BS PD CEN TR 16632-2014 Isothermal Conduction Calorimetry (ICC) for the determination of heat of hydration of cement State of Art Report and Recommendations《用于测定水泥水化热的等温传.pdf

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1、BSI Standards Publication PD CEN/TR 16632:2014 Isothermal Conduction Calorimetry (ICC) for the determination of heat of hydration of cement: State of Art Report and RecommendationsPD CEN/TR 16632:2014 PUBLISHED DOCUMENT National foreword This Published Document is the UK implementation of CEN/TR 166

2、32:2014. The UK participation in its preparation was entrusted to Technical Committee B/516/12, Sampling and testing. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a cont

3、ract. Users are responsible for its correct application. The British Standards Institution 2014. Published by BSI Standards Limited 2014 ISBN 978 0 580 83044 0 ICS 91.100.10 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under

4、the authority of the Standards Policy and Strategy Committee on 30 June 2014. Amendments issued since publication Date Text affectedPD CEN/TR 16632:2014TECHNICAL REPORT RAPPORT TECHNIQUE TECHNISCHER BERICHT CEN/TR 16632 June 2014 ICS 91.100.10 English Version Isothermal Conduction Calorimetry (ICC)

5、for the determination of heat of hydration of cement: State of Art Report and Recommendations Bestimmung der Hydratationswrme von Zement durch isotherme Wrmeflusskalorimetrie: Stand der Technik und Empfehlungen This Technical Report was approved by CEN on 26 November 2013. It has been drawn up by th

6、e Technical Committee CEN/TC 51. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, M

7、alta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014

8、CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TR 16632:2014 EPD CEN/TR 16632:2014 CEN/TR 16632:2014 (E) 2 Contents Page Foreword 4 Introduction .5 1 Basic principle and key points of ICC .6 1.1 Basic Principle .6 1.2 Key points

9、of ICC .7 2 Normative references 7 3 Technical data sheets of available calorimeters 7 4 Experimental data 8 5 Calibration 9 5.1 Calibration of isothermal heat conduction calorimeters .9 5.2 Determination of the baseline . 11 5.3 Open question . 11 6 Final remarks . 12 7 Scope and field of applicati

10、on . 13 8 Terms and definitions 13 9 Apparatus 14 9.1 General . 14 9.2 Thermostat 15 9.3 Calorimeter technical parameters . 15 10 Calibration . 16 10.1 General . 16 10.2 Steady state calibration . 17 10.2.1 General . 17 10.2.2 Calibration coefficient () . 17 10.2.3 Time constant (). 17 10.3 Pulse ca

11、libration . 18 10.3.1 General . 18 10.3.2 Time constant (). 19 10.4 Determination of the calorimeter parameters 19 10.5 Improvement of common calibration procedure . 19 11 Sample . 19 11.1 General . 19 11.2 Test sample . 19 11.3 Reference sample . 20 12 Testing procedure. 20 12.1 General . 20 12.2 M

12、ethod A - “External mixing” 20 12.3 Method B - “Internal mixing” . 21 12.4 Measurement . 21 12.5 Calculations . 21 12.6 Result . 22 Annex A (informative) Glossary 23 A.1 Ampoule . 23 A.2 Ampoule holder . 23 PD CEN/TR 16632:2014 CEN/TR 16632:2014 (E) 3 A.3 Baseline23 A.4 Calibration coefficient.23 A.

13、5 Isothermal.23 A.6 Reference .23 A.7 Thermal power .23 Bibliography24PD CEN/TR 16632:2014 CEN/TR 16632:2014 (E) 4 Foreword This document (CEN/TR 16632:2014) has been prepared by Technical Committee CEN/TC 51 “Cement and building limes”, the secretariat of which is held by NBN. Attention is drawn to

14、 the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. It is divided into two sections. The first section is a State of Art Report of the test method based on the

15、 collection of the technical data sheets of the calorimeters adopted in the European cement laboratories and also on the collection of the results of several experimental activities. The second section is made of recommendations for the measurement of heat of hydration of cement by ICC. Based on the

16、 State of Art Report, this section provides some basic elements of the test procedure with the aim to become a first guide for the laboratories that are currently using ICC or for those laboratories that would start to adopt this method. By using the information and adopting the procedures given in

