FINAL DRAFT UGANDA 
STANDARD  
  FDUS EAS 148-8 
First  Edition  
2018-mm-dd 
 
 Reference number  
FDUS EAS 148-8: 2017 
© UNBS 201 8 
  
Cement — Test methods — Part 8: Heat of hydration — Solution 
method  
 FDUS EAS 148 -8:2017 
ii                © UNBS  2018  - All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2018  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including photocopying and microfilm, with out prior written 
permission from UNBS.  
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 FDUS EAS 148 -8:2018 
© UNBS  2018  - All rights reserved                 iii National foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade, Industry and 
Cooperatives established under Cap 327, of the Laws of Ugan da, as amended.  UNBS is mandated to co -
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National E nquiry Point on TBT Agreement of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists o f representatives of 
consumers, traders, academicians, manufacturers, government and other stakeholders.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee revi ews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
This Uganda Standard, US EAS 148 -8: 2017, Cement — Test methods — Part 8: Heat of hydration — 
Solution method , is identical with and has been reproduced from an East African Standard, EAS 148 -8: 2017 , 
Cement — Test methods — Part 8: Heat of hydration — Solution method , and adopted as a Uganda 
Standard.  
The committee responsible for this document is Technical Committee  UNBS/TC 3, Building and construction .  
This standard cancels and replaces US 100 -8:2016, Cement — Test methods — Part 8: Heat of hydration — 
Solution method (2nd Edition) , which has been technically revised.  
  EAS 148 -8: 201 7 
ICS 91.100.10  
© EAS 2017                                                                                                                         Second Edition  2017  
 
EAST AFRICAN STANDARD  
Cement  — Test methods  — Part 8: Heat of hydration — Solution method  
EAST AFRICAN COMMUNITY  EAS 148 -8: 201 7 
ii © EAC 2017  – All rights reserved  
 Copyright notice  
This EAC document is copyright -protected by EAC. While the reproduction of this document by 
participants in the EAC standards development process is permitted without pri or permission from EAC, 
neither this document nor any extract from it may be reproduced, stored or transmitted in any form for 
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Requests for permission to reproduce this document for the purpose o f selling it should be addressed 
as shown below or to EAC’s member body in the country of the requester:  
© East African Community  2017— All rights reserved  
East African Community  
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Reproduction for sales purposes may be subject to royalty payments or a licensing agreement.  
Violators may be persecuted  EAS 148 -8: 201 7 
© EAC 2017  – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ............................  iv 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Principle  ................................ ................................ ................................ ................................ .................  1 
4 Materials  ................................ ................................ ................................ ................................ .................  2 
4.1 Acid mixture  ................................ ................................ ................................ ................................ ...........  2 
4.2 Zinc oxide (ZnO)  ................................ ................................ ................................ ................................ .... 2 
4.3 Anhydrous cement  ................................ ................................ ................................ ................................  2 
4.4 Hydrated cement  ................................ ................................ ................................ ................................ ... 2 
5 Apparatus  ................................ ................................ ................................ ................................ ...............  2 
6 Calorimeter calibration  ................................ ................................ ................................ .........................  4 
6.1 Principle  ................................ ................................ ................................ ................................ .................  4 
6.2 Procedure  ................................ ................................ ................................ ................................ ...............  5 
6.3 Calculation of calibration characteristics  ................................ ................................ ...........................  5 
6.3.1  Corrected temperature increase, ΔTc ................................ ................................ ................................ .. 5 
6.3.2  Thermal leakage coefficient, K ................................ ................................ ................................ .............  5 
6.2 Thermal capacity, C ................................ ................................ ................................ ...............................  6 
7 Determinat ion of heat of solution  ................................ ................................ ................................ ........  6 
7.1 Heat of solution of anhydrous cement  ................................ ................................ ................................  6 
7.1.1  Procedure  ................................ ................................ ................................ ................................ ...............  6 
7.1.2  Calculation  ................................ ................................ ................................ ................................ .............  7 
7.1.3  Expression of results  ................................ ................................ ................................ ............................  8 
7.2 Heat of solution of hydrated cement  ................................ ................................ ................................ ... 8 
7.2.1  Procedure  ................................ ................................ ................................ ................................ ...............  8 
7.2.2  Correction for bound water  ................................ ................................ ................................ ..................  8 
7.2.3  Calculation  ................................ ................................ ................................ ................................ .............  9 
7.2.4  Expression of results.  ................................ ................................ ................................ .........................  10 
8 Heat of hydration  ................................ ................................ ................................ ................................ . 10 
8.1 Calculati on of results  ................................ ................................ ................................ ..........................  10 
8.2 Reporting of results  ................................ ................................ ................................ ............................  10 
8.3 Precision  ................................ ................................ ................................ ................................ ..............  10 
8.3.1 Repeatability  ................................ ................................ ................................ ................................ ........  10 
8.3.2  Reproducibility  ................................ ................................ ................................ ................................ .... 10 
Bibliography  ................................ ................................ ................................ ................................ ........................  1 
 EAS 148 -8: 201 7 
iv © EAC 2017  – All rights reserved  
 Foreword  
Development of the East A frican Standards has been necessitated by the need for harmonizing requirements 
governing quality of products and services in the East African Community. It is envisaged that through 
harmonized standardization, trade barriers that are encountered when good s and services are exchanged 
within the Community will be removed.  
