1、Designation: C128 15Standard Test Method forRelative Density (Specific Gravity) and Absorption of FineAggregate1This standard is issued under the fixed designation C128; 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.1. Scope1.1 This test method covers the determination of relativedensity (specific gravity) and the absorption of fine aggregates.T
3、he relative density (specific gravity), a dimensionless quality,is expressed as oven-dry (OD), saturated-surface-dry (SSD), oras apparent relative density (specific gravity). The OD relativedensity is determined after drying the aggregate. The SSDrelative density and absorption are determined after
4、soaking theaggregate in water for a prescribed duration.1.2 This test method is not intended to be used for light-weight aggregates that comply with Specification C332 GroupI aggregates.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thi
5、sstandard.1.4 The text of this test method references notes andfootnotes that provide explanatory material. These notes andfootnotes (excluding those in tables and figures) shall not beconsidered as requirements of this test method.1.5 This standard does not purport to address all of thesafety conce
6、rns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C29/C29M Test Method for Bulk Density (“
7、Unit Weight”)and Voids in AggregateC70 Test Method for Surface Moisture in Fine AggregateC117 Test Method for Materials Finer than 75-m (No. 200)Sieve in Mineral Aggregates by WashingC125 Terminology Relating to Concrete and Concrete Ag-gregatesC127 Test Method for Relative Density (Specific Gravity
8、)and Absorption of Coarse AggregateC330 Specification for Lightweight Aggregates for Struc-tural ConcreteC332 Specification for Lightweight Aggregates for Insulat-ing ConcreteC188 Test Method for Density of Hydraulic CementC566 Test Method for Total Evaporable Moisture Content ofAggregate by DryingC
9、670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC702 Practice for Reducing Samples ofAggregate to TestingSizeC1252 Test Methods for Uncompacted Void Content of FineAggregate (as Influenced by Particle Shape, SurfaceTexture, and Grading) (Withdrawn 2
10、015)3D75 Practice for Sampling AggregatesD854 Test Methods for Specific Gravity of Soil Solids byWater Pycnometer2.2 AASHTO Standard:AASHTO T 84 Specific Gravity and Absorption of FineAggregates43. Terminology3.1 DefinitionsFor definitions of terms used in thisstandard, refer to Terminology C125.4.
11、Summary of Test Method4.1 A sample of aggregate is immersed in water for 24 6 4h to essentially fill the pores. It is then removed from the water,the water is dried from the surface of the particles, and themass determined. Subsequently, the sample (or a portion of it)is placed in a graduated contai
12、ner and the volume of the sampleis determined by the gravimetric or volumetric method. Finally,1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregatesand is the direct responsibility of SubcommitteeC09.20 on Normal Weight Aggregates.Current edition approv
13、ed Jan. 1, 2015. Published March 2015. Originallyapproved in 1936. Last previous edition approved in 2012 as C12812. DOI:10.1520/C0128-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume
14、information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington,
15、DC 20001,http:/www.transportation.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1the sample is oven-dried and the mass determined again. Usingthe mass values thus obtained and formulas in this test method,it is possible to calcul
16、ate relative density (specific gravity) andabsorption.5. Significance and Use5.1 Relative density (specific gravity) is the ratio of mass ofan aggregate to the mass of a volume of water equal to thevolume of the aggregate particles also referred to as theabsolute volume of the aggregate. It is also
17、expressed as theratio of the density of the aggregate particles to the density ofwater. Distinction is made between the density of aggregateparticles and the bulk density of aggregates as determined byTest Method C29/C29M, which includes the volume of voidsbetween the particles of aggregates.5.2 Rel
18、ative density is used to calculate the volume occu-pied by the aggregate in various mixtures containing aggregateincluding hydraulic cement concrete, bituminous concrete, andother mixtures that are proportioned or analyzed on an absolutevolume basis. Relative density (specific gravity) is also used
19、inthe computation of voids in aggregate in Test Method C29/C29M and in Test Method C1252. Relative density (specificgravity) (SSD) is used in the determination of surface moistureon fine aggregate by displacement of water in Test MethodC70. Relative density (specific gravity) (SSD) is used if theagg
