CEN/TR 16632:2014
(Main)Isothermal Conduction Calorimetry (ICC) for the determination of heat of hydration of cement: State of Art Report and Recommendations
Isothermal Conduction Calorimetry (ICC) for the determination of heat of hydration of cement: State of Art Report and Recommendations
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 temperature, 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 sample 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 output 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 vary.
(...)
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 measured. It is not easy to solve this problem designing a calorimeter provided with an internally mixing device having the proper efficacy.
1.2 Key points of ICC
When performing ICC measurements on cement samples some key points have to be considered and 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 (measured 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 available for the time being;
- Check that the ampoule is vapour tight enough (so that endothermic thermal powers of evaporation do not influence the measurements).
Bestimmung der Hydratationswärme von Zement durch isotherme Wärmeflusskalorimetrie: Stand der Technik und Empfehlungen
1 Grundprinzip und Eckpunkte der isothermen Wärmeflusskalorimetrie
1.1 Grundprinzip
Das Prüfverfahren wurde entwickelt, um die Hydratationswärme von Zement zu ermitteln. Die Messung findet bei weitgehend konstanter Temperatur statt, sofern die Messapparatur entsprechend dafür ausgelegt ist. Somit wird vorausgesetzt, dass es sich um eine „isotherme Bestimmung der Hydratationswärme von Zement“ handelt.
Ein isothermes Wärmeflusskalorimeter (im folgenden Kalorimeter genannt) besteht aus einer thermo¬statischen Wärmesenke, auf der zwei Wärmeflusssensoren angebracht sind. Die zu prüfende Probe (Prüfprobe) wird in eine Ampulle eingebracht, die durch eine Halterung mit einem der Wärmeflusssensoren in Kontakt steht. Eine inerte Referenzprobe wird in Kontakt mit dem anderen Wärmeflusssensor platziert. Die Probenampulle und die Referenzampulle sind durch die Wärmeflusssensoren thermisch mit einer thermostatischen Wärmesenke verbunden. Der Messwert des Kalorimeters ergibt sich aus der Differenz der Werte, die die Wärmeflusssensoren der Probe und der Referenz messen. Bild 1 zeigt ein allgemeines Schema eines Wärmeflusskalorimeters.
Die tatsächliche Gestaltungsweise einer Messapparatur, ob aus dem Handel oder dem Eigenbau, kann jedoch davon abweichen.
Določanje toplote hidratacije cementa z izotermno kondukcijsko kalorimetrijo (ICC): stanje tehnike in priporočila
Standard CEN/TR 16632 je zasnovan za določanje toplote hidratacije cementa pri mešanju z vodo. Merjenje poteka pri konstantni temperaturi, če sta instrument in merjenje dobro zasnovana, zato se predvideva, da gre za »izotermno toploto hidratacijo cementa«.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2014
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Isothermal Conduction Calorimetry (ICC) for the determination of heat of hydration of
cement: State of Art Report and Recommendations
Bestimmung der Hydratationswärme von Zement durch isotherme
Wärmeflusskalorimetrie: Stand der Technik und Empfehlungen
Ta slovenski standard je istoveten z: CEN/TR 16632:2014
ICS:
91.100.10 Cement. Mavec. Apno. Malta Cement. Gypsum. Lime.
Mortar
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL REPORT
CEN/TR 16632
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
June 2014
ICS 91.100.10
English Version
Isothermal Conduction Calorimetry (ICC) for the determination of
heat of hydration of cement: State of Art Report and
Recommendations
Bestimmung der Hydratationswärme von Zement durch
isotherme Wärmeflusskalorimetrie: Stand der Technik und
Empfehlungen
This Technical Report was approved by CEN on 26 November 2013. It has been drawn up by the 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, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16632:2014 E
worldwide for CEN national Members.
Contents Page
Foreword .4
Introduction .5
1 Basic principle and key points of ICC .6
1.1 Basic Principle .6
1.2 Key points 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 application . 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 (ε) . 17
10.2.3 Time constant (τ). 17
10.3 Pulse calibration . 18
10.3.1 General . 18
10.3.2 Time constant (τ). 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 Method 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
A.3 Baseline . 23
A.4 Calibration coefficient . 23
A.5 Isothermal. 23
A.6 Reference . 23
A.7 Thermal power . 23
Bibliography . 24
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 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
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 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 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.
Introduction
In 2007, CEN/TC 51, through resolution 495, agreed that WG 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 available, 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 aspects 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 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
document 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.
PART A
State of art 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 temperature, 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 sample 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 output 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 vary.
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 measured. It is not easy to solve this problem
designing a calorimeter provided with an internally mixing device having the proper efficacy.
...
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