TAM AIR Brochure - TA Instruments

TA Instruments
TAM AIR

New Castle, DE USA
Lindon, UT USA
Elstree, United Kingdom
Shanghai, China
Beijing, China
Taipei, Taiwan
Tokyo, Japan
Seoul, Korea
Bangalore, India
Paris, France
Eschborn, Germany
Brussels, Belgium
Etten-Leur, Netherlands
Sollentuna, Sweden
Milano, Italy
Barcelona, Spain
Melbourne, Australia
Mexico City, Mexico

TAM AIR
Technical Specifications 7
TAM Technology 8
TAM Ampoules 10
Applications 12

TAM AIR Isothermal microcalorimetry
The ideal tool for large scale calorimetric experiments,
capable of measuring 8 samples simultaneously

A POWERFUL TOOL FOR THE STUDY OF
CEMENT HYDRATION PROCESSES
Instrument of choice for standardized testing on cement
Determining the heat of hydration of cement is important and traditionally, the heat of
hydration has been determined by measuring the heat of solution (ASTM C186). More recently,
isothermal calorimetry tests using TAM Air are increasing because it accurately and reliably
measures the heat of hydration (ASTM C1702). The samples tested in the TAM Air are usually
paste samples, where the cement hydration process can continuously be followed over time. The
shape of the heat flow curve will reflect the cement hydration process and the different phases of
the complex process can be determined. The addition of admixtures will change the shape of the
heat flow curve, and the admixture effect can be quantified. The integrated heat flow over time will
give the extent of hydration. Using isothermal calorimetry, the heat of hydration is measured with
TAM Air by monitoring the heat flow from the specimen while both the specimen and the surrounding
environment are maintained at the same temperature. The TAM Air is widely used for
studying the reaction kinetics of pure cement pastes as well as the temperature dependence
of the reaction. TAM Air is an excellent tool for quality control in cement plants, for optimization
of additives to give a cement a certain property as well as a general research tool for the
cement laboratory.
Phase 1: Rapid initial process - Dissolution of ions and initial hydration
Phase 2: Dormant period - Associated with a low heat evolution and
slow dissolution of silicates
Phase 3: Acceleration period - Silicate hydration
Phase 4: Retardation period - Sulphate depletion and slowing down of
the silicate hydration process
Heat Evolution / mW/g
5
4 1
3
3
2
1
2
0
0 10
4
20 30 40 50 60
Time (h)
4 5

TAM AIR
SPECIFICATIONS
Thermostat Specifications
Calorimeter Positions 8
Operating Temperature Range 5 - 90 °C
Thermostat Type
Air
Thermostat Stability ± 0.02 °C
Limit of Detection 4 µW
Precision ±20 µW
Calorimeter Specifications
Short Term Noise < ± 2.5 µW
Precision ± 20 µW
Baseline over 24 hours
Drift

