ASTM C186-2015 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

1、Designation: C186 15Standard 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 in pare

2、ntheses 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 ofhydration of a hydraulic cement by measuring the heat ofsolution of the dry cement and the he

3、at of solution of a separateportion of the cement that has been partially hydrated for 7 andfor 28 days, the difference between these values being the heatof hydration for the respective hydrating period.1.2 The results of this test method may be inaccurate ifsome of the components of the hydraulic

4、cement are insolublein the nitric acid/hydrofluoric acid solution.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 Values in SI units shall be obtained by measurement inSI units or by appropriate conversion, using the Rul

5、es forConversion and Rounding given in Standard IEEE/ASTM SI10, or measurements made in other units.1.5 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 heal

6、th practices and determine the applica-bility or regulatory limitations prior to use. WarningFreshhydraulic cementitious mixtures are caustic and may causechemical burns to skin and tissue upon prolonged exposure.22. Referenced Documents2.1 ASTM Standards:3C109/C109M Test Method for Compressive Stre

7、ngth ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)C114 Test Methods for Chemical Analysis of HydraulicCementC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC1005 Specification for Reference Masses and Devices forDetermining Mass a

8、nd Volume for Use in the PhysicalTesting of Hydraulic CementsE11 Specification for Woven Wire Test Sieve Cloth and TestSievesIEEE/ASTM SI 10 Standard for Use of the InternationalSystem of Units (SI): The Modern Metric System3. Significance and Use3.1 The purpose of this test is to determine if the h

9、ydrauliccement under test meets the heat of hydration requirement ofthe applicable hydraulic cement specification.3.2 This test may also be used for research purposes when itis desired to determine the heat of hydration of hydrauliccement at any age.NOTE 1When tests are performed for research purpos

10、es, usefuladditional information can be obtained by determining fineness, chemicaland compound compositions.3.3 Determination of the heat of hydration of hydrauliccements provides information that is helpful for calculatingtemperature rise in mass concrete.4. Apparatus4.1 Calorimetric Apparatus:4.1.

11、1 CalorimeterThe calorimeter, such as that illustratedin Fig. 1, shall consist of a 0.5-L, wide-mouth vacuum jar, withcork stopper, or other suitable non-reactive stopper held in asuitably insulated container (see 4.1.2) to keep the vacuum jarin position and to protect the jar from undue temperature

12、fluctuations. The vacuum jar shall be coated on the interiorwith a material resistant to hydrofluoric acid, such as a bakedphenolic resin, a baked vinyl chloride acetate resin, or bees-wax. The acid-resistant coating shall be intact and free ofcracks at all times; it shall be examined frequently and

13、 renewedwhenever necessary. As another means of protecting thevacuum jar, a plastic liner of suitable size may be used insteadof coating the interior of the jar. The contents of the vacuum jarshall not change more than 0.001C/min per degree differencefrom room temperature when filled with 425 g of t

14、he acidspecified in 6.2, stoppered, and allowed to stand unstirred for1This test method is under the jurisdiction of ASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.26 on Heat of Hydration.Current edition approved Jan. 1, 2015. Published January 2015. Originallyappro

15、ved in 1944. Last previous edition approved in 2013 as C186 13. DOI:10.1520/C0186-15.2Section on Safety, Manual of Cement Testing, Annual Book of ASTMStandards, Vol 04.01.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Ann

16、ual 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 States130 min. The temperature for this check shall approximate thestarting tempera

17、tures to be used in making the determination.4.1.2 Insulated ContainerThe container shall have aninsulating layer of a material such as non-reactive foam, cotton,or fiber-glass, which shall be at least 25 mm in thickness andshall encase the sides and bottom of the vacuum jar, but shallbe so arranged

18、 as to permit easy removal of the jar.4.1.3 ThermometersTwo thermometers are required. Oneis a high-precision thermometer required to determine tempera-ture rise associated with dissolution of cement during determi-nations. For purposes of this test method, this thermometer iscalled the solution the

19、rmometer. The other thermometer is usedfor measuring sample temperature before introduction into thecalorimeter and air temperature during the determination. Forpurposes of this test method, it is called the reference ther-mometer.4.1.3.1 Solution thermometerThe solution thermometershall be readable

