Wojciech Tarasiuk, Leon Demianiuk
Influence of Chosen Process and Material Parameters on the Quality of Silicate Product
INFLUENCE OF CHOSEN PROCESS-MATERIAL PARAMETERS
ON THE QUALITY OF SAND-LIME BRICK
Wojciech TARASIUK *, Leon DEMIANIUK **
* Department of Mechanics and Applied Computer Science, Faculty of Mechanical Engineering,
Bialystok University of Technology, Wiejska 45 C, 15-351 Białystok, Poland
** Department of Machine Design and Maintenance, Faculty of Mechanical Engineering,
Bialystok University of Technology, Wiejska 45 C, 15-351 Białystok, Poland
[email protected], [email protected]
Abstract: The results of experimental studies on the influence of process and material parameters on quality of a lime-sand product.
The quality is determined on the basis of compressive strength in the direction of compaction of the finished product. The obtained results
can be helpful in choosing granulometric composition of lime-sand mixture and determining compaction pressure for products with specific
quality requirements.
Key words: Compaction, Lime-Sand Mixture, Quality of a Lime-Sand Product
1. INTRODUCTION
Silicate products form a large percentage of building materials
manufactured nowadays. They are made of the lime-sand mixture, which is a mixture of siliceous sand, lime and water. During
mixing of these ingredients in silos or reactors the lime is slaked
(Skalamowski, 1973). So prepared mixture is thickened in the
moulding machines at fixed pressure (Królikowski, 2006),
and then autoclaved (Wolfke, 1986). The process, called product
hardening, consists of exposing the molded product to water
vapour at a pressure of 1.6 MPa and a temperature of 203° C
(Wolfke, 1986).
In order to increase the competitiveness of silicate products
their quality improvement is required. The main parameters
by which the quality was determined were compressive strength
RC and the density of the product. They depend on both material
and process factors. The material factor which was examined was
the granulometric composition of sand-lime mixture. Its influence
on the quality of the finished product is described in the literature
on compacting materials of plant origin (Demianiuk, 2011)
and compacting sand-lime mixture with the pigment addition
(Tarasiuk and Krupicz, 2009). The investigated process factor was
the value of pressure per area unit of the moulding piston, which
is referred as the compaction pressure further in the article.
The desirable result is a product of low density and high compressive strength RC.
directly from the production line, after the process of lime slaking.
It was subjected to the sieve analysis where granulometric composition of each fraction was determined. The average percentage
of each fraction and the standard deviation of 5 sample analyses
presents Fig. 2.
2. LIME-SAND MIXTURE
In order to verify the assumptions made in the introduction
part, the experiment was carried out according to a given schedule. The realisation plan of the experiment is shown in Fig. 1.
The mixture used in the experiment was obtained from factory
“Silikaty-Białystok”. It was collected on the day of experiment
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Fig. 1. Layout of the conducted research
acta mechanica et automatica, vol.6 no.1 (2012)
Samples for compressive strength tests were prepared
in a steel mould.. The photo and schematic diagram with basic
dimensions are shown in Fig. 4a and b.
[%mass]
a)
b)
PISTON
over
MOULD
Particle diameter
Fig. 2. Sieve analysis of the base mixture
Mass of the mixture used in each analysis was 0.5 kg. Three
granulometric compositions were chosen on the basis of analyses
results. The first composition was the original one of the lime-sand
lime
mixture taken directly from the production line.
line The next two were
the results of the separation of mixturess characterized by the
particle size within the range 0 – 0.6 mm and 0 – 1.2 mm. The
percentage of each granulometric fraction in the mixtures shown
in Tab. 1.
Fig. 4. Mould and piston used in sand-lime
sand
mortar compaction
Each sample was prepared from 200 g of the mixture. Compaction force increased at a rate of 2 kN/sec.
kN
The parameters
needed for the determination of compaction characteristics were
recorded. On the bases of collected data the compaction curve
was obtained for each sample. The compaction curve for the base
mixture is presented, as an example, in Fig. 5.
Particle size [mm]
0 – 0.25
0.25 – 0.6
0.6 – 1.2
1.2 – 2.0
2.0 – 4.0
Base mixture
0 – 0.66 mm
0 – 1.2 mm
Fraction content [% weight]
42.9 %
52.88 %
47 %
37.8 %
47.22 %
41.3 %
10.8 %
11.7 %
5.5 %
3%
-
Density [kg/m3]
Tab. 1. Granulometric composition of mixtures used in the experiment
The analyzed process parameter was the compaction pressure Pa. In the experiment Pa = 10, 20, 30, 40 and 50 MPa
was applied. During the compaction process the moisture content
of analyzed mixture was approximately 5%.
