ASTM C311/C311M-24

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: C311/C311M − 22 C311/C311M − 24
Standard Test Methods for
Sampling and Testing FlyCoal Ash or Natural Pozzolans for
Use in Portland-Cement Concrete
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 U.S. Department of Defense.
1. Scope*
1.1 These test methods cover procedures for sampling and testing flycoal ash and raw or calcined pozzolans for use in
portland-cement concrete.
1.2 The procedures appear in the following order:
Sections
Sampling 7
CHEMICAL ANALYSIS
Reagents and apparatus 10
Moisture content 11 and 12
Loss on ignition 13 and 14
Silicon dioxide, aluminum oxide, iron oxide,
calcium oxide, magnesium oxide, sulfur
trioxide, sodium oxide and potassium
oxide
Available alkali 16 and 17
Ammonia 18
PHYSICAL TESTS
Density 19
Fineness 20
Increase of drying shrinkage of mortar bars 21 – 23
Soundness 24
These test methods are under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and are the direct responsibility of Subcommittee C09.24
on Supplementary Cementitious Materials.
Current edition approved Feb. 1, 2022Jan. 1, 2024. Published February 2022February 2024. Originally approved in 1953. Last previous edition approved in 20182022
as C311/C311M – 18.C311/C311M – 22. DOI: 10.1520/C0311_C0311M-22.10.1520/C0311_C0311M-24.
*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
C311/C311M − 24
Air-entrainment of mortar 25 and 26
Strength activity index with portland cement 27 – 30
Strength activity index 27 – 30
Water requirement 31
Effectiveness of Fly Ash or Natural Pozzolan in
Controlling Alkali-Silica Reactions
Effectiveness of Coal Ash or Natural Pozzolan in
Controlling Alkali-Silica Reactions
Effectiveness of Fly Ash or Natural Pozzolan in
Contributing to Sulfate Resistance
Effectiveness of Coal Ash or Natural Pozzolan in
Contributing to Sulfate Resistance
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
NOTE 1—Sieve size is identified by its standard designation in Specification E11. The alternative designation given in parentheses is for information only
and does not represent a different standard sieve size.
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.
1.5 The text of this standard references notes and footnotes that provide explanatory information. These notes and footnotes
(excluding those in tables) shall not be considered as requirements of this standard.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C109/C109M Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 50 mm [2 in.] Cube Specimens)
C114 Test Methods for Chemical Analysis of Hydraulic Cement
C125 Terminology Relating to Concrete and Concrete Aggregates
C150/C150M Specification for Portland Cement
C151/C151M Test Method for Autoclave Expansion of Hydraulic Cement
C157/C157M Test Method for Length Change of Hardened Hydraulic-Cement Mortar and Concrete
C185 Test Method for Air Content of Hydraulic Cement Mortar
C188 Test Method for Density of Hydraulic Cement
C204 Test Methods for Fineness of Hydraulic Cement by Air-Permeability Apparatus
C219 Terminology Relating to Hydraulic and Other Inorganic Cements
C226 Specification for Air-Entraining Additions for Use in the Manufacture of Air-Entraining Hydraulic Cement
C227 Test Method for Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method) (Withdrawn 2018)
C430 Test Method for Fineness of Hydraulic Cement by the 45-μm (No. 325) Sieve
C441/C441M Test Method for Effectiveness of Pozzolans or Ground Blast-Furnace Slag in Preventing Excessive Expansion of
Concrete Due to the Alkali-Silica Reaction
C595/C595M Specification for Blended Hydraulic Cements
C604 Test Method for True Specific Gravity of Refractory Materials by Gas-Comparison Pycnometer
C618 Specification for Coal Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
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 the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
C311/C311M − 24
C778 Specification for Standard Sand
C1012/C1012M Test Method for Length Change of Hydraulic-Cement Mortars Exposed to a Sulfate Solution
C1437 Test Method for Flow of Hydraulic Cement Mortar
C1697 Specification for Blended Supplementary Cementitious Materials
D1426 Test Methods for Ammonia Nitrogen In Water
D4326 Test Method for Major and Minor Elements in Coal Ash By X-Ray Fluorescence
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
2.2 ACI Document:
ACI 201.2R Guide to Durable Concrete
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, refer to Terminology C125 and Terminology C219.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 bottom ash, n—ash that results from the process of combustion of ground or powdered coal that is not transported by 24 flue
gases.