In order to achieve this objective, the Community established an East African Standards Committee mandated 
to develop and issue East African Standards.   
The Committee is composed of repres entatives of the National Standards Bodies in Partner States, together 
with the representatives from the private sectors and consumer organizations. Draft East African Standards 
are circulated to stakeholders through the National Standards Bodies in the Pa rtner States. The comments 
received are discussed and incorporated before finalization of standards, in accordance with the procedures 
of the Community.  
East African Standards are subject to review, to keep pace with technological advances. Users of the Ea st 
African Standards are therefore expected to ensure that they always have the latest versions of the standards 
they are implementing .  
EAS 148-8 was prepared by Technical Committee EASC /TC/026, Cement, lime, clay and related products . 
In the preparation of this East African Standard, reference was made to the following standard:  
The assistance derived from the above source is hereby acknowledged with thanks.  
EN 196 -8: 20 10; Methods testing cement — Part 8: Heat of hydration – Solution method.  
This second cancels and replaces the first edition (EAS  148-8: 2000), which has been technically revised.  
EAS 148 consists of the following parts, under the general title  Cements — Test methods : 
Part 1: Determination of strength  
Part 2: Chemical analysis of cement  
Part 3: Determination of setting times and soundness  
Part 4: Quantitative Determination of constituents  
Part 5: Pozzolanicity test for pozzolanic cement  
Part 6: Determination  of fineness  
Part 7: Method of taking and preparing samples of cement  
Part 8: Heat of hydration — Solution method  
 EAST AFRICAN STANDARD  EAS 148 -8:201 7 
 
© EAC 2017  – All rights reserved  1 
 Cement  — Test methods  — Part 8: Heat of hydration — Solution method  
1 Scope  
This East African S tandard lays down the methods for determini ng the heat of hydration by means of solution 
calorimetry, also known as the solution method. The heat of hydration is expressed in joules per gram of 
cement.  
This standard is applicable to cements and hydraulic binders whatever their chemical composition.  
NOTE 1  Another procedure, called the semi -adiabatic method, is described in ISO 29582 -2. Either procedure can be 
used independently.  
NOTE 2  It has been demonstrated that the best correlation between the two methods is obtained at seven days for the 
soluti on method compared with 41 h for the semi -adiabatic method (ISO 29582 -2). 
2 Normative references  
The following referenced documents are indispensable for the application of this document. For dated 
references, only the edition cited applies. For undated re ferences, the latest edition of the referenced 
document (including any amendments) applies.  
EAS 18 -1, Cement  — Part 1: Composition, specifications and conformity criteria for common cements  
ISO 29582 -2, Cement —Test methods — Part 2: Heat of hydration – Semi-adiabatic  method  
3 Principle  
3.1 The method involves measuring the heats of solution, in acid mixture, of anhydrous cement and cement 
hydrated under standardized conditions for a predetermined period of time, for example seven days.  
