1、Designation: C1761/C1761M 15C1761/C1761M 17Standard 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. Scope*1.1 This specification covers lightweight aggregate intended to provide water for internal curing of co
3、ncrete. 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
4、contributors 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 equivalen
5、ts; 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 Specificati
6、on 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 specification references notes and footnotes that provide explanatory material. These notes and footnotes(excluding those in tables and figures)
7、 shall not be considered as requirements of the standard.1.4 This specification 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 applica
8、bility of regulatorylimitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the Worl
9、d Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C29/C29M Test Method for Bulk Density (“Unit Weight”) and Voids in AggregateC40C40/C40M Test Method for Organic Impurities in Fine Aggregates for ConcreteC87C87/C87M Test Method for Effect of
10、Organic Impurities in Fine Aggregate on Strength of MortarC114 Test Methods for Chemical Analysis of Hydraulic CementC125 Terminology Relating to Concrete and Concrete AggregatesC128 Test Method for Relative Density (Specific Gravity) and Absorption of Fine AggregateC136C136/C136M Test Method for Si
11、eve Analysis of Fine and Coarse AggregatesC142C142/C142M 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 AggregatesC702C702/C702M Practice for
12、 Reducing Samples of Aggregate to Testing SizeC1498 Test Method for Hygroscopic Sorption Isotherms of Building MaterialsC1608 Test Method for Chemical Shrinkage of Hydraulic Cement PasteC1698 Test Method for Autogenous Strain of Cement Paste and MortarD75D75/D75M Practice for Sampling Aggregates1 Th
13、is specification 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 April 1, 2015June 15, 2017. Published May 2015July 2017. Originally approved in
14、2012. Last previous edition approved in 20132015 asC1761/C1761M 13b.C1761/C1761M 15. DOI: 10.1520/C1761_C1761M-15.10.1520/C1761_C1761M-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume i
15、nformation, refer to the standards 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 adequatel
16、y 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM Inter
17、national, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this practice, refer to Terminology C125.3.2 Definitions of Terms Specif
18、ic 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 penetrating into the permeable pores of the particles after being submerged for 72 h, expressed as percentage of oven-drymass.3.2.2 autogenous shrink
19、age, nreduction in volume due to chemical shrinkage of a sealed cementitious mixture, not subjectedto external forces and under constant temperature, measured from the time of final setting.3.2.2.1 DiscussionThe chemical shrinkage leads to emptying of the internal pores (see self-desiccation) that c
20、auses the formation of menisci in thepartially water-filled pores. The menisci in turn give rise to internal tensile stresses that cause bulk shrinkage. While autogenousshrinkage is due to the chemical shrinkage, the magnitude of autogenous shrinkage is less than the chemical shrinkage after setting
21、occurs, because the aggregate particles and the hydrated cement paste network restrain the shrinkage. The restraint may in turn leadto cracking.3.2.3 chemical shrinkage, nthe reduction in volume of cementitious paste that occurs during hydration because the hydrationproducts occupy less volume than
22、the volume occupied originally by the water and unhydrated cementitious materials.3.2.4 density (OD), nof lightweight 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 partic
23、les but does not include thevoids between the particles.3.2.5 desorption (D), nof lightweight aggregate, the decrease in mass of lightweight aggregate originally containing absorbedwater due to water leaving the permeable pores as the aggregate attains moisture equilibrium with the surrounding envir
24、onmentmaintained at constant temperature and a relative humidity less than 100 %, and expressed as a percentage of the 72-h absorption.3.2.6 internal curing, nsupplying water within a cementitious mixture using pre-wetted lightweight aggregate, or othermaterials that readily release water from withi
25、n the particles, thereby mitigating self-desiccation and sustaining hydration.3.2.7 oven-dry (OD), adjrelated to lightweight aggregate particles, the condition in which the 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 co
26、nstant 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 temperature.3.2.9 wetted surface-dry (WSD), adjrelated to lightweight aggregate particles, the condition in which the permeable pores ofl
27、ightweight 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 self-desiccation, nreduction in the internal relative humidity of a sealed cementitious mixture, due to chemicalshrinkage, that ma
28、y reduce the rate of hydration or stop hydration.3.3 Symbols: A72 = the 72-h absorption, expressed as a percentage of the oven-dry mass.D = the desorption, expressed as a percentage of the A72 absorption.GOD = relative density (oven-dry) of lightweight aggregate.GODN = relative density (oven-dry) of
29、 normal weight aggregate.MLWA = calculated mass of oven-dry lightweight aggregate needed for internal curing per unit volume of concrete,kg/m3 lbyd3.MNWA = mass of normal weight aggregate in oven-dry condition to be removed, kg/m3 lbyd3.MOD = mass of lightweight aggregate specimen in oven-dry condit
30、ion, 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 surface-dry condit
31、ion and subsequently stored at 94 % relativehumidity, g.Cf = cementitious materials content of concrete mixture, kg/m3 lbyd3.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 to wetted su
32、rface-dry condition (0 to 1.0).w/cm = water-cementitious materials ratio, kg/kg lb/lb.C1761/C1761M 172max = 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 surfa
33、ce-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 aggre
34、gate 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 p
35、urchaseorder as applicable.4.1.1 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 aggregate or
36、 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 with thisspecifi
37、cation 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 general types of li
38、ghtweight 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, scoria, and
39、tuff.5.2 The aggregate shall be composed predominately of lightweight-cellular and granular inorganic materials.6. Chemical Requirements6.1 Organic ImpuritiesTest Method C40C40/C40M. Lightweight aggregate shall not produce a color darker than the standardcolor solution, unless it is demonstrated tha
40、t when the aggregate is tested for the effect of organic impurities on strength of mortar,the relative strength at 7 days, determined in accordance with Test Method C87C87/C87M, is not less than 95 %.6.2 StainingTest Method C641. Lightweight aggregate shall produce a stain index of less than 60. Lig
41、htweight 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 o
42、f lightweight 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 tha
43、t cause the ignition loss.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)16)300 m(No. 50)150 m(No. 100)75 mA(No. 200)Fine aggregate:4.75 m
44、m to 0 (No. 4 to 0) . . . . . . . . . 100 85100 . . . 4080 1035 525 . . .4.75 mm to 0 (No. 4 to 0) . . . . . . . . . 100 65100 . . . 1580 035 025 . . .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 .
45、. . 1050 015 . . . . . . . . . . . . 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 . . . .
46、 . . 520 215 0109.5 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 1737. Physical Properties7.1 Clay Lumps a
47、nd Friable ParticlesTest Method C142C142/C142M. The total amount of clay lumps and friable particlesshall not exceed 2 % by dry mass.7.2 GradingTest Method C136C136/C136M as modified in Specification C330/C330M. The grading shall conform to therequirements shown in Table 1 or established by mutual a
48、greement 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 grading of the lightweight aggregate can be
49、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).37.2.1 Uniformity of GradingFor continuing shipments of 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
