ASTM C294-2012 Standard Descriptive Nomenclature for Constituents of Concrete Aggregates《混凝土集料成分的标准描述术语》.pdf

1、Designation:C29405 Designation: C294 12Standard Descriptive Nomenclature forConstituents of Concrete Aggregates1This standard is issued under the fixed designation C294; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l

2、ast 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. Scope1.1 This descriptive nomenclature provides

3、 brief descriptions of some of the more commonly occurring, or more important,natural and artificial materials of which mineral aggregates are composed. The descriptions provide a basis for understanding theseterms as applied to concrete aggregates. When appropriate, brief observations regarding the

4、 potential effects of using the naturaland artificial materials in concrete are discussed.NOTE 1These descriptions characterize minerals and rocks as they occur in nature and blast-furnace slag or lightweight aggregates that are preparedby the alteration of the structure and composition of natural m

5、aterial. Information about lightweight aggregates areis given in Specifications C330, C331,and C332.1.2 This standard does not include descriptions of constituents of aggregates used in radiation shielding concrete. SeeDescriptive Nonmenclature C638.1.3 The values stated in SI units are to be regard

6、ed as standard. No other units of measurement are included in this standard.2. Referenced Documents2.1 ASTM Standards:2C125 Terminology Relating to Concrete and Concrete AggregatesC227 Test Method for Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method)C289 Test Method fo

7、r Potential Alkali-Silica Reactivity of Aggregates (Chemical Method)C330 Specification for Lightweight Aggregates for Structural ConcreteC331 Specification for Lightweight Aggregates for Concrete Masonry UnitsC332 Specification for Lightweight Aggregates for Insulating ConcreteC638 Descriptive Nomen

8、clature of Constituents of Aggregates for Radiation-Shielding Concrete3. Terminology3.1 For definitions of terms in this standard, refer to Terminology C125.4. Significance and Use3.1This4.1 This descriptive nomenclature provides information on terms commonly applied to concrete aggregates. Thisstan

9、dard is intended to assist in understanding the meaning and significance of the terms.3.2Many4.2 Many of the materials described frequently occur in particles that do not display all the characteristics given in thedescriptions, and most of the described rocks grade from varieties meeting one descri

10、ption to varieties meeting another with allintermediate stages being found.3.3The4.3 The accurate identification of rocks and minerals can, in many cases, be made only by a qualified geologist,mineralogist, or petrographer using the apparatus and procedures of these sciences. Reference to these desc

11、riptions may, however,serve to indicate or prevent gross errors in identification. Identification of the constituent materials in an aggregate may assist incharacterizing its engineering properties, but identification alone cannot provide the sole basis for predicting behavior of aggregatesin servic

12、e. Aggregates of any type or combination of types may perform well or poorly in service depending upon the exposureto which the concrete is subjected, the physical and chemical properties of the matrix in which they are embedded, their physicalcondition at the time they are used, and other factors.

13、Constituents that may occur only in minor amounts in the aggregate may1This descriptive nomenclature is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.65 on Petrography.Current edition approved Jan.July 1, 2005.201

14、2. Published January 2005.September 2012. Originally approved in 1952. Last previous edition approved in 20042005 asC29404.C29405. DOI: 10.1520/C0294-05.10.1520/C0294-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Ann

15、ual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not b

16、e technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Driv

17、e, PO Box C700, West Conshohocken, PA 19428-2959, United States.or may not decisively influence its performance. Information about concrete aggregate performance in concrete has been publishedby ASTM.3CONSTITUENTS OF NATURAL MINERAL AGGREGATES4.5. Classes and Types4.1The5.1 The materials found as co

18、nstituents of natural mineral aggregates are minerals and rocks.45.2 Minerals are naturally occurring inorganic substances of more or less definite chemical composition and usually of aspecific crystalline structure. The physical nature of the rock-forming minerals and aspects of crystal chemistry d

19、etermine theimportant physical and chemical properties of natural mineral aggregates. Certain assemblages of rock-forming minerals possessdesirable qualities for use as aggregates in cementitious materials.45.2.1 Minerals are characterized by their crystallographic, physical, and optical properties

