ASTM C186-2015a Standard Test Method for Heat of Hydration of Hydraulic Cement《水硬性水泥水合热的标准试验方法》.pdf

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1、Designation: C186 15C186 15aStandard Test Method forHeat of Hydration of Hydraulic Cement1This standard is issued under the fixed designation C186; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number

2、 in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the heat of hydration of a hydraulic cement by measuring the heat of solutionof the dry cement a

3、nd the heat of solution of a separate portion of the cement that has been partially hydrated for 7 and for 28 days,the difference between these values being the heat of hydration for the respective hydrating period.1.2 The results of this test method may be inaccurate if some of the components of th

4、e hydraulic cement are insoluble in thenitric acid/hydrofluoric acid solution.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 Values in SI units shall be obtained by measurement in SI units or by appropriate conversion

5、, using the Rules for Conversionand Rounding given in Standard IEEE/ASTM SI 10, or measurements made in other units.1.5 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

6、 safety and health practices and determine the applicability or regulatorylimitations prior to use. WarningFresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin andtissue upon prolonged exposure.22. Referenced Documents2.1 ASTM Standards:3C109/C109M Test Method for C

7、ompressive Strength of Hydraulic Cement Mortars (Using 2-in. or 50-mm Cube Specimens)C114 Test Methods for Chemical Analysis of Hydraulic CementC670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction MaterialsC1005 Specification for Reference Masses and Devices fo

8、r Determining Mass and Volume for Use in the Physical Testing ofHydraulic CementsE11 Specification for Woven Wire Test Sieve Cloth and Test SievesIEEE/ASTM SI 10 Standard for Use of the International System of Units (SI): The Modern Metric System3. Significance and Use3.1 The purpose of this test is

9、 to determine if the hydraulic cement under test meets the heat of hydration requirement of theapplicable hydraulic cement specification.3.2 This test may also be used for research purposes when it is desired to determine the heat of hydration of hydraulic cementat any age.NOTE 1When tests are perfo

10、rmed for research purposes, useful additional information can be obtained by determining fineness, chemical andcompound compositions.3.3 Determination of the heat of hydration of hydraulic cements provides information that is helpful for calculating temperaturerise in mass concrete.4. Apparatus4.1 C

11、alorimetric Apparatus:1 This test method is under the jurisdiction of ASTM Committee C01 on Cement and is the direct responsibility of Subcommittee C01.26 on Heat of Hydration.Current edition approved Jan. 1, 2015April 1, 2015. Published January 2015May 2015. Originally approved in 1944. Last previo

12、us edition approved in 20132015 asC186 13.C186 15. DOI: 10.1520/C0186-15.10.1520/C0186-15A.2 Section on Safety, Manual of Cement Testing, Annual Book of ASTM Standards, Vol 04.01.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org.

13、For Annual Book of ASTM Standardsvolume information, 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

14、 not be technically possible to adequately 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.Copyright ASTM International, 100 Barr Harbo

15、r Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.1.1 CalorimeterThe calorimeter, such as that illustrated in Fig. 1, shall consist of a 0.5-L,0.5 L, wide-mouth vacuum jar,with cork stopper, or other suitable non-reactive stopper held in a suitably insulated container (see 4.1.

16、2) to keep the vacuum jarin position and to protect the jar from undue temperature fluctuations. The vacuum jar shall be coated on the interior with a materialresistant to hydrofluoric acid, such as a baked phenolic resin, a baked vinyl chloride acetate resin, or beeswax. The acid-resistantcoating s

17、hall be intact and free of cracks at all times; it shall be examined frequently and renewed whenever necessary. As anothermeans of protecting the vacuum jar, a plastic liner of suitable size may be used instead of coating the interior of the jar.The contentsof the vacuum jar shall not change more th

18、an 0.001C/min per degree difference from room temperature when filled with 425 gof the acid specified in 6.2, stoppered, and allowed to stand unstirred for 30 min. The temperature for this check shall approximatethe starting temperatures to be used in making the determination.4.1.2 Insulated Contain

19、erThe container shall have an insulating layer of a material such as non-reactive foam, cotton, orfiber-glass, which shall be at least 25 mm in thickness and shall encase the sides and bottom of the vacuum jar, but shall be soarranged as to permit easy removal of the jar.4.1.3 ThermometersTwo thermo

