ASTM C512-87(1994)

Standard Test Method for Creep of Concrete in Compression

SCOPE
1.1 This test method covers the determination of the creep of molded concrete cylinders subjected to sustained longitudinal compressive load. This test method is limited to concrete in which the maximum aggregate size does not exceed 2 in. (50 mm).  
1.2 The values stated in inch-pound units are to be regarded as the standard.  
1.3 This standard does not purport to address all of the safety problems, 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: 31-Dec-1993
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: C09 - Concrete and Concrete Aggregates
• Drafting Committee: C09.61 - Testing for Strength

Relations

• Replaced By: ASTM C512-02 - Standard Test Method for Creep of Concrete in Compression
• Effective Date: 10-Aug-2002

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: C 512 – 87 (Reapproved 1994)
Standard Test Method for
Creep of Concrete in Compression
This standard is issued under the fixed designation C 512; 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 tions for the prototype structure. Current theories and effects of
material and environmental parameters are presented in ACI
1.1 This test method covers the determination of the creep
SP-9, Symposium on Creep of Concrete.
of molded concrete cylinders subjected to sustained longitudi-
3.3 In the absence of a satisfactory hypothesis governing
nal compressive load.This test method is limited to concrete in
creep phenomena, a number of assumptions have been devel-
which the maximum aggregate size does not exceed 2 in. (50
oped that have been generally substantiated by test and
mm).
experience.
1.2 The values stated in inch-pound units are to be regarded
3.3.1 Creep is proportional to stress from 0 to 40 % of
as the standard.
concrete compressive strength.
1.3 This standard does not purport to address all of the
3.3.2 Creep has been conclusively shown to be directly
safety concerns, if any, associated with its use. It is the
proportional to paste content throughout the range of paste
responsibility of the user of this standard to establish appro-
contents normally used in concrete. Thus the creep character-
priate safety and health practices and determine the applica-
istics of concrete mixtures containing aggregate of maximum
bility of regulatory limitations prior to use.
size greater than 2 in. (50 mm) may be determined from the
2. Referenced Documents
creepcharacteristicsof theminus2-in. (minus50-mm)fraction
obtained by wet-sieving. Multiply the value of the character-
2.1 ASTM Standards:
istic by the ratio of the cement paste content (proportion by
C39 Test Method for Compressive Strength of Cylindrical
volume) in the full concrete mixture to the paste content of the
Concrete Specimens
sieved sample.
C 192 Practice for Making and Curing Concrete Test Speci-
3.4 The use of the logarithmic expression (Section 8) does
mens in the Laboratory
not imply that the creep strain-time relationship is necessarily
C 470 Specification for Molds for Forming Concrete Test
an exact logarithmic function; however, for the period of one
Cylinders Vertically
year, the expression approximates normal creep behavior with
C 617 Practice for Capping Cylindrical Concrete Speci-
sufficient accuracy to make possible the calculation of param-
mens
eters that are useful for the purpose of comparing concretes.
C 670 Practice for Preparing Precision and Bias Statements
3.5 There are no data that would support the extrapolation
for Test Methods for Construction Materials
of the results of this test to tension or torsion.
3. Significance and Use
4. Apparatus
3.1 This test method measures the load-induced time-
4.1 Molds—Molds shall be cylindrical conforming to the
dependent compressive strain at selected ages for concrete
provisions of Practice C 192C 192, or to the provisions of
under an arbitrary set of controlled environmental conditions.
Specification C 470C 470. If required, provisions shall be
3.2 This test method can be used to compare creep poten-
made for attaching gage studs and inserts, and for affixing
tials of different concretes. A procedure is available, using the
integral bearing plates to the ends of the specimen as it is cast.
developed equation (or graphical plot), for calculating stress
4.1.1 Horizontal molds shall conform to the requirements of
from strain data within massive non-reinforced concrete struc-
the section on horizontal molds for creep test cylinders of
tures. For most specific design applications, the test conditions
Practice C 192C 192. A horizontal mold that has proven
set forth herein must be modified to more closely simulate the
satisfactory is shown in Fig. 1.
anticipated curing, thermal, exposure, and loading age condi-
4.2 Loading Frame, capable of applying and maintaining
the required load on the specimen, despite any change in the
ThistestmethodisunderthejurisdictionofASTMCommitteeC-9onConcrete dimension of the specimen. In its simplest form the loading
