1、Designation: C638 09Standard Descriptive Nomenclature ofConstituents of Aggregates for Radiation-ShieldingConcrete1This standard is issued under the fixed designation C638; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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*1.1 This descriptive nomenclature is i
3、ntended to give accu-rate descriptions of some common or important naturallyoccurring and synthetic constituents of aggregates forradiation-shielding concrete, that, at the same time, are notcommon or important constituents of concrete aggregates ingeneral use. While most of the minerals and rocks d
4、iscussedbelow may occur in small quantities in aggregates in generaluse, they are not major constituents of such aggregates.Common constituents of aggregates in general use are de-scribed in Descriptive Nomenclature C294. Radiation-shielding concrete often contains such aggregates, but otherspecial
5、aggregates are used in some circumstances.1.2 The synthetic aggregates included are ferrophosphorusand boron frit.1.3 The descriptions are not adequate to permit the identi-fication of materials, since accurate identification of naturaland synthetic aggregate constituents in many cases can only bema
6、de by a qualified geologist, mineralogist, or petrographer,using the apparatus and procedures of those sciences.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.2. Referenced Documents2.1 ASTM Standards:2C294 Descriptive Nome
7、nclature for Constituents of Con-crete Aggregates3. Types of Materials3.1 Two classes of materials are described below. The firstclass consists of minerals and rocks formed from them, andsynthetic materials, that have high relative density (specificgravity) and in addition contain substantial propor
8、tions ofatoms of high or moderately high atomic weight. They arereferred to as heavy or high-density aggregates. The secondclass consists of minerals and synthetic glasses of substantialboron content that are particularly effective in absorbingthermal neutrons without producing highly penetrating ga
9、mmarays. The boron-frit glasses are included because of theirfrequent use.HEAVY AGGREGATES4. Descriptions of Naturally Occurring Constituents4.1 Members of this group have higher relative density(specific gravity) than aggregates in general use. Six are ironminerals, of which five are important iron
10、 ore minerals and thesixth is an ore of titanium. Two are barium minerals worked asthe principal sources of barium salts. The other is ferrophos-phorus, a mixture of synthetic iron phosphides.4.2 The constituents are described below first as minerals,and then as major constituents of ores when their
11、 aspect asmajor constituents of ores affects the behavior of ores asconcrete aggregates.5. Iron Minerals and Ores5.1 Hematite (Fe2O3)Hematite has a hardness of 5 to 6 onMohs scale (will be scratched by hard steel), and a relativedensity (specific gravity) of 5.26 when pure. The color variesfrom brig
12、ht red to dull red to steel gray; luster varies frommetallic to submetallic to dull; the streak is cherry red orreddish brown; it is nonmagnetic.5.1.1 Hematite OresRocks of which hematite is the majorconstituent vary from one deposit to another, and within thedeposit, in specific gravity, toughness,
13、 compactness, amount ofimpurities, degree of weathering, and suitability for use asconcrete aggregate. Hematite appears to be the iron ore mineralmost exploited as a source of iron. The ores of the LakeSuperior region are banded sedimentary ores consisting oflayers rich in hematite, and sometimes go
14、ethite, iron silicates,such as stilpnomelane, minnesotaite, greenalite, grunerite, andiron carbonate, alternating with silica-rich layers of chert orfine-grained quartz or a mixture. The Birmingham, AL ores are1This descriptive nomenclature is under the jurisdiction of ASTM CommitteeC09 on Concrete
15、and Concrete Aggregates and is the direct responsibility ofSubcommittee C09.41 on Pre-placed Aggregate Concrete for Radiation Shielding.Current edition approved Dec. 1, 2009. Published January 2010. Originallyapproved in 1973. Last previous edition approved in 2002 as C63892(2002). DOI:10.1520/C0638
16、-09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this
