1、Designation: C1761/C1761M 12Standard Specification forLightweight Aggregate for Internal Curing of Concrete1This standard is issued under the fixed designation C1761/C1761M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers lightweight aggregate intendedto provide water for internal curing of concrete. It includ
3、es testmethods for determining the absorption and desorption prop-erties of lightweight aggregate.NOTE 1Internal curing provides an additional source of water tosustain hydration and substantially reduce the early-age autogenousshrinkage and self-desiccation that can be significant contributors toea
4、rly-age cracking. Appendix X1 provides guidance on calculating thequantity of lightweight aggregate for internal curing.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, each
5、system shall be used independently of the other. Combiningvalues from the two systems may result in non-conformance.Some values have only SI units because the inch-poundequivalents are not used in practice.NOTE 2Sieve size is identified by its standard designation in Speci-fication E11. The alternat
6、ive designation given in parentheses is forinformation only and does not represent a different standard sieve size.1.3 The text of this standard references notes and footnotesthat provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas
7、 requirements of the standard.1.4 This standard does not purport to address all of thesafety 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 limitation
8、s prior to use.2. Referenced Documents2.1 ASTM Standards:2C29/C29M Test Method for Bulk Density (“Unit Weight”)and Voids in AggregateC40 Test Method for Organic Impurities in Fine Aggregatesfor ConcreteC87 Test Method for Effect of Organic Impurities in FineAggregate on Strength of MortarC114 Test M
9、ethods for Chemical Analysis of HydraulicCementC125 Terminology Relating to Concrete and Concrete Ag-gregatesC128 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Fine AggregateC136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC142 Test Method for Clay Lum
10、ps and Friable Particles inAggregatesC330/C330M Specification for Lightweight Aggregates forStructural ConcreteC641 Test Method for Iron Staining Materials in Light-weight Concrete AggregatesC702 Practice for Reducing Samples of Aggregate to Test-ing SizeC1498 Test Method for Hygroscopic Sorption Is
11、otherms ofBuilding MaterialsC1608 Test Method for Chemical Shrinkage of HydraulicCement PasteC1698 Test Method for Autogenous Strain of Cement Pasteand MortarD75 Practice for Sampling AggregatesE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 Definitions:3.1.1 For de
12、finitions of terms used in this practice, refer toTerminology C125.3.2 Definitions of Terms Specific to This Standard:3.2.1 absorption, A72, nof lightweight aggregate, theincrease in mass of a specimen of oven-dry lightweightaggregate due to water penetrating into the permeable pores ofthe particles
13、 after being submerged for 72 h, expressed aspercentage of oven-dry mass.1This specification is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.21 on Lightweight Aggregates and Concrete.Current edition approved June
14、15, 2012. Published August 2012. DOI: 10.1520/C1761_C1761M-12.2For 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
15、.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.2 autogenous shrinkage, nreduction in volume due tochemical shrinkage of a sealed cementitious mixture, notsubjected to external forces and under constant temperature,measured from
16、 the time of final setting.3.2.3 chemical shrinkage, nthe reduction in volume ofcementitious paste that occurs during hydration because thehydration products occupy less volume than the volumeoccupied originally by the water and unhydrated cementitiousmaterials.3.2.4 density (OD), nthe mass of oven-
17、dry lightweightaggregate particles per unit volume of aggregate particles,where the volume includes the permeable and impermeablepores within the particles but does not include the voidsbetween the particles.3.2.5 desorption, nthe decrease in mass of lightweightaggregate originally containing absorb
18、ed water due to waterleaving the permeable pores as the aggregate attains moistureequilibrium with the surrounding environment maintained atconstant temperature and a relative humidity less than 100 %.3.2.6 internal curing, nsupplying water within a cemen-titious mixture using pre-wetted lightweight
19、 aggregate, or othermaterials that readily release water from within the particles,thereby mitigating self-desiccation and sustaining hydration.3.2.7 oven-dry (OD), adjrelated to aggregate particles,the condition in which the specimen of lightweight aggregatehas been dried by heating in an oven at 1
