Designation: C311/C311M − 13

Standard Test Methods for

Sampling and Testing Fly Ash or Natural Pozzolans for Use
in Portland-Cement Concrete1
This standard is issued under the fixed designation C311/C311M; 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.
This standard has been approved for use by agencies of the Department of Defense.

1. Scope* NOTE 1—Sieve size is identified by its standard designation in Speci-

fication D1426. The alternative designation given in parentheses is for
1.1 These test methods cover procedures for sampling and information only and does not represent a different standard sieve size.
testing fly ash and raw or calcined pozzolans for use in 1.4 This standard does not purport to address all of the
portland-cement concrete. safety concerns, if any, associated with its use. It is the
1.2 The procedures appear in the following order: responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
Sections 1.5 The text of this standard references notes and footnotes
Sampling 7 that provide explanatory information. These notes and foot-
CHEMICAL ANALYSIS
Reagents and apparatus 10
notes (excluding those in tables) shall not be considered as
Moisture content 11 and 12 requirements of this standard.
Loss on ignition 13 and 14
Silicon dioxide, aluminum oxide, iron oxide, calcium
oxide, magnesium oxide, sulfur trioxide, sodium
2. Referenced Documents
oxide 2.1 ASTM Standards:2
and potassium oxide 15
Available alkali 16 and 17 C33 Specification for Concrete Aggregates
Ammonia 18 C109/C109M Test Method for Compressive Strength of
PHYSICAL TESTS Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube
Density 19
Fineness 20 Specimens)
Increase of drying shrinkage of mortar bars 21-23 C114 Test Methods for Chemical Analysis of Hydraulic
Soundness 24 Cement
Air-entrainment of mortar 25 and 26
Strength activity index with portland cement 27-30 C125 Terminology Relating to Concrete and Concrete Ag-
Water requirement 31 gregates
Effectiveness of Fly Ash or Natural Pozzolan in C150 Specification for Portland Cement
Controlling Alkali-Silica Reactions 32
Effectiveness of Fly Ash or Natural Pozzolan in C151 Test Method for Autoclave Expansion of Hydraulic
Contributing to Sulfate Resistance 34 Cement
C157/C157M Test Method for Length Change of Hardened
Hydraulic-Cement Mortar and Concrete
1.3 The values stated in either SI units or inch-pound units C185 Test Method for Air Content of Hydraulic Cement
are to be regarded separately as standard. The values stated in Mortar
each system may not be exact equivalents; therefore, each C188 Test Method for Density of Hydraulic Cement
system shall be used independently of the other. Combining C204 Test Methods for Fineness of Hydraulic Cement by
values from the two systems may result in non-conformance Air-Permeability Apparatus
with the standard. C219 Terminology Relating to Hydraulic Cement
C226 Specification for Air-Entraining Additions for Use in
the Manufacture of Air-Entraining Hydraulic Cement
1
These test methods are under the jurisdiction of ASTM Committee C09 on
Concrete and Concrete Aggregates and are the direct responsibility of Subcommit-
2
tee C09.24 on Supplementary Cementitious Materials. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2013. Published March 2013. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1953. Last previous edition approved in 2011 as C311–11b. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C0311-13. the ASTM website.

*A Summary of Changes section appears at the end of this standard

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 C311/C311M − 13
C227 Test Method for Potential Alkali Reactivity of 4. Significance and Use
Cement-Aggregate Combinations (Mortar-Bar Method) 4.1 These test methods are used to develop data for com-
C430 Test Method for Fineness of Hydraulic Cement by the parison with the requirements of Specification C618 or Speci-
45-µm (No. 325) Sieve fication C1697. These test methods are based on standardized
C441 Test Method for Effectiveness of Pozzolans or Ground testing in the laboratory and are not intended to simulate job
Blast-Furnace Slag in Preventing Excessive Expansion of conditions.
Concrete Due to the Alkali-Silica Reaction 4.1.1 Strength Activity Index—The test for strength activity
C604 Test Method for True Specific Gravity of Refractory index is used to determine whether fly ash or natural pozzolan
Materials by Gas-Comparison Pycnometer results in an acceptable level of strength development when
C618 Specification for Coal Fly Ash and Raw or Calcined used with hydraulic cement in concrete. Since the test is
Natural Pozzolan for Use in Concrete performed with mortar, the results may not provide a direct
C670 Practice for Preparing Precision and Bias Statements correlation of how the fly ash or natural pozzolan will
for Test Methods for Construction Materials contribute to strength in concrete.
C778 Specification for Sand 4.1.2 Chemical Tests—The chemical component determina-
C1012 Test Method for Length Change of Hydraulic- tions and the limits placed on each do not predict the
Cement Mortars Exposed to a Sulfate Solution performance of a fly ash or natural pozzolan with hydraulic
C1437 Test Method for Flow of Hydraulic Cement Mortar cement in concrete, but collectively help describe composition
C1697 Specification for Blended Supplementary Cementi- and uniformity of the material.
tious Materials
D1426 Test Methods for Ammonia Nitrogen In Water 5. Materials
D4326 Test Method for Major and Minor Elements in Coal
5.1 Graded Standard Sand—The sand used for making test
and Coke Ash By X-Ray Fluorescence
specimens for the activity index with lime or portland cement
E11 Specification for Woven Wire Test Sieve Cloth and Test
shall be natural silica sand conforming to the requirements for
Sieves
graded standard sand in Specification C778.
2.2 ACI Document:3
NOTE 2—Segregation of Graded Sand—The graded standard sand
ACI 201.2R Guide to Durable Concrete should be handled in such a manner as to prevent segregation, since
variations in the grading of the sand cause variations in the consistency of
3. Terminology the mortar. In emptying bins or sacks, care should be exercised to prevent
the formation of mounds of sand or craters in the sand, down the slopes
3.1 Definitions: of which the coarser particles will roll. Bins should be of sufficient size to
3.1.1 For definitions of terms used in this test method, refer permit these precautions. Devices for drawing the sand from bins by
to Terminology C125 and Terminology C219. gravity should not be used.