These standardized h ydration conditions are as follows:  
a) water/cement ratio 0.40;  
b) use of neat cement paste; and  
c) storage at constant temperature of ( 20.0 ± 0.2) oC during the whole hydration process.  
3.2 The heat of hydration for each period, Hi, is obtained from the differenc e between the heat of solution 
anhydrous cement, Qa, and that of hydrated cement, Qi. EAS 148 -8: 201 7 
2 © EAC 2017  – All rights reserved  
 4 Materials  
4.1 Acid mixture  
4.1.1  Analytical reagent quality acid mixture, obtained by adding 2.760 g of 40  % hydrofluoric acid (HF) for 
every 100.0 g of ( 2.00 ± 0.01) m ol/L nitric  acid (HNO 3) or 2.600 m L of hydrofluoric acid for every 100.0 m L of 
nitric acid.  
WARNING  Hydrofluoric acid can cause painful skin burns which heal only with difficulty and precautions in 
handling this very corrosive substance should be strictly  observed.  
4.1.2  The quantity (mass or volume) of acid to be used, which is common to all tests, shall be measured to 
± 0.2 %.  
4.2 Zinc oxide (ZnO)  
Use zinc oxide of analytical quality to determine the thermal capacity of the calorimeter. Weigh 40 g - 50 g. 
Ignite at (950 ± 25) ˚C for 1 h. Cool in desiccators. Grind to pass a 125 -µm sieve. Store in a desiccator.  
4.3 Anhydrous cement  
Store anhydrous cement, from which metallic iron has been removed with a magnet, in a sealed container to 
avoid absorption of water or carbon dioxid e. Bring the test sample to ambient temperature and carefully 
homogenize it before use.  
4.4 Hydrated cement  
Prepare the hydrated cement test sample by vigorously mixing, either manually or mechanically, (100.0 ± 0.1) 
g of anhydrous cement with (40.0 ± 0.1) g of distilled or deionised water for 3 min at ambient temperature.  
Place the resulting paste in plastic or glass cylindrical vials (three for ach hydration period to be tested) so that 
each vial contains 15 g - 20 g of material. Seal the vials by means of a stopper and, if necessary, with paraffin 
wax or similar material and store them horizontally in a thermostatic bath maintained at a temperature of (20.0 
± 0.2) oC. 
5 Apparatus  
5.1 Calorimeter ; As illustrated in figure 1, comprising of the following:  
a) Dissolution vessel , consisting of: an insulated flask for example Dewar flask, placed either in a heat 
insulated container set inside a box constructed of insulating material for example wood, plastics, or 
immersed in a thermostatic water bath regulated to ± 0.2 oC; and an insulated stopper (made of cork 
or plastics) through which holes are provided for the thermometer, the stirrer and the funnel used for 
introducing the sample. The insulation of the calorimeter shall ensure that the thermal leakage 
coeffici ent, K (determined in accordance with 6.3), is less than 0.06 K per 15 min for each Kelvin 
above ambient temperature. The internal surface of the flask, that part of thermometer immersed in 
the acid mixture and the lower part of the stopper, shall be acid mixture resistant.  
b) Thermometer , ether a Beckmann thermometer with a 5 ˚C to 6 oC scale and subdivision every 0.01 
oC or other measurement apparatus of an equal or higher accuracy such as a thermistor or platinum 
resistance thermometer, positioned such that  the end of the thermometer is at least 4 cm below the 
level of the liquid surface. Expressed temperature readings with a resolution of ± 0.002 oC. Adjust the 
zero of the Beckman thermometer so that the upper limit of the scale is approximately the ambient , or 
water bath, temperature. Calibrate the thermometer is a thermostatic bath against a 0.01 oC 
graduated and calibrated thermometer.  
c) Funnel , of acid mixture resistant plastics, through which the sample is introduced into the flask and 
which extends below  the lower part of the stopper by 5 mm to 6 mm and is sealed during the test.  EAS 148 -8: 201 7 
© EAC 2017  – All rights reserved  3 
 d) Stirrer , of acid mixture resistant plastics, positioned such that the blades are as close as possible to 
the bottom of the flask and rotated by a motor at a speed of (450 ± 50) m in-1. The motor shall be low 
power rated for example a motor of a few watts) so as to prevent any excessive heat emission from 
affecting measurements.  