TAM AIR Technology
Monitoring the thermal activity or heat flow of chemical, physical and biological processes provides information which cannot be generated with other techniques.
Isothermal microcalorimetry is a powerful technique for studying heat production or consumption and is non-destructive and non-invasive to the sample. The TAM Air
offers unmatched sensitivity and long term temperature stability with flexible sample requirements.
When using microcalorimetry there is little or no sample pretreatment required; solids, liquids and gasses can all be analyzed. Unlike other techniques that may only
give time interval snapshots of data, microcalorimetry presents continuous real-time data that reflects the process or processes taking place in the sample.
High Performance Temperature Control and Stability
The TAM Air is an air based thermostat, utilizing a heat sink to conduct the heat
away from the sample and effectively minimize outside temperature disturbances.
The calorimeter channels are held together in a single removable block. This block
is contained in a thermostat that uses circulating air and an advanced temperature
regulating system to keep the temperature very stable within ±0.02°K. The high
accuracy and stability of the thermostat makes the calorimeter well suited for heat
flow measurements over extended periods of time, e.g. weeks. The baseline drift
is less than 40 µw/24 hours with very low short term noise. TAM Air Assistant,
a powerful, flexible and easy-to-use software package is used for instrument control,
experimental setup, data analysis and reporting of results.
Isothermal Microcalorimetry
When heat is produced in a sample, isothermal microcalorimetry measures
the heat flow. The sample is placed in an ampoule that is in contact with
a heat flow sensor that is in also in contact with a heat sink. When heat
is produced or consumed by any process, a temperature gradient across
the sensor is developed. This will generate a voltage, which is measured.
The voltage is proportional to the heat flow across the sensor and to the
rate of the process taking place in the sample ampoule. This signal is
recorded continuously and in real-time.
For each sample there is a reference that is on a parallel heat flow sensor.
During the time that the heat flow is monitored, any temperature fluctuations
entering the instrument will influence both the sample and the reference
sensors equally. This architecture allows a very accurate determination
of heat that is produced or consumed by the sample alone while other
non-sample heat disturbances are efficiently factored out.
TAM Air 8-Channel Calorimeter
The TAM AIR 8 Channel calorimeter consists of an
eight (8) channel calorimeter block and data
logging system required for use with the TAM AIR
thermostat. The calorimeters are twin-type (sample and
reference), and designed for use with 20 ml glass or plastic
ampoules or the 20 ml Admix ampoules.
8 9

TAM Air Ampoules
The ampoules used in the TAM Air are designed to handle up to 20 ml volumes. Either glass, stainless steel or plastic (HDPE) closed ampoules are available,
which enables maximum flexibility for sample management and maximum sensitivity.
Admix Ampoule
The Admix Ampoule is a 20 ml accessory available for initiating
reactions inside the calorimeter, and can be used for monitoring
a reaction from the initial injection. The Admix ampoule can be
configured with or without a motor for stirring. For suspensions such
as mixtures of cement and water, manual stirring is recommended.
For liquid systems, a motor may be used for stirring. The admix ampoule
can only be used with 20 ml disposable glass ampoules.
10
11

Applications
Cement Paste Setting Time
The synergy of citric acid (CA) and calcium nitrate (CN) is
clearly seen from the rate of hydration heat. CA is essentially a
setting retarder relative to the reference, although the heat of
hydration is slightly reduced and CN is clearly a setting accelerator.
Together they behave as a hardening retarder lowering the rate of
hydration heat and distributing it over a longer time.
The rate of hydration heat for the same mixtures at 40 °C shows
that the function as hardening retarder is reduced at higher
temperature. This data along with the cumulative heat data indicate that
the admixture combination may not function in the practical semiadiabatic
case of massive concrete. 1
Rate of Hydration Heat (mW/g Cement)
Rate of Hydration Heat (mW/g Cement)
4
3.5
3
2.5
2
1.5
1
0.5
0.00
0
4
3.5
3
2.5
2
1.5
1
0.5
0.00
0
Isothermal Calorimetry of Paste at 20 ˚C
0.15% CA
0.15% CA/1.5% CN
Reference
1.5% CN
6 12 18 24 30 36 42 48
Time (h)
Isothermal Calorimetry of Paste at 40 ˚C
0.15% CA (AN)
0.15% CA+1.5% CN (AN)
Reference (AN)
1.5% CN (AN)
6 12 18 24 30 36 42 48
Hydration of Calcium Sulfate Hemihydrate
Identical samples of 2g of Calcium Sulfate Hemihydrate powder were
mixed with a hydrating agent at a liquid to solid ratio of 0.50 using
an admix ampoule in the TAM Air. The blue curve shows a sample
hydrated with deionized water. The red curve is a sample hydrated
with a 5% Sodium Chloride solution. It is demonstrated that sodium
chloride accelerates the calcium sulfate hydration reaction.
Normalized Heat Flow (W/g)
6.00
5.00
4.00
2.00
1.00
0.00
0.0
0.2
0.4 0.6 0.8 1.0 1.2
Time (hr)
Time (h)
12
13