20、regate is in a saturated surface-dry condition, that is, if itsabsorption has been satisfied.Alternatively, the relative density(specific gravity) (OD) is used for computations when theaggregate is dry or assumed to be dry.5.3 Apparent relative density (specific gravity) pertain to thesolid material
21、 making up the constituent particles not includingthe pore space within the particles that is accessible to water.This value is not widely used in construction aggregatetechnology.5.4 Absorption values are used to calculate the change in themass of an aggregate material due to water absorbed in the
22、porespaces within the constituent particles, compared to the drycondition, if it is deemed that the aggregate has been in contactwith water long enough to satisfy most of the absorptionpotential. The laboratory standard for absorption is that ob-tained after submerging dry aggregate for a prescribed
23、 periodof time. Aggregates mined from below the water table com-monly have a moisture content greater than the absorptiondetermined by this test method, if used without opportunity todry prior to use. Conversely, some aggregates that have notbeen continuously maintained in a moist condition until us
24、edare likely to contain an amount of absorbed moisture less thanthe 24-h soaked condition. For an aggregate that has been incontact with water and that has free moisture on the particlesurfaces, the percentage of free moisture is determined bydeducting the absorption from the total moisture contentd
25、etermined by Test Method C566 by drying.5.5 The general procedures described in this test method aresuitable for determining the absorption of aggregates that havehad conditioning other than the 24-h soak, such as boilingwater or vacuum saturation. The values obtained for absorptionby other test met
26、hods will be different than the values obtainedby the prescribed 24-h soak, as will the relative density(specific gravity) (SSD).6. Apparatus6.1 BalanceA balance or scale having a capacity of 1 kgor more, sensitive to 0.1 g or less, and accurate within 0.1 % ofthe test load at any point within the r
27、ange of use for this testmethod. Within any 100-g range of test load, a differencebetween readings shall be accurate within 0.1 g.6.2 Pycnometer (for Use with Gravimetric Procedure)Aflask or other suitable container into which the fine aggregatetest sample can be readily introduced and in which the
28、volumecontent can be reproduced within 6 0.1 cm3. The volume ofthe container filled to mark shall be at least 50 % greater thanthe space required to accommodate the test sample. A volu-metric flask of 500-cm3capacity or a fruit jar fitted with apycnometer top is satisfactory for a 500-g test sample
29、of mostfine aggregates.6.3 Flask (for Use with Volumetric Procedure)A Le Chat-elier flask as described in Test Method C188 is satisfactory foran approximately 55-g test sample.6.4 Mold and Tamper for Surface Moisture TestThe metalmold shall be in the form of a frustum of a cone withdimensions as fol
30、lows: 40 6 3-mm inside diameter at the top,906 3-mm inside diameter at the bottom, and 75 6 3mminheight, with the metal having a minimum thickness of 0.8 mm.The metal tamper shall have a mass of 340 6 15 g and a flatcircular tamping face 25 6 3 mm in diameter.6.5 OvenAn oven of sufficient size, capa
31、ble of maintain-ing a uniform temperature of 110 6 5 C (230 6 9 F).7. Sampling7.1 Sample the aggregate in accordance with Practice D75.Thoroughly mix the sample and reduce it to obtain a testspecimen of approximately 1 kg using the applicable proce-dures described in Practice C702.8. Preparation of
32、Test Specimen8.1 Place the test specimen in a suitable pan or vessel anddry in the oven to constant mass at a temperature of 110 6 5C (230 6 9 F). Allow it to cool to comfortable handlingtemperature (approximately 50 C), cover with water, either byimmersion or by the addition of at least 6 % moistur
33、e to thefine aggregate, and permit to stand for 24 6 4 h. WhenSpecification C330 or Specification C332 Group II lightweightaggregates are used, immerse the aggregate in water at roomtemperature for a period of 72 6 4 h, stirring for at least oneminute every 24 h.8.1.1 When the absorption and relativ
34、e density (specificgravity) values are to be used in proportioning concretemixtures in which the aggregates will be in their naturallymoist condition, the requirement in 8.1 for initial drying isoptional, and, if the surfaces of the particles in the sample havebeen kept continuously wet until tested