3.2.1.1 Discussion—
This definition of bottom ash does not include the residue resulting from: (1) fluidized bed combustion, (2) the burning of
municipal solid waste or any other refuse with coal, or (3) the burning of industrial or municipal solid waste in incinerators.
3.2.2 coal ash, n—fly ash and bottom ash resulting from the process of combustion of ground or powdered coal obtained either
from current power plant production or harvested from landfills or impoundments.
3.2.3 composite sample, n—a sample that is constructed by combining equal portions of grab or regular samples.
3.2.4 established source, n—a source for which at least six months of continuous production quality assurance records from a test
frequency required for a new source are available, sampled at the source.
3.2.5 grab sample, n—a sample that is taken in a single operation from a conveyor delivering to bulk storage, from bags, or from
a bulk shipment.
3.2.5.1 Discussion—
A grab sample may or may not reflect the composition or physical properties of a single lot of flycoal ash or natural pozzolan. This
type of sample can be used to characterize small amounts of material.
3.2.6 new source, n—a source for which less than six months of production records are available, sampled at the source.
3.2.7 regular sample, n—a sample that is constructed by combining equal portions of grab samples that were taken at
predetermined times or locations from any single lot of material.
4. Significance and Use
4.1 These test methods are used to develop data for comparison with the requirements of Specification C618 or Specification
C1697. These test methods are based on standardized testing in the laboratory and are not intended to simulate job conditions.
4.1.1 Strength Activity Index—The test for strength activity index is used to determine whether flycoal ash or natural pozzolan
results in an acceptable level of strength development when used with hydraulic cement in concrete. Since the test is performed
with mortar, the results may not provide a direct correlation of how the flycoal ash or natural pozzolan will contribute to strength
in concrete.
4.1.2 Chemical Tests—The chemical component determinations and the limits placed on each do not predict the performance of
a flycoal ash or natural pozzolan with hydraulic cement in concrete, but collectively help describe composition and uniformity of
the material.
Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI 48333-9094, http://www.aci-int.org.
C311/C311M − 24
5. Materials
5.1 Graded Standard Sand—The sand used for making test specimens for the activity index with lime or portland cement shall
be natural silica sand conforming to the requirements for graded standard sand in Specification C778.
NOTE 2—Segregation of Graded Sand—The graded standard sand 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 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 of which the coarser particles will roll. Bins should be of sufficient size to permit these precautions.
Devices for drawing the sand from bins by gravity should not be used.
5.2 Hydrated Lime—The hydrated lime used in the tests shall be reagent-grade calcium hydroxide, 95 % minimum calculated as
Ca(OH) (Note 3), and have a minimum fineness of 2500 m /kg as determined in accordance with Test Method C204.
NOTE 3—The calcium hydroxide should be protected from exposure to carbon dioxide. Material remaining in an opened container after a test should not
be used for subsequent tests.
5.3 Portland Cement—The portland cement used in the Strength Activity Index with Portland Cement test cement used for all tests
shall comply with the requirements of Specification C150/C150M Type I or II or the requirements for Specification C595/C595M
Type IL and have a minimum compressive strength of 35 MPa (5000 psi) at 28 days and total equivalent alkalies (Na O + 0.658
K O) not less than 0.50 % nor more than 0.80 %. The specification, type, producer, and source of the cement shall be included with
the results of tests that involve cement.
NOTE 4—The results from test methods that involve the use of cement may vary depending on the type, producer, or source of the cement used. This
potential variation should be considered if comparing with previous test results obtained using a different cement.
5.3.1 The use of a locally available portland cement in the Strength Activity Index or a project cement that does not meet the
requirements of the section on Materials is permitted when the variations from the requirements of the section on Materials are
reported and when the use of such portland cement is requested. The specification, type, producer, and source of the cement shall
be included with the results of tests that involve cement.
6. Sample Type and Size
6.1 Grab samples and regular samples shall have a mass of at least 2 kg (4 lb).
6.2 Grab samples or regular samples taken at prescribed intervals over a period of time (see Table 1), may be combined to form
a composite sample representative of the flycoal ash or natural pozzolan produced during that period of time.
