Figure 3. The primary result fromtwelve measurements of samples ofthe same cement paste, but with sixdifferent concentrations of anadditive (0, 0.10, 0.15, 0.20, 0.30and 0.50%, two samples of eachconcentration were tested).

Figure 3 shows the result of themeasurement of the hardening ofa mortar with six differentconcentrations of an additive.Note that it is possible to seedouble peaks for the lowerconcentrations, but not for thehigher ones. The two peaks areprobably from the main reactionsof the two main components(C

3S, C

3A). It can be seen from

figure 3 that the TAM Aircalorimeter is an excellentinstrument for the study ofretardation.

Adiabatic and semi-adiabaticcalorimeters are commonly usedin cement and concrete research.For cement paste and mortarmeasurements, the isothermalcalorimeter has been shown to bea better instrument than anadiabatic calorimeter as it givesquantitative data with very highresolution. The isothermal

Results and discussionFigures 1 and 2 show the resultof the measurements on twelvesamples of identical composition.It can be seen that the spread ofthe results is very low.

Figure 1. The primary result fromtwelve measurements of samples ofthe same cement paste

Figure 2. The integrated resultfrom twelve measurements ofsamples of the same cement paste

0 1 20 21 300

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2

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3

341

5

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calorimeter is calibrated to give athermal power output, instead ofa quite arbitrary temperatureincrease as in the semi-adiabaticcalorimeter. The thermal powerresolution of the TAM Aircalorimeter is in the order of 2.5mW. The only limitation is thesample size, which is a maximumof 20 ml. This is because the heatproduced has to be conductedaway from the sample during themeasurement. It is therefore notadvisable to use the TAM Aircalorimeter with aggregates largerthan 5 mm.

Further experimentsThe TAM Air calorimeter isprimarily an instrument for thestudy of the induction period andthe main stages of the hydration.Interesting applications includethe influence on hydration of glassfillers, waste products, slags andother materials often used inconcrete. It should be possible toassess the activation of suchmaterials and to evaluate theireffect on the hydration.

The heat production is a result ofthe hardening processes in thecement paste. It has been shownthat the degree of hydration, theheat produced and the strengthare related (Taplin 1959, Byfors1980). Isothermal calorimetricmeasurements can therefore formthe basis of design criteria for thestrength and temperaturedevelopment in concretestructures, as for example, in theminimisation of crackdevelopment.

Figure 3. The primary result fromtwelve measurements of samples ofthe same cement paste, but with sixdifferent concentrations of anadditive (0, 0.10, 0.15, 0.20, 0.30and 0.50%, two samples of eachconcentration were tested).

Figure 3 shows the result of themeasurement of the hardening ofa mortar with six differentconcentrations of an additive.Note that it is possible to seedouble peaks for the lowerconcentrations, but not for thehigher ones. The two peaks areprobably from the main reactionsof the two main components(C

3S, C

3A). It can be seen from

figure 3 that the TAM Aircalorimeter is an excellentinstrument for the study ofretardation.

Adiabatic and semi-adiabaticcalorimeters are commonly usedin cement and concrete research.For cement paste and mortarmeasurements, the isothermalcalorimeter has been shown to bea better instrument than anadiabatic calorimeter as it givesquantitative data with very highresolution. The isothermal

Results and discussionFigures 1 and 2 show the resultof the measurements on twelvesamples of identical composition.It can be seen that the spread ofthe results is very low.

Figure 1. The primary result fromtwelve measurements of samples ofthe same cement paste

Figure 2. The integrated resultfrom twelve measurements ofsamples of the same cement paste

0 1 20 21 300

041

2

241

3

341

5

541

6

789:;<;=

7=:>9

?@;A

BC

:>;

<;9

D<E

0 1 20 21 300

10

200

210

789:;<;=

FG9

G@?

78H:

;=:?7;

<;I<

E

0 1 20 21 30 310

2

3

5

6

1

calorimeter is calibrated to give athermal power output, instead ofa quite arbitrary temperatureincrease as in the semi-adiabaticcalorimeter. The thermal powerresolution of the TAM Aircalorimeter is in the order of 2.5mW. The only limitation is thesample size, which is a maximumof 20 ml. This is because the heatproduced has to be conductedaway from the sample during themeasurement. It is therefore notadvisable to use the TAM Aircalorimeter with aggregates largerthan 5 mm.

Further experimentsThe TAM Air calorimeter isprimarily an instrument for thestudy of the induction period andthe main stages of the hydration.Interesting applications includethe influence on hydration of glassfillers, waste products, slags andother materials often used inconcrete. It should be possible toassess the activation of suchmaterials and to evaluate theireffect on the hydration.

The heat production is a result ofthe hardening processes in thecement paste. It has been shownthat the degree of hydration, theheat produced and the strengthare related (Taplin 1959, Byfors1980). Isothermal calorimetricmeasurements can therefore formthe basis of design criteria for thestrength and temperaturedevelopment in concretestructures, as for example, in theminimisation of crackdevelopment.