17、the document it will be possible to compare in a more reliable way both the performances of the different calorimeters and the test results. Annex A (informative) provides a Glossary. PD CEN/TR 16632:2014 CEN/TR 16632:2014 (E) 5 Introduction In 2007, CEN/TC 51, through resolution 495, agreed that WG

18、 12/TG 3 investigates the suitability for standardization of the test method based on isothermal conduction calorimetry (ICC). The Task Group 3 has been reactivated and held its first meeting in 2008. Since no national standard on ICC for the determination of heat of hydration of cement was availabl

19、e, TG 3 started its activity on the item by gathering the available information on recommendations or published scientific papers, inter-laboratory experimental exercises. The available information, collected into a State of Art report, has been analysed and discussed in order to identify those aspe

20、cts of the test method that can be already considered consolidated as well as those elements that still need further development. The second step of the activity was the redaction of a Recommendations document including a testing procedure for the measuring of heat of hydration of cement by ICC. The

21、 circulation of this document in the laboratory actually involved in ICC testing, would lead to the application of uniform general principles and, therefore, to a better data reproducibility. In this CEN/TR, the State of Art document and the Recommendations document are reviewed into a single docume

22、nt divided into two parts: a) State of art report on the application of ICC for the determination of heat of hydration of cement; b) Recommendations for the measurement of Heat of Hydration of Cement by Isothermal Conduction Calorimetry. PD CEN/TR 16632:2014 CEN/TR 16632:2014 (E) 6 PART A State of a

23、rt report on the application of ICC for the determination of heat of hydration of cement 1 Basic principle and key points of ICC 1.1 Basic Principle The test method is designed to measure the heat of hydration of cement when mixed with water. The measurement takes place at essentially constant tempe

24、rature, if the instrument and the measurement are well designed, therefore it is assumed to be the “isothermal heat of hydration of cement”. An isothermal heat conduction calorimeter (here called calorimeter) consists of a thermostatic heat sink upon which two heat flow sensors are placed. The sampl

25、e is placed in an ampoule that is placed in an ampoule holder that is in contact with one of the heat flow sensors, and an inert reference is placed in contact with the other. The sample ampoule and the reference ampoule are thermally connected by heat flow sensors to a thermostatic heat sink. The o

26、utput from the calorimeter is the difference between the outputs from the sample heat flow sensor and the reference heat flow sensor. A general scheme of a heat conduction calorimeter is given in Figure 1. However the actual design of an individual instrument, whether commercial or home-built, may v

27、ary. Key 1 thermostat 2 heat flow sensors 3 heat sunk 4 sample 5 reference Figure 1 A schematic drawing of a heat conduction calorimeter Most part of the calorimeters can measure the heat of hydration of samples mixed outside from the instrument, therefore the heat produced during the mixing is not

28、measured. It is not easy to solve this problem designing a calorimeter provided with an internally mixing device having the proper efficacy. PD CEN/TR 16632:2014 CEN/TR 16632:2014 (E) 7 1.2 Key points of ICC When performing ICC measurements on cement samples some key points have to be considered and

29、 correctly managed: Constant value of the temperature of the thermostat; Stability of the temperature of the thermostat all over the test duration; Control of the maximum difference between sample temperature and thermostat temperature (isothermal conditions); The baseline of the instrument (measure

30、d with an inert sample of similar thermal properties of test sample) should be both repeatable and stable; Calibration of the calorimeter. The method currently used is based on the joule effect produced by a resistor feed with an electrical current; no standard material for the calibration is availa

31、ble for the time being; Check that the ampoule is vapour tight enough (so that endothermic thermal powers of evaporation do not influence the measurements). 2 Normative references Not applicable. 3 Technical data sheets of available calorimeters One of the expected results from this CEN/TR is a gene

32、ral and comprehensive overview of the technical data sheets of the currently existing conduction calorimeters because the quality of the test results of ICC is strongly influenced by the characteristics of the apparatus, where the word “characteristics” has to be intended in the sense of “fit for us

33、e” when measuring heat of hydration of cement. A number of instruments that have been used for calorimetric measurements on cement have been considered and their technical specifications have been compared. The list of the instruments that have been considered is given in Table 1. Table 1 List of In