Applications
Cement Sulfate
This figure shows
depletion peak
peak – can be used
sulfate content of
of the laboratory
that 2.5% added
bring the resulting
SO 3 level. Several
in the field to perform
ground cement.
Calorimetry serves
approximate values
admixture incompatibility
or changes in raw
reactivity of the aluminate
for soluble SO 3 . 2
can be used to assess
to the cement production,
Cement Thermal Profiles with Contaminants
Cement setting thermal profiles can be influenced by
contaminants. The graph shows the steady decrease in
thermal power as the contamination of the cement mortar
by a mixture of soil and sawdust increases (0; 0.9; 2.5 and
5.9% of w/c=0.6 cement mortar). Influence on hydration
rate of a mixture of soil and sawdust. 3
Setting Time of Cement
The TAM Air calorimeter has been shown to be excellent
for diagnosis of problems related to setting time and
premature stiffening of cement. The blue curve in the figure to
the right represents an industrial cement produced with too little
soluble calcium sulfate. This cement suffers from early
stiffening because of the aluminate reactions at 1–1.5 hours
hydration indicated by the unusually small silicate peak at
5-10 hours. When 0.5% (purple curve) and 1.0% (red
curve) of calcium sulfate hemi-hydrate was added to the
hydration. It also suffers from low early strength, because the
aluminate hydrates formed retard the strength-giving silicate
2
1.5
1
0.5
0
2.5
1.5
1.0
Depletion
how Lerch’s criteria - sulfate
to occur after the main silicate
6.00
for a rapid indication of the optimum
a laboratory ground clinker. The results
5.00
Second Peak
screening shown indicates
SO 3 might be sufficient to
4.00
0
Portland cement to optimum
3.00
factors may cause cement manufactured
20
different as compared to the laboratory
2.00
Sulfate Depletion
1.00
as an excellent indication as to the
to aim for to avoid setting time and
0.00
issues. Furthermore, the calorimetry
0 2 4 6 8 10 12 14 16 18 20 22 24
the efficiency of any changes made
Time (h)
such as changes in gypsum type
material or fuel that may influence the
phase and thereby the demand
cement the undesired early peak disappeared, and
the strength-giving silicate peak regained its normal shape.
0.5
The results indicate that premature stiffening is caused by a
lack of soluble calcium sulfate.
0
0 5
Heat Flow (mW/g)
Thermal Power / mW/g
Heat Flow (µW/g)
No Contamination
Low Contamination
Medium Contamination
High Contamination
40 60 80 100
Time (h)
10 15 20
Time (h)
14
15

Applications
Cement Blending
0.003
This figure provides plots of the heat release rate (heat flow) for the first 24 h of hydration for six cement pastes examined by Isothermal
0.002
calorimetry (3 pure and 3 blends). In general, results for the two replicate specimens for each cement paste fall directly on top of one another. For
the three initial cements, the heat release during the first 24 h increases with increasing cement fineness, as would be expected due to the increased
0.001
(in contact with water) surface area. Interestingly, for these six cements based on a single clinker, the peak in heat release rate always occurs at
0.000
about 6 h, while by 24 h, the heat release rate has diminished to a value close to 0.001 W/g cement.
The heat flows measured during the first 24 h for the three blended cements are predicted quite well by applying the simple law of mixtures. The
0.007
results imply that for the w/c = 0.4 cement pastes examined in this study, the particles are likely hydrating independently of one another during
0.006
the first 24 h, such that the degree of hydration of blends of the fine and coarse cements can be quite accurately computed simply as a weighted
average of their (measured) individual hydration rates.
0.005
4
0.004
0.003
0.002
0.001
0.000
Heat Flow (W/g cement)
Heat Flow (W/g cement)
0.007
0.006
0.005
0.004
0
0
Type l/la
Type l/lb
Type ll/Va
Type ll/Vb
Type llla
Type llla
4 8 12 16 20 24
Time (hr)
50:50 Blend
50:50 Estimated
Type ll/V
4 8 12 16 20 24
Time (hr)
Heat Flow (W/g cement)
Heat Flow (W/g cement)
0.005
0.004
0.003
0.002
0.001
0.000
0
0.007
0.006
0.005
0.004
0.003
0.002
0.001
0.000
0
4 8 12
Time (hr)
75:25 Blend
75:25 Blend
75:25 Estimated
16 20 24
25:75 Blend
25:75 Blend
25:75 Estimated
4 8 12 16 20 24
Time (hr)
16
17

