ASTM C1753-2015 Standard Practice for Evaluating Early Hydration of Hydraulic Cementitious Mixtures Using Thermal Measurements《使用热测量法评估液压胶凝混合物早期水化的标准实施规程》.pdf

《ASTM C1753-2015 Standard Practice for Evaluating Early Hydration of Hydraulic Cementitious Mixtures Using Thermal Measurements《使用热测量法评估液压胶凝混合物早期水化的标准实施规程》.pdf》由会员分享，可在线阅读，更多相关《ASTM C1753-2015 Standard Practice for Evaluating Early Hydration of Hydraulic Cementitious Mixtures Using Thermal Measurements《使用热测量法评估液压胶凝混合物早期水化的标准实施规程》.pdf（19页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: C1753 15Standard Practice forEvaluating Early Hydration of Hydraulic CementitiousMixtures Using Thermal Measurements1This standard is issued under the fixed designation C1753; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi

2、sion, the 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.1. Scope1.1 This practice describes the apparatus and procedure forevaluating relative differences in early hydr

3、ation of hydrauliccementitious mixtures such as paste, mortar, or concrete,including those containing chemical admixtures, varioussupplementary cementitious materials (SCMs), and other finelydivided materials, by measuring the temperature history of aspecimen.1.2 Calorimetry is the measurement of he

4、at lost or gainedduring a chemical reaction such as cement hydration; calori-metric measurements as a function of time can be used todescribe and evaluate hydration and related early-age propertydevelopment. Calorimetry may be performed under isothermalconditions (as described in Practice C1679) or

5、under adiabaticor semi-adiabatic conditions. This practice cannot be describedas calorimetry because no attempt is made to measure orcompute the heat evolved from test specimens due tohydration, but it can in many cases be used for similarevaluations. Variables that should be considered in the appli

6、-cation of this practice are discussed in the Appendix.1.3 UnitsThe values stated in either SI units or inch-pound units shall be regarded separately as standard. Thevalues stated in each system may not be exact equivalents;therefore, each system must be used independently of the other.Combining val

7、ues from the two systems may result in non-conformance with the standard. Some values have only SI unitsbecause the inch-pound equivalents are not used in practice.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the

8、 user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1Warning: Fresh hydraulic cementitious mixtures are causticand may cause chemical burns to skin and tissue upon prolongedexposure.22. Referenced D

9、ocuments2.1 ASTM Standards:3C39/C39M Test Method for Compressive Strength of Cylin-drical Concrete SpecimensC125 Terminology Relating to Concrete and Concrete Ag-gregatesC172/C172M Practice for Sampling Freshly Mixed Con-creteC192/C192M Practice for Making and Curing Concrete TestSpecimens in the La

10、boratoryC219 Terminology Relating to Hydraulic CementC305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC403/C403M Test Method for Time of Setting of ConcreteMixtures by Penetration ResistanceC494/C494M Specification for Chemical Admixtures forConcreteC10

11、05 Specification for Reference Masses and Devices forDetermining Mass and Volume for Use in the PhysicalTesting of Hydraulic CementsC1679 Practice for Measuring Hydration Kinetics of Hy-draulic Cementitious Mixtures Using Isothermal Calorim-etry3. Terminology3.1 DefinitionsFor definitions of terms u

12、sed in thispractice, refer to Terminology C125, Terminology C219, andPractice C1679.3.2 Definitions of Terms Specific to This Standard:3.2.1 adiabatic, adjoccurring without exchange of heatwith the environment.3.2.2 exotherm, nheat evolution during hydration as evi-denced by an increase in measured

13、specimen temperatureshown in the thermal profile.1This practice is under the jurisdiction of ASTM Committee C09 on Concreteand ConcreteAggregates and is the direct responsibility of Subcommittee C09.48 onPerformance of Cementitious Materials and Admixture Combinations.Current edition approved Aug. 1

14、, 2015. Published September 2015. DOI:10.1520/C1753-152Section on Safety Precautions, Manual of Aggregate and Concrete Testing,Annual Book of ASTM Standards, Vol. 04.02.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annua

15、l Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.3 inert specimen, nspecimen placed within the samethermal environment as t

16、he test specimen(s), made of anonreactive material of similar heat capacity and the samemass as the reacting test specimen(s).3.2.3.1 DiscussionThe difference between the tempera-ture of the hydrating test specimen(s) and the inert specimenrepresents the change in specimen temperature due to hydra-t

