ASTM C120-00

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Designation: C 120 – 00
Standard Test Methods of
Flexure Testing of Slate (Modulus of Rupture, Modulus of
Elasticity)
This standard is issued under the fixed designation C 120; 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.
INTRODUCTION
Due to the unique properties of slate, the flexure test is better adapted to use for strength and
elasticity determinations than either compression or tension tests. Furthermore, several uses of slates
are such that these determinations are of special interest and value, besides furnishing comparative
data.
The property of slate termed “grain” causes a slab of the material to break transversely in one
direction somewhat more readily than at right angles to this direction. For this reason it is desirable
to test the strength and elasticity both parallel and perpendicular to the grain.
In the quarrying of slate, blasting is frequently resorted to, and for this reason certain portions of
the material may have been unduly strained. Low or erratic strength results on some of the test
specimens should be regarded in the light of defective material.
1. Scope between various slates. These test methods also provide one
element in the comparison of slates.
1.1 These test methods cover determination of the modulus
of rupture and modulus of elasticity of slate by means of
MODULUS OF RUPTURE
flexure tests.
1.2 This standard does not purport to address all of the
5. Test Specimens
safety concerns, if any, associated with its use. It is the
5.1 Structural or Electrical Slate— Six representative
responsibility of the user of this standard to establish appro-
specimens, 12 by 1 ⁄2 by 1 in. (305 by 38.1 by 25.4 mm) in
priate safety and health practices and determine the applica-
size, of the particular slate under consideration shall be tested.
bility of regulatory limitations prior to use.
5.2 Roofing Slate—At least six specimens 4 in. (101.6 mm)
3 1
in width, 4 in. or more in length, and of thickness ⁄16 to ⁄4 in.
2. Referenced Documents
(4.8 to 6.4 mm).
2.1 ASTM Standards:
C 99 Test Method for Modulus of Rupture of Dimension
6. Preparation of Specimens
Stone
6.1 Structural or Electrical Slate— Split the slate for the
C 119 Terminology Relating to Dimension Stone
test to a thickness of approximately 1 ⁄4 in. (31.8 mm) and then
saw into strips 12 in. (304.8 mm) in length by 1 ⁄2in. (38.1 mm)
3. Terminology
in width. Cut half of these with the length parallel to the grain
3.1 Definitions—All definitions are in accordance with Ter-
and half with the length perpendicular to the grain. Plane or rub
minology C 119.
downthe12by1 ⁄2-in.(304.8by38.1-mm)facestoathickness
of approximately 1 in. (25.4 mm), taking care to have the
4. Significance and Use
finished surfaces as nearly parallel as practicable.
4.1 These test methods are useful in indicating the differ-
6.2 Roofing Slate—Cut one 4 by 4-in. (101.6 by 101.6-mm)
ences in flexure (modulus of rupture, modulus of elasticity)
specimen, of the thickness of the slate, from each of six
shingles. Cut no part of the specimen nearer than 1 in. (25.4
These test methods are under the jurisdiction of ASTM Committee C-18 on
mm) to a sheared edge or a nail hole. Mark the direction of the
Dimension Stone and are the direct responsibility of Subcommittee C18.01 on Test
length of the shingle on each specimen, and do not resurface
Methods.
the split faces.
Current edition approved April 10, 2000. Published May 2000. Originally
published as C 120 – 25 T. Last previous edition C 120 – 90 (1994).
Annual Book of ASTM Standards, Vol 04.07.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 120
7. Conditioning 13. Procedure
7.1 Dry the specimens for 48 h in a ventilated oven at a 13.1 Support and load the test specimen in the same way as
temperature of 60°C 6 2°C (140°F 6 4°F). At the 46th, 47th
for the flexural strength determination, except that the roofing
and 48th hour, weigh the specimens to ensure that the weight slate specimen shall be supported on a 6-in. (152.4-mm) span.
is the same. If the weight continues to drop, continue to dry the
Set any type of deflectometer, capable of reading to 0.001 in.
specimens until there are three successive hourly readings with (0.025 mm), to measure deflections at mid-span (Note 1). Stop
the same weight.
the loading at each 50-lbf (222-N) increment, and record the
corresponding deflections.
8. Marking and Measuring
NOTE 1—It is not ordinarily feasible to set the deflectomer to read zero
8.1 On structural or electrical slate, rule the center lines with
when there is no
...