3.2 Definitions of Terms Specific to This Standard: 5.2 Hydrated Lime—The hydrated lime used in the tests
3.2.1 composite sample, n—a sample that is constructed by shall be reagent-grade calcium hydroxide, 95 % minimum
combining equal portions of grab or regular samples. calculated as Ca(OH)2 (Note 3), and have a minimum fineness
of 2500 m2/kg as determined in accordance with Test Method
3.2.2 established source, n—a source for which at least six C204.
months of continuous production quality assurance records
from a test frequency required for a new source are available, NOTE 3—The calcium hydroxide should be protected from exposure to
carbon dioxide. Material remaining in an opened container after a test
sampled at the source.
should not be used for subsequent tests.
3.2.3 grab sample, n—a sample that is taken in a single 5.3 Portland Cement—The portland cement used in the
operation from a conveyor delivering to bulk storage, from Strength Activity Index with Portland Cement test shall comply
bags, or from a bulk shipment. with the requirements of Specification C150 and have a
3.2.3.1 Discussion—A grab sample may or may not reflect minimum compressive strength of 35 MPa (5000 psi) at 28
the composition or physical properties of a single lot of fly ash days and total alkalies (Na2O + 0.658 K2O) not less than
or natural pozzolan. This type of sample can be used to 0.50 % nor more than 0.80 %.
characterize small amounts of material. 5.3.1 The use of a locally available portland cement in the
3.2.4 new source, n—a source for which less than six Strength Activity Index or a project cement that does not meet
months of production records are available, sampled at the the requirements of the section on Materials is permitted when
source. the variations from the requirements of the section on Materials
3.2.5 regular sample, n—a sample that is constructed by are reported and when the use of such portland cement is
combining equal portions of grab samples that were taken at requested.
predetermined times or locations from any single lot of
6. Sample Type and Size
material.
6.1 Grab samples and regular samples shall have a mass of
at least 2 kg (4 lb).
3
Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington 6.2 Grab samples or regular samples taken at prescribed
Hills, MI 48333-9094, http://www.aci-int.org. intervals over a period of time (see Table 1), may be combined

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 C311/C311M − 13
TABLE 1 Minimum Sampling and Testing FrequencyA 8.2 Samples shall be stored in clean, airtight containers
Test Sample Type
Jobsite or New Established identified with the source and lot or period of time represented.
SourceB SourceB
Untested portions of the sample shall be retained for at least
Moisture content Regular Daily or each Daily or each
Loss on ignition 90 Mgc 360 MgC one month after all test results have been reported.
Fineness (100 Tons) (400 Tons)
Density and the Composite Monthly or each Monthly or each 9. Testing Frequency
other tests in 1 800 MgC 2 900 MgC
Specification (2 000 Tons) (3 200 Tons)
C618, Tables 1
9.1 General—When required, the purchaser shall specify
and 2 the amount of testing for available alkalies, reactivity with
A
It should be noted that the minimum test frequency given in Table 1 is not cement alkalies, drying shrinkage, and air-entrainment. Make
necessarily the frequency needed for quality control programs on some fly ash or all other tests on regular or composite samples chosen as
natural pozzolans.
B
For definitions, refer to the Terminology section.
specified in Table 1.
C
Whichever comes first.
CHEMICAL ANALYSIS

