ASTM C618-23e1

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.
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Designation: C618 − 23
Standard Specification for
Coal Ash and Raw or Calcined Natural Pozzolan for Use in
Concrete
This standard is issued under the fixed designation C618; 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.
ε NOTE—Editorial corrections were made to the text and Table 2 in March 2023.
1. Scope* C125 Terminology Relating to Concrete and Concrete Ag-
gregates
1.1 This specification covers coal ash and raw or calcined
C136/C136M Test Method for Sieve Analysis of Fine and
natural pozzolan, for use in concrete where cementitious or
Coarse Aggregates
pozzolanic action, or both, is desired, or where other properties
C311/C311M Test Methods for Sampling and Testing Fly
normally attributed to coal ash or natural pozzolans may be
Ash or Natural Pozzolans for Use in Portland-Cement
desired, or where both objectives are to be achieved.
Concrete
NOTE 1—Finely divided materials may tend to reduce the entrained air
C1778 Guide for Reducing the Risk of Deleterious Alkali-
content of concrete. Hence, if a coal ash or natural pozzolan is added to
Aggregate Reaction in Concrete
any concrete for which entrainment of air is specified, provision should be
made to ensure that the specified air content is maintained by air content
3. Terminology
tests and by use of additional air-entraining admixture or use of an
air-entraining admixture in combination with air-entraining hydraulic
3.1 Definitions:
cement.
3.1.1 For definitions of terms used in this specification refer
1.2 The values stated in SI units are to be regarded as
to Terminology C125.
standard. No other units of measurement are included in this
3.2 Definitions of Terms Specific to This Standard:
standard.
3.2.1 coal ash, n—fly ash and bottom ash resulting from the
1.3 The text of this standard references notes and footnotes, process of combustion of ground or powdered coal obtained
which provide explanatory information. These notes and foot- either from current power plant production or harvested from
notes (excluding those in tables and figures) shall not be
landfills or impoundments.
considered as requirements of the standard.
3.2.2 bottom ash, n—ash that results from the process of
1.4 This international standard was developed in accor-
combustion of ground or powdered coal that is not transported
dance with internationally recognized principles on standard- by flue gases.
ization established in the Decision on Principles for the
3.2.2.1 Discussion—This definition of bottom ash does not
Development of International Standards, Guides and Recom-
include the residue resulting from: (1) fluidized bed
mendations issued by the World Trade Organization Technical
combustion, (2) the burning of municipal solid waste or any
Barriers to Trade (TBT) Committee.
other refuse with coal, or (3) the burning of industrial or
municipal solid waste in incinerators.
2. Referenced Documents
2.1 ASTM Standards:
4. Classification
4.1 Class N—Raw or calcined natural pozzolans that com-
ply with the applicable requirements for the class as given
This specification is under the jurisdiction of ASTM Committee C09 on
herein, such as some diatomaceous earths; opaline cherts and
Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee
C09.24 on Supplementary Cementitious Materials.
shales; tuffs and volcanic ashes or pumicites, calcined or
Current edition approved March 1, 2023. Published March 2023. Originally
uncalcined; and various materials requiring calcination to
approved in 1968. Last previous edition approved in 2022 as C618–22. DOI:
induce satisfactory properties, such as some clays and shales.
10.1520/C0618-23E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.2 Class F—Coal ash that meets the applicable require-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
ments for this class as given herein. This class of coal ash has
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. pozzolanic properties.
*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
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C618 − 23
TABLE 1 Chemical Requirements
Class
N F C
Silicon dioxide (SiO ) plus aluminum oxide (Al O ) plus iron oxide (Fe O ), 70.0 50.0 50.0
2 2 3 2 3
min, %
Calcium oxide (CaO), % report only 18.0 max. >18.0
Sulfur trioxide (SO ), max, % 4.0 5.0 5.0
Moisture content, max, % 3.0 3.0 3.0
A
Loss on ignition, max, % 10.0 6.0 6.0
A
The use of Class F coal ash containing up to 12.0 % loss on ignition may be approved by the user if either acceptable performance records or laboratory test results are
made available.
TABLE 2 Physical Requirements
Class
N F C
Fineness:
Amount retained when wet-sieved on 45 μm (No. 325) sieve, max, % 34 34 34
A † †
Amount retained on 150-μm (No. 100) sieve, max, % 10 10
B
Strength activity index:
C C C
With portland cement, at 7 days, min, percent of 75 75 75
control
C C C
With portland cement, at 28 days, min, percent of 75 75 75
control
Water requirement, max, percent of control 115 105 105
Uniformity requirements:
The density and fineness of individual samples
shall not vary from the average established by the
ten preceding tests, or by all preceding tests if the
number is less than ten, by more than:
Density, max variation from average, % 5 5 5
Percent retained on 45-μm (No. 325), max variation, 5 5 5
percentage points from average
A
Limit only applies to coal ash that is harvested or coal ash containing bottom ash. Determine the amount retained in accordance with Test Method C136/C136M using
a sample size of 15 g ± 5 g
B
The strength activity index with portland cement is not to be considered a measure of the compressive strength of concrete containing the coal ash or natural pozzolan.
The mass of coal ash or natural pozzolan specified for the test to determine the strength activity index with portland cement is not considered to be the proportion
recommended for the concrete to be used in the work. The optimum amount of coal ash or natural pozzolan for any specific project is determined by the required properties
of the concrete and other constituents of the concrete and is to be established by testing. Strength activity index with portland cement is a measure of reactivity with a given
cement and is subject to variation depending on the source of both the coal ash or natural pozzolan and the cement.
C
Meeting the 7 day or 28 day strength activity index will indicate specification compliance.
†
Editorially corrected in March 2023.
4.3 Class C—Coal ash that meets the applicable require- 6.2 The purchaser shall indicate which procedure, A or B,
ments for this class as given herein. This class of coal ash, in shall be used when specifying requirements for effectiveness in
addition to having pozzolanic properties, also has some cemen- contribution to sulfate resistance under Table 3.
titious properties.
7. Chemical Composition
NOTE 2—Class F coal ash is typically produced from burning anthracite
7.1 Coal ash and natural pozzolans shall conform to the
or bituminous coal, but may also be produced from subbituminous coal
requirements as to chemical composition prescribed in Table 1.
and from lignite. Class C coal ash is typically produced from burning
lignite or subbituminous coal, and may also be produced from anthracite
NOTE 4—The chemical component determinations and the limits placed
or bituminous coal.
on each do not predict the performance of the coal ash or natural pozzolan
with hydraulic cement in concrete, but collectively help describe compo-
5. Materials and Manufacture
sition and uniformity of the material.
5.1 It is permitted to process coal ash and natural pozzolans
8. Physical Properties
to meet the requ
...