NOTE  The method does not deal with the standardization of the calorimetric apparatus, or the measuring 
instruments. Insulated flasks with a volume of about 650 mL have proved to be suitable.  
 EAS 148 -8: 201 7 
4 © EAC 2017  – All rights reserved  
 Key 
1 flask 
2 container  
3 box 
4 stopper  
5 thermometer  
6 stirrer  
7 funnel  
8 stopper  
9 insulating material  
10 flask support  
11 ambient thermometer  
12 stirrer motor  
Figure  1 — Typical heat of solution calorimeter apparatus  
5.2 Thermostatic bath , for example  water bath, for storing the hydrated samples at a temperature of (20.0 
± 0.2) oC. 
5.3 Mortar or electric grinder , for crushing the hydrated samples.  
5.4 Plastics or glas s vials , of capacity approximately 20 mL, for storing the hydrated paste.  
5.5 Sieve,  of mesh size 125 µm. 
5.6 Sieve , of mesh size 600 µm. 
5.7 Chronometer , graduated in seconds, for timing the temperature readings.  
5.8 Two platinum crucibles , of capacity ap proximately 20 mL, for ignition of samples.  
5.9 Electric furnace , naturally ventilated, capable of operating at (950 ± 25) oC, for ignition of samples.  
5.10 Analytical balance , capable of weighing to an accuracy of ± 0.0001 g.  
5.11 Balance , of capacity 2 k g, capable of weighing to an accuracy of ± 0.2 g.  
6 Calorimeter calibration  
6.1 Principle  
Calibration of the calorimeter is carried out in order to determine its thermal capacity and thermal leakage 
coefficient. These characteristics are determined by diss olving the ignited zinc oxide (4.2) in the acid mixture 
(4.1) and measuring the temperature of the calorimeter at fixed intervals of time. The temperature of acid EAS 148 -8: 201 7 
© EAC 2017  – All rights reserved  5 
 mixture shall be set that after the dissolution reaction the calorimeter temperature is at le ast 0.5 oC below the 
ambient temperature. Where a water bath is used the temperature of the bath is considered to be the ambient 
temperature for the calorimeter.  
6.2 Procedure  
6.2.1  Measure a quantity of acid mixture (4.1) by mass or volume to ± 0.2 % such  that the liquid level will be 
approximately 2 cm below the calorimeter stopper. Place the acid mixture in the flask. Immediately before the 
determination of the thermal capacity, ignite the zinc oxide at (950 ± 25) oC for a maximum of 5 min and cool 
in a desiccator to room temperature. The quantity of zinc oxide to be used, weighed to ± 0.0001 g, is that 
required to satisfy Equation(1):  
160
oxidezincof Massmixtureacidof Mass
 (1) 
6.2.2  Carry out the procedure as follows:  
a) preliminary period: stir the acid mixture for 40 mi n - 50 min;  
b) pre-period: when the rate of temperature increase is constant, start the timing using the chronometer 
(5.7) and record the initial temperature;  
c) sample introduction : after 15 min record the temperature,  T0, and immediately add the zinc oxide 
sample to the acid mixture taking not more than 1 min;  
d) dissolution period: stir the mixture for 30 min, after which the dissolution is considered as being 
complete, and then record the temperature Record the ambient temperature, Ta. If the difference 
between  Ta and 
30T  is less than 0.5 oC then repeat the test; and  
e) post-period : record the final temperature after a further 15 min,  in order to reduce reading errors, 
determine  temperatures,  and as the average of five different readings recorde d at intervals of min 1 
over the period 2 min before to 2 min after the prescribed time, Ti that is. T i-2, T i-I, T i, T i+I, 
Ti+2).Determine the value of T0 by extrapolation of the function of temperature against time in period T-
4 to T-1. If the extrapolated  value differs from the T 0 reading by more than ± 0.002 oC then replace T0 
by the extrapolated value. If more than a trace of zinc oxide is found adhering to the tip of the funnel 
or to the stopper when the calorimeter is opened, repeat the calibration .  
NOTE The temperature readings will therefore effectively start 17 min before the zinc oxide sample is introduced and 
the last reading will take place 47 min after its introduction. The total duration of the calibration is 64 min.  