20、meters are required. One is a high-precision thermometer required to determine temperaturerise associated with dissolution of cement during determinations. For purposes of this test method, this thermometer is called thesolution thermometer. The other thermometer is used for measuring sample tempera

21、ture before introduction into the calorimeterand air temperature during the determination. For purposes of this test method, it is called the reference thermometer.4.1.3.1 Solution thermometerThe solution thermometer shall be readable to 0.001C. The solution thermometer may be eithera Beckman type (

22、see Note 2), which is a mercury-in-glass type that only outputs temperature differentials, or a digital type thatgives actual temperature outputs. If a Beckman type is used, it shall be graduated to at least 0.01C, with readings to 0.001C thatcan be estimated by interpolation between these graduatio

23、ns. It shall also have a temperature range of at least 6C.NOTE 2 If the part of the thermometer that will be in contact with the test solution is sensitive to the nitric and hydrofluoric acids in the test solution,then it is recommended that this part of the thermometer be coated with a resistant ma

24、terial to prolong the service life of the thermometer.4.1.3.2 Reference thermometerThe reference thermometer shall be any type that reads to a precision of at least 0.1C.FIG. 1 CalorimeterC186 15a24.1.4 FunnelThe funnel through which the sample is introduced into the calorimeter shall be glass or pl

25、astic and shall havea stem inside diameter of at least 6 mm (see Note 3).NOTE 3The minimum diameter is to prevent clogging of the powdered cement sample. The length of the stem will need to be adjusted so that thesample is delivered without the tip becoming wet from the acid solution, which will cau

26、se the funnel to become clogged and necessitate aborting thedetermination. The angle of the stem will need to be adjusted so that sample is not delivered onto the rotating stirrer, which will cause sample to cakeat the liquid line.4.1.5 Stirring AssemblyThe stirrer shall be a three-bladed polyethyle

27、ne propeller having the dimensions shown in Fig. 2, andshall extend as closely as possible to the bottom of the calorimeter. The motor shall be of the constant-speed type, at least 37 W,and shall be equipped with a geared speed reducer so that one speed, in the range of 5.8 to 11.7 rev/s, can be mai

28、ntained constant.NOTE 4The stirrer shown in Fig. 2 may be readily made from a commercially available three-bladed polyethylene propeller having a propellerdiameter of 34 mm, shaft diameter of 6 mm, and a shaft length of approximately 455 mm. The function of the stirrer is two-fold: to maintain unifo

29、rmtemperature throughout the liquid, and to supply sufficient agitation to keep the solid in suspension in the acid mixture. Since a stirrer capable of keepingthe solid in suspension generates considerable heat in the calorimeter, it is important that the stirrer speed and, hence the rate of heat ge

30、neration, bemaintained constant. Because such constancy is difficult to achieve with other types of motors, a synchronous motor with a geared speed reducer isrecommended.4.2 MixerAmoderate-speed mechanical mixer, such as a milk-shake type stirrer, capable of intimately mixing the cement andwater to

31、a uniform paste.4.3 StorageStorage space with temperature controlled at 23.0 6 2.0C.4.4 Mortar, approximately 200 mm in diameter, and pestle for grinding the partially hydrated samples.4.5 Drying Oven, maintained at 100 to 110C.4.6 Sieves, 150-m150 m (No. 100) and 850-m850 m (No. 20), conforming to

32、Specification E11.4.7 Crucibles, platinum, 30-mL30 mL capacity, with covers, for loss on ignition determination.4.8 Muffle Furnace, or suitable burners capable of maintaining a temperature of 900 to 950C.4.9 Analytical Balance and Analytical Weights, conforming to the requirements prescribed in Test

33、 Methods C114 for weighingout calorimetric samples and for loss on ignition weighings.4.10 Weights and Weighing Devices, conforming to the requirements of Specification C1005. The weighing device shall beevaluated at a total load of 1000 g.FIG. 2 StirrerC186 15a35. Reagents and Materials5.1 Purity o

34、f ReagentsReagent-grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specifications are available.4 Other grades may be used, p

