1、Designation: C1761/C1761M 12C1761/C1761M 13Standard 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 revi
2、sion, the year 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 intended to provide water for internal curing of con
3、crete. It includes testmethods for determining the absorption and desorption properties of lightweight aggregate.NOTE 1Internal curing provides an additional source of water to sustain hydration and substantially reduce the early-age autogenous shrinkage andself-desiccation that can be significant c
4、ontributors to early-age cracking. Appendix X1 provides guidance on calculating the quantity of lightweightaggregate for internal curing.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalent
5、s; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance. Some values have only SI units because the inch-pound equivalents are not used inpractice.NOTE 2Sieve size is identified by its standard designation in Specificatio
6、n E11. The alternative designation given in parentheses is for informationonly and does not represent a different standard sieve size.1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall
7、 not be considered as requirements of the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of r
8、egulatorylimitations 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 Aggregates for ConcreteC87 Test Method for Effect of Organic Impurities in Fine Aggregate on Strengt
9、h of MortarC114 Test Methods for Chemical Analysis of Hydraulic CementC125 Terminology Relating to Concrete and Concrete AggregatesC128 Test Method for Density, Relative Density (Specific Gravity), and Absorption of Fine AggregateC136 Test Method for Sieve Analysis of Fine and Coarse AggregatesC142
10、Test Method for Clay Lumps and Friable Particles in AggregatesC330/C330M Specification for Lightweight Aggregates for Structural ConcreteC641 Test Method for Iron Staining Materials in Lightweight Concrete AggregatesC702 Practice for Reducing Samples of Aggregate to Testing SizeC1498 Test Method for
11、 Hygroscopic Sorption Isotherms of Building MaterialsC1608 Test Method for Chemical Shrinkage of Hydraulic Cement PasteC1698 Test Method for Autogenous Strain of Cement Paste and MortarD75 Practice for Sampling AggregatesE11 Specification for Woven Wire Test Sieve Cloth and Test Sieves1 This specifi
12、cation is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.21 onLightweight Aggregates and Concrete.Current edition approved June 15, 2012May 15, 2013. Published August 2012July 2013. Originally approved in 2012. La
13、st previous edition approved in 2012 asC1761/C1761M 12. DOI: 10.1520/C1761_C1761M-12.10.1520/C1761_C1761M-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the stan
14、dards Document Summary page on the ASTM website.This 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 be technically possible to adequately depict all changes accurate
15、ly, 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 Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1
16、3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this practice, refer to Terminology C125.3.2 Definitions of Terms Specific to This Standard:3.2.1 absorption, A72, nof lightweight aggregate, the increase in mass of a specimen of oven-dry lightweight aggregate dueto water penetrat
17、ing into the permeable pores of the particles after being submerged for 72 h, expressed as percentage of oven-drymass.3.2.2 autogenous shrinkage, nreduction in volume due to chemical shrinkage of a sealed cementitious mixture, not subjectedto external forces and under constant temperature, measured
18、from the time of final setting.3.2.3 chemical shrinkage, nthe reduction in volume of cementitious paste that occurs during hydration because the hydrationproducts occupy less volume than the volume occupied originally by the water and unhydrated cementitious materials.3.2.4 density (OD), nof lightwe
19、ight aggregate, the mass of oven-dry lightweight aggregate particles per unit volume ofaggregate particles, where the volume includes the permeable and impermeable pores within the particles but does not include thevoids between the particles.3.2.5 desorption, nof lightweight aggregate, the decrease