6.3 Calculation of calibrat ion characteristics  
6.3.1  Corrected temperature increase, ΔTc  
Calculate the corrected temperature increase,  ΔTc, in Kelvins, from Equation (2):  
) (2) (Δ 30 45 0 30 T T T T TC 
 (2) 
where  
30T
and 
45T are the average values of five measurements made at intervals of 1 min.  
6.3.2 Thermal leakage coefficient, K 
Calculate the thermal leakage coefficient, K, in Kelvins per 15 min per Kelvin temperature difference, (K/15 
min.K-1), from Equation (3):  EAS 148 -8: 201 7 
6 © EAC 2017  – All rights reserved  
 
)) (-) (
0 3030 45 15 0
T (TT T TTK
  (3) 
6.2 Thermal capacity, C 
6.2.1  Calculate the thermal ca pacity, C, in joules per Kelvin, from Equation (4):  
)] (0.50) (30 0.364 077.43[1
Δf aTT   f
cT
TPC
 (4) 
where  
P is the mass of zinc oxide, in grams (g);  
Tf is the temperature at the end of the dissolution period, in degrees Celcius (oC) that is  temperature in 
degrees Celcius corresponding to the zero on the Beckmann thermometer;  
Ta is the temperature that is  ambient temperature of zinc oxide when introduced into the calorimeter, in 
degrees Celsius (oC); 
1 077.43  is the heat of solution of zinc oxide at 30 oC, in joules  per gram (j.g-1); 
-0.364  is the temperature coefficient of the heat of solution of zinc oxide, in joules per gram per Kelvin 
(J.g-1.K-1); 
0.50  is the specific heat of zinc oxide, in joules per gram per Kelvin (J.g-1.K-1). 
6.2.2  Calculate the thermal capa city, C, expressed to two decimal places, and the thermal leakage 
coefficient, K, expressed to four decimal places, as the mean values of five calibrations of the calorimeter. If K 
is not less than 0.06 K per 15 min per Kelvin temperature difference then t he calorimeter does not meet the 
requirements (see 5.1,a)).  
NOTE  Calibration characteristics should be redetermined whenever:  
a) the thermometer has been recalibrated;  
b) either the thermometer, the stirrer or the flask have been renewed or modified; and  
c) the ope rator considers that is necessary.  
7 Determination of heat of solution  
7.1 Heat of solution of anhydrous cement  
7.1.1  Procedure  
7.1.1.1  General  
7.1.1.1.1  Use acid mixture of the same composition, quantity and initial temperature as used for calibration 
of the calorimeter (see 6.2).The quantity of sample, weighed to ± 0.0001 g, is the amount required to satisfy 
Equation (5):   
2 140
cement anhydrousof Massmixtureacidof Mass
 (5) EAS 148 -8: 201 7 
© EAC 2017  – All rights reserved  7 
 7.1.1.1.2  After the preliminary stirring period of the acid mixture (see 6.2, a), follow the procedures gi ven in 
7.1.1.2 applicable to all cements and hydraulic binders or 7.1.1.3 applicable to Portland cements.  
7.1.1.2  Procedure applicable to all cements and hydraulic binders  
7.1.1.2.1  Record the temperature ₸-15 and start the chronometer. Record the temperat ure,T0, after 15 min 
and immediately introduce the sample, taking not more than 1 min. Record the temperature, ₸30 after a 
dissolution period of 30 min.  
7.1.1.2.2  Follow the procedure  for reading temperature given in 6.2 for the anhydrous sample, to avoid 
reading errors.  
7.1.1.3  Portland cement (CEM I according to FDEAS 18 -1) 
7.1.1.3.1  Record the temperature, T0, start the chronometer and immediately introduce the sample, taking 
not more than 1 min. After a dissolution period of 30 min record the temperatur e, ₸30. After a further post -
period of 15 min record the temperature,  ₸45. 
7.1.1.3.2  Follow the procedure for reading temperature given in 6.2 for the anhydrous sample, to avoid 
reading errors.  