20、and their chemical composition. Thecrystallographic properties of minerals may be determined by x-ray diffraction and optical properties (1-6). The physical propertiesof minerals include but are not limited to crystal habit, cleavage, parting, fracture, hardness, specific gravity, luster, color, str

21、eak,magnetism, luminescence, and pyroelectricity (7). The optical properties of minerals include but are not limited to refractive index,birefringence, optic sign, pleochroism, and sign of elongation (2-5). Methods to determine the chemical composition of mineralsinclude but are not limited to optic

22、al properties (5), flame photometry (7,8), chemical spot tests (9,10), various staining techniques(11), x-ray fluorescence, and electron microscopy (12-14).45.2.2 Different minerals may have the same chemical composition but different crystallographic and physical properties. Suchsets of minerals ar

23、e known as polymorphs. Distinguishing between some polymorphs can be important for determining thesuitability of aggregates for use in cementitious materials.4.3Rocks5.3 Rocks are classified according to origin into three major divisions: igneous, sedimentary, and metamorphic. Thesethree major group

24、s are subdivided into types according to mineral and chemical composition, texture, and internal structure. Mostrocks are composed of several minerals but some are composed of only one mineral. Certain examples of the rock quartzite arecomposed exclusively of the mineral quartz, and certain limeston

25、es are composed exclusively of the mineral calcite. Individualsand grains frequently are composed of particles of rock, but they may be composed of a single mineral, particularly in the finersizes.45.3.1 Igneous rocks form from molten matter either at or below the earths surface.45.3.2 Sedimentary r

26、ocks form near the earths surface by the accumulation and consolidation of the products of weatheringand erosion of existing rocks, or by direct chemical precipitation. Sedimentary rocks may form from pre-existing igneous,metamorphic, or sedimentary rocks.45.3.3 Metamorphic rocks form from pre-exist

27、ing igneous, sedimentary, or metamorphic rocks by the action of heat or pressureor both.5.6. Silica Minerals5.16.1 Quartza very common hard mineral composed of silica (SiO2). It will scratch glass and is not scratched by a knife. Whenpure it is colorless with a glassy (vitreous) luster and a shell-l

28、ike (conchoidal) fracture. It lacks a visible cleavage (the ability tobreak in definite directions along even planes) and, when present in massive rocks such as granite, it usually has no characteristicshape. It is resistant to weathering and is therefore an important constituent of many sand and gr

29、avel deposits and many sandstones.It is also abundant in many light-colored igneous and metamorphic rocks. Some strained, or intensely fractured (granulated), andmicrocrystalline quartz may be potentially deleteriously reactive with the alkalies in the hydraulic cement paste.5.26.2 Opala hydrous for

30、m of silica (SiO2 nH2O) which occurs without characteristic external form or internal crystallinearrangement as determined by ordinary visible light methods. When X-ray diffraction methods are used, opal may show someevidences of internal crystalline arrangement. Opal has a variable water content, g

31、enerally ranging from 3 to 9 %. The specificgravity and hardness are always less than those of quartz. The color is variable and the luster is resinous to glassy. It is usuallyfound in sedimentary rocks, especially some cherts, and is the principal constituent of diatomite. It is also found as a sec

32、ondarymaterial filling cavities and fissures in igneous rocks and may occur as a coating on gravel and sand. The recognition of opal inaggregates is important because it is potentially deleteriously reactive with the alkalies in hydraulic cement paste or with thealkalies from other sources, such as

33、aggregates containing zeolites, and ground water.5.36.3 Chalcedonychalcedony has been considered both as a distinct mineral and a variety of quartz. It is frequently composedof a mixture of microscopic fibers of quartz with a large number of submicroscopic pores filled with water and air. The proper

34、ties3Klieger, P., and Lamond, J. F., editors, Significance of Tests and Properties of Concrete and Concrete-Making Materials, ASTM STP 169C, 1994.C294 122of chalcedony are intermediate between those of opal and quartz, from which it can sometimes be distinguished only by laboratorytests. It frequent

35、ly occurs as a constituent of the rock chert and is potentially deleteriously reactive with the alkalies in hydrauliccement paste.5.46.4 Tridymite and cristobalitehigh temperature crystalline forms of silica (SiO2) sometimes found in volcanic rocks. They aremetastable at ordinary temperatures and pr

