ASTM C638-92(1997)
(Terminology)Standard Descriptive Nonmenclature of Constituents of Aggregates for Radiation-Shielding Concrete
Standard Descriptive Nonmenclature of Constituents of Aggregates for Radiation-Shielding Concrete
SCOPE
1.1 This nomenclature is intended to give accurate descriptions of some common or important naturally occurring and synthetic constituents of aggregates for radiation-shielding concrete, that, at the same time, are not common or important constituents of concrete aggregates in general use. While most of the minerals and rocks discussed below may occur in small quantities in aggregates in general use, they are not major constituents of such aggregates. Common constituents of aggregates in general use are described in Descriptive Nomenclature C294. Radiation-shielding concrete often contains such aggregates, but other special aggregates are used in some circumstances.
1.2 The synthetic aggregates included are ferrophosphorus and boron frit.
1.3 The descriptions are not adequate to permit the identification of materials, since accurate identification of natural and synthetic aggregate constituents in many cases can only be made by a qualified geologist, mineralogist, or petrographer, using the apparatus and procedures of those sciences.
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Designation: C 638 – 92 (Reapproved 1997)
Standard Descriptive Nomenclature of
Constituents of Aggregates for Radiation-Shielding
Concrete
This standard is issued under the fixed designation C 638; 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. Scope HEAVY AGGREGATES
1.1 This nomenclature is intended to give accurate descrip-
4. Descriptions of Naturally Occurring Constituents
tions of some common or important naturally occurring and
4.1 Members of this group have higher specific gravities
synthetic constituents of aggregates for radiation-shielding
than aggregates in general use. Six are iron minerals, of which
concrete, that, at the same time, are not common or important
five are important iron ore minerals and the sixth is an ore of
constituents of concrete aggregates in general use. While most
titanium. Two are barium minerals worked as the principal
of the minerals and rocks discussed below may occur in small
sources of barium salts. The other is ferrophosphorus, a
quantities in aggregates in general use, they are not major
mixture of synthetic iron phosphides.
constituents of such aggregates. Common constituents of
4.2 The constituents are described below first as minerals,
aggregates in general use are described in Descriptive Nomen-
and then as major constituents of ores when their aspect as
clature C 294. Radiation-shielding concrete often contains such
major constituents of ores affects the behavior of ores as
aggregates, but other special aggregates are used in some
concrete aggregates.
circumstances.
1.2 The synthetic aggregates included are ferrophosphorus
5. Iron Minerals and Ores
and boron frit.
5.1 Hematite (Fe O )—Hematite has a hardness of 5 to 6 on
2 3
1.3 The descriptions are not adequate to permit the identi-
Mohs’ scale (will be scratched by hard steel), and a specific
fication of materials, since accurate identification of natural
gravity of 5.26 when pure. The color varies from bright red to
and synthetic aggregate constituents in many cases can only be
dull red to steel gray; luster varies from metallic to submetallic
made by a qualified geologist, mineralogist, or petrographer,
to dull; the streak is cherry red or reddish brown; it is
using the apparatus and procedures of those sciences.
nonmagnetic.
5.1.1 Hematite Ores—Rocks of which hematite is the major
2. Referenced Documents
constituent vary from one deposit to another, and within the
2.1 ASTM Standards:
deposit, in specific gravity, toughness, compactness, amount of
C 294 Descriptive Nomenclature of Constituents of Natural
impurities, degree of weathering, and suitability for use as
Mineral Aggregates
concrete aggregate. Hematite appears to be the iron ore mineral
3. Types of Materials most exploited as a source of iron. The ores of the Lake
Superior region are banded sedimentary ores consisting of
3.1 Two classes of materials are described below. The first
layers rich in hematite, and sometimes goethite, iron silicates,
class consists of minerals and rocks formed from them, and
such as stilpnomelane, minnesotaite, greenalite, grunerite, and
synthetic materials, that have high specific gravity and in
iron carbonate, alternating with silica-rich layers of chert or
addition contain substantial proportions of atoms of high or
fine-grained quartz or a mixture. The Birmingham, AL ores are
moderately high atomic weight. They are referred to as heavy
oolitic with hematite replacements of oölites and fossils in a
or high-density aggregates. The second class consists of
matrix that ranges from fine-grained earthy hematite, with or
minerals and synthetic glasses of substantial boron content that
without calcite, to crystalline calcite. Hematite ores dust in
are particularly effective in absorbing thermal neutrons without
handling, with the dust ranging in color from moderate red to
producing highly penetrating gamma rays. The boron-frit
dusky red to moderate reddish brown (5R 4/6 to 5R 3/4 to 10R
glasses are included because of their frequent use.