10. General
to form a composite sample representative of the fly ash or 10.1 All apparatus, reagents and techniques shall comply
natural pozzolan produced during that period of time. with the requirements of Test Methods C114.
6.3 Composite samples shall have a mass of at least 4 kg (8
10.2 Purity of Water—Unless otherwise indicated, refer-
lb).
ences to water shall be understood to mean distilled water or
6.4 The sampling shall be done by, or under the direction of, water of equal purity.
a responsible representative of the purchaser.
MOISTURE CONTENT
7. Sampling Procedure
7.1 The fly ash or natural pozzolan may be sampled by any 11. Procedure
one of the following methods: 11.1 Dry a weighed sample, as received, to constant mass in
7.1.1 From Bulk Storage at Point of Discharge or from Rail an oven at 110 6 5 °C [230 6 10 °F].
Cars and Road Tankers—A sample may be taken by siphon
tube during loading or by sampling tube from each loaded car 12. Calculation
or tanker. If the load is sampled at the point of discharge into
the rail car or tanker, the top surface shall be removed to a 12.1 Calculate the percentage of moisture to the nearest
depth of at least 200 mm (8 in.) before sampling. The sample 0.1 %, as follows:
shall be identified with at least the date and shipment number.
7.1.2 From Bags in Storage—The regular sample shall Moisture content, % 5 ~ A/B ! 3 100 (1)
comprise increments of equal size taken by sampling tube from
three bags selected at random from one lot of bagged material. where:
The sample shall be identified with date and lot number. A = mass loss during drying, and
7.1.3 From Conveyor Delivering to Bulk Storage—Take one B = mass as received.
sample of 2 kg (4 lb) or more of the material passing over the
conveyor. This may be secured by taking the entire test sample LOSS ON IGNITION
in a single operation, known as the grab sample method, or by
combining several equal portions taken at regular intervals, 13. Procedure
known as the regular sample method. Automatic samplers may 13.1 Determine loss on ignition in accordance with the
be used to obtain samples. procedures outlined in Test Methods C114, except that the
7.2 Samples shall be treated as described in Section 8. material remaining from the determination of moisture content
shall be ignited to constant mass in an uncovered porcelain, not
NOTE 4—Some methods of loading or delivery of fly ash or natural
pozzolan, particularly from an airstream or conveyor belt, may create platinum, crucible at 750 6 50 °C.
stratification or segregation in the material stream. Sampling techniques
must be designed to ensure that the sample is representative of the material 14. Calculation
shipped.
14.1 Calculate the percentage of loss on ignition to the
8. Preparation and Storage of Samples nearest 0.1, as follows:
8.1 Prepare composite samples for the tests required in
Section 9, by arranging all grab or regular samples into groups Loss on ignition, % 5 ~ A/B ! 3 100 (2)
covering the period or quantity to be represented by the
where:
sample. Take equal portions from each, sufficient to produce a
composite sample large enough for the tests required. Mix the A = loss in mass between 110 and 750 °C,
B = mass of moisture-free sample used.
composite sample thoroughly.

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 C311/C311M − 13
SILICON DIOXIDE, ALUMINUM OXIDE, IRON OXIDE, 17. Calculation and Report
CALCIUM OXIDE, MAGNESIUM OXIDE, SULFUR 17.1 Calculate the results as weight percent of the original
TRIOXIDE, SODIUM OXIDE AND POTASSIUM OXIDE sample material. Report as equivalent percentage of sodium
oxide (Na2O), calculated as follows:
15. Procedure
15.1 Determine the percentages of these oxides as required Equivalent Na 2 O, % 5 Na2 O, %10.658 3 K 2 O, % (3)
in accordance with the applicable sections of Test Methods
C114 for materials having an insoluble residue greater than
1 % (Note 5). Analysts performing sodium oxide and potas- AMMONIA
sium oxide determinations shall observe the precautions out- 18. Procedure
lined in the applicable section of Test Methods C114. Most
pozzolans dissolve completely in lithium borate fluxes. 18.1 Weigh 1.00 g of the fly ash sample into a 125-mL
Erlenmeyer flask. Add 100 mL of ammonia-free water. Place a
NOTE 5—Rapid and instrumental methods may be employed similar to neoprene rubber stopper on the flask and swirl the contents to
those in Test Methods C114 and D4326.
thoroughly mix the sample and the water.
AVAILABLE ALKALI 18.2 Filter the mixture using a medium-textured filter paper
and save the filtrate for the ammonia determination.
16. Procedure
18.3 Determine the concentration of ammonia in the filtrate
16.1 Weigh 5.0 g of the sample and 2.0 g of hydrated lime in accordance with the procedures outlined in Test Methods
on a piece of weighing paper, carefully mix using a metal D1426, Method A–Direct Nesslerization or Method B–Selec-
spatula, and transfer to a small plastic vial of approximately tive Ion Electrode.
25-mL capacity. Add 10.0 mL of water to this mixture, seal the
18.4 Calculate the ammonia concentration of the fly ash as
vial by securing the cap or lid to the vial with tape (Note 6),
follows:
blend by shaking until the mixture is uniform, and store at
38 6 2 °C. Ammonia, mg/kg 5 N W 3 V W /W fa (4)