36、essures. They are rare minerals in aggregates except in areas where volcanic rocks areabundant. A type of cristobalite is a common constituent of opal. Tridymite and cristobalite are potentially deleteriously reactivewith the alkalies in hydraulic cement paste.6.7. Feldspars6.1The7.1 The minerals of

37、 the feldspar group are the most abundant rock-forming minerals in the crust of the earth. They areimportant constituents of all three major rock groups, igneous, sedimentary, and metamorphic. Since all feldspars have goodcleavages in two directions, particles of feldspar usually show several smooth

38、 surfaces. Frequently, the smooth cleavage surfacesshow fine parallel lines.All feldspars are slightly less hard than, and can be scratched by, quartz and will, when fresh, easily scratcha penny. The various members of the group are differentiated by chemical composition and crystallographic propert

39、ies. Thefeldspars orthoclase, sanidine, and microcline are potassium aluminum silicates, and are frequently referred to as potassiumfeldspars. The plagioclase feldspars include those that are sodium aluminum silicates and calcium aluminum silicates, or bothsodium and calcium aluminum silicates. This

40、 group, frequently referred to as the “soda-lime” group, includes a continuous series,of varying chemical composition and optical properties, from albite, the sodium aluminum feldspar, to anorthite, the calciumaluminum feldspar, with intermediate members of the series designated oligoclase, andesine

41、, labradorite, and bytownite.Potassium feldspars and sodium-rich plagioclase feldspars occur typically in igneous rocks such as granites and rhyolites, whereas,plagioclase feldspars of higher calcium content are found in igneous rocks of lower silica content such as diorite, gabbro, andesite,and bas

42、alt.7.Ferromagnesian Minerals7.1Many igneous and metamorphic rocks contain dark green to black minerals that are generally silicates of iron or magnesium,or of both. They include the minerals of the amphibole, pyroxene, and olivine groups. The most common amphibole mineral ishornblende; the most com

43、mon pyroxene mineral is augite; and the most common olivine mineral is forsterite. Dark mica, such asbiotite and phlogopite, are also considered ferromagnesian minerals. The amphibole and pyroxene minerals are brown to green toblack and generally occur as prismatic units. Olivine is usually olive gr

44、een, glassy in appearance, and usually altered. Biotite hasexcellent cleavage and can be easily cleaved into thin flakes and plates. These minerals can be found as components of a varietyof rocks, and in sands and gravels. Olivine is found only in dark igneous rocks where quartz is not present, and

45、in sands and gravelsclose to the olivine source.8. Ferromagnesian Minerals8.1 Many igneous and metamorphic rocks contain dark green to black minerals that are generally silicates of iron or magnesium,or of both. They include the minerals of the amphibole, pyroxene, and olivine groups. The most commo

46、n amphibole mineral ishornblende; the most common pyroxene mineral is augite; and the most common olivine mineral is forsterite. Dark mica, such asbiotite and phlogopite, are also considered ferromagnesian minerals. The amphibole and pyroxene minerals are brown to green toblack and generally occur a

47、s prismatic units. Olivine is usually olive green, glassy in appearance, and usually altered. Biotite hasexcellent cleavage and can be easily cleaved into thin flakes and plates. These minerals can be found as components of a varietyof rocks, and in sands and gravels. Olivine is found only in dark i

48、gneous rocks where quartz is not present, and in sands and gravelsclose to the olivine source.9. Micaceous Minerals89.1 Micaceous minerals have perfect cleavage in one direction and can be easily split into thin flakes. The mica minerals ofthe muscovite group are colorless to light green; of the bio

49、tite group, dark brown to black or dark green; of the lepidolite group,white to pink and red or yellow; and of the chlorite group, shades of green. Another mica, phlogopite, is similar to biotite,commonly has a pearl-like luster and bronze color, and less commonly is brownish red, green, or yellow. The mica minerals arecommon and occur in igneous, sedimentary, and metamorphic rocks, and are common as minor to trace components in many sandsand gravels. The muscovite, biotite, lepidolite, and phlogopite minerals cleave into flakes and plates that are elastic; the chloritemine