34、struments considered for the analysis of technical data sheets Instrument Manufacturer Thermal Activity Monitor TAM AIR Thermometric, Sweden Thermal Activity Monitor TAM 2277 Thermometric, Sweden Thermal Activity Monitor TAM III TA instruments ToniCAL 7338 Toni Technik MS 80 Calorimeter Setaram C 80

35、 Calorimeter Setaram Calorimeter Italcementi Italcementi Basically the relevant specifications of each instrument are useful to describe two main aspects: sensitivity and related uncertainty; PD CEN/TR 16632:2014 CEN/TR 16632:2014 (E) 8 stability (Baseline drift, Baseline noise). The final result of

36、 this activity should be the identification and definition of performance requirements for ICC suitable for the determination of heat of hydration of cements, but with reference to this expected result, the collected data does not allow to reach this objective. Unfortunately the data provided by the

37、 technical sheets are not expressed in a standardised way, so any comparison of the characteristics of the calorimeter has to be preceded by a unification of the definitions and expression of the main instrumental parameters. TG 3 has already defined a program of the activity suitable to fill the ga

38、p related to: unified procedures for the determination of fundamental technical specifications; technical specifications for performances related to Sensitivity and Stability. 4 Experimental data Several inter-laboratories round-robin exercises have been collected: International inter-laboratory tri

39、al 2003 by Lund University; Swiss inter-laboratory trials 2005/2006 (Cemsuisse); German inter-laboratory trials 2006/2007 (VDZ); NL reference test on cement; Experiences from US (PCA); Validation of conduction calorimetry (VDZ). All these tests had two main objectives: determination of precision dat

40、a of ICC method; comparison of ICC test results with the corresponding results of the reference methods: solution method (EN 196-8) and semi-adiabatic method (EN 196-9). In practice, only few data are available for semi-adiabatic method, therefore no comparison can be made for semi-adiabatic method

41、and ICC, while for the solution method there is a lacking of data for Type II, Type IV and Type V cements. Focusing only on the comparison of ICC with solution method, the following considerations can be made: 1) repeatability (within-laboratory precision) is better than for solution calorimetry (5

42、6) J/g 1)for ICC vs. 8 J/g for EN 196-8); 2) reproducibility (inter-laboratory precision) is somewhat better than for solution calorimetry (ranges from 10 to 20 J/g1 for ICC vs. 18 J/g for EN 196-8); 3) comparative testing data with solution method (EN 196-8) are quite limited and even more limited

43、with semi-adiabatic method (EN 196-9); 1) Determined for duration of test ranging from 3 d to 7 d. PD CEN/TR 16632:2014 CEN/TR 16632:2014 (E) 9 4) solution method data at 7d and ICC data at 7d do not match very well; 5) some systematic deviation seems to exist between the data of two methods: values

44、 from ICC are higher than those from Solution Method; 6) for the time being no sound correlation has been found between ICC data and solution method data; characteristics of instruments seem to play a role; 7) some doubts still exist about the capability of the method to measure with the needed accu

45、racy the heat of hydration in the time interval 3 d - 7 d when the heat flow developed by the cement paste is very low. 5 Calibration 5.1 Calibration of isothermal heat conduction calorimeters Calibration is in general a fundamental activity of a test method. The ICC of cement does not represent an

46、exception to this rule. This test method is completely automated and, therefore, the precision intended as repeatability and reproducibility (or extended uncertainty) is determined by: 1) design and construction of the calorimeter; 2) proper use and maintenance; 3) calibration procedure. Points 1) a

47、nd 2) depend on manufacturer activity and training of users, while point 3) should be considered at a more general level. Currently the calibration is made by producing a known electrical thermal power close to where the sample will be placed in the calorimeter and measuring the electrical signal by

48、 the data acquisition equipment. Heaters can be placed in sample ampoules with inert contents or fixed in the ampoule holders. Key 1 calibration heater 1 2 calibration heater 2 Figure 2 A schematic drawing of the set-up for the simultaneous calibration of two calorimeters PD CEN/TR 16632:2014 CEN/TR

49、 16632:2014 (E) 10 There are two ways of calibration: steady-state calibration that is convenient for manual calibration and pulse calibration that is done on automated systems. These two ways of calibrating give the same result. Steady-state calibration is made by first measuring the baseline U 1 before the calibration. The current to the heater is then turned on until a new stable output value is obtained. When the output is constant, its value is noted as U C . The current is then switched off and the signal returns back to the bas