NOTE 6—To ensure that moisture loss from the paste does not occur, where:
place the sealed vial in a sealable container (such as a small sample or NW = ammonia concentration of the water extract deter-
mason jar), add sufficient water to cover the bottom of the container, and mined by Test Methods D1426, mg/L,
seal.
VW = volume of water used for extracting ammonia from
16.2 Open the vial at the age of 28 days and transfer the the fly ash sample, mL, and
contents to a 250-mL casserole. Break up and grind the cake Wfa = mass of fly ash sample used in the test, g.
with a pestle, adding a small amount of water, if necessary, so
that a uniform slurry containing no lumps is obtained (Note 7). PHYSICAL TESTS
Add sufficient water to make the total volume 200-mL. Let
DENSITY
stand 1 h at room temperature with frequent stirring. Filter
through a medium-textured filter paper onto a 500-mL volu- 19. Procedure
metric flask. Wash thoroughly with hot water (eight to ten 19.1 Determine the density of the sample in accordance
times). with the procedure described in Test Method C188 or Test
NOTE 7—At times it may be necessary to break the vial and peel off the Method C604 as modified below.
plastic from the solid cake. In such cases, care should be exercised to
avoid the loss of material and to remove all solid material from the 19.2 For Test Method C188, follow the procedure except
fragments of the vial. If the cake is too hard to break up and grind in the use a quantity of fly ash or natural pozzolan weighed to the
casserole, a mortar should be used. nearest 0.05 g, of about 50 g.
16.3 Neutralize the filtrate with dilute HCl (1 + 3), using 1 19.3 For Test Method C604 use an amount of material that
to 2 drops of phenolphthalein solution as the indicator. Add is appropriate for the instrument.
exactly 5 mL of dilute HCl (1 + 3) in excess. Cool the solution 19.3.1 Determine the density of the material as received. Do
to room temperature and fill the flask to the mark with distilled not prepare sample as described in Section 6 of Test Method
water. Determine the amount of sodium and potassium oxides C604.
in the solution using the flame photometric procedure, de- 19.4 In the final report of the density value, indicate which
scribed in Test Methods C114, except that the standard test method was used in measuring density.
solutions shall be made up to contain 8 mL of calcium chloride
(CaCl2) stock solution per litre of standard solution, and the FINENESS, AMOUNT RETAINED WHEN WET-SIEVED ON
solution as prepared shall be used in place of the solution of A45-µm (NO. 325) SIEVE
cement.
20. Procedure
NOTE 8—The standard solutions made up with 8 mL of calcium
chloride (CaCl2) stock solution contain the equivalent of 504 ppm of CaO. 20.1 Determine the amount of the sample retained when
Tests have shown that this amount closely approximates the amount of wet-sieved on a 45-µm (No. 325) sieve, in accordance with
calcium dissolved in the test solution. Test Method C430, with the following exceptions.

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 C311/C311M − 13
20.1.1 Calibrate the 45-µm (No. 325) sieve using a cement Control Mix Test Mix
standard (SRM 114). Calculate the sieve correction factors as Portland cement, g 500 500
Fly ash or natural None 125
follows: pozzolan, g
Graded standard 1375 1250
sand, g
CF 5 std 2 obs (5) Water sufficient to produce a flow of 100 to 115 %

where:
CF = the sieve correction factor, %, (include a negative
sign when appropriate), 22. Procedure
std = the certified residue value for the SRM, %, and
obs = the observed residue value for the SRM, %. 22.1 Cure and measure the test specimens in accordance
with Test Method C157/C157M, except that the moist-curing
20.1.2 Calculate the fineness of the fly ash or natural period (including the period in the molds) shall be 7 days, and
pozzolan to the nearest 0.1 % as follows: the comparator reading at the age of 24 6 1⁄2 h shall be omitted.
Immediately after taking the comparator reading at the end of
R C 5 R S 1CF (6) the 7-day moist-curing period, store the specimens in accor-
dance with Test Method C157/C157M, and after 28 days of air
where: storage, take a comparator reading for the specimens in
RC = corrected sieve residue, %, accordance with Test Method C157/C157M.
RS = observed residue for the test sample, %, and
CF = the sieve correction factor, %. 23. Calculation and Report
If the residue retained for the test sample is equal to zero 23.1 Calculate the increase in drying shrinkage of the
(RS = 0), then the sieve correction factor shall not be added to mortar bars, Si, as follows:
the test result to calculate the corrected sieve residue. In such
cases, the corrected fineness shall be reported as zero. Si 5 St 2 Sc (7)
NOTE 9—Test Method C430 has been adopted for testing fly ash where:
fineness. However, certain requirements, such as cleaning of sieves and
interpretation of the test results, are sometimes not appropriate for fly St = average drying shrinkage of the test specimens calcu-
ashes. lated as follows, and
Sc = average drying shrinkage of the control specimens
20.2 Numerical examples for calibrating a fineness sieve
calculated as follows:
and calculating the corrected fineness.
20.2.1 Calibrating a fineness sieve (NIST standard reference @ initial CRD 2 CRD# 3 100
S5 (8)
material SRM 114p was used in this example): G

Certified residue retained on a 45 2 µm sieve where:

