Environmental Engineering Reference
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to form calcium-sillicates, which increase
FS
[3, 27-29]. According to the
SOP model developed, it is concluded that i ne-grained calcite reacted to
SiO
2
in most of the samples, since the terms SiO
2
xCaO and Al
2
O
3
xCaO
showed strong inl uence on
FS
. CaOxMgO (dolomite) inl uenced mate-
rials densii cation, which was observed by the inl uence in ANOVA cal-
culation. Firing temperature mostly inl uenced
FS
in terms conjuncted to
Na
2
O, TiO
2
, and Fe
2
O
3
.
Alkali oxides facilitate the creation of a liquid phase, which promotes
densii cation in reaction with silicon and aluminum [30]. h e highest
impact on