ASTM C235-68

Method of Test for Scratch Hardness of Coarse Aggregate Particles (Withdrawn 1976)

General Information

• Status: Withdrawn
• Technical Committee: C09 - Concrete and Concrete Aggregates
• Drafting Committee: C09.20 - Aggregates

Standards Content (Sample)

AIDDUCAN ASSOCIATIOl'f STATB
IDGHWAY OPFICIALS STANDARD
AASHO NO.: T 189
Standard Method o/ Test /or
SCRATCH HARDNESS OF COARSE AGGREGATE PARTICLES
ASTM Designation: C 235- 68
This Standard of the American Society for Testing and Materials is issued under
the fixed designation C 235; the number immediately following the designa­
tion 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.
Scope
face of the aggregate particle. If the par­
ticle contains more than one type of
1. (a) This method of test covers a
rock and is partly hard and partly soft,
procedure for determining the quantity
it should be classed as "soft" only if the
of soft particles in coarse aggregates on
soft portion is one third or more of the
the basis of scratch hardness. It is in­
volume of the particle. Scratch hardness
tended to be used to identify materials
tests can be made on the exposed surface
that are soft, including those which are
of a particle provided consideration is
so poorly bonded that the separate par­
given to softening of the surface due to
ticles in the piece are easily detached
weathering. A particle with a thin, soft
from the mass. The test is not intended to
and weathered surface and a hard core
identify other types of deleterious ma­
should normally be classed as "soft."
terials in aggregates separate mention of
which should be made in specifications.
Apparatus
(b) The method is intended primarily
2. Brass Rod, -h in. in diameter,
for field use in estimating the quality of a
with a rounded point, mounted in a
deposit of coarse aggregate. It will be
device so that a load of 2 ± 0.1 lb is
helpful in the laboratory, and when used
applied to the specimen tested. A suitable
with visual inspection will afford a fast,
design for this apparatus is shown in
convenient means of determining the
Fig. 1. The brass rod shall be of suit­
amount of soft particles in aggregate.
able hardness so that when filed to a
(c) In case of question, the scratch test
sharp point, it will scratch a copper
should be made on a freshly broken sur-
penny (U. S. Lincoln design) but fail
to scratch a nickel (U. S. Jefferson
1 Under the standardization procedure of the
design). For use in the field, brass rod
Society, this method is under the jurisdiction
of the specified size and hardness can be
of Ule ASTM Committees C-9 on Concrete and
Concrete Acgrecates. A list of members may be mounted into the wooden shaft of an
found in the ASTM Yearbook. This standard is
ordinary lead pencil.
the direct responsibility of Subcommittee III-I
on Miscellaneous Tests for Hardened Concrete.
Samples
Current edition accepted Sept. 13, 1968.
Oti&inlill,Y issued 1949. Replaces C 235-62 T.
3. (a) Coarse aggregate for the test
184
9-58

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TEST FOR SCRATCH HARDNESS OF COARSE AGGREGATES
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