5 8.24 % ~ obtained from standard certificateS! = drying shrinkage of test or control specimens,
%,
Measured residue retained on a 45 2 µm sieve
initial CRD = difference between the comparator reading of
5 7.12 % ~ measured in the laboratory! the specimen and the reference bar at 7 days
Correction factor ~ CF! 5 standard value ~ std! 2 observed value ~ obs! of moist curing,
5 8.24 2 7.12 5 1.12 % CRD = difference between the comparator reading of
the specimen and the reference bar at 28 days
20.2.2 Calculating a corrected fineness value for a cali- of drying, and
brated sieve (fly ash A was used in this example): G = the gage length of the specimens 250 mm (10
Amount of fly ash A retained on the sieve:R s in.).
5 15.2 % ~ expressed as a % of sample mass! 23.2 Report the results to the nearest 0.01. If the average
drying shrinkage of the control specimens is larger than the
Corrected sieve residue for fly ash A:R c 5 R s 1CF 5 15.211.12
average drying shrinkage of the test specimens, prefix a minus
5 16.3 % sign to the increase of drying shrinkage of mortar bars
INCREASE OF DRYING SHRINKAGE OF MORTAR BARS reported.
SOUNDNESS
21. Test Specimen
21.1 Prepare test specimens in accordance with the proce- 24. Procedure
dures described in Test Method C157/C157M, except mold 24.1 Conduct the soundness test in accordance with Test
three mortar bars from both the control mix and the test mix Method C151, except that the specimens shall be molded from
using the following proportions: a paste composed of 25 parts by mass of fly ash or natural
pozzolan and 100 parts by mass of a portland cement conform-
ing to Specification C150.

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 C311/C311M − 13
AIR-ENTRAINMENT OF MORTAR STRENGTH ACTIVITY INDEX WITH PORTLAND CEMENT

25. Procedure 27. Specimens

25.1 Using portland cement conforming to the requirements 27.1 Mold the specimens from a control mixture and from a
for Type I or Type II of Specification C150, prepare a test test mixture in accordance with Test Method C109/C109M.
mixture in accordance with Test Method C185, using the The portland cement used in the Strength Activity Index test
following proportions: shall comply with the requirements of Specification C150 and
Test Mix with the alkali and strength limits given in the section on
Portland cement, g 300 Materials. In the test mixture, replace 20 % of the mass of the
Fly ash or natural pozzolan 75 amount of cement used in the control mixture by the same mass
20–30 standard sand, g 1125
Water, mL, sufficient to give a flow of 80 to 95 Y of the test sample. Make six-cube batches as follows:
Neutralized Vinsol resin solution, mL,A sufficient Z 27.1.1 Control Mixture:
to produce an air content of 18 ± 3 %
A
The amount of Vinsol resin solution used shall be considered as part of
the mixing water.
500 g of portland cement
1375 g of graded standard sand
242 mL of water
25.2 The neutralized Vinsol resin solution used in this
section on Air-Entrainment of Mortar shall be either a com-
mercial neutralized Vinsol resin solution or a neutralized
27.1.2 Test Mixture:
Vinsol resin solution prepared in accordance with Specification
C226. If it is necessary to dilute either of these solutions, use
distilled or demineralized water. (Note 10.)
400 g of portland cement
NOTE 10—Dissolved minerals in drinking water may precipitate Vinsol 100 g of test sample
resin solutions and greatly diminish its air-entraining characteristics. 1375 g of graded standard sand
mL of water required for flow ± 5 of control mixture
25.3 Prepare two test mixtures with sufficient neutralized
Vinsol resin to produce an air content of 15 to 18 % in the first
mix and 18 to 21 % in the second mix. Then, determine by
interpolation the amount of Vinsol resin, expressed as mass 27.2 Number of Specimens:
percent of the cement, required to produce an air content of 27.2.1 Since Specification C618 specifies that “meeting the
18 %. 7 day or 28 day Strength Activity Index will indicate specifi-
cation compliance” only one age might be required. At the
26. Calculation option of the producer or the user after preparing six-cube
batches, only three cubes of control and test mixtures need to
26.1 Calculate the air content of the test mixtures as be molded for either 7 or 28 day testing.
follows:
28. Storage of Specimens
Air content, volume % 5 100@ 1 2 ~ W a /W c !# (9)
28.1 After molding, place the specimens and molds (on the
W a 5 W/400 (10) base plates) in the moist room or closet at 23.0 6 2.0 °C
300111251751 ~ 300 3 P 3 0.01! [73.4 6 3 °F] for 20 to 24 h. While in the moist room or closet,
Wc 5 (11)
FS D S D S D S
300
3.15
1
1125
2.65
1
75
D
1
300 3 P 3 0.01
1 DG protect the surface from dripping water. Remove the molds
from the moist room or closet and remove the cubes from the
molds. Place and store the cubes in saturated lime water as
where:
specified in Test Method C109/C109M.
Wa = actual mass per unit of volume of mortar as determined
by Test Method C185, g/mL, NOTE 11—Take care to ensure against zones of stratification or pockets
W = mass of the specified 400 mL of mortar (see Test of variation in temperature in the curing chamber.
Method C185), g,
Wc = theoretical mass per unit of volume, calculated on an 29. Compressive Strength Test
air-free basis and using the values for density and 29.1 Determine the compressive strength, as specified in
quantities of the materials in the mix, g/mL, Test Method C109/C109M, of three specimens of the control
P = percentage of mixing water plus Vinsol resin solution mixture and three specimens of the test mixture at ages of 7
based on mass of cement, and days, or 28 days, or both, depending upon how many speci-
D = density of fly ash or natural pozzolan in the mixture,
mens were molded as prescribed in the section on Number of
Mg/m3.
Specimens.

