ASTM C1812-15

Standard Practice for Design of Journal Bearing Supports to be Used in Fiber Reinforced Concrete Beam Tests

SIGNIFICANCE AND USE
4.1 The presence of friction in the supporting rollers used when testing a fiber-reinforced concrete beam will increase the apparent load resistance of the beam. Roller supports designed in accordance with this practice will provide a relatively low and consistent value of friction at the supports.  
4.2 Two types of rollers are used to support a beam. One includes a cylindrical bearing that allows the roller assembly to rotate along an axis parallel to the longitudinal axis of the beam and thereby accommodate any warping introduced during specimen fabrication. The other roller does not include the cylindrical bearing.  
4.3 The rollers are designed for use with 150 mm [6 in.] or 100 mm [4 in.] deep beams of square cross-section.  
4.4 A method is provided for correcting the apparent load resistance measured using the roller with a known value of the effective coefficient of friction of the roller supports to obtain an estimate of the load resistance in the absence of friction.
SCOPE
1.1 This practice prescribes the design of journal-bearing type rollers to support each end of fiber-reinforced concrete beams tested using Test Method C1399/C1399M or Test Method C1609/C1609M. The roller design is intended to provide a consistent and relatively low value of effective coefficient of friction at the beam supports. The bearing design incorporates metal-on-metal sliding surfaces lubricated with grease.
Note 1: During the progress of a test, a crack or cracks open on the underside of the beam between the loaded third points causing the underside of each portion of the beam to move away from the center. The design is intended to provide for unlimited rotation of the roller at the point of contact with the test beam in response to this motion.
Note 2: The design of the supporting rollers is a significant factor in determining the magnitude of the arching forces that cause error in flexural test results.2 Improperly designed supporting rollers can influence the apparent flexural behavior of fiber-reinforced concrete beams.3 The effective coefficient of friction can be determined using a method similar to that described by Bernard.4  
1.2 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
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: 30-Jun-2015
• Technical Committee: C09 - Concrete and Concrete Aggregates
• Drafting Committee: C09.42 - Fiber-Reinforced Concrete

Standards Content (Sample)

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
Designation: C1812 − 15
StandardPractice for
Design of Journal Bearing Supports to be Used in Fiber
1
Reinforced Concrete Beam Tests
This standard is issued under the fixed designation C1812; 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.
1. Scope priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 This practice prescribes the design of journal-bearing
type rollers to support each end of fiber-reinforced concrete
2. Referenced Documents
beams tested using Test Method C1399/C1399M or Test
5
2.1 ASTM Standards:
Method C1609/C1609M. The roller design is intended to
C125 Terminology Relating to Concrete and Concrete Ag-
provide a consistent and relatively low value of effective
gregates
coefficient of friction at the beam supports. The bearing design
C1399/C1399M Test Method for Obtaining Average
incorporates metal-on-metal sliding surfaces lubricated with
Residual-Strength of Fiber-Reinforced Concrete
grease.
NOTE 1—During the progress of a test, a crack or cracks open on the C1609/C1609M Test Method for Flexural Performance of
underside of the beam between the loaded third points causing the
Fiber-Reinforced Concrete (Using BeamWithThird-Point
underside of each portion of the beam to move away from the center. The
Loading)
design is intended to provide for unlimited rotation of the roller at the
D4950 Classification and Specification for Automotive Ser-
point of contact with the test beam in response to this motion.
vice Greases
NOTE 2—The design of the supporting rollers is a significant factor in
6
determining the magnitude of the arching forces that cause error in
2.2 SAE International Standard:
2
flexural test results. Improperly designed supporting rollers can influence
J 404 Chemical Composition of SAE Alloy Steels
3
the apparent flexural behavior of fiber-reinforced concrete beams. The
effective coefficient of friction can be determined using a method similar
4 3. Terminology
to that described by Bernard.
3.1 Definitions:
1.2 Units—The values stated in either SI units or inch-
3.1.1 For definitions of terms used in this practice, refer to
pound units are to be regarded separately as standard. The
Terminology C125.
values stated in each system may not be exact equivalents;
3.2 Definitions of Terms Specific to This Standard:
therefore,eachsystemshallbeusedindependentlyoftheother.
3.2.1 effective coeffıcient of friction, n—a dimensionless
Combining values from the two systems may result in non-
ratio of the horizontal force required to initiate rotation of the
conformance with the standard.
roller support applied at the contact point between the roller
1.3 This standard does not purport to address all of the
and test beam divided by the normal force applied at the same
safety concerns, if any, associated with its use. It is the
point (see Fig. 1).
responsibility of the user of this standard to establish appro-
3.2.2 roller, n—a journal bearing capable of continuous
rotation without exhibiting a significant variation in resistance
to rotation.
1
This practice is under the jurisdiction of ASTM Committee C09 on Concrete
andConcreteAggregatesandisthedirectresponsibilityofSubcommitteeC09.42on
Fiber-Reinforced Concrete.
4. Significance and Use
Current edition approved July 1, 2015. Published September 2015. DOI:
4.1 The presence of friction in the supporting rollers used
10.1520/C1812-15.
2
Zollo,R.F.,2013.“AnalysisofSupportApparatusforFlexuralLoad-deflection
when testing a fiber-reinforced concrete beam will increase the
Testing: Minimizing Bias,” Journal of Testing and Evaluation,ASTM International,
apparent load resistance of the beam. Roller supports designed
Vol. 41, No. 1, pp. 1-6.
3
Wille, K. and Parra-Montesinos, G.J., 2012. “Effect of Beam Size, Casting
Method, and Support Conditions on Flexural Behavior of Ultra-High-Performance
5
Fiber-Reinforced Concrete,” ACI Journal of Materials, Vol. 109, No. 3, pp. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
379-388. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
4
Bernard, E.S., 2014. “Influence of friction in supporting rollers on the apparent Standards volume information, refer to the standard’s Document Summary page on
flexural performance of third-point loaded fibre reinforced concrete beams,” the ASTM website.
6
Advanced Civil Engineering Materials, ASTM International Vol. 2, No. 1, pp. Available from SAE International (SAE), 400 Commonwealth Dr.,Warrendale,
158-176. PA 15096, http://aerospace.sae.org.
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