20、 in mass of lightweight aggregate originally containing absorbedwater due to water leaving the permeable pores as the aggregate attains moisture equilibrium with the surrounding environmentmaintained at constant temperature and a relative humidity less than 100 %.3.2.6 internal curing, nsupplying wa
21、ter within a cementitious mixture using pre-wetted lightweight 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 lightweight aggregate particles, the condition in which th
22、e specimen of lightweightaggregate has been dried by heating in an oven at 110 6 5 C 230 6 10 F for sufficient time to reach a constant mass.3.2.8 relative density, (OD), nof lightweight aggregate, the ratio of the density (OD) of the lightweight aggregate to thedensity of water at a stated temperat
23、ure.3.2.9 wetted surface-dry (WSD), adjrelated to lightweight aggregate particles, the condition in which the permeable pores oflightweight aggregate particles are filled with water, to the extent achieved by submerging an oven-dry specimen for 72 h, and thesurfaces of the particles are dry.3.2.10 s
24、elf-desiccation, nreduction in the internal relative humidity of a sealed cementitious mixture as a result of chemicalshrinkage.3.3 Symbols:A72 = the 72-h absorption, expressed as a percentage of the oven-dry mass.GOD = relative density (oven-dry) of lightweight aggregate.GODN = relative density (ov
25、en-dry) of normal weight aggregate.MLWA = calculated mass of oven-dry lightweight aggregate needed for internal curing per unit volume of concrete,kg/m3 lb/yd3.MNWA = mass of normal weight aggregate in oven-dry condition to be removed, kg/m3 lb/yd3.MOD = mass of lightweight aggregate specimen in ove
26、n-dry condition, g.MPS = mass of pycnometer containing lightweight aggregate specimen and filled with water, g.MPW = mass of pycnometer filled with water, g.MSD = mass of lightweight aggregate specimen in wetted surface-dry condition, g.M94 = equilibrium mass of aggregate originally in wetted surfac
27、e-dry condition and subsequently stored at 94 % relativehumidity, g.Cf = cementitious materials content of concrete mixture, kg/m3 lb/yd3.CS = chemical shrinkage of cementitious material, expressed as kg water/kg of cement lb/lb (see Note 3).S = degree of saturation of lightweight aggregate relative
28、 to wetted surface-dry condition (0 to 1.0).w/cm = water-cementitious materials ratio, kg/kg lb/lb.max = maximum potential degree of hydration of cementitious materials expressed as a decimal fraction (0 to 1.0).WLWA = mass of water released by lightweight aggregate in going from the wetted surface-
29、dry condition to the equilibrium massat a relative humidity of 94 %, expressed as a fraction of the oven-dry mass.NOTE 3Chemical shrinkage is measured in units of volume of water per unit mass of cement. In using the value of chemical shrinkage to calculatethe required amount of lightweight aggregat
30、e for internal curing, the volume of water is converted to the mass of water. Hence chemical shrinkage isexpressed as mass of water per unit mass of cement.4. Ordering Information4.1 The direct purchaser of lightweight aggregate for internal curing shall include the following information in the purc
31、haseorder as applicable.C1761/C1761M 1324.1.1 Reference to this specification, as Specification C1761.4.1.2 Whether the order is for fine aggregate, coarse aggregate, or combined fine and coarse aggregate.4.1.3 Quantity in metric tons tons or cubic meters cubic yards.4.1.4 If the order is for coarse
32、 aggregate or combined fine and coarse aggregate, provide the nominal size designation as givenin Table 1 or alternative grading as agreed between the purchaser and aggregate supplier.4.1.5 Whether certification shall be furnished indicating that the material was sampled and tested in accordance wit
33、h thisspecification and found to meet the requirements.4.1.6 Whether a report of the results of aggregate tests shall be furnished.4.1.7 Whether the results of tests of concrete properties are required.4.1.8 Any exceptions or additions to this specification.5. Materials and Manufacture5.1 Two genera
34、l types of lightweight aggregate are covered by this specification, as follows:5.1.1 Aggregates produced by expanding, pelletizing, or sintering products such as blast-furnace slag, clay, diatomite, fly ash,shale, or slate, and5.1.2 Aggregate prepared by processing natural materials, such as pumice,