35、rovided it is first ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.5.2 Hydrofluoric Acid (sp gr 1.15)Concentrated hydrofluoric acid (HF).5.3 Nitric Acid (2.00 N)The 2.00 N HNO3, for use in the calorimeter, shall be pre

36、pared and standardized in large quantities.Optionally, the dilute HNO3 may be made up with 127 mL of concentrated HNO3 (sp gr 1.42) per litre of solution, provided thatheat capacity determinations are made with each batch of diluted HNO3 so prepared.5.4 WaxParaffin wax, or other suitable wax, for se

37、aling vials.5.5 Zinc Oxide (ZnO)The ZnO shall be heated at 900 to 950C for 1 h, then cooled in a desiccator, ground to pass a150-m150 m (No. 100) sieve, and stored. Immediately prior to a heat capacity determination, 7 g of the ZnO so prepared shallbe heated for not more than 5 min at 900 to 950C, c

38、ooled to room temperature in a desiccator, and weighed accurately forintroduction into the calorimeter.NOTE 5The rate of solution of the ZnO varies with the preliminary treatment. The procedure described results in a product which dissolves at aboutthe same rate as the dry cement.6. Determination of

39、 Heat Capacity of Apparatus6.1 To determine the heat capacity of the system (that is, the number of joules required to raise the temperature of thecalorimeter and contents 1C), measure the corrected temperature rise obtained by dissolving 7 g of ignited ZnO in the specifiedacid mixture (see 6.2 6.7)

40、.6.2 Transfer approximately 400 g of the 2.00 N HNO3, which has been cooled to the temperature indicated by the lower rangeof the Beckmann thermometer (ordinarily about 4 to 5C below room temperature), into the vacuum jar, add 8.0 mL of HF (sp gr1.15), weigh, and add sufficient additional 2.00 N HNO

41、3 to bring the total weight of the solution to 425.0 g. Then, assemble thecalorimeter and start the stirring motor. Take care that the stirrer blades or shaft do not touch the thermometer, the sides or bottomof the jar, or the cork stopper. The lower end of the funnel stem shall extend approximately

42、 6 mm below the lower surface of thestopper and at least 12 mm above the level of the liquid. The upper end of the bulb of the Beckmann thermometer shall be at least38 mm below the surface of the liquid. Place it at the same depth in all determinations. After an initial stirring period of at least20

43、 min to allow the temperature of the system to become uniform, record the temperature of the room to the nearest 0.1C, thetemperature of the acid to the nearest 0.001C, record the time, and then immediately introduce the prepared ZnO through thefunnel at a uniform rate (see Note 6). Complete the int

44、roduction of the ZnO in not less than 1 or more than 2 min. Brush any ZnOclinging to the funnel stem into the acid mixture by means of a small “camels-hair” brush.NOTE 6The temperature of the sample shall be identical with that of the room when the sample is introduced into the calorimeter.6.3 Read

45、the temperature, to the nearest 0.001C, at 20 min and again at 40 min after beginning the introduction of the sample.The temperature rise in the first 20 min includes temperature rise due to the heat of solution of the sample and any heat gain orheat loss to the environment. This is called the solut

46、ion period. The temperature change during the second 20-min20 min periodis due to heat loss or gain to or from the environment. It is used to correct the temperature rise in the solution period to give theactual heat of solution of the sample. The second 20-min20 min period is called the correction

47、period.6.4 Calculate the corrected temperature rise as follows:Ro52020 (1)R 5Ro240220!where:Ro = observed temperature rise, C,20 = calorimeter temperature at the end of the solution period,0 = calorimeter temperature when sample was introduced,R = corrected temperature rise, C, and40 = calorimeter t

48、emperature at the end of the correction period.6.5 Calculate the heat capacity of the calorimeter and contents as follows (see Note 7):4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe

49、 American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.C186 15a4C 5W107210.4302t!10.5T 2t!#R (2)where:C = heat capacity, kJ/C,W = mass of ZnO, g,t = final temperature of the calorimeter, C (20 plus temperature, C, at which the Beckmann thermometer reading is zero),T = temperature of the ZnO (room temperature), C, when introduced into the calorime