Summary:
This thesis includes the study of clays which overlay the attapulgite –
saponite deposit in the area of Piloroi, Municipality of Ventzia of Grevena, in
relation to their mineralogical composition, as well as the research of their
suitability in the production of light weight aggregates, and hence their
application in building projects, as commercial products, etc.
The attapulgite - saponite deposit in the stream of Piloroi of Ventzia resulted
from the alteration of the ultrabasic rocks of the Vourino area, which at a
first stage provided materials rich in smectite. Thereafter under the activity
of diagenetic factors and solutions rich in Si, the present deposit resulted.
The attapulgite – saponite is rich in magnesium in fibrous - elongated
(attapulgite), as well as granular – compact texture (saponite). It is formed
under the presence of liquids rich in magnesium.
The deposit is characterized by high porosity, high viscosity, high ion
exchange capacity , it is stable at high temperatures and it does not expand.
Thus, it is not affected by electrolytes; has excellent thixotropic abilities
and great ability of adsorption. Based on these properties, it can be used as
oil-fat absorbent, as filler in paints, in perforations/drillings, molecular
filters, litter, cosmetics and medicines.
For the manufacture of the light weight aggregates, the original material was
mixed with sawdust to improve its properties (hardness, strength, expansion,
etc.). Sintering of the samples in a laboratory oven followed, to dry out the
water that was in it.
It was further studied the mineralogy, texture, structure of sintered pellets
and comparison of these with similar industrial and laboratory products took
place. Further, there were carried out mineralogical and chemical studies, both
to the original soil samples by the X-ray fluorescence method (XRF), and to
sintered pellets by using scanning electron microscopy (SEM) and X-ray
diffractometer (XRD)
The pellets are characterized by absence of CaCO3, that mean good quality of
pellets as long as it concerns their uses, but also presence of glass phase
involves good resistance of samples.
The pellets present appreciable technical and mechanic characteristics. In
combination with the high reserves that have been located in the region and the
small cost of excavation and treatment, this material is advisable for the
production of LWA - light weight aggregates.
To study the quality of the lightweight aggregates measurements and
correlations between them were carried out concerning the apparent specific
weight, the apparent volume, the diameter and their rupture, load.
The result of this sintering process is the production of a synthetic material
with low bulk density (0,55 – 0,80 g/cm³) and good compressive strength
(tensile strength 2000 Ν/g).
The low density and the big porosity in combination with the big resistance in
compressive strength, make the material ideal as material of fulfillment of
bases and subbases in the road construction, so that is decreased the land
pressure in structures, avoiding likely problems, with low cost.
Based on the above results, it is suggested the use of the lightweight
aggregates of attapulgite – saponite as insulators, as filler material for
bases and bedrocks and in technical works in general. Lastly, it is suggested
the conduct of further research to ensure the safe use of these lightweight
aggregates in building works.
Keywords:
Attapulgite, Saponite, lightweight, aggregates, Piloroi
