphases (1);additionalinformationmay
perpendicular to that line and counting continues in the
be found in the Appendix X1.
oppositedirection,orthemountisrepositionedtoapointatthe
original starting boundary to keep the same direction of travel.
10. Counting Pro
...