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 C311/C311M − 13
30. Calculation 33. Report
30.1 Calculate the strength activity index with portland 33.1 Include in the report for each test mixture comparison
cement as follows: made:
33.1.1 The 14 day expansion of the test mixture as a percent
Strength activity index with portland cement = of the control mixture at that age,
(A/B) × 100 (11) 33.1.2 The identification and chemical analysis of the fly
ash or natural pozzolan,
33.1.3 The mass percentage of fly ash or natural pozzolan
where: based on the total mass of cement plus fly ash or natural
A = average compressive strength of test mixture cubes, pozzolan in the test mixture, and
MPa (psi), and 33.1.4 The alkali content of control and test mixture ce-
B = average compressive strength of control mix cubes, ments as equivalent alkali (Na2O + 0.658 K2O).
MPa (psi).
EFFECTIVENESS OF FLY ASH OR NATURAL POZZOLAN
IN CONTRIBUTING TO SULFATE RESISTANCE

WATER REQUIREMENT 34. Procedure

34.1 Compare the length change of mortar bars with abso-
31. Calculation lute expansion limits or compare the length change of mortar
31.1 Calculate the water requirement for the Strength Ac- bars made with a control cement with the length change of
tivity Index with Portland Cement as follows: mortar bars made with fly ash or natural pozzolan and a test
cement, in accordance with Test Method C1012, as modified in
Water requirement, percentage of control = the following paragraphs. Results shall be evaluated using
(Y/242 × 100) (12) absolute limits (Procedure A) or the relative expansion limits
where: (Procedure B) in Specification C618, Table 2A.
Y = water required for the test mixture to be 65 of control
34.2 Control Mixture for Procedure A—A control mixture is
flow.
not mandatory since performance measured using Procedure A
EFFECTIVENESS OF FLY ASH OR NATURAL POZZOLAN is based on maximum expansion of the test mixture. If a
IN CONTROLLING ALKALI SILICA-REACTIONS (SEE control mixture is made for Procedure A then proportion it as
Appendix X1) required in Test Method C1012 using a cement meeting the
requirements of Specification C150, Type II or Type V.
32. Procedure
34.3 Test Mixture Using Fly Ash or Natural Pozzolan for
32.1 Determine expansion of mortar made with a fly ash or Procedure A—Make the combined quantity of cement plus fly
natural pozzolan and a test cement as a percent of expansion of ash or natural pozzolan, by mass, the same as the total cement
mortar made with low alkali cement in accordance with Test content of the control mixture described in the Making Mortars
Method C441 as modified in the following paragraphs: section of Test Method C1012. The proportion of fly ash or
32.1.1 Control Mixture— The control mixture will be made natural pozzolan may be varied using from 15 % to 50 %, by
as required in Test Method C441 except that the control cement mass, of the total cement plus fly ash or natural pozzolan. Any
shall have an alkali content (as equivalent Na2O) less than type of portland cement may be used to prepare test mixtures.
0.60 % (Note 12).
34.4 Control Mixture for Procedure B—Make the control
NOTE 12—Generally, the control cement should have an alkali content mixture for Procedure B as required in Test Method C1012
as equivalent Na2O between 0.50 and 0.60 %. However, lower alkali with the cement that is proposed for use in the project or a
control cement may be used, if desired, to demonstrate equivalence.
cement that through performance or definition (Specification
32.1.2 Test Mixture Using Fly Ash or Natural Pozzolan— C150, Section 1) is expected to give satisfactory results (or a
The combined quantity of cement plus fly ash or natural cement for which the contribution to sulfate resistance is
pozzolan shall total 400 g (see Appendix X1). Use 900 g of known and is satisfactory).
borosilicate glass aggregate and sufficient mixing water to
produce a flow between 100 and 115 % as determined in NOTE 14—The control cement should be chosen to give sulfate
accordance with Test Method C1437. The cement used in the resistance for the expected level of sulfate exposure. Experience has
shown that Type II cements are often used for moderate levels of
test mixture shall have an alkali content greater than that of the exposure. Type V cement is commonly used for severe exposures (see
cement in the control mixture (Note 13). X2.2 of Appendix X2).
NOTE 13—Generally, this test cement will have an alkali content equal 34.5 Test Mixture for Using Fly Ash or Natural Pozzolan for
to or higher than that used in the job. Procedure B—Make the combined quantity of cement plus fly
32.1.3 Store and measure specimens as required in Test ash or natural pozzolan, by mass, the same as the total cement
Method C227. Measure length of specimens at ages of 1 and 14 used in the control mixture. The proportion of fly ash or natural
days. pozzolan may be varied from 15 % to 50 % of the total cement

