ASTM C215-97e1

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact
ASTM International (www.astm.org) for the latest information.
e1
Designation: C 215 – 97
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Fundamental Transverse, Longitudinal, and
1
Torsional Resonant Frequencies of Concrete Specimens
This standard is issued under the fixed designation C 215; 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 (e) indicates an editorial change since the last revision or reapproval.
1
e NOTE—The values for “cylinder” and “prism” in 9.1 were editorially corrected in April 1999.
1. Scope on the specimen. The driving frequency is varied until the
measured specimen response reaches a maximum amplitude.
1.1 This test method covers measurement of the fundamen-
The value of the frequency causing maximum response is the
tal transverse, longitudinal, and torsional resonant frequencies
resonant frequency of the specimen. The fundamental frequen-
of concrete prisms and cylinders for the purpose of calculating
cies for the three different modes of vibration are obtained by
dynamic Young’s modulus of elasticity, the dynamic modulus
proper location of the driver and the pickup unit.
of rigidity (sometimes designated as “the modulus of elasticity
3.3 In the impact resonance method, a supported specimen
in shear”), and dynamic Poisson’s ratio.
is struck with a small impactor and the specimen response is
1.2 Values in SI units are the standard.
measured by a lightweight accelerometer on the specimen. The
1.3 This standard does not purport to address all of the
output of the accelerometer is recorded. The fundamental
safety concerns, if any, associated with its use. It is the
frequency of vibration is determined by using digital signal
responsibility of the user of this standard to establish appro-
processing methods or counting zero crossings in the recorded
priate safety and health practices and determine the applica-
waveform. The fundamental frequencies for the three different
bility of regulatory limitations prior to use.
modes of vibration are obtained by proper location of the
2. Referenced Documents impact point and the accelerometer.
2.1 ASTM Standards:
4. Significance and Use
C 31 Practice for Making and Curing Concrete Test Speci-
2 4.1 This test method is intended primarily for detecting
mens in the Field
significant changes in the dynamic modulus of elasticity of
C 42 Test Method for Obtaining and Testing Drilled Cores
2 laboratory or field test specimens that are undergoing exposure
and Sawed Beams of Concrete
to weathering or other types of potentially deteriorating influ-
C 192 Practice for Making and Curing Concrete Test Speci-
2 ences.
mens in the Laboratory
4.2 The value of the dynamic modulus of elasticity obtained
C 469 Test Method for Static Modulus Elasticity and Pois-
2 by this test method will, in general, be greater than the static
son’s Ratio of Concrete in Compression
modulus of elasticity obtained by using Test Method C 469.
C 670 Practice for Preparing Precision and Bias Statements
2
The difference depends, in part, on the strength level of the
for Test Methods for Construction Materials
concrete.
3. Summary of Test Method 4.3 The conditions of manufacture, the moisture content,
and other characteristics of the test specimens (see section on
3.1 The fundamental resonant frequencies are determined
Test Specimens) materially influence the results obtained.
using one of two alternative procedures: (1) the forced reso-
4.4 Different computed values for the dynamic modulus of
nance method or (2) the impact resonance method. The same
elasticity may result from widely different resonant frequencies
testing procedure is used for all specimens of an associated
of specimens of different sizes and shapes of the same
series.
concrete. Therefore, comparison of results from specimens of
3.2 In the forced resonance method, a supported specimen is
different sizes or shapes should be made with caution.
forced to vibrate by an electro-mechanical driving unit. The
specimen response is monitored by a lightweight pickup unit
5. Apparatus
5.1 Forced Resonance Apparatus (Fig. 1):
1
This test method is under the jurisdiction of ASTM Committee C-9 on Concrete
5.1.1 Driving Circuit—The driving circuit shall consist of a
and Concrete Aggregates and is the direct responsibility of Subcommittee C09.64 on
variable frequency audio oscillator, an amplifier, and a driving
Nondestructive and In-Place Testing.
Current edition approved Aug. 10, 1997. Published June 1998. Originally
unit. The oscillator shall be calibrated to read within 62% of
published as C 215 – 47 T. Last previous edition C 215 –
...