35、 scoria, and tuff.5.2 The aggregate shall be composed predominately of lightweight-cellular and granular inorganic materials.6. Chemical Requirements6.1 Organic ImpuritiesTest Method C40. Lightweight aggregate shall not produce a color darker than the standard colorsolution, unless it is demonstrate
36、d that when the aggregate is tested for the effect of organic impurities on strength of mortar, therelative strength at 7 days, determined in accordance with Test Method C87, is not less than 95 %.6.2 StainingTest Method C641. Lightweight aggregate shall produce a stain index of less than 60. Lightw
37、eight aggregateproducing a stain index of 60 or higher shall be subject to rejection if the deposited stain is found upon chemical analysis to containan iron content, expressed as Fe2O3, equal to or greater than 1.5 mg/200 g of sample.6.2.1 Loss on IgnitionTest Method C114. The loss on ignition of l
38、ightweight aggregates shall not exceed 5 %.NOTE 4Some aggregate may contain carbonates or water of hydration that contribute to loss on ignition but may not affect the quality of the product.Therefore, when evaluating an aggregate, consideration should be given to the material characteristics that c
39、ause the ignition loss.7. Physical Properties7.1 Clay Lumps and Friable ParticlesTest Method C142. The total amount of clay lumps and friable particles shall not exceed2 % by dry mass.7.2 GradingTest Method C136 as modified in Specification C330/C330M. The grading shall conform to the requirementssh
40、own in Table 1 or established by mutual agreement between interested parties.NOTE 5In general, a volume of lightweight aggregate (fine or a combination of coarse and fine) for internal curing will replace an equal volume ofnormal weight aggregate in an existing conventional concrete mixture. The gra
41、ding of the lightweight aggregate can be chosen to closely match theexisting grading of the normal weight aggregates, or to fill in a gap in the existing normal weight aggregate grading, such as using a mid-range sizelightweight aggregate to enhance the gradation of a gap-graded mixture (1).33 The b
42、oldface numbers in parentheses refer to the list of references at the end of this 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. 160
43、)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 . . . . . . . . . . . . 01019.0 to 4.75 mm (34 in. to No.4) 100 90100 . . . 1050 015 .
44、. . . . . . . . . . . 01012.5 to 4.75 mm (12 in. to No. 4) . . . 100 90100 4080 540 020 010 . . . . . . 0109.5 to 2.36 mm (38 in. to No. 8) . . . . . . 100 80100 540 020 010 . . . . . . 010Combined fine and coarse aggregate:12.5 mm to 0 (12 in. to 0) . . . 100 95100 . . . 5080 . . . . . . 520 215 01
45、09.5 mm to 0 (38 in. to 0) . . . . . . 100 90100 6590 3565 . . . 1025 515 010A The surfaces of pyro-processed lightweight aggregate particles finer than the 75 m (No. 200) sieve are not deleterious and may be moderately pozzolanic.C1761/C1761M 1337.2.1 Uniformity of GradingFor continuing shipments o
46、f fine aggregate from a given source, the fineness modulus shall notvary more than 7 % from the base fineness modulus. The base fineness modulus shall be that value that is typical of the source.The purchaser has the authority to approve a change in the base fineness modulus. For coarse aggregate an
47、d combined fine andcoarse aggregate, the uniformity of grading requirements of Specification C330/C330M shall apply.7.3 Bulk DensityTest Method C29/C29M. The dry bulk density using the shoveling method of compaction shall conform tothe requirements of Table 2 using a 14 L 12 ft3 measure.7.4 Water Ab
48、sorptionThe lightweight aggregate shall have a 72-h absorption not less than 5 % when tested in accordance withSection 10.7.5 Desorption PropertiesThe lightweight aggregate shall release at least 85 % of its absorbed water at 94 % relative humiditywhen tested in accordance with Section 11; that is,
49、the following condition shall be satisfied:WLWA$0.85 A72100 % (1)8. Sampling8.1 Sample lightweight aggregates in accordance with Practice D75.8.2 Reduce sample to test sizes in accordance with Practice C702.9. Number of Tests and Retests9.1 Tests on AggregatesOne representative sample is required of sufficient size to prepare specimens for the following tests:organic impurities, staining, loss on ignition, grading, clay lumps and friable particles, bulk density, absorption and relative d