7.1.2  Calculation  
7.1.2.1  Corrected temperature increase  
On the basis of the temperature readings taken in accordance with 7.1.1.2 or 7.1.1.3 calculate ΔTc from the 
Equation (6) or (7):  
a) all cements and hydraulic binders; and  
) () 2) (Δ O 30 15 3030 T TK T T T T 0 c   
 (6) 
where  
K is the thermal leakage coefficient, in Kelvins per 15 min p er Kelvin temperature difference, (K/15 
min.K -1). 
b) Portland cements (CEM I)  
) 2) (Δ 30 3030   T T T T 0 c
 (7) 
7.1.2.2  Heat of solution  
Calculate the heat of solution of anhydrous cement, 
aQ in joules per gram (J.g-1), from Equation (8):  
20 0.8) (0.8  f a fc
a T TT
pΔTcQ
 (8) 
where  
cΔT
 is the corrected temperature increase, in Kelvin (K);  
C is the thermal capacity of the calorimeter, in joules per Kelvin  (J.K-1); 
P is the mass of anhydrous cement, in grams (g);  EAS 148 -8: 201 7 
8 © EAC 2017  – All rights reserved  
 Tf is the temperature at the end of the anhydrous cement dissolution period, in degrees Celcius (oC); 
Ta is the temperature of the anhydrous cement that is ambient temperature when introduced into the 
calorimeter, in degrees Celcius (oC); 
0.8 is the specific heat of  anhydrous cement, in joules per gram per Kelvin (J.g-1.K-1); 
-0.8 is the temperature coefficient of the heat of solution of the anhydrous cement, in joules per gram per 
Kelvin (J.g-1.K-1); 
NOTE  The last term in the equation has been introduced so as to co rrect the value of the heat of solution for any 
divergence from the reference temperature, 20 oC. 
7.1.3  Expression of results  
Express the heat of solution of the anhydrous cement,
 ₐ , as the mean of two measurements, expressed to 
one decimal pl ace. If the difference between the two measurements is greater than 14 J.g-1 carry out a third 
test. Reject any result which differs from the mean of these values by more than ± 7 J.g-1. If one result is 
rejected, calculate the mean from the remaining two values.  
NOTE  The standard deviation of repeatability σr, for the measurement of heat of solution of anhydrous cement is 5 
J.g-1. Therefore, results of two properly conducted tests by the same operator on samples of the same cement should not 
differ from ea ch other by more than 14 J.g-1. 
7.2 Heat of solution of hydrated cement  
7.2.1  Procedure  
7.2.1.1  Remove the sample of hydrated cement (4.4) from the vial, and crush quickly, so that the whole 
sample passes the 600 -µm sieve (5.6).When crushing by means of a  rapid crusher this for (45 ± 15) s. 
Complete the reduction in not more than 15 min so minimising contact with air and avoiding carbon dioxide 
absorption. Alternatively these procedures can be undertaken in a nitrogen atmosphere in a glove box.  
7.2.1.2  Place the sample in a sealed container and homogenise by shaking, either manually or 
mechanically. Weigh the three samples from the same vial, required for the calorimetric and determination of 
bound water correction, in quick sequence to avoid loss of water or carbon dioxide absorption. Increase the 
quantity of the hydrated sample used to determine the heat of solution by 40 % over that used to test the 
anhydrous sample. Weigh the hydrated sample to ± 0.0001 g. Carry out the calorimetric determination as for 
the anhydrous cement (see 7.1.1).  
7.2.1.3  Commence the heat of solution determination within the following times according to the specified 
hydration age:  
a) ± 30 min for hydration ages less than three days;  
NOTE  In the case of time inconsistency when using a  single calorimeter it is essential to use sample of hydrated 
cement taken from two separate mixes made at different time.  
b) ± 1 h for hydration ages greater than, or equal to, three days and less than seven days; and  
c) ± 2 h for hydration ages greater than, o r equal to, seven days.  
7.2.2  Correction for bound water  
7.2.2.1  Correct the mass of the hydrated sample to its anhydrous mass by determining the bound water 
by igniting portions of the same of the anhydrous cement and a cement of hydrated cement from a vi al as 
used for the calorimetric determination. Weigh two 2 g samples to ± 0.0001 g. Ignite using platinum crucibles, 
at (950 ± 25) oC for 1 h, the cool in a desiccator to ambient temperature and weigh immediately.  EAS 148 -8: 201 7 
© EAC 2017  – All rights reserved  9 
 7.2.2.2  The maximum deviation between the two determinations of percentage mass change in ignition 
for either the anhydrous, ma, or hydrated, m h, cement shall not be greater than 0.1 %.  