17、 standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.oolitic with hematite replacements of olites and fossils in amatrix that ranges from fine-grained earthy hematite, with orwithout calcite, to crystalline calcite. Hematite ores
18、 dust inhandling, with the dust ranging in color from moderate red todusky red to moderate reddish brown (5R 4/6 to 5R 3/4 to 10R4/6).35.2 Ilmenite (FeTiO3with minor Mg and Mn)Ilmenite hasa hardness of 5 to 6 and relative density (specific gravity) of4.72 6 0.04 when pure. The color is iron black wi
19、th metallicto submetallic luster; the streak is black; it is feebly magnetic.5.2.1 Ilmenite OresThese ores consist of crystalline il-menite with either magnetite or hematite and constituents ofthe associated gabbroic or anorthositic rocks. Massive ilmeniteores can form coarsely crystalline massive t
20、ough rocks butvary, from deposit to deposit, and within a deposit, in relativedensity (specific gravity), composition, hardness, and suitabil-ity for use as concrete aggregate. Many ilmenite ores consist ofilmenite disseminated in rock rather than concentrated as amajor rock-forming mineral. Ilmenit
21、e concentrated from beachsands is usually altered to a variable degree, and its mechanicalproperties probably differ from those of unaltered ilmenite.One of the most widely used types of heavy aggregates isilmenite ore.5.3 Lepidocrocite (FeO(OH)Lepidocrocite has a hard-ness of 5 and relative density
22、 (specific gravity) of 4.09 whenpure. The color varies from ruby red to reddish brown and thestreak is dull orange. Lepidocrocite and goethite occur to-gether, and lepidocrocite may be a constituent of goethite andlimonite ores.5.4 Goethite (HFeO2)Goethite has the same chemicalcomposition as lepidoc
23、rocite but crystallizes differently. Thehardness is 5 to 512 and the relative density (specific gravity)is 4.28 6 0.01 when pure and 3.3 to 4.3 in massive goethite.The color varies with the form, from crystals that are blackishbrown with imperfect adamantine-metallic luster, to dull orsilky luster i
24、n fibrous varieties; massive goethite is yellowishbrown to reddish brown; clayey material is brownish yellow toocher yellow. The streak is brownish yellow to ocher yellow.5.4.1 Goethite OresThese ores range from hard toughmassive rocks to soft crumbling earths; these alterationsfrequently occur with
25、in fractions of an inch.5.5 LimoniteA general name for hydrous iron oxides ofunknown composition frequently cryptocrystalline goethitewith adsorbed and capillary water, and probably mixtures ofsuch goethite with similar lepidocrocite or hematite, or both,with adsorbed and capillary water4. The relat
26、ive density(specific gravity) ranges from 2.7 to 4.3 and the color frombrownish black through browns to yellows. Limonite depositsrange from recognizable crystalline goethite to dull massivematerial of indefinite composition, and therefore, properlylimonite. Limonites of high iron content are also c
27、alled browniron ores. Frequently they contain sand, colloidal silica, clays,and other impurities.5.6 Magnetite (FeFe2O4)Magnetite has a hardness of 512to 612 and relative density (specific gravity) of 5.17 when pure.It is strongly magnetic; the color is black with metallic tosemimetallic luster; the
28、 streak is black.5.6.1 Magnetite OresThese ores can form dense, tough,usually coarse-grained rocks with few impurities. Magnetiteores are associated with metamorphic or igneous or sedimen-tary rocks, and therefore, the impurities associated with mag-netite ores may include a wide variety of rock-for
29、ming andaccessory minerals. Magnetite occurs in association withhematite and ilmenite; magnetic ores are widely distributed,but many are not suitable for use as heavy aggregate becausethe magnetite occurs disseminated through rock rather than asa major rock-forming mineral. One of the most widely us
30、edtypes of heavy aggregates is magnetite ore.6. Barium Minerals6.1 Witherite (BaCO3)Witherite has a hardness of 3 to 312and a relative density (specific gravity) of 4.29 when pure. Thecolor ranges from colorless to white to grayish or many palecolors. Like calcite and aragonite, witherite is decompo
31、sedwith effervescence by dilute hydrochloric acid (HCl). Wither-ite, the second most common barium mineral, occurs withbarite and galena. England is the chief producer of witherite,and barium-containing heavy aggregates in Great Britain mightbe expected to contain witherite as a major constituent.6.
