ASTM C293-94

Standard Test Method for Flexural Strength of Concrete (Using Simple Beam With Center-Point Loading)

SCOPE
1.1 This test method covers determination of the flexural strength of concrete specimens by the use of a simple beam with center-point loading. It is not an alternative to Test Method C78.
1.2 The values stated in inch-pound units are to be regarded as standard. The SI equivalent of inch-pound units has been rounded where necessary for practical application.
1.3 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-Feb-2002
• 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 C293-00 - Standard Test Method for Flexural Strength of Concrete (Using Simple Beam With Center-Point Loading)
• Effective Date: 10-Feb-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: C 293 – 94
Standard Test Method for
Flexural Strength of Concrete (Using Simple Beam With
Center-Point Loading)
This standard is issued under the fixed designation C 293; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope compliance with specifications or as a basis for proportioning,
mixing and placement operations. This test method produces
1.1 This test method covers determination of the flexural
values of flexural strength significantly higher than Test
strength of concrete specimens by the use of a simple beam
Method C 78 (Note 1).
with center-point loading. It is not an alternative to Test
Method C 78.
NOTE 1—The testing laboratory performing this test method may be
1.2 The values stated in inch-pound units are to be regarded evaluated in accordance with Practice C 1077.
as standard. The SI equivalent of inch-pound units has been
4. Apparatus
rounded where necessary for practical application.
4.1 The testing machine shall conform to the requirements
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the of the sections on Basis of Verification, Corrections, and Time
Interval Between Verifications of Practices E 4. Hand operated
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- testing machines having pumps that do not provide a continu-
ous loading to failure in one stroke are not permitted. Motor-
bility of regulatory limitations prior to use.
ized pumps or hand operated positive displacement pumps
2. Referenced Documents
having sufficient volume in one continuous stroke to complete
2.1 ASTM Standards: a test without requiring replenishment are permitted and shall
C 31 Practice for Making and Curing Concrete Test Speci- be capable of applying loads at a uniform rate without shock or
mens in the Field interruption.
C 78 Test Method for Flexural Strength of Concrete (Using 4.2 Loading Apparatus—The mechanism by which forces
Simple Beam with Third Point Loading) are applied to the specimen shall employ a load-applying block
C 192 Practice for Making and Curing Concrete Test Speci- and two specimen support blocks. It shall ensure that all forces
mens in the Laboratory are applied perpendicular to the face of the specimen without
C 617 Practice for Capping Cylindrical Concrete Speci- eccentricity. A diagram of an apparatus that accomplishes this
mens purpose is shown in Fig. 1.
C 1077 Practice for Laboratories Testing Concrete and Con- 4.2.1 All apparatus for making center-point loading flexure
crete Aggregates for Use in Construction and Criteria for tests shall be similar to Fig. 1 and maintain the span length and
Laboratory Evaluation central position of the load-applying block with respect to the
E 4 Practices for Force Verification of Testing Machines support blocks constant within 60.05 in. (61.3 mm).
4.2.2 Reactions shall be parallel to the direction of the
3. Significance and Use
applied load at all times during the test, and the ratio of the
3.1 This test method is used to determine the modulus of
horizontal distance between the point of load application and
rupture of specimens prepared and cured in accordance with nearest reaction to the depth of the beam shall be 1.5 6 2%.
Practices C 31 or C 192. The strength determined will vary
4.2.3 The load-applying and support blocks shall not be
where there are differences in specimen size, preparation, more than 2 ⁄2 in. (64 mm) high, measured from the center or
moisture condition, or curing.
the axis of pivot, and shall extend at least across the full width
3.2 The results of this test method may be used to determine of the specimen. Each hardened bearing surface in contact with
the specimen shall not depart from a plane by more than 0.002
in. (0.05 mm) and shall be a portion of a cylinder, the axis of
This test method is under the jurisdiction of ASTM Committee C-9 on Concrete
which is coincidental with either the axis of the rod or center
and Concrete Aggregatesand is the direct responsibility of Subcommittee C09.61on
Testing Concrete for Strength.
of the ball, whichever the block is pivoted upon. The angle
Current edition approved April 15, 1994. Published June 1994. Originally
subtended by the curved surface of each block shall be at least
published as C 293 – 52 T. Last previous edition C 293 – 79.
2 45° (0.79 rad). The load-applying and support blocks shall be
Annual Book of ASTM Standards, Vol 04.02.
Annual Book of ASTM Standards, Vol 03.01. maintained in a vertical position and in contact with the rod or
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C 293
NOTE 1—Apparatus may be used inverted.
FIG. 1 Diagrammatic View of a Suitable Apparatus for Flexure Test of Concrete by Center-Point Loading Method.
ball by means of spring-loaded screws that hold them in Apply the load at such a rate that constantly increases the
contact with the pivot rod or ball. The rod in the center extreme fiber stress between 125 and 175 psi/min (0.86 and
load-applying block in Fig. 1 may be omitted when a spheri- 1.21 MPa/min), when calculated in accordance with 7.1, until
cally seated bearing block is used. rupture occurs.
7. Measur
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