using the blends of sulfoaluminate ferrite belite (SAFB) clinkers and ordinary
Portland cement (OPC) in mass ratio 85:15 with Al2O3,
and starch, polyphosphate (poly-P) or butylacrylate/acrylonitrile were subjected
to moist atmospheres (ambient, 52 and 100% relative humidity (RH)) to investigate
their moisture resistance. Their chemical, thermal, electron microscopic and
magnetic properties were also studied before and after moisture attack. Butylacrylate/acrylonitrile
(BA/AN) copolymer was found to be the most suitable for MDF cement synthesis
since the sample containing BA/AN showed the best moisture resistant. There
are significant differences in scanning electron microscopy (SEM) of MDF cements
before and after moisture attack and with different polymers. New data on
the paramagnetic nonhysteresis magnetization curves for all the samples are
observed. The MDF cements synthesized from SAFB clinker with dissolved poly-P
give the best signal/noise (S/N) ratio. Three main temperature regions on TG curves
of both series of MDF cements are observed. In the inter-phase section of
MDF cements, the content of classical cement hydrates decomposing by 250C
is increased. Combustion of organic material took place by 550C. In the
temperature range 550-800C, the decomposition of CaCO3
Methods of thermal analysis are employed in a study of the high-temperature properties of three different types of glass fiber
reinforced cement composites together with the measurements of their thermal and hygric parameters. First, basic TG and DTG
measurements are carried out to get the first insight into the high-temperature behavior of the analyzed materials. Then,
mercury porosimetry and scanning electron microscopy of specimens subjected to the temperatures of 600 and 800C are performed
and compared to the reference specimens not exposed to any thermal load. Finally, measurements of thermal and hygric parameters
of the studied materials are done and matched with the results of the material characterization experiments. Three main effects
are found to influence the thermal and hygric properties of the analyzed materials. The first is the decomposition of the
cement matrix, which is clearly a negative factor. The second is the positive effect of the presence of fibers that could
partially keep the cement matrix together even after significant decomposition of cement hydration products. The third important
factor affecting the thermal and hygric properties is the composition of the particular materials. The application of vermiculite
aggregates instead of sand is found to be clearly positive because of its porous character leading to the bulk density decrease
without worsening the other properties. Also, wollastonite aggregates are a better choice than sand because of its fibrous
character that could partially magnify the effect of fiber reinforcement.
This paper analyzes the effect of fly ash chemical character on early Portland cement hydration and the possible adverse effects
generated by the addition of gypsum. Behaviour was analyzed for pure Portland cements with varying mineralogical compositions
and two types of fly ash, likewise differing in chemical composition, which were previously characterized under sulphate attack
as: silicic-ferric-aluminic or aluminic-silicic ash in chemical character, irrespective if they are in nature, siliceous or
siliceous and aluminous materials according to the ASTM C 618-94a.
The experimental results showed that water demand for paste with a normal consistency increased with the replacement ratio
in fly ash with a more aluminic than silicic chemical character, whereas it declined when silicic-ferric-aluminic ash was
used. On the other hand, the differences between the total heat of hydration released at the first valley and the second peak
also clearly differentiated the two types of ash. While the relative differences increased in the more aluminic than silicic
ash, they declined in the more silicic than aluminic. In another vein, the findings indicate that within a comparable Blaine
fineness range, the reactive alumina (Al2O3r−) content in pozzolanic additions has a greater effect on mortar strength than the reactive silica (SiO2r−) content, at least in early ages up to 28 days. Finally, the adverse effect generated in the presence of excess gypsum is
due primarily to the chemical interaction between the gypsum and the C3A in the Portland cement and the reactive alumina (Al2O3r−) in the fly ash.
Wojciech Zielenkiewicz was born in Warsaw on 6 June 1933. He studied chemistry
at the Warsaw University and graduated in 1955. His master thesis in the field
of nuclear chemistry dealt with the enrichment of bromobenzene by the Szilard-Chalmers
method. Since 1955 his professional career has mostly been related to the
Institute of Physical Chemistry of the Polish Academy of Sciences (PAS) founded
in the same year.
Wojciech Zielenkiewicz worked under the supervision of Prof. Wojciech Świętosławski.
This cooperation had a powerful influence on Zielenkiewicz both as a researcher
and as a person. His strong interest in thermochemistry at that time resulted
partly from his research interest and partly from his attraction to one of
the students doing her diploma who later became his wife. Zielenkiewicz’s
PhD thesis carried out under Świętosławski’s supervision
concerned the thermochemistry of cement hydration. For the purposes of this
work, Zielenkiewicz constructed his first calorimeter – a labyrinth
flow calorimeter which was a modified version of the first such calorimeter
constructed by Świętosławski and Malawski in 1935. The calorimeter
was applied for the determination of the heat of cement hardening.