Compaction pressure [MPa]
3. DENSIFICATION
Fig. 5. Compaction characteristics of the base compound
4. COMPRESSIVE STRENGTH
Compaction of selected lime-sand mixtures
ixtures was carried
out on MTS 322 universal testing machine (Fig. 3), which allowed
the recording of compaction force and the height of the sample.
sample
Compacted samples were subjected to autoclaving and seasoning (7 days). After that a compressive strength test was conducted. The test was carried out on the MTS 322 universal testing
machine with the head (Fig. 6) that enabled a parallel arrangement of sample and head surfaces.
surfaces
Fig. 3. The materials testing machine MTS 322
Fig. 6. The head used during the compression tests
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Wojciech Tarasiuk, Leon Demianiuk
Influence of Chosen Process and Material Parameters on the Quality of Silicate Product
5. RESULTS
Density
The outcome of the experiment were average density values
of selected mixture samples at various compaction pressures. The
results are shown in the following order:
− base mixture - Fig. 7;
− mixture of particle size 0 – 0.6 - Fig. 8;
− mixture of particle size 0 – 1.2 - Fig. 9.
The mixture of particle size 0 – 0.6 mm was found to be the
one of the lowest density, but only at low compaction pressures
(Pa = 10 i 20 MPa). At higher pressures, the same mixture had
the highest density among all the investigated mixtures.
The results regarding compressive strength RC are shown in
graphs:
− base mixture - Fig. 10;
− mixture of particle size 0 – 0.6 - Fig. 11;
− mixture of particle size 0 – 1.2 - Fig. 12.
Compression pressure
Fig. 10. The compressive strength RC dependence
on compaction pressure Pa for base mixture
Density
Fig. 7. The density dependence on the compaction pressure Pa
for the base mixture
Compaction pressure [MPa]
Fig. 11. The compressive strength RC dependence on compaction
pressure Pa for the mixture of particle size 0 – 0.6 mm
Density
Fig. 8. The density dependence on the compaction pressure Pa
for the mixture of particle size 0 – 0.6 mm
Compaction pressure [MPa]
Fig. 9. The density dependence on the compaction pressure Pa
for the mixture of particle size 0 – 1.2 mm
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Fig. 12. The compressive strength RC dependence on compaction
pressure Pa for the mixture of particle size 0 – 1.2 mm
acta mechanica et automatica, vol.6 no.1 (2012)
base mortar
REFERENCES
1. Demianiuk L. (2011), Reseach on the miscanthus giganteus comco
paction process (in Polish), Acta Agrophysica,
Agrophysica Vol. 17, Nr 1, 43-53.
2. Królikowski M. (2006), Technological regime of silicate manufacture
(in Polish), 13-14.
3. Skalamowski W. (1973), Technology of building materials (in Polish), vol. II, Arkady, Warszawa, 306-307.
306
4. Tarasiuk W., Krupicz B. (2009),
(2009) Analysis of friction forces in the
lime-sand
sand mixture compaction process (in Polish), Tribologia,
Nr 3, 273-283.
5. Wolfke S. (1986), Technology of lime-sand
lime
products (in Polish),
Arkady, Warszawa 1986.
Fig. 13. Comparison of compressive strength RC correlation
with the compaction pressure Pa
promot
grant
Acknowledgement: The work was performed as part of promoter’s
N N504 085538.
The sample of a particle size 0 - 0.6 mm was characterised
by the highest strength. For Pa = 50 MPa, this difference in this
value exceeded 20% in relation to the other mixtures (Fig. 13).
6. CONCLUSIONS
The results indicate that:
− increase in compaction pressure Pa within the range
of 10 MPa to 50 MPa causes an increase in the compressive
strength of calcium silicate,
− the mixture of particle size 0 – 0.6 mm has the highest comco
pressive strength the whole range of compacting pressures
applied in the experiment,
− the mixture of particle size 0 – 0.66 mm at a compaction pressure Pa = 10 MPa has the lowest density with maximum compression strength RC,
− a proper choice of the mixture granulometric composition
allows to obtain a finished product with a lower weight
and higher compressive strength.
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