20、 to 0.001C. The solution thermometer may beeither a Beckman type (see Note 2), which is a mercury-in-glass type that only outputs temperature differentials, or adigital type that gives actual temperature outputs. If a Beckmantype is used, it shall be graduated to at least 0.01C, withreadings to 0.00

21、1C that can be estimated by interpolationbetween these graduations. It shall also have a temperaturerange of at least 6C.NOTE 2 If the part of the thermometer that will be in contact with thetest solution is sensitive to the nitric and hydrofluoric acids in the testsolution, then it is recommended t

22、hat this part of the thermometer becoated with a resistant material to prolong the service life of thethermometer.4.1.3.2 Reference thermometerThe reference thermom-eter shall be any type that reads to a precision of at least 0.1C.4.1.4 FunnelThe funnel through which the sample isintroduced into the

23、 calorimeter shall be glass or plastic andshall have a stem inside diameter of at least 6 mm (see Note 3).NOTE 3The minimum diameter is to prevent clogging of the pow-dered cement sample. The length of the stem will need to be adjusted sothat the sample is delivered without the tip becoming wet from

24、 the acidsolution, which will cause the funnel to become clogged and necessitateaborting the determination. The angle of the stem will need to be adjustedso that sample is not delivered onto the rotating stirrer, which will causesample to cake at the liquid line.4.1.5 Stirring AssemblyThe stirrer sh

25、all be a three-bladedpolyethylene propeller having the dimensions shown in Fig. 2,FIG. 1 CalorimeterC186 152and shall extend as closely as possible to the bottom of thecalorimeter. The motor shall be of the constant-speed type, atleast 37 W, and shall be equipped with a geared speed reducerso that o

26、ne speed, in the range of 5.8 to 11.7 rev/s, can bemaintained constant.NOTE 4The stirrer shown in Fig. 2 may be readily made from acommercially available three-bladed polyethylene propeller having apropeller diameter of 34 mm, shaft diameter of 6 mm, and a shaft lengthof approximately 455 mm. The fu

27、nction of the stirrer is two-fold: tomaintain uniform temperature throughout the liquid, and to supplysufficient agitation to keep the solid in suspension in the acid mixture.Since a stirrer capable of keeping the solid in suspension generatesconsiderable heat in the calorimeter, it is important tha

28、t the stirrer speedand, hence the rate of heat generation, be maintained constant. Becausesuch constancy is difficult to achieve with other types of motors, asynchronous motor with a geared speed reducer is recommended.4.2 MixerA moderate-speed mechanical mixer, such as amilk-shake type stirrer, cap

29、able of intimately mixing thecement and water to a uniform paste.4.3 StorageStorage space with temperature controlled at23.0 6 2.0C.4.4 Mortar, approximately 200 mm in diameter, and pestlefor grinding the partially hydrated samples.4.5 Drying Oven, maintained at 100 to 110C.4.6 Sieves, 150-m (No. 10

30、0) and 850-m (No. 20), con-forming to Specification E11.4.7 Crucibles, platinum, 30-mL capacity, with covers, forloss on ignition determination.4.8 Muffle Furnace, or suitable burners capable of maintain-ing a temperature of 900 to 950C.4.9 Analytical Balance and Analytical Weights, conformingto the

31、 requirements prescribed in Test Methods C114 forweighing out calorimetric samples and for loss on ignitionweighings.4.10 Weights and Weighing Devices, conforming to therequirements of Specification C1005. The weighing deviceshall be evaluated at a total load of 1000 g.5. Reagents and Materials5.1 P

32、urity of ReagentsReagent-grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beus

33、ed, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Hydrofluoric Acid (sp gr 1.15)Concentrated hydroflu-oric acid (HF).5.3 Nitric Acid (2.00 N)The 2.00 N HNO3, for use in thecalorimeter, shall be

34、 prepared and standardized in large quan-tities. Optionally, the dilute HNO3may be made up with127 mL of concentrated HNO3(sp gr 1.42) per litre of solution,4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reage

35、nts notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 2 StirrerC186 153provided that heat capacity determinat