20、10 6 5 C 230 6 10F for sufficient time to reach a constant mass.3.2.8 relative density, (OD), nthe ratio of the density(OD) of the lightweight aggregate to the density of water at astated temperature.3.2.9 wetted surface-dry (WSD), adjrelated to lightweightaggregate particles, the condition in which
21、 the permeablepores of lightweight aggregate particles are filled with water, tothe extent achieved by submerging an oven-dry specimen for72 h, and the surfaces of the particles are dry.3.2.10 self-desiccation, nreduction in the internal relativehumidity of a sealed cementitious mixture as a result
22、ofchemical shrinkage.3.3 Symbols:A72= the 72-h absorption, expressed as a percentage of theoven-dry mass.GOD= relative density (oven-dry) of lightweight aggregate.GODN= relative density (oven-dry) of normal weight aggre-gate.MLWA= calculated mass of oven-dry lightweight aggregateneeded for internal
23、curing per unit volume of concrete,kg/m3lb/yd3.MNWA= mass of normal weight aggregate in oven-dry con-dition to be removed, kg/m3lb/yd3.MOD= mass of lightweight aggregate specimen in oven-drycondition, g.MPS= mass of pycnometer containing lightweight aggregatespecimen and filled with water, g.MPW= ma
24、ss of pycnometer filled with water, g.MSD= mass of lightweight aggregate specimen in wettedsurface-dry condition, g.M94= equilibrium mass of aggregate originally in wettedsurface-dry condition and subsequently stored at 94 % relativehumidity, g.Cf= cementitious materials content of concrete mixture,
25、kg/m3lb/yd3.CS = chemical shrinkage of cementitious material, expressedas kg water/kg of cement lb/lb (see Note 3).S = degree of saturation of lightweight aggregate relative towetted surface-dry condition (0 to 1.0).w/cm = water-cementitious materials ratio, kg/kg lb/lb.amax= maximum potential degre
26、e of hydration of cementi-tious materials expressed as a decimal fraction (0 to 1.0).WLWA= mass of water released by lightweight aggregate ingoing from the wetted surface-dry condition to the equilibriummass at a relative humidity of 94 %, expressed as a fraction ofthe oven-dry mass.NOTE 3Chemical s
27、hrinkage is measured in units of volume of waterper unit mass of cement. In using the value of chemical shrinkage tocalculate the required amount of lightweight aggregate for internal curing,the volume of water is converted to the mass of water. Hence chemicalshrinkage is expressed as mass of water
28、per unit mass of cement.4. Ordering Information4.1 The direct purchaser of lightweight aggregate for inter-nal curing shall include the following information in thepurchase order as applicable.4.1.1 Reference to this specification, as SpecificationC1761.4.1.2 Whether the order is for fine aggregate,
29、 coarse aggre-gate, or combined fine and coarse aggregate.4.1.3 Quantity in metric tons tons or cubic meters cubicyards.4.1.4 If the order is for coarse aggregate or combined fineand coarse aggregate, provide the nominal size designation asgiven in Table 1 or alternative grading as agreed between th
30、epurchaser and aggregate supplier.4.1.5 Whether certification shall be furnished indicating thatthe material was sampled and tested in accordance with thisspecification and found to meet the requirements.4.1.6 Whether a report of the results of aggregate tests shallbe furnished.4.1.7 Whether the res
31、ults of tests of concrete properties arerequired.4.1.8 Any exceptions or additions to this specification.5. Materials and Manufacture5.1 Two general types of lightweight aggregate are coveredby this specification, as follows:5.1.1 Aggregates produced by expanding, pelletizing, orsintering products s
32、uch as blast-furnace slag, clay, diatomite,fly ash, shale, or slate, and5.1.2 Aggregate prepared by processing natural materials,such as pumice, scoria, and tuff.5.2 The aggregate shall be composed predominately oflightweight-cellular and granular inorganic materials.6. Chemical Requirements6.1 Orga
33、nic ImpuritiesTest Method C40. Lightweightaggregate shall not produce a color darker than the standardC1761/C1761M 122color solution, unless it is demonstrated that when the aggre-gate is tested for the effect of organic impurities on strength ofmortar, the relative strength at 7 days, determined in
34、 accor-dance with Test Method C87, is not less than 95 %.6.2 StainingTest Method C641. Lightweight aggregateshall produce a stain index of less than 60. Lightweightaggregate producing a stain index of 60 or higher shall besubject to rejection if the deposited stain is found uponchemical analysis to
