ASTM_C_638_-_14.pdf

Designation:C63814Standard 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 of 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 U.S.Department of Defense.1.Scope*1.1 This descriptive nomenclature is intended 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 discussedbelow 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 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 bemade 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:2C125 Terminology Relating to Concrete and Concrete Ag-gregatesC219 Terminology Relating to Hydraulic CementC294 Descriptive Nomenclature for Constituents of Con-crete Aggregates3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminologies C125 and C219.4.Types of Materials4.1 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 proportions 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 gammarays.The boron-frit glasses are included because of theirfrequent use.HEAVY AGGREGATES5.Descriptions of Naturally Occurring Constituents5.1 Members of this group have higher relative density(specific gravity)than aggregates in general use.Six are ironminerals,of which five are important iron ore minerals and thesixth is an ore of titanium.Two are barium minerals worked astheprincipalsourcesofbariumsalts.Theotherisferrophosphorus,a mixture of synthetic iron phosphides.5.2 The constituents are described below first as minerals,and then as major constituents of ores when their aspect asmajor constituents of ores affects the behavior of ores asconcrete aggregates.6.Iron Minerals and Ores6.1 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 bright red to dull red to steel gray;luster varies frommetallic to submetallic to dull;the streak is cherry red orreddish brown;it is nonmagnetic.6.1.1 Hematite OresRocks of which hematite is the majorconstituent vary from one deposit to another,and within the1This descriptive nomenclature is under the jurisdiction of ASTM CommitteeC09 on Concrete and Concrete Aggregates and is the direct responsibility ofSubcommittee C09.41 on Hydraulic Cement Grouts.Current edition approved June 1,2014.Published June 2014.Originallyapproved in 1973.Last previous edition approved in 2009 as C638 09.DOI:10.1520/C0638-14.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 deposit,in specific gravity,toughness,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 goethite,iron silicates,such as stilpnomelane,minnesotaite,greenalite,grunerite,andiron carbonate,alternating with silica-rich layers of chert orfine-grained quartz or a mixture.Th