and Concrete Aggregates a nd is the direct responsibility of Subcommittee C09.70
on Elastic and Inelastic.
Current edition approved July 9, 1987. Published August 1987. Originally
ϵ1 3
published as C 512 – 63 T. Last previous edition C 512 – 82 (1992) . Available from the American Concrete Institute, P. O. Box 19150, Detroit, MI
Annual Book of ASTM Standards, Vol 04.02. 48219.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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.
C 512 – 87 (1994)
This may be a permanently installed hydraulic pressure gage or
a hydraulic jack and a load cell inserted in the frame when the
load is applied or adjusted.
4.3 Strain-Measuring Device—Suitable apparatus shall be
provided for the measurement of longitudinal strain in the
specimen to the nearest 10 millionths. The apparatus may be
embedded, attached, or portable. If a portable apparatus is
used,gagepointsshallbeattachedtothespecimeninapositive
manner. Attached gages relying on friction contact are not
permissible. If an embedded device is used, it shall be situated
so that its strain movement occurs along the longitudinal axis
of the cylinder. If external devices are used, strains shall be
measured on not less than two gage lines spaced uniformly
around the periphery of the specimen. The gages may be
instrumented so that the average strain on all gage lines can be
read directly. The effective gage length shall be at least three
times the maximum size of aggregate in the concrete. The
strain-measuring device shall be capable of measuring strains
FIG. 1 Horizontal Mold for Creep Specimens
for at least 1 year without change in calibration.
NOTE 1—Systems in which the varying strains are compared with a
frame consists of header plates bearing on the ends of the
constant-length standard bar are considered most reliable, but unbonded
loaded specimens, a load-maintaining element that may be
electrical strain gages are satisfactory.
either a spring or a hydraulic capsule or ram, and threaded rods
5. Test Specimens
to take the reaction of the loaded system. Bearing surfaces of
the header plates shall not depart from a plane by more than
5.1 Specimen Size—The diameter of each specimen shall be
0.001 in. (0.025 mm). In any loading frame, several specimens
6 6 ⁄16 in. (or 150 6 1.6 mm), and the length shall be at least
may be stacked for simultaneous loading. The length between
11 ⁄2 in. (292 mm). When the ends of the specimen are in
header plates shall not exceed 70 in. (1780 mm). When a
contact with steel bearing plates, the specimen length shall be
hydraulic load-maintaining element is used, several frames
at least equal to the gage length of the strain-measuring
may be loaded simultaneously through a central hydraulic
apparatus plus the diameter of the specimen. When the ends of
pressure-regulating unit consisting of an accumulator, a regu-
the specimen are in contact with other concrete specimens
lator, indicating gages, and a source of high pressure, such as
similar to the test specimen, the specimen length shall be at
a cylinder of nitrogen or a high-pressure pump. Springs such as
least equal to the gage length of the strain-measuring apparatus
railroad car springs may be used to maintain the load in frames 1
plus 1 ⁄2 in. (38 mm). Between the test specimen and the steel
similar to those described above; the initial compression shall
bearing plate at each end of a stack, a supplementary nonin-
be applied by means of a portable jack or testing machine.
strumented cylinder whose diameter is equal to that of the test
When springs are used, care should be taken to provide a
cylinders and whose length is at least half its diameter shall be
spherical head or ball joint, and end plates rigid enough to
installed.
ensure uniform loading of the cylinders. Fig. 2 shows an
5.2 Fabricating Specimens—The maximum size of aggre-
acceptable spring-loaded frame. Means shall be provided for
gate shall not exceed 2 in. (50-mm) (Section 3). Vertically cast
measuring the load to the nearest 2 % of total applied load.
cylinders shall be fabricated in accordance with the provisions
of Practice C 192C 192. The ends of each cylinder shall meet
the planeness requirements described in the scope of Practice
C 617C 617 (Note 2). Horizontally cast specimens shall be
consolidated by the method appropriate to the consistency of
the concrete as indicated in the methods of consolidation
section of Practice C 192C 192. Care must be taken to ensure
that the rod or vibrator does not strike the strain meter. When
vibration is used, the concrete shall be placed in one layer and
the vibrating element shall not exceed 1 ⁄4 in. (32 mm) in
diameter.When rodding is used, the concrete shall be placed in
two approximately equal layers and each layer shall be rodded
25 times evenly along each side of the strain meter. After
consolidation the concrete shall be struck off with trowel or
float, then trowelled the
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