4/6).
5.2 Ilmenite (FeTiO with minor Mg and Mn)—Ilmenite has
a hardness of 5 to 6 and specific gravity of 4.72 6 0.04 when
This nomenclature is under the jurisdiction of ASTM Committee C-9 on
pure. The color is iron black with metallic to submetallic luster;
Concrete and Concrete Aggregatesand is the direct responsibility of Subcommittee
C09.41on Concrete for Radiation Shielding.
Current edition approved March 15, 1992. Published May 1992. Originally
published as C 638 – 73. Last previous edition C 638 – 84(1990). National Research Council, Washington, DC, Rock Color Chart (1948)
Annual Book of ASTM Standards, Vol 04.02. reissued 1964 by Geological Soc. Am., New York, NY.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
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.
C 638
the streak is black; it is feebly magnetic. a major rock-forming mineral. One of the most widely used
5.2.1 Ilmenite Ores—These ores consist of crystalline il- types of heavy aggregates is magnetite ore.
menite with either magnetite or hematite and constituents of
6. Barium Minerals
the associated gabbroic or anorthositic rocks. Massive ilmenite
ores can form coarsely crystalline massive tough rocks but
6.1 Witherite (BaCO )—Witherite has a hardness of 3 to 3 ⁄2
vary, from deposit to deposit, and within a deposit, in specific
and a specific gravity of 4.29 when pure. The color ranges from
gravity, composition, hardness, and suitability for use as
colorless to white to grayish or many pale colors. Like calcite
concrete aggregate. Many ilmenite ores consist of ilmenite
and aragonite, witherite is decomposed with effervescence by
disseminated in rock rather than concentrated as a major
dilute hydrochloric acid (HCl). Witherite, the second most
rock-forming mineral. Ilmenite concentrated from beach sands
common barium mineral, occurs with barite and galena.
is usually altered to a variable degree, and its mechanical
England is the chief producer of witherite, and barium-
properties probably differ from those of unaltered ilmenite.
containing heavy aggregates in Great Britain might be ex-
One of the most widely used types of heavy aggregates is
pected to contain witherite as a major constituent.
ilmenite ore.
6.2 Barite (BaSO ) (also, but improperly, called barytes)—
5.3 Lepidocrocite (FeO(OH))—Lepidocrocite has a hard-
Barite has a hardness of 3 to 3 ⁄2 and a specific gravity of 4.50
ness of 5 and specific gravity of 4.09 when pure. The color when pure. The color ranges from colorless to white to many
varies from ruby red to reddish brown and the streak is dull
usually pale colors.
orange. Lepidocrocite and goethite occur together, and lepi- 6.2.1 Barite is the most common barium mineral and the
docrocite may be a constituent of goethite and limonite ores.
major barium ore. It occurs in veins transecting many kinds of
5.4 Goethite (HFeO )—Goethite has the same chemical
rocks, concentrated in sedimentary rocks, and as residual
composition as lepidocrocite but crystallizes differently. The
nodules in clays formed by the solution of sedimentary rocks.
hardness is 5 to 5 ⁄2 and the specific gravity is 4.28 6 0.01
In many of its occurrences it is accompanied by clay or a
when pure and 3.3 to 4.3 in massive goethite. The color varies
calcium sulfate mineral (gypsum or anhydrite) or both. Al-
with the form, from crystals that are blackish brown with
though barite from residual deposits is often weathered, it is
imperfect adamantine-metallic luster, to dull or silky luster in
possible to obtain clean, well-graded barite aggregate.
fibrous varieties; massive goethite is yellowish brown to
7. Ferrophosphorus
reddish brown; clayey material is brownish yellow to ocher
yellow. The streak is brownish yellow to ocher yellow.
7.1 Ferrophosphorus, a material produced in the production
5.4.1 Goethite Ores—These ores range from hard tough
of phosphorus, consists of a mixture of iron phosphides, and
massive rocks to soft crumbling earths; these alterations
has been used as coarse and fine aggregate in radiation-
frequently occur within fractions of an inch.
shielding concrete. Published specific gravities range from 5.72
5.5 Limonite—A general name for hydrous iron oxides of
to 6.50 for coarse aggregate. The coarse aggregate is reported
unknown composition frequently cryptocrystalline goethite
to degrade easily and has been associated with extreme
with adsorbed and capillary water, and probably mixtures of
retardation of set in concrete. Ferrophosphorus in concrete
such goethite with similar lepidocrocite or hematite, or both,
releases flammable, and possibly toxic, gases which can
with adsorbed and capillary water . The specific gravity ranges
develop high
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