1、Designation: C128 12Standard Test Method forDensity, Relative Density (Specific Gravity), and Absorptionof Fine Aggregate1This 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
2、 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 Department of Defense.1. Scope1.1 This test method covers the
3、determination of the averagedensity of a quantity of fine aggregate particles (not includingthe volume of voids between the particles), the relative density(specific gravity), and the absorption of the fine aggregate.Depending on the procedure used, the density, in kg/m3(lb/ft3)is expressed as oven-
4、dry (OD), saturated-surface-dry (SSD), oras apparent density. Likewise, relative density (specific grav-ity), a dimensionless quality, is expressed as OD, SSD, or asapparent relative density (apparent specific gravity). The ODdensity and OD relative density are determined after drying theaggregate.
5、The SSD density, SSD relative density, and absorp-tion are determined after soaking the aggregate in water for aprescribed duration.1.2 This test method is used to determine the density of theessentially solid portion of a large number of aggregateparticles and provides an average value representing
6、 thesample. Distinction is made between the density of aggregateparticles as determined by this test method, and the bulkdensity of aggregates as determined by Test Method C29/C29M, which includes the volume of voids between theparticles of aggregates.1.3 This test method is not intended to be used
7、for light-weight aggregates that comply with Specification C332 GroupI aggregates.1.4 The values stated in SI units are to be regarded as thestandard for conducting the tests. The test results for densityshall be reported in either SI units or inch-pound units, asappropriate for the use to be made o
8、f the results.1.5 The text of this test method references notes andfootnotes which provide explanatory material. These notes andfootnotes (excluding those in tables and figures) shall not beconsidered as requirements of this test method.1.6 This standard does not purport to address all of thesafety
9、concerns, 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 Densi
10、ty (“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 Density, Relative Density (Sp
11、ecificGravity), 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 Contentof Aggre
12、gate by DryingC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC702 Practice for Reducing Samples of Aggregate to Test-ing SizeD75 Practice for Sampling AggregatesD854 Test Methods for Specific Gravity of Soil Solids byWater Pycnometer2.2 AASHTO Sta
13、ndard:AASHTO No. T 84 Specific Gravity andAbsorption of FineAggregates33. Terminology3.1 Definitions:1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.20 on Normal Weight Aggregates.Current edition
14、 approved April 1, 2012. Published May 2012. Originallyapproved in 1936. Last previous edition approved in 2007 as C12807a. DOI:10.1520/C0128-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
15、volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.1Copyright ASTM International, 100 Barr
16、 Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.1 absorption, nthe increase in mass of aggregate dueto water penetrating into the pores of the particles, during aprescribed period of time but not including water adhering tothe outside surface of the particles, express
17、ed as percentage ofthe dry mass.3.1.2 density, nthe mass per unit volume of a material,expressed as kilograms per cubic metre (pounds per cubicfoot).3.1.2.1 density (OD), nthe mass of oven-dry aggregateparticles per unit volume of aggregate particles, including thevolume of permeable and impermeable
18、 pores within particles,but not including the voids between the particles.3.1.2.2 density (SSD), nthe mass of saturated-surface-dryaggregate per unit volume of the aggregate particles, includingthe volume of impermeable pores and permeable, water-filledpores within the particles, but not including t
19、he voids betweenthe particles.3.1.2.3 apparent density, nthe mass per unit volume of theimpermeable portion of the aggregate particles.3.1.3 oven-dry (OD), adjrelated to aggregate particles,the condition in which the aggregates have been dried byheating in an oven at 110 6 5 C for sufficient time to
20、 reach aconstant mass.3.1.4 relative density (specific gravity), nthe ratio of thedensity of a material to the density of water at a statedtemperature; the values are dimensionless.3.1.4.1 relative density (specific gravity), (OD), nthe ratioof the density (OD) of the aggregate to the density of wat
21、er ata stated temperature.3.1.4.2 relative density (specific gravity), (SSD), nTheratio of the density (SSD) of the aggregate to the density ofwater at a stated temperature.3.1.4.3 apparent relative density (apparent specific gravity),nthe ratio of the apparent density of aggregate to the densityof
22、water at a stated temperature.3.1.5 saturated-surface-dry (SSD), adjrelated to aggre-gate particles, the condition in which the permeable pores ofaggregate particles are filled with water to the extent achievedby submerging in water for the prescribed period of time, butwithout free water on the sur
23、face of the particles.3.1.6 For definitions of other terms related to aggregates seeTerminology C125.4. 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 particl
24、es, and themass determined. Subsequently, the sample (or a portion of it)is placed in a graduated container and the volume of the sampleis determined by the gravimetric or volumetric method. Finally,the sample is oven-dried and the mass determined again. Usingthe mass values thus obtained and formul