6.3 Composite samples shall have a mass of at least 4 kg (8 lb).
6.4 The sampling shall be done by, or under the direction of, a responsible representative of the purchaser.
A
TABLE 1 Minimum Sampling and Testing Frequency
Jobsite or New Established
Test Sample Type
B B
Source Source
Moisture content Regular Daily or each Daily or each
c C
Loss on ignition 90 Mg 360 Mg
(400 Tons)
Fineness (100 Tons)
Density and the Composite Monthly or each Monthly or each
C C
other tests in 1 800 Mg 2 900 Mg
(2 000 Tons) (3 200 Tons)
Specification
C618, Tables 1
and 2
A
It should be noted that the minimum test frequency given in Table 1 is not
necessarily the frequency needed for quality control programs on some flycoal ash
or natural pozzolans.
B
For definitions, refer to the Terminology section.
C
Whichever comes first.
C311/C311M − 24
7. Sampling Procedure
7.1 The flycoal ash or natural pozzolan may be sampled by any one of the following methods:
7.1.1 From Bulk Storage at Point of Discharge or from Rail Cars and Road Tankers—A sample may be taken by siphon tube
during loading or by sampling tube from each loaded car 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 depth of at least 200 mm (8 in.) before sampling. The sample shall be identified
with at least the date and shipment number.
7.1.2 From Bags in Storage—The regular sample shall comprise increments of equal size taken by sampling tube from three bags
selected at random from one lot of bagged material. The sample shall be identified with date and lot number.
7.1.3 From Conveyor Delivering to Bulk Storage—Take one 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 in a single operation, known as the grab sample method, or by
combining several equal portions taken at regular intervals, known as the regular sample method. Automatic samplers may be used
to obtain samples.
7.2 Samples shall be treated as described in Section 8.
NOTE 5—Some methods of loading or delivery of flycoal ash or natural pozzolan, particularly from an airstream or conveyor belt, may create stratification
or segregation in the material stream. Sampling techniques must be designed to ensure that the sample is representative of the material shipped.
8. Preparation and Storage of Samples
8.1 Prepare composite samples for the tests required in Section 9, by arranging all grab or regular samples into groups covering
the period or quantity to be represented by the sample. Take equal portions from each, sufficient to produce a composite sample
large enough for the tests required. Mix the composite sample thoroughly.
8.2 Samples shall be stored in clean, airtight containers identified with the source and lot or period of time represented. Untested
portions of the sample shall be retained for at least one month after all test results have been reported.
9. Testing Frequency
9.1 General—When required, the purchaser shall specify the amount of testing for available alkalies, reactivity with cement
alkalies, drying shrinkage, and air-entrainment. Make all other tests on regular or composite samples chosen as specified in Table
1.
CHEMICAL ANALYSIS
10. General
10.1 All apparatus, reagents and techniques shall comply with the requirements of Test Methods C114.
10.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean distilled water or water of equal
purity.
MOISTURE CONTENT
11. Procedure
11.1 Dry a weighed sample, as received, to constant mass in an oven at 110 °C 6 5 °C [230 °F 6 10 °F].
12. Calculation
12.1 Calculate the percentage of moisture to the nearest 0.1 %, as follows:
C311/C311M − 24
Moisture content,%5 A/B ×100 (1)
~ !
where:
A = mass loss during drying, and
B = mass as received.
LOSS ON IGNITION
13. Procedure
13.1 Using a representative sample of material remaining from the determination of moisture content, determine loss on ignition
by the procedure described below:
13.1.1 Determine the tare mass of a clean, cool, uncovered, porcelain crucible, and record the tare mass of the crucible (A) to the
nearest 0.0001 g.
NOTE 6—The tare mass of crucibles should be determined by preheating the empty crucible to constant mass at the same temperature and under the same
conditions as used for the final ignition of a residue, and cooling in a desiccator for the same period of time used for the crucible containing the residue.
13.1.2 In the crucible, place an amount of material between 0.5 and 4 g and record the combined mass of the crucible and material
(B) to the nearest 0.0001 g.
13.1.3 Ignite the crucible and material to constant mass in a furnace at 750 6 50 °C. Constant mass shall be obtained by any of
the following methods: 1) firing for 45 minutes, 2) successive firings until constant mass is established by measuring the loss
between two successive firings. When using successive firings, the initial firing duration shall be at least 15 minutes and subsequent
firings at least 5 minutes in duration. The loss after each firing is calculated using the equation given in 14.1 and the difference
between two successive firings shall be less than 0.1 % for the mass to be considered constant.