NOTE 1  Alternative instrumental methods such as thermogravimetry or automatic water and carbon dioxide analysers  
may be used for this determination.  
NOTE 2  The bound water correction may be determined from the calcium oxide (CaO) content by chemical analysis or 
X-ray fluorescence, instead of by ignition. Calcium oxide determination requires greater accuracy as an er ror in the 
calcium oxide content affects the heat of hydration by a factor of two compared with the percentage mass change on 
ignition method.  
NOTE 3  If the cement contains oxidizable components then the determination by calcium oxide content 
should be us ed. 
7.2.3  Calculation  
7.2.3.1  Calculate the corrected temperature rise, 
  from Equations  (6) and (7) for hydrated cement.  
7.2.3.2  Calculate the heat of solution,  
aQ in joules per gram of hydrated cement, from Equation (9):   
20)(1.3) (1.7Δ
 f a fc
i T TTTcQ
FP
 (9) 
where  
P is the mass of hydrated cement, in grams (g);  
Tf is the temperature at the end of the dissolution period of the hydrated sample, in degrees Celcius 
(oC); 
Ta is the temperature of the hydrated cement that is ambient temperature when introduced into the 
calorimeter in degrees Celcius (oC). 
F is the correction factor for bound water;  
1.7 is the specific heat of hydrated cement, in joules per gram per Kelvin (J.g-1.K-1); 
-1.3 is the temperature coefficient of the  heat of solution of hydrated cement, in joules per gram per Kelvin 
(J.g-1.K-1). 
Calculate the correction factor for bound water from Equation (10) or (11):  
a) Based on ignition, and:  
2n
mmF

100100
 (10) 
where  
mn is the mass change on ignition of the  hydrated sample, in percent by mass (%);  
m2  is the mass change on ignition of the anhydrous sample, in percent by mass (%);  
b) Based on the lime content:  EAS 148 -8: 201 7 
10 © EAC 2017  – All rights reserved  
 
ah
CCF (11) 
Ch is the calcium oxide content of the hydrated sample, in pe rcent by mass (%);  
Ca is the calcium oxide content of the anhydrous sample, in percent by mass (%).  
7.2.4  Expression of results.  
Express the heat of solution of the hydrated sample
 i, as the mean of two measurements, expressed to o ne 
decimal place. For each measurement use a new sample, taken from a different vial of the same set (see 4.4).  
NOTE  The precision and acceptance limits for results of determination of heat of solution of the hydrated sample are 
the same as those given fo r anhydrous cement (see 7.1.3).  
8 Heat of hydration  
8.1 Calculation of results  
Calculate the heat of hydration of cement, Hi, expressed in joules per gram and referenced to 20 oC, as the 
difference between the heats of solution of anhydrous and hydrated cem ent obtained in accordance with 7.1.2 
and 7.2.3 from Equation (12):  
i a i Q QH
 (12) 
8.2 Reporting of results  
Report the results of the heat of hydration, Hi , expressed in joules per gram of cement, to the nearest whole 
number.  
8.3 Precision  
8.3.1 Repeatability  
8.3.1.1  The standard deviation of repeatability, σr, of the heat of hydration is 8 J.g-1. 
8.3.1.2  Therefore, if two results of properly conducted tests from the same laboratory on samples of the 
same cement are compared, they should not differ from each other by more than 22 J.g-1. 
8.3.2  Reproducibility  
8.3.2.1  The standard deviation of reproducibility, σR, is 18 J.g-1. 
8.3.2.2  Therefore, if the results of two properly conducted tests from two different laboratories on 
samples of the same  cement are compared, they should not differ from each other by more than 50 J.g-1. 
 EAS 148 -8: 2015    
 
© EAC 2017  – All rights reserved  
  
 Bibliography  
[1] EN 196 -8: 20 10; Methods testing cement — Part 8: Heat of hydration – Solution method.