Applications
Food Testing
This figure shows the Thermal treatment of carrot juice resulting in
increased shelf life only at the highest treatment temperature.
The measured thermal power is the heat from the microbiological
activity in the sample. It is seen that the lower treatment
temperatures gave only slightly lower thermal powers, but that the
70 °C treatment gave a substantially delayed signal. At 20 °C
the shelf life was thus increased by more than 50% by the 70 °C
treatment. 5
6
Epoxy Curing
5
Here we see the heat production and the heat production rate as a
function of time. It can be seen that the spread of results is low and that
after an initial reaction period of five hours the heat production rate
4
decrease is similar to an exponential decay. After 45 h the thermal
power is approx. 0.06 mW/g, i.e. 600 μW for a l0g sample.
3
As the detection limit for TAM Air is better than 3 μW it would still
be possible to follow the reaction for an even longer time than was
2
done here. 6
Thermal power / mW
log (Heat Production rate, mW/g)
4
3
2
1
0
0
1
fresh
50˚C
60˚C
70˚C
20 40 60 80 100 120
Time (h)
0
0 20 40
(Time, h)
Fungal Growth
At each temperature multiple inoculated specimens were
measured. This figure shows the results at the five temperatures. It
is seen that the results for each temperature agrees rather well with
each other. Calorimetric measurements can be a valuable addition
to the measurement techniques for predictive microbiology. 7
TAM Air Battery Testing
The properties of batteries during discharge with three different
resistance loads are shown. Single channels in TAM Air
were charged with 1.5 V alkaline batteries, size AAA. Three
resistors of different values were placed in an adjacent channel
500
for connection to the batteries. The solid line represents the
useful energy in the battery which is the heat production
measured in the resistor, while the dotted line is the heat production
0
from the battery itself, i.e. the internal losses.
300
The batteries were fully discharged during the course of the
200
evaluation in the TAM Air. The lowest resistances cause a
100
rapid drain of the battery (e.g. as in a flashlight) whereas the
highest resistances cause a very low rate of discharge (e.g. as in an
0
alarm clock). 8
Thermal power / µW
Heat Production Rate, mW
700
600
500
400
300
200
100
50
0
0
25˚C
20˚C
15˚C
50 100 150 200
Time (h)
1.35 R/Ω
0 0.5 1 1.5
11.2 R/Ω
0 5 10 15
33.4 R/Ω
0
0 10 20 30 40 50 60
Time, h
30˚C
10˚C
18
19

NOTES
1
Justness, H., Wuyts, F. and D. Van Gemert. Hardening Retarders for Massive Concrete. Thesis. Catholic University of Leuven. 2007
2s22
Paul Sandberg, Grace Construction Products, W. R. Grace & Co. 2004.
3
Dr. L. Wadsö, University of Lund, Sweden 2002
4
Bentz, D.P. Blending Different Fineness Cements to Engineer the Properties of Cement-Based Materials. Mag. Concrete Res.
5
F. Gomez and L. Wadsö. Isothermal Calorimetry for Biological Applications in Food Science and Technology. 2000.
6
Wadso, L. Curing of Epoxy Adhesive Studied by TAM Air. TA Instruments Application Note 2007
7
Lars Wadsö and Yujing Li. A test of models for fungal growth based on metabolic heat rate measurements. 2000
8
Lars Wadso. Investigations into Dry Cell Battery Discharge Rates using TAM Air. 2000. TA Instruments, AN 314-03.

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