32、2 Barite (BaSO4) (also, but improperly, called barytes)Barite has a hardness of 3 to 312 and a relative density (specificgravity) of 4.50 when pure. The color ranges from colorless towhite to many usually pale colors.6.2.1 Barite is the most common barium mineral and themajor barium ore. It occurs i
33、n veins transecting many kinds ofrocks, concentrated in sedimentary rocks, and as residualnodules in clays formed by the solution of sedimentary rocks.In many of its occurrences it is accompanied by clay or acalcium sulfate mineral (gypsum or anhydrite) or both. Al-though barite from residual deposi
34、ts is often weathered, it ispossible to obtain clean, well-graded barite aggregate.7. Ferrophosphorus7.1 Ferrophosphorus, a material produced in the productionof phosphorus, consists of a mixture of iron phosphides, andhas been used as coarse and fine aggregate in radiation-shielding concrete. Publi
35、shed relative density (specific gravity)range from 5.72 to 6.50 for coarse aggregate. The coarseaggregate is reported to degrade easily and has been associatedwith extreme retardation of set in concrete. Ferrophosphorus inconcrete releases flammable, and possibly toxic, gases whichcan develop high p
36、ressures if confined5.7.2 Several iron phosphides are known, including silvergray to blue gray Fe2P, with relative density (specific gravity)3National Research Council, Washington, DC, Rock Color Chart (1948)reissued 1964 by Geological Soc. Am., New York, NY.4Palache, Charles, et al., The System of
37、Mineralogy of J. D. Dana and E. S.Dana, Vol 1, Elements, Sulfides, Sulfosalts, Oxides, Ed. 7, New York, NY, 1944, p685.5Clendenning, T. G., Kellam, B., and MacInnis, C., “Hydrogen Evolution fromFerrophosphorous Aggregate in Portland Cement Concrete,” Journal of theAmerican Concrete Institute , No 12
38、, December 1968, Proceedings, Vol 65, pp.10211028.Mather, Bryant, discussion of Davis, Harold S., “Concrete for RadiationShieldingIn Perspective,” and closure by author in“ Concrete for NuclearReactors,” ACI SP-34, Vol 1, 1972 , pp 1113.C638 092of 6.50, FeP2with relative density (specific gravity) o
39、f 5.07,and Fe3P and FeP. Ferrophosphorus aggregates are silver graybut develop some rusty staining on exposure.BORON-CONTAINING MATERIALS8. Boron Minerals8.1 The gamma rays that result from neutron capture by thelighter isotope of boron, boron-10, are much less penetratingthan those which result fro
40、m neutron capture by hydrogen; andfor this reason boron and boron compounds are often used inneutron shields. The unusually high capture capability ofboron-10 permits its use in relatively small quantities. Boron ismost frequently incorporated in the concrete as borate mineralsor synthetic boron fri
41、ts. Both methods of incorporating boroncause some retardation of time of setting of the concrete, whichcan be counteracted by the use of a suitable accelerator. Theexperience recorded in the United States suggests that the costof synthetic frits, which is higher than the cost of borate, maybe counte
42、rbalanced by uniform composition of the frits, whichpermits effective control of the properties of the concrete.8.2 Minerals that are commercially important sources ofboron are principally sodium, calcium, and magnesium borateprecipitates from waters in arid volcanic regions, or alterationproducts o
43、f such precipitates (Table 1)6. These hydratedminerals include some that are easily altered by changes inrelative humidity and temperature. Some of them are soluble inor partly decomposed by cold water. Clay, gypsum, and salt arefound in borate deposits. The presence of one or more of thesein varyin
44、g unknown amounts in a borate ore used in shieldingconcrete may cause problems in making concrete with con-trolled strength, setting time, volume stability, and workability,aside from the problem of varying degrees of retardation as thetime composition, and thus the solubility, of the borate ore may
45、range from lot to lot or within a lot.8.3 Borate production in the United States is virtuallylimited to borax and borax derivates obtained from naturalbrines at Searles Lake, CA, and brines produced by treatingborates from the Kramer deposit at Boron, CA. Californiacolemanite deposits, which also co
46、ntain ulexite, are apparentlynot regularly worked but colemanite ores have been obtainedfrom them for use in shielding concrete. Turkish borate ores,which have been referred to as “borocalcite,” but probably areulexite or colemanite or mixtures of the two, have been used inshielding concrete in Germ
47、any and Japan7.8.4 Boron minerals that are stable and insoluble are usuallynot available in large quantities for use as aggregates. Therecorded exceptions are described below.8.4.1 Paigeite(Fe+Mg)Fe+BO5)Paigeite has a hard-ness of 5 and specific gravity ranging from 4.7 at the paigeiteend to 3.6 at
48、the ludwigite end of the paigeite-ludwigite series.It is coal black or greenish black and insoluble in water, andtough. It is a high-temperature mineral occurring with magne-tite in contact metamorphic deposits. Paigeite has been used asa heavy boron-containing aggregate in Japan.8.4.2 Tourmaline (N
49、a(Mg, Fe, Mn, Li, Al)3Al6Si6O18(BO3)3(OH,F)4)Tourmaline has a hardness of 7 and specificgravity ranging from 3.03 to 3.25; it ranges widely in color, butcommon varieties are brown or black. It is characteristically amineral of granites, pegmatites, and pneumatolytic veins, butpersists as a detrital mineral in sediments. Concrete havingeffective neutron-shielding characteristics has been describedin which the coarse aggregate was serpentine and the fineaggregate a tourmaline sand concentrate.9. Boron-Frit Glasses9.1 Boron-frit glasses are clear, colorl