35、, the requirement in 8.1for 24 6 4 h soaking or 72 6 4 h is also optional.NOTE 1Values for absorption and for relative density (specificgravity) (SSD) may be significantly higher for aggregate not oven driedC128 152before soaking than for the same aggregate treated in accordance with 8.1.8.2 Decant
36、excess water with care to avoid loss of fines (seealso Appendix X1), spread the sample on a flat nonabsorbentsurface exposed to a gently moving current of warm air, andstir frequently to secure homogeneous drying. Employ me-chanical aids such as tumbling or stirring to assist in achievingthe saturat
37、ed surface-dry condition, if desired. Continue thisoperation until the test specimen approaches a free-flowingcondition. Follow the procedure in 8.3 to determine if surfacemoisture is still present on the constituent fine aggregateparticles. Make the first trial for surface moisture when there issti
38、ll some surface water in the test specimen. Continue dryingwith constant stirring and test at frequent intervals until the testindicates that the specimen has reached a surface-dry condi-tion. If the first trial of the surface moisture test indicates thatmoisture is not present on the surface, it ha
39、s been dried past thesaturated surface-dry condition. In this case, thoroughly mix afew millilitres of water with the fine aggregate and permit thespecimen to stand in a covered container for 30 min. Thenresume the process of drying and testing at frequent intervalsfor the onset of the surface-dry c
40、ondition.8.3 Test for Surface MoistureHold the mold firmly on asmooth nonabsorbent surface with the large diameter down.Place a portion of the partially dried fine aggregate loosely inthe mold by filling it to overflowing and heaping additionalmaterial above the top of the mold by holding it with th
41、ecupped fingers of the hand holding the mold. Lightly tamp thefine aggregate into the mold with 25 light drops of the tamper.Start each drop approximately 5 mm above the top surface ofthe fine aggregate. Permit the tamper to fall freely undergravitational attraction on each drop. Adjust the starting
42、 heightto the new surface elevation after each drop and distribute thedrops over the surface. Remove loose sand from the base andlift the mold vertically. If surface moisture is still present, thefine aggregate will retain the molded shape. Slight slumping ofthe molded fine aggregate indicates that
43、it has reached asurface-dry condition.8.3.1 Some fine aggregate with predominately angular-shaped particles or with a high proportion of fines does notslump in the cone test upon reaching the surface-dry condition.Test by dropping a handful of the fine aggregate from the conetest onto a surface from
44、 a height of 100 to 150 mm, andobserve for fines becoming airborne; presence of airborne finesindicates this problem. For these materials, consider thesaturated surface-dry condition as the point that one side of thefine aggregate slumps slightly upon removing the mold.NOTE 2The following criteria h
45、ave also been used on materials thatdo not readily slump:(1) Provisional Cone TestFill the cone mold as describedin 8.3 except only use 10 drops of the tamper. Add more fineaggregate and use 10 drops of the tamper again. Then addmaterial two more times using 3 and 2 drops of the tamper,respectively.
46、 Level off the material even with the top of themold, remove loose material from the base; and lift the moldvertically.(2) Provisional Surface TestIf airborne fines are notedwhen the fine aggregate is such that it will not slump when itis at a moisture condition, add more moisture to the sand, andat
47、 the onset of the surface-dry condition, with the hand lightlypat approximately 100 g of the material on a flat, dry, clean,dark or dull nonabsorbent surface such as a sheet of rubber, aworn oxidized, galvanized, or steel surface, or a black-paintedmetal surface. After 1 to 3 s, remove the fine aggr
48、egate. Ifnoticeable moisture shows on the test surface for more than 1to 2 s then surface moisture is considered to be present on thefine aggregate.(3) Colorimetric procedures described by Kandhal and Lee,Highway Research Record No. 307, p. 44.(4) For reaching the saturated surface-dry condition on
49、asingle size material that slumps when wet, hard-finish papertowels can be used to surface dry the material until the point isjust reached where the paper towel does not appear to bepicking up moisture from the surfaces of the fine aggregateparticles.9. Procedure9.1 Test by either the gravimetric procedure in 9.2 or thevolumetric procedure in 9.3. Make all determinations of massto 0.1 g.9.2 Gravimetric (Pycnometer) Procedure:9.2.1 Partially fill the pycnometer with water. Introduce intothe pycnometer 500 6 10 g of saturated surface-dry fineaggregate prepared as de