Copyright by ASTM Int'l (all rights reserved); 7

 C311/C311M − 13
plus fly ash or natural pozzolan by mass. Any type of portland 36.1.2 The single-operator standard deviation for the
cement may be used to prepare test mixtures. Strength Activity Index test has been found to be 3.7 % (1s).
34.6 For either Procedure A or B, store and measure This does not appear to vary either with material or with test
specimens as required in Test Method C1012 for at least 6 age, over the range of 7 to 28 days. Therefore, results of two
months. properly conducted tests by the same operator on the same
material should not differ by more than 10.5 % (d2s) of the
NOTE 15—Evaluation of the sulfate resistance of cementitious materials average of the two results.
for use in certain situations or critical structures may require longer
periods of storage and additional length measurements. Refer to Test
36.1.3 The multilaboratory standard deviation for the
Method C1012 for guidance on this matter. Strength Activity Index test has been found to be 4.5 % (1s).
This does not appear to vary either with material or with test
35. Report age, over the range of 7 to 28 days. Therefore, results of two
35.1 In addition to the information required in Test Method properly conducted tests in different laboratories on the same
C1012, report the following information for each mixture material should not differ by more than 12.7 % (d2s) of the
comparison made: average of the two results.
36.1.4 Since there is no accepted reference material suitable
35.2 For Procedure A, the age and expansion as a specific
for determining the bias for this procedure, no statement on
amount,
bias is being made.
35.3 For Procedure B, the age and expansion as a percent of
36.2 Chemical Analysis:
the control mixture at that age,
36.2.1 Precision and bias estimates for the test methods in
35.4 The identification and chemical analysis including C3A Test Methods C114 when applied to the analysis of pozzolans
content of the cements used in both the control and test were calculated from an interlaboratory study involving 7
mixtures, laboratories each analyzing 4 NIST SRM fly ashes. A research
35.5 The identification and chemical analysis of the fly ash report describing the results of this study is available from
or natural pozzolan used in the test mixtures, ASTM.5
36.2.2 Precision—Within-laboratory (W/L) and between-
35.6 The mass percentages of the fly ash or natural pozzolan
laboratory (B/L) estimates of standard deviation and estimates
based on the total mass of cement plus fly ash or natural
of maximum differences expected between duplicate determi-
pozzolan in the test mixture.
nations in 95 % of comparisons6 are summarized in Table 2.
PRECISION AND BIAS 36.2.3 Bias—Statistically significant bias was found in the
determination of CaO and MgO. CaO determinations averaged
36. Precision and Bias 0.46 % higher than the value certified for the SRM. MgO
36.1 Strength Activity Index Test: determinations averaged 0.19 % higher than the value certified
36.1.1 Precision was determined from two interlaboratory for the SRM.
studies involving two Class C fly ashes, two Class F fly ashes, 36.3 Ammonia:
and one Class N pozzolan. Participating laboratories numbered 36.3.1 Precision of Method A (Direct Nesslerization)—The
12 and 7 in the two studies.4 single-laboratory coefficient of variation (repeatability) has
been found to be 9.2 % (1s %). The reproducibility of this test
4
Supporting data have been filed at ASTM International Headquarters and may method is being determined.
be obtained by requesting Research Report RR:C09-1001. 36.3.2 Precision of Method B (Selective Ion Electrode)—
The single-laboratory coefficient of variation (repeatability)
TABLE 2 Within and Between Lab Precision Estimates for C114 has been found to be 7.4 % (1s %). The reproducibility of this
Methods Applied to the Analysis of Fly AshA test method is being determined.
1s d2s 36.3.3 Bias—Since there is no accepted reference material
Oxide
W/L B/L W/L B/L suitable for determining the bias for these procedures, no
SiO2 0.62 0.86 1.75 2.45 statement on bias is being made.
Al2O3 1.46 2.29 4.12 6.48
Fe2O3
<2 % 0.12 0.11 0.34 0.31 37. Keywords
$2 % 0.12 0.25 0.34 0.71
CaO 0.63 0.74 1.79 2.09 37.1 fly ash; natural pozzolan
MgO 0.20 0.21 0.55 0.61
SO3 0.10 0.16 0.28 0.45
Moisture 0.05 0.06 0.15 0.17
LOI 0.09 0.12 0.25 0.35 5
Supporting data have been filed at ASTM International Headquarters and may
A
The four values for SO3 were editorially corrected to reflect updated research be obtained by requesting Research Report RR:C09-1008.
6
reports associated with this standard. These values represent, respectively, the (1s) and (d2s) limits as described in
Practice C670.

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 C311/C311M − 13
APPENDIXES

(Nonmandatory Information)

