ASTM C918-02

Standard Test Method for Measuring Early-Age Compressive Strength and Projecting Later-Age Strength

SCOPE
1.1 This test method covers a procedure for making and curing concrete specimens and for testing them at an early age. The specimens are stored under standard-curing conditions and the measured temperature history is used to compute a maturity index that is related to strength gain.
1.2 This test method also covers a procedure for using the results of early-age compressive-strength tests to project the potential strength of concrete at later ages.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Jul-2002
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: C09 - Concrete and Concrete Aggregates
• Drafting Committee: C09.61 - Testing for Strength

Relations

• Replaces: ASTM C918-97e1 - Standard Test Method for Measuring Early-Age Compressive Strength and Projecting Later-Age Strength
• Effective Date: 10-Jul-2002
• Replaced By: ASTM C918/C918M-07 - Standard Test Method for Measuring Early-Age Compressive Strength and Projecting Later-Age Strength
• Effective Date: 15-Jul-2007

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
Designation:C918–02
Standard Test Method for
Measuring Early-Age Compressive Strength and Projecting
1
Later-Age Strength
This standard is issued under the fixed designation C 918; 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 (ϵ) indicates an editorial change since the last revision or reapproval.
1. Scope C 470 Specification for Molds for Forming Concrete Test
4
Cylinders Vertically
1.1 This test method covers a procedure for making and
C 617 Practice for Capping Cylindrical Concrete Speci-
curing concrete specimens and for testing them at an early age.
4
mens
The specimens are stored under standard-curing conditions and
C 670 Practice for Preparing Precision and Bias Statements
themeasuredtemperaturehistoryisusedtocomputeamaturity
4
for Test Methods for Construction Materials
index that is related to strength gain.
C 1074 Practice for Estimating Concrete Strength by the
1.2 This test method also covers a procedure for using the
4
Maturity Method
results of early-age compressive-strength tests to project the
C 1231 Practice for Use of Unbonded Caps in Determina-
potential strength of concrete at later ages.
tion of Compressive Strength of Hardened Concrete Cyl-
1.3 The values stated in SI units are to be regarded as the
4
inders
standard. The values given in parentheses are for information
only.
3. Terminology
1.4 The text of this standard references notes and footnotes
3.1 Definitions:
which provide explanatory material. These notes and footnotes
3.1.1 Refer to Practice C 1074C 1074 for the definitions of
(excluding those in tables and figures) shall not be considered
the following terms: datum temperature, equivalent age, ma-
as requirements of the standard.
turity, maturity function, maturity index, and temperature–time
1.5 This standard does not purport to address all of the
factor.
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 potential strength, n—the strength of a test specimen
priate safety and health practices and determine the applica-
that would be obtained at a specified age under standard curing
bility of regulatory limitations prior to use.
conditions.
2. Referenced Documents 3.2.2 prediction equation, n—the equation representing the
straight-line relationship between compressive strength and the
2.1 ASTM Standards:
logarithm of the maturity index.
C 31/C 31M Practice for Making and Curing Concrete Test
2 3.2.2.1 Discussion—The prediction equation is used to
Specimens in the Field
project the strength of a test specimen based upon its measured
C39 Test Method for Compressive Strength of Cylindrical
3 early-age strength. The general form of the prediction equation
Concrete Specimens
used in this test method is:
C 192/C 192M Practice for Making and Curing Concrete
4
Test Specimens in the Laboratory
S 5 S 1 b~ log M 2 log m! (1)
M m
1
where:
This test method is under the jurisdiction of ASTM Committee C09 on
S = projected strength at maturity index M,
Concrete and ConcreteAggregates and is the direct responsibility of Subcommittee
M
C09.61 on Testing for Strength.
S = measured compressive strength at maturity index m,
m
Current edition approved July 10, 2002. Published August 2002. Originally
b = slope of the line,
ϵ1
published as C 918 – 80. Last previous edition C 918 – 97 .
M = maturity index under standard curing conditions, and
2
Annual Book of ASTM Standards, Vol 04.10.
3 m = maturity index of the specimen tested at early age.
Annual Book of ASTM Standards, Vol 04.07.
4
Annual Book of ASTM Standards, Vol 04.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
C918–02
The prediction equation is developed by performing compressive
procedures for using the measured in-place maturity index to
strength tests at various ages, computing the corresponding maturity
estimate in-place strength.
indices at the test ages, and plotting the compressive strength as a
function of the logarithm of the maturity index.Abest-fit line is drawn
6. Apparatus
through the data and the slope of this line is used in the prediction
equation.
6.1 Equipment and Small Tools, for fabricating specimens
and measuring the characteristics of fresh concrete, shall
3.2.3 projected strength, n—the potential strength estimated
conform to the applicable requirement
...