36、ions are made with eachbatch of diluted HNO3so prepared.5.4 WaxParaffin wax, or other suitable wax, for sealingvials.5.5 Zinc Oxide (ZnO)The ZnO shall be heated at 900 to950C for 1 h, then cooled in a desiccator, ground to pass a150-m (No. 100) sieve, and stored. Immediately prior to aheat capacity

37、determination,7goftheZnOsoprepared shallbe heated for not more than 5 min at 900 to 950C, cooled toroom temperature in a desiccator, and weighed accurately forintroduction into the calorimeter.NOTE 5The rate of solution of the ZnO varies with the preliminarytreatment. The procedure described results

38、 in a product which dissolves atabout the same rate as the dry cement.6. Determination of Heat Capacity of Apparatus6.1 To determine the heat capacity of the system (that is, thenumber of joules required to raise the temperature of thecalorimeter and contents 1C), measure the corrected tempera-ture

39、rise obtained by dissolving7gofignited ZnO in thespecified acid mixture (see 6.2 6.7).6.2 Transfer approximately 400 g of the 2.00 N HNO3,which has been cooled to the temperature indicated by thelower range of the Beckmann thermometer (ordinarily about 4to 5C below room temperature), into the vacuum

40、 jar, add8.0 mL of HF (sp gr 1.15), weigh, and add sufficient additional2.00 N HNO3to bring the total weight of the solution to425.0 g. Then, assemble the calorimeter and start the stirringmotor. Take care that the stirrer blades or shaft do not touch thethermometer, the sides or bottom of the jar,

41、or the cork stopper.The lower end of the funnel stem shall extend approximately6 mm below the lower surface of the stopper and at least12 mm above the level of the liquid. The upper end of the bulbof the Beckmann thermometer shall be at least 38 mm belowthe surface of the liquid. Place it at the sam

42、e depth in alldeterminations.After an initial stirring period of at least 20 minto 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 prepar

43、ed ZnO through thefunnel at a uniform rate (see Note 6). Complete the introduc-tion of the ZnO in not less than 1 or more than 2 min. Brushany ZnO clinging to the funnel stem into the acid mixture bymeans of a small “camels-hair” brush.NOTE 6The temperature of the sample shall be identical with that

44、 ofthe room when the sample is introduced into the calorimeter.6.3 Read the temperature, to the nearest 0.001C, at 20 minand again at 40 min after beginning the introduction of thesample. The temperature rise in the first 20 min includestemperature rise due to the heat of solution of the sample anda

45、ny heat gain or heat loss to the environment. This is called thesolution period. The temperature change during the second20-min period is due to heat loss or gain to or from theenvironment. It is used to correct the temperature rise in thesolution period to give the actual heat of solution of the sa

46、mple.The second 20-min period is called the correction period.6.4 Calculate the corrected temperature rise as follows:Ro5 202 0(1)R 5 Ro2 402 20!where:Ro= observed temperature rise, C,20= calorimeter temperature at the end of the solutionperiod,0= calorimeter temperature when sample was introduced,R

47、 = corrected temperature rise, C, and40= calorimeter temperature at the end of the correctionperiod.6.5 Calculate the heat capacity of the calorimeter andcontents as follows (see Note 7):C 5W107210.430 2 t!10.5T 2 t!#R(2)where:C = heat capacity, kJ/C,W = mass of ZnO, g,t = final temperature of the c

48、alorimeter, C (20plustemperature, C, at which the Beckmann thermometerreading is zero),T = temperature of the ZnO (room temperature), C, whenintroduced into the calorimeter, andR = corrected temperature rise, C.NOTE 7The heat of solution of ZnO is 1072 kJ/kg at 30C. This valueincreases 0.4 kJ/kg for

49、 each degree decrease in temperature below 30C.The heat capacity of ZnO is 0.5 kJ/kgK. The heat required to bring theZnO to the final temperature of the calorimeter must be included in theeffective heat of solution.6.6 If more than a trace of ZnO is found adhering to the tipof the funnel or to the stopper when the calorimeter is opened,reject the test.6.7 Redetermine the heat capacity at the following times:6.7.1 When the Beckmann thermometer (if used) is reset,6.7.2 When a new coating is applied to the solutionth