X1. COMMENTARY ON SECTION 32

X1.1 Test procedures in Section 32 are designed to deter- delineate any increase in expansion. The fly ash or natural
mine the effectiveness of fly ash, or natural pozzolan, in pozzolan percentage used may need to be sufficiently high to
preventing excessive expansion resulting from a reaction demonstrate that the percentage exceeds the pessimum if such
between certain aggregates and alkalies in portland-cement pessimum exists for the combination.
mixtures. Tests are made in accordance with Test Method C441
using: X1.6 Selection of the Low Alkali Control Cement—The test
X1.1.1 400 g of portland cement or a combined total of procedure in this test method and requirements in Specification
cement plus fly ash or natural pozzolan of 400 g, C618 are designed to measure the relative effectiveness of the
fly ash or natural pozzolan in reducing expansion due to
X1.1.2 900 g of borosilicate glass, and alkali-silica reactions. The effectiveness is a function of both
X1.1.3 Sufficient water to obtain a flow of 100 to 115 %. the alkali content of the cement used in the test mixture and the
percentage of fly ash or natural pozzolan. The higher the alkali
X1.2 The control mixture is made with a low-alkali portland content of the test mixture cement and the lower the percentage
cement. The test mixture, made of a test percentage of the fly of fly ash or natural pozzolan used, the more effective the fly
ash or natural pozzolan, can be made with the same cement or ash or natural pozzolan. This test procedure and the 100 %
any other cement having an equivalent alkali content greater criterion of Specification C618 can be used as a guide to
than 0.60 %. enhance field performance of job mixtures if it is assumed that
X1.3 Interpretation of Results—The fly ash or natural use of the low alkali control cement will prevent excessive
pozzolan should be considered “effective” when used at expansion in service with materials proposed for use in the job.
percentages equal to or greater than the percentages used in the This is the situation when the aggregates proposed for use
test mixture with cements having alkali contents that do not contain rapidly reactive constituents but do not exceed 0.05 %
exceed by more than 0.05 percentage points the alkali content expansion in three months or 0.10 % expansion in six months
of the cement used in the test mixture. when tested with the control cement in Test Method C227. In
such instances the control cement used in this test method
X1.4 Selection of the Percentage of Fly Ash or Natural should have an alkali content as required to control the
Pozzolan—It may be necessary to make test mixtures with expansive reactions of the aggregates being used, for example
several percentages of fly ash or natural pozzolan to determine in the 0.50 to 0.60 % range. See the appendix to Specification
the minimum amount necessary to be considered “effective” in C33.
reducing expansion to the level produced by the “control”
low-alkali cement. The minimum amount of fly ash or natural X1.6.1 Certain reactive aggregates have been identified
pozzolan should be 15 % by mass of cementitious material. which produce deleterious expansion after many years of
service when used with cements with equivalent alkali contents
X1.5 Selection of the Alkali Content of the Cement Used in well below 0.60 %. Often these reactive aggregates do not
the Test Mixture—In some instances it may not be necessary to produce expansions in Test Method C227 exceeding those
demonstrate that the fly ash or natural pozzolan will reduce discussed in the appendix of Specification C33 until a much
expansion, but rather that it will not increase expansion. In this later age, perhaps one or two years. In such instances the use
instance the test and control mixtures should be made with the of a control cement with an alkali content significantly less
same low alkali cement used in the control mixture to better than 0.60 % is appropriate.

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 C311/C311M − 13

X2. COMMENTARY ON SECTION 34

X2.1 The test procedures in Section 34 are designed to addition of fly ash or natural pozzolan influences sulfate
evaluate the performance of particular fly ashes or natural resistance. However, as referenced in Test Method C1012,
pozzolans in contributing to the resistance or durability of research has indicated that mortars meeting the expansion
concrete in a sulfate environment. Tests are made on mortars in criteria will perform adequately. Under Procedure B, the fly ash
accordance with Test Method C1012. or natural pozzolan will be considered to be able to contribute
to sulfate resistance if the expansion of the test mixture does
X2.2 The control mixture should be made with a cement
not exceed that of the control mixture at an exposure time of at
that by performance or definition (Specification C150, Section
least 6 months. It is recommended that the proportion of fly ash
1.1) is expected to give satisfactory results for the anticipated
or natural pozzolan used in the test mixture be the same one
level of sulfate exposure. ACI 201.2R recommends Type II
cement when the sulfate content, expressed as SO4, is 0.10 to proposed for use in the project 6 2 %, and that the C3A content
0.20 percent in soils or 150 to 1500 ppm in waters. ACI 201.2R of the project cement be equal to, or less than, that which was
recommends Type V cements when the sulfate content, ex- used in the test mixtures. See Appendix X1, Technical
pressed as SO4, is 0.20 to 2.0 % in soils, or 1500 to 10 000 ppm Background, Test Method C1012.
in waters. The test mixtures for both procedures may be made
X2.4 Selection of the Percentage of Fly Ash or Natural
with varying percentages of fly ash or natural pozzolan. Test
Pozzolan—It may be necessary to make test mixtures with
mixtures can use cements with equal or higher or lower C3A
several percentages of fly ash or natural pozzolan to determine
contents that might not have given satisfactory results when
used alone. the amount necessary to obtain adequate resistance to different
concentrations of sulfates. Percentages used in a project should
X2.3 Interpretation of Results—The absolute expansion be within 2 % of those that are successful in the test mixtures
limits used in Procedure A make it difficult to ascertain how the or should be between two percentages that are successful.

SUMMARY OF CHANGES

Committee C09 has identified the location of selected changes to these test methods since the last issue,
C311–11b, that may impact the use of these test methods. (Approved February 1, 2013)

(1) Section 1.3 was revised to conform to a combined standard. (4) Revised standard temperature and drying oven tempera-
(2) The term “weight” is replaced with “mass” where used in tures to agree with C09 standards. Other temperatures are
the standard. expressed in SI only.
(3) Standard room and drying temperatures defined by C09.95
coordination document are inserted where needed. Other tem-
peratures are expressed in SI only.

Committee C09 has identified the location of selected changes to these test methods since the last issue,
C311–11a, that may impact the use of these test methods. (Approved December 1, 2011)

(1) Revised Section 3 Terminology.

(2) Revised 4.1 by including a reference to Specification
C1697.

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