13.1.4 Remove the crucible at the end of ignition and allow it to cool in a desiccator to room temperature. Measure and record
the final mass of the crucible and material (C) to the nearest 0.0001 g.
14. Calculation
14.1 Calculate the percentage of loss on ignition to the nearest 0.1 %, as follows:
B 2 C
Loss on ignition, % 5 ×100 (2)
S D
B 2 A
where:
A = tare mass of crucible,
B = mass of moisture-free material and crucible, and
C = mass of ignited material and crucible.
SILICON DIOXIDE, ALUMINUM OXIDE, IRON OXIDE, CALCIUM OXIDE, MAGNESIUM OXIDE, SULFUR TRIOXIDE,
SODIUM OXIDE AND POTASSIUM OXIDE
15. Procedure
15.1 Determine the percentages of these oxides as required in accordance with the applicable sections of Test Methods C114 for
materials having an insoluble residue greater than 1 % (Note 67). Analysts performing sodium oxide and potassium oxide
determinations shall observe the precautions outlined in the applicable section of Test Methods C114. Most pozzolans dissolve
completely in lithium borate fluxes.
NOTE 7—Rapid and instrumental methods may be employed similar to those in Test Methods C114 and D4326.
C311/C311M − 24
AVAILABLE ALKALI
16. Procedure
16.1 Weigh 5.0 g of the sample and 2.0 g of hydrated lime on a piece of weighing paper, carefully mix using a metal spatula, and
transfer to a small plastic vial of approximately 25 mL capacity. Add 10.0 mL of water to this mixture, seal the vial by securing
the cap or lid to the vial with tape (Note 78), blend by shaking until the mixture is uniform, and store at 38 °C 6 2 °C.
NOTE 8—To ensure that moisture loss from the paste does not occur, place the sealed vial in a sealable container (such as a small sample or mason jar),
add sufficient water to cover the bottom of the container, and seal.
16.2 Open the vial at the age of 28 days and transfer the contents to a 250 mL casserole. Break up and grind the cake with a pestle,
adding a small amount of water, if necessary, so that a uniform slurry containing no lumps is obtained (Note 89). Add sufficient
water to make the total volume 200 mL. Let stand 1 h at room temperature with frequent stirring. Filter through a medium-textured
filter paper onto a 500 mL volumetric flask. Wash thoroughly with hot water (eight to ten times).
NOTE 9—At times it may be necessary to break the vial and peel off the 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 fragments of the vial. If the cake is too hard to break up and grind in the casserole, a mortar
should be used.
16.3 Neutralize the filtrate with dilute HCl (1 + 3), using 1 to 2 drops of phenolphthalein solution as the indicator. Add exactly
5 mL of dilute HCl (1 + 3) in excess. Cool the solution to room temperature and fill the flask to the mark with distilled water.
Determine the amount of sodium and potassium oxides in the solution using the flame photometric procedure, described in Test
Methods C114, except that the standard solutions shall be made up to contain 8 mL of calcium chloride (CaCl ) stock solution per
litre of standard solution, and the solution as prepared shall be used in place of the solution of cement.
NOTE 10—The standard solutions made up with 8 mL of calcium chloride (CaCl ) stock solution contain the equivalent of 504 ppm of CaO. Tests have
shown that this amount closely approximates the amount of calcium dissolved in the test solution.
17. Calculation and Report
17.1 Calculate the results as weight percent of the original sample material. Report as equivalent percentage of sodium oxide
(Na O), calculated as follows:
Equivalent Na O,%5 Na O,%10.658 ×K O,% (3)
2 2 2
AMMONIA
18. Procedure
18.1 Weigh 1.00 g of the flycoal ash sample into a 125-mL Erlenmeyer flask. Add 100 mL of ammonia-free water. Place a
neoprene rubber stopper on the flask and swirl the contents to thoroughly mix the sample and the water.
18.2 Filter the mixture using a medium-textured filter paper and save the filtrate for the ammonia determination.
18.3 Determine the concentration of ammonia in the filtrate in accordance with the procedures outlined in Test Methods D1426,
Method A–Direct Nesslerization or Method B–Selective Ion Electrode.