35、contain an iron content, expressed asFe2O3, equal to or greater than 1.5 mg/200 g of sample.6.2.1 Loss on IgnitionTest Method C114. The loss onignition of lightweight aggregates shall not exceed 5 %.NOTE 4Some aggregate may contain carbonates or water of hydrationthat contribute to loss on ignition
36、but may not affect the quality of theproduct. Therefore, when evaluating an aggregate, consideration should begiven to the material characteristics that cause the ignition loss.7. Physical Properties7.1 Clay Lumps and Friable ParticlesTest Method C142.The total amount of clay lumps and friable parti
37、cles shall notexceed 2 % by dry mass.7.2 GradingTest Method C136 as modified in Specifica-tion C330/C330M. The grading shall conform to the require-ments shown in Table 1 or established by mutual agreementbetween interested parties.NOTE 5In general, a volume of lightweight aggregate (fine or acombin
38、ation of coarse and fine) for internal curing will replace an equalvolume of normal weight aggregate in an existing conventional concretemixture. The grading of the lightweight aggregate can be chosen to closelymatch the existing grading of the normal weight aggregates, or to fill in agap in the exi
39、sting normal weight aggregate grading, such as using amid-range size lightweight aggregate to enhance the gradation of agap-graded mixture (1).37.2.1 Uniformity of GradingFor continuing shipments offine aggregate from a given source, the fineness modulus shallnot vary more than 7 % from the base fin
40、eness modulus. Thebase fineness modulus shall be that value that is typical of thesource. The purchaser has the authority to approve a change inthe base fineness modulus. For coarse aggregate and combinedfine and coarse aggregate, the uniformity of grading require-ments of Specification C330/C330M s
41、hall apply.7.3 Bulk DensityTest Method C29/C29M. The dry bulkdensity using the shoveling method of compaction shallconform to the requirements of Table 2 using a 14 L 12 ft3measure.7.4 Water AbsorptionThe lightweight aggregate shallhave a 72-h absorption not less than 5 % when tested inaccordance wi
42、th Section 10.7.5 Desorption PropertiesThe lightweight aggregate shallrelease at least 85 % of its absorbed water at 94 % relativehumidity when tested in accordance with Section 11; that is,the following condition shall be satisfied:WLWA$0.85A72100 %(1)8. Sampling8.1 Sample lightweight aggregates in
43、 accordance with Prac-tice D75.8.2 Reduce sample to test sizes in accordance with PracticeC702.9. Number of Tests and Retests9.1 Tests on AggregatesOne representative sample isrequired of sufficient size to prepare specimens for the follow-ing tests: organic impurities, staining, loss on ignition, g
44、rading,clay lumps and friable particles, bulk density, absorption andrelative density (OD), and desorption from WSD to 94 %relative humidity.9.2 Tests on Internally Cured ConcreteWhen specified bythe purchaser, at least three specimens are required for each ofthe following tests of concrete: compres
45、sive strength, shrink-age, resistance to freezing and thawing, and presence of popoutmaterials. At least eight specimens are required for splittingtensile strength tests. Tests shall be performed in accordancewith Specification C330/C330M and test results shall complywith Specification C330/C330M.3T
46、he boldface numbers in parentheses refer to the list of references at the end ofthis standard.TABLE 1 Grading RequirementsNominal Size DesignationPercentages (Mass) Passing Sieves Having Square Openings25.0 mm(1 in.)19.0 mm(34 in.)12.5 mm(12 in.)9.5 mm(38 in.)4.75 mm(No. 4)2.36 mm(No. 8)1.18 mm(No.
47、160)300 m(No. 50)150 m(No. 100)75 mA(No. 200)Fine aggregate:4.75 mm to 0 (No. 4 to 0) . . . . . . . . . 100 85100 . . . 4080 1035 525 . . .Coarse aggregate:25.0 to 4.75 mm (1 in. to No. 4) 95100 . . . 2560 . . . 010 . . . . . . . . . . . . 01019.0to4.75mm(34 in. to No.4) 100 90100 . . . 1050 015 . .
48、 . . . . . . . . . . 01012.5to4.75mm(12 in. to No. 4) . . . 100 90100 4080 540 020 010 . . . . . . 0109.5to2.36mm(38 in. to No. 8) . . . . . . 100 80100 540 020 010 . . . . . . 010Combined fine and coarse aggregate:12.5mmto0(12 in. to 0) . . . 100 95100 . . . 5080 . . . . . . 520 215 0109.5mmto0(38
49、in. to 0) . . . . . . 100 90100 6590 3565 . . . 1025 515 010AThe surfaces of pyro-processed lightweight aggregate particles finer than the 75 m (No. 200) sieve are not deleterious and may be moderately pozzolanic.TABLE 2 Maximum Dry Loose Bulk DensitySize DesignationMaximum Densitykg/m3lb/ft3Fine aggregate 1120 70Coarse aggregate 880 55Combined fine and coarse aggregate 1040 65C1761/C1761M 123TEST METHODS10. Absorption and Relative Density10.1 Scope:10.1.1 This test method uses the p