17、ion. Interpretation can often be improved by comparingtemperature histories after subtracting the temperature of thecorresponding inert specimen (reference temperature), whichtends to account for the effects of changing environmenttemperature during the measurement period.3.2.4 main peak response, n

18、the initial temperature riseand subsequent temperature drop in the measured thermalprofile that starts at the end of the dormant period and, for amixture with normal sulfate balance, lasts for several hours.3.2.5 reference temperature, nthe temperature of the inertspecimen in a test series at the ti

19、me corresponding to aparticular temperature of the test specimen.3.2.6 sulfate demand, nthe level of soluble calcium sulfatein a hydrating cementitious mixture required to maintainnormal hydration behavior for a specific combination ofmixture proportions, materials properties, initial mixturetempera

20、ture, and test temperature.3.2.7 sulfate imbalance threshold, nthe condition of acementitious mixture in terms of mixture proportions, materi-als properties, initial mixture temperature, and testtemperature, for which a small change in any of these variablescan result in abnormal hydration behavior

21、due to depletion ofcalcium sulfate in solution.3.2.8 test specimen, na hydraulic cementitious mixturebeing evaluated for its thermal response.3.2.9 test temperature, nthe temperature of the air orinsulation, if any, surrounding the test specimen containers atthe start of temperature measurement, nor

22、mally intended toremain constant.3.2.10 thermal profile, nthe temperature of a hydratingmixture (before or after subtraction of the referencetemperature), plotted as a function of hydration time, thatprovides an indication of the rate of hydration over time.3.2.10.1 DiscussionAn example thermal prof

23、ile is shownin Fig. 1. On the vertical axis Ttestrefers to the temperature ofthe test specimen and Trefrefers to the temperature of the inert(reference) specimen. The shape of the thermal profile isaffected not only by mixture hydration but also by thespecimen type and mass, mixture proportions, spe

24、cimen initialtemperature, specimen container size and shape, insulation (ifany) provided around the specimen container, and the tempera-ture of the surrounding environment. Additional guidance isprovided in the Appendix.3.2.11 time of setting marker, nthe point marked on thethermal profile indicatin

25、g the hydration time when a selectedfraction of the main peak amplitude is attained and that is usedas a relative indicator of time of setting.4. Summary of Practice4.1 Athermal measurement test system consists of tempera-ture measuring devices, data collection equipment, and speci-men containers of

26、 similar volume, shape, and material, capableof similarly isolating each test specimen and an inert specimen.The specific insulation values for specimen containers and thetest temperature are selected based on the intended testobjectives. Related guidance is provided in the Appendix.NOTE 1(A) initia

27、l exotherm from dissolution of cement and initial hydration, principally of calcium aluminates; (B) dormant period temperaturereduction associated with very low heat evolution indicating slow and well-controlled hydration; (C) main peak response associated primarily withhydration reactions contribut

28、ing to setting and early strength development, with maximum temperature at (D). The maximum temperature (D) and therates of temperature rise and fall that shape the main peak response (C) are affected not only by hydration but by the related cooling response of thespecimen.FIG. 1 Example Thermal Pro

29、file of a Portland Cement Paste Mixture (Inert Specimen Temperature Subtracted from Test Specimen Tem-perature)C1753 1524.2 Mixtures composed of cementitious materials, water,and optionally chemical admixtures, or aggregate, or both, areprepared and introduced into specimen containers for collec-tio

30、n of temperature data.4.3 Thermal profiles are plotted using a common time scalethat begins at the time of initial mixing of water withcementitious materials, which is the start of hydration time.The measured thermal profiles allow qualitative comparison ofearly hydration kinetics, such as retarding

31、 or acceleratingtrends, as influenced by different combinations of materials,and abnormal hydration behaviors that can interfere withsetting and strength development.5. Significance and Use5.1 This practice provides a means of assessing the relativeearly hydration performance of various test mixture

32、s comparedwith control mixtures that are prepared in a similar manner.5.2 Thermal profiles are used to evaluate the hydrationbehavior of hydraulic cementitious mixtures after the additionof water. They may provide indications concerning settingcharacteristics, compatibility of different materials, s

33、ulfatebalance, relative heat of hydration, and early strength devel-opment. They can be used to evaluate the effects ofcompositions, proportions, and time of addition of materials aswell as the initial mixture and test temperatures. Thermalprofile testing is an effective tool for identifying perform