18.4 Calculate the ammonia concentration of the flycoal ash as follows:
Ammonia, mg/kg 5 N ×V /W (4)
W W fa
where:
N = ammonia concentration of the water extract determined by Test Methods D1426, mg/L,
W
C311/C311M − 24
V = volume of water used for extracting ammonia from the fly ash sample, mL, and
W
V = volume of water used for extracting ammonia from the coal ash sample, mL, and
W
W = mass of fly ash sample used in the test, g.
fa
W = mass of coal ash sample used in the test, g.
fa
PHYSICAL TESTS
DENSITY
19. Procedure
19.1 Determine the density of the sample in accordance with the procedure described in Test Method C188 or Test Method C604
as modified below.
19.2 For Test Method C188, follow the procedure except use a quantity of flycoal ash or natural pozzolan weighed to the nearest
0.05 g, of about 50 g.
19.3 For Test Method C604 use an amount of material that is appropriate for the instrument.
19.3.1 Determine the density of the material as received. Do not prepare sample as described in Section 6 of Test Method C604.
19.4 In the final report of the density value, indicate which test method was used in measuring density.
FINENESS, AMOUNT RETAINED WHEN WET-SIEVED ON A45-μm (NO. 325) SIEVE
20. Procedure
20.1 Determine the amount of the sample retained when wet-sieved on a 45 μm (No. 325) sieve, in accordance with Test Method
C430, with the following exceptions.
20.1.1 Calibrate the 45-μm (No. 325) sieve using a cement standard (SRM 114). Calculate the sieve correction factors as follows:
CF 5 std 2 obs (5)
where:
CF = the sieve correction factor, %, (include a negative sign when appropriate),
std = the certified residue value for the SRM, %, and
obs = the observed residue value for the SRM, %.
20.1.2 Calculate the fineness of the flycoal ash or natural pozzolan to the nearest 0.1 % as follows:
R 5 R 1CF (6)
C S
where:
R = corrected sieve residue, %,
C
R = observed residue for the test sample, %, and
S
CF = the sieve correction factor, %.
If the residue retained for the test sample is equal to zero
(R = 0), then the sieve correction factor shall not be added to the test result to calculate the corrected sieve residue. In such cases,
S
the corrected fineness shall be reported as zero.
NOTE 11—Test Method C430 has been adopted for testing flycoal ash fineness. However, certain requirements, such as cleaning of sieves and
interpretation of the test results, are sometimes not appropriate for flycoal ashes.
C311/C311M − 24
20.2 Numerical examples for calibrating a fineness sieve and calculating the corrected fineness.
20.2.1 Calibrating a fineness sieve (NIST standard reference material SRM 114p was used in this example):
Certified residue retained on a 45 2 μm sieve
58.24 % obtained from standard certificate
~ !
Measured residue retained on a 45 2 μm sieve
57.12 % measured in the laboratory
~ !
Correction factor ~CF!
5standard value ~std! 2 observed value ~obs!
58.24 2 7.12 5 1.12 %
20.2.2 Calculating a corrected fineness value for a calibrated sieve (fly(coal ash A was used in this example):
Amount of fly ash A retained on the sieve:R
s
515.2 % expressed as a % of sample mass
~ !
Amount of coal ash A retained on the sieve:R
s
515.2 % expressed as a % of sample mass
~ !
Corrected sieve residue for fly ash A:R
c
5R 1CF
s
515.211.12
516.3 %
Corrected sieve residue for coal ash A:R
c
5R 1CF
s
515.211.12
516.3 %
INCREASE OF DRYING SHRINKAGE OF MORTAR BARS
21. Test Specimen
21.1 The cement used in the Drying Shrinkage of Mortar Bars test shall comply with the requirements in the section on Materials
21.2 Prepare test specimens in accordance with the procedures described in Test Method C157/C157M, except mold three mortar
bars from both the control mix and the test mix using the following proportions:
Control Mix Test Mix
Portland cement, g 500 500
Cement, g 500 500
Fly ash or natural None 125
pozzolan, g
Coal ash or natural None 125
pozzolan, g
Graded standard 1375 1250
sand, g
Water sufficient to produce a flow of 100 to 115 %
22. Procedure
22.1 Cure and measure the test specimens in accordance with Test Method C157/C157M, except that the moist-curing period
(including the period in the molds) shall be 7 days, and the comparator reading at the age of 24 h 6 ⁄2 h shall be omitted.
...