25、as in this test method,it is possible to calculate density, relative density (specificgravity), and absorption.5. Significance and Use5.1 Relative density (specific gravity) is the characteristicgenerally used for calculation of the volume occupied by theaggregate in various mixtures containing aggr
26、egate includingportland cement concrete, bituminous concrete, and othermixtures that are proportioned or analyzed on an absolutevolume basis. Relative density (specific gravity) is also used inthe computation of voids in aggregate in Test Method C29/C29M. Relative density (specific gravity) (SSD) is
27、 used in thedetermination of surface moisture on fine aggregate by dis-placement of water in Test Method C70. Relative density(specific gravity) (SSD) is used if the aggregate is wet, that is,if its absorption has been satisfied. Conversely, the density orrelative density (specific gravity) (OD) is
28、used for computa-tions when the aggregate is dry or assumed to be dry.5.2 Apparent density and apparent relative density (apparentspecific gravity) pertain to the solid material making up theconstituent particles not including the pore space within theparticles that is accessible to water. This valu
29、e is not widelyused in construction aggregate technology.5.3 Absorption values are used to calculate the change in themass of an aggregate material due to water absorbed in the porespaces within the constituent particles, compared to the drycondition, when it is deemed that the aggregate has been in
30、contact with water long enough to satisfy most of the absorp-tion potential. The laboratory standard for absorption is thatobtained after submerging dry aggregate for a prescribedperiod of time. Aggregates mined from below the water tablecommonly have a moisture content greater than the absorptionde
31、termined by this test method, if used without opportunity todry prior to use. Conversely, some aggregates which have notbeen continuously maintained in a moist condition until usedare likely to contain an amount of absorbed moisture less thanthe 24-h soaked condition. For an aggregate that has been
32、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 contentdetermined by Test Method C566 by drying.5.4 The general procedures described in this test method aresuitable for determini
33、ng 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 methods will be different than the values obtainedby the prescribed 24-h soak, as will the density (SSD) orrelative density (
34、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 range of use for this testmethod. Within any 100-g range of test load, a differencebetween readings shall b
35、e 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 volumecontent can be reproduced within 6 0.1 cm3. The volume ofthe container filled to mark shall be at le
36、ast 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 of mostfine aggregates.C128 1226.3 Flask (for Use with Volumetric Procedure)A LeChatelier flask as describ
37、ed in Test Method C188 is satisfactoryfor an 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 follows: 40 6 3-mm inside diameter at the top,906 3-mm inside diameter at the bottom, and 75 6 3mminhei
38、ght, 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, capable of maintain-ing a uniform temperature of 110 6 5 C (230 6 9 F).7. Sampling7.1 Sample the aggrega
39、te 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 Test Specimen8.1 Place the test specimen in a suitable pan or vessel anddry in the oven to constant
40、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 % moisture to thefine aggregate, and permit to stand for 24 6 4 h. WhenSpecification C330 or Specification C3
41、32 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 relative density (specificgravity) values are to be used in proportioning concretemixtures in which the agg
42、regates 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, the requirement in 8.1for 24 6 4 h soaking or 72 6 4 h is also optional.NOTE 1Values for absorptio
43、n and for relative density (specific grav-ity) (SSD) may be significantly higher for aggregate not oven dried beforesoaking than for the same aggregate treated in accordance with 8.1.8.2 Decant excess water with care to avoid loss of fines (seealso Appendix X1), spread the sample on a flat nonabsorb
44、entsurface 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 saturated surface-dry condition, if desired. Continue thisoperation until the test specimen approaches a free-flo
45、wingcondition. 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 isstill some surface water in the test specimen. Continue dryingwith constant stirring and test at frequent int
46、ervals 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 has been dried past thesaturated surface-dry condition. In this case, thoroughly mix afew millilitres of wat
47、er 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 condition.8.3 Test for Surface MoistureHold the mold firmly on asmooth nonabsorbent surface with the large
48、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 thecupped fingers of the hand holding the mold. Lightly tamp thefine aggregate into the mold with 25 light d
49、rops 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 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 it has reached asurface-dry condition.8.3.1 Some fine aggregate with p
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1