- Type of paper
: Paper in journal
Title: The Bulk Model and the Behavior of Fresh Concrete
- Authors:
- Krstulović, Petar (70770)
Journal: Građevinar
Number: 1
Volume: 47
Year: 1995
Pages: from 1 to 8
Language: hrvatski
Summary: Further research of the range of normal specimens has been
made and the upper boundary of the range, which separates the stable
specimens from the unstable ones, is defined more closely. For the first
time the right part of the range, which presents the lean specimens, has
been investigated in more detail. The specimen of maximum concentration of
aggregate, which characterizes such a samples, has been defined. The
influence of type and greding of the aggregate and cement on the shape and
position of the entire range of normal specimens has been also
investigated.
On the basis of statistical evaluation of test results, mathematical
expressions and diagrams, which define the relationship between composition
and slump of stable fresh concrete specimens, are developed.
The most important contribution of this research is the analysis of the
influence of stability of the specimens on their behavior. At the stable
specimens, the value of slump depends on the relationship of aggregate and
paste concentrations. Greater slump is obtained primarily by the increase
of volumetric concentration of the paste. With the increase of
concentration of water only, the stability of the specimen is impaired
simultaneously.
Keywords: Bulk model, workability, bleeding, stability of specimen, stability boundary, unstable specimen.
- Type of paper
: Paper in proceedings
Title: More about Limestone in Cement
- Authors:
- Popović, Krešimir (73141)
- Krstulović, Petar (70770)
- Kamenić, Nevenka (20024)
- Editors
- Radić, Jure
Proceedings title: Graditelji u obnovi Hrvatske
Language: hrvatski
Place: Zagreb
Year: 1994
Pages: from 629 to 635
Meeting: Treći radni sabor DHGK
Held: from 10/13/94 to 10/15/94
Summary: The justifiability of the use of limestone filler as an
addition to cement is considered herein. The recent theoretical and
experimental achievements in this particular field are presented.
Discussing grindability, influence on hydration and efficiency of cement
and clinker respectively, different opinions are compared from tehnical and
economic aspects. Some recent papers and approaches to this respect are
presented in more detail.
As a general conclusion, the use of limestone filler is efficient from
economic aspect, if limestone is added in quantities to the order of value
of 5 %, despite the fact that limestone filler somewhat reduces the
strength of cement composites.
Keywords: Bulk model, intergrinding, grading, hydration, filler, pozzolan, efficiency, economy.
- Type of paper
: Ph.D.
Title: RHEOLOGICAL PROPERTIES OF FRESH CONCRETE UNDER VIBRATION
Faculty: Građevinski fakultet Zagreb
Date of defense: 04/23/91
Language: hrvatski
Number of pages: 165
Summary: The first part presents a review of information from
literature and the analysis of the present aproach, with special attention
to rheological testing methods.
The theoretical part gives a derivation of Bingham model oscillations due
to excitation of the basis, taking into account the effect of buoyancy to
the piston. Depending on the parameter of viscosity and yield value, six
different types of model oscillations may appear. The vibration rheometer
has been developed. Its essential parts are standard vebe-mold and
cylindrical mass that penetrates the specimen. The penetration velocity and
amplitude of mass oscillations are measured and the parameters of
rheological model of the specimen are calculated, using the computer
program.
The final chapter contains the comparison of the test results with the data
from literature and describes the limitations and possibilities of further
development of the theory and the apparatus.
Keywords: Specimen, bulk model, rheological model, rheometer, oscillatory system, types of oscillations, viscosity parameter, yield value.
- Type of paper
: Manuscript
Title: The New Method of Testing Fresh Concrete Under Vibration
- Authors:
- Krstulović, Petar (70770)
Language: hrvatski
Summary: On the basis of standard Vebe-method, a practical method
for simple testing of fresh concrete, using the vibration rheometer, has
been developed. The specimens of the entire range of normal specimens were
tested, for two types of aggregate.
The expressions and diagrams that define a relationship between the bulk
model and the behavior of fresh concrete specimen, from a neat paste to a
neat aggregate, have been developed, using methods of mathematical
statistics. It has been found that a good correlation between parameter of
behavior of the specimen in the vibration rheometer and the slump exists,
for stable specimens. The irregularities of the behavior of unstable
specimens are also presented.
Keywords: Vibration rheometer, modified Vebe-time, slump, bulk model, correlation.