34、ancesensitivities or trends, and may help to reduce the number ofconcrete test mixtures required to develop and qualifymixtures, especially those to be subject to variable ambientenvironments. It may be used by concrete producers, materialssuppliers, and other practitioners to support mixturedevelop

35、ment, selection of material types or sources, optimiza-tion of proportions, or troubleshooting of field problems.5.3 This practice can be used to understand concrete prob-lems related to slump loss, setting, and early strength, butresults may not predict field concrete performance. Perfor-mance veri

36、fication with concrete is needed to quantify thetrends identified using thermal testing.5.4 This practice can be used to evaluate the effects ofchemical admixtures on the thermal profiles of cementitiousmixtures. This can be especially useful in selecting dosagesappropriate for different ambient con

37、ditions.5.5 Thermal measurement testing as described in this prac-tice may have similar significance and use as isothermalcalorimetry described by Practice C1679 or some types ofnear-adiabatic calorimetry. The selection of which practice ormethods to use may depend on specific applications andcircum

38、stances. The thermal profiles obtained by this practicemay have similar shapes to isothermal hydration profiles asobtained by Practice C1679, but thermal profiles from thispractice do not provide quantitative measurement of heat ofhydration, are affected by various details of the test conditionsand

39、mixtures (see 3.2.10 and the Appendix), and are subject togreater variability. Equipment used for this practice is lessexpensive than isothermal or near-adiabatic calorimeters andmay be more easily adapted for use in the field or where a largenumber of different specimens and mixtures must be evalua

40、tedin a short time period. Identification of the sulfate depletionpoint of a mixture (as described in Practice C1679)isnotgenerally possible using thermal measurement testing.5.6 To evaluate the potential for abnormal hydration, it isimportant that the test temperatures and the initial temperatureso

41、f the mixture be selected to represent the range of expectedinitial concrete field temperatures.5.7 This practice is not intended to provide results that canbe compared across laboratories using different equipment norto provide quantitative measurements or corrected approxima-tions of actual hydrat

42、ion heat. It should not be cited in projectspecifications or otherwise used for the purpose of acceptanceor rejection of concrete. It is intended to serve as a simple andexpedient tool for comparison of the relative early-age hydra-tion performance of different specific combinations of materi-als th

43、at are prepared and stored under the same conditions.6. Apparatus6.1 Devices for Preparing Specimens:6.1.1 Weights and Weighing Devices, used for preparation oflaboratory test mixtures up to 5 kg 11 lb total mass shallconform to the requirements of Specification C1005. Forpreparing test mixtures of

44、greater total mass including concretebatches in the laboratory, weighing devices shall conform tothe requirements of Practice C192/C192M.6.1.2 Graduated Cylinders, shall conform to the require-ments of Specification C1005. The permissible variation forgraduated cylinders of less than 100-mL capacity

45、 shall be 61.0% of the indicated capacity.6.1.3 Graduated Syringes, if used, shall be of suitablecapacities to contain the desired volume of liquid admixtureand shall be accurate to 6 3% of the required volume.6.1.4 Mixing Apparatus, capable of producing a uniformmixture.6.2 Thermal Measurement Test

46、 Equipment and Data Acqui-sition SystemActual design of the equipment, whether com-mercial or custom-built, may vary, but it shall meet thefollowing requirements for the selected type, shape, and massof the specimen, insulation (if any) surrounding the specimencontainer, initial mixture temperature,

47、 and test temperature.6.2.1 Temperature sensors shall be thermistors or thermo-couples with measurement accuracy of 6 1.0 C 2 F.6.2.2 The signal-to-noise ratio shall be at least 5.0. Signal isdefined as the difference between the highest and the lowesttemperatures measured from the dormant period th

48、rough themain peak response (Fig. 1) for a test specimen in the testseries without admixture or SCMs (Fig. 2). Noise is defined asthe difference between the highest and the lowest temperaturesmeasured during the time period in which the signal isestablished (Fig. 2) for an inert specimen having a ma

49、ss similarto that of the test specimens. The inert specimen shall remainin the same environment as the test specimens to indicate boththe effects of changes in ambient temperature as well as anythermal influences of adjacent test specimens (see also 6.2.5).NOTE 2The minimum signal-to-noise ratio is more important thanspecific requirements for insulation value of the specimen container orenvironment (see Appendix for guidance). Selected specimen containersand insulation configurations (if any) may vary with mixture type,C1753 153specimen mass, and initial mix