After his PhD, Zielenkiewicz
worked on several other calorimeters for the study of heat of cement hydration
with the quasi-adiabatic method as well as on ‘conduction’ calorimeters
for the examination of the first phase of cement hydration. This activity
resulted in a monograph Calorimetry and Thermochemistry of Cement written
in collaboration with T. Krupa and published in 1975.
In the following years, his scientific interests
were focused mostly on various aspects of the transfer of heat energy in time,
i.e. thermokinetics. He constructed a number of calorimeters for this type
of measurements and, together with his co-workers, elaborated new numerical
methods of determination of thermokinetics. Those methods were assessed at
international symposia on thermokinetics organised by Zielenkiewicz in cooperation
with the French Association of Calorimetry and Thermal Analysis (AFCAT). In
this period, he established regular cooperation with scientists from France,
Spain, and the USA. Research on thermokinetics includes not only theoretical
studies but also experimental works. Most of the experiments conducted at
the Department of Calorimetry headed by Prof. Zielenkiewicz were connected
with inclusion compounds, particularly Werner complexes as well as porfyrine
the last twenty years, Zielenkiewicz conducted research in the scope of biomolecules.
The study resulted in the determination of thermodynamic properties of over
60 derivatives of nucleic acid bases and the establishment of new correlations
between enthalpic, volume, and structural properties of the compounds examined.
His most recent interests concerned the study of enthalpic processes of protein
long and intensive work in the field of calorimetry and thermokinetics has
appeared in numerous books and publications presenting his research results.
He is the author of 7 monographs, a number of chapters in a monograph and
about 200 scientific publications. They include, among others, Analysis of
Course of Heat Effect in n-n Calorimeters, Signal Processing of Calorimetric
System, Dynamic Theory (later translated into Russian and published in Russia),
Advances in Calorimetry and Thermochemistry, Theory of Calorimetry written
together with E. Margas and published in 2002 by Kluwer and the most recent
book, Calorimetry, published in 2005.
Prof. Zielenkiewicz has also been active as a supervisor.
He assisted and supported the realisation of 14 completed PhD theses of the
employees at the Institute of Physical Chemistry and is supervising 3 more
students of the Institute. Moreover, he has been involved in the realization
of several more PhD theses both in Poland and abroad.
For many years Prof. Zielenkiewicz combined his activity
on research with research coordination. He managed the organizational units
of the Polish Academy of Sciences as the Director General of the PAS and as
a Deputy Scientific Secretary. For 6 years he was a Scientific Secretary of
the Division of Mathematical, Physical and Chemical Sciences of PAS. In the
years 1968–2003 he headed the Laboratory and Department of Calorimetry
and he was a director of the Institute of Physical Chemistry for 19 years.
His directorship in the Institute happened in a very difficult period for
Poland, i.e. when the Marshall Law was introduced in 1981. As numerous employees
of the Institute were involved in the illegal Solidarity movement at that
time, the position of a director of such an institution was extremely uncomfortable
and required great abilities in dealing with the communist authorities in
such a way as to protect those employees. It must be said that Prof. Zielenkiewicz
faced this challenge with success.
Prof. Zielenkiewicz was also an initiator of the
Polish conferences on calorimetry and thermal analysis. The first one was
held over 30 years ago. These conferences created an opportunity
for Polish researchers to exchange their opinions and learn about the world
research trends. Numerous outstanding scientists were guests at these conferences.
Many of them are members of the Polish Society of Calorimetry and Thermal
Zielenkiewicz has been awarded many state and foreign medals and distinctions,
among others, Wojciech Świętosł;awski’s Medal and the Calvet
Award given by the French Association of Calorimetry and Thermal Analysis
(AFCAT) as well as the most prominent Polish state orders including the Order
of Polonia Restituta (the Knight’s Cross) and the Order of Labour Banner.
He is a corresponding member of the Polish Academy of Sciences and the Royal
Academy of Sciences in Barcelona.
Dr. Paweł Gierycz
in order to eliminate the residual non combined free water [ 16 ]. As during these drying steps the water/cement ratio is decreased significantly, which decreases the cementhydration rate, any possible little acceleration during drying was considered
catalyst reacts with calcium hydroxide (a product of cementhydration) as a pozzolanic material [ 5 – 7 ]; in the compositions with calcium aluminate cements the FCC catalyst is an active additive [ 8 ].
The authors, investigating Portland cement
have been found very few references. Dweck et al. [ 14 ] present a method to study cementhydration at ambient temperatures by using a micro processes non-conventional DTA system.
Criado et al. [ 15 ] develop an alternative method applied to
replacement of 10 wt% cement with zeolite (mortars B and D) changes the cementhydration. Thus, hillebrandite and xonotlite have not been indicated in samples cured for 120 days in water, which may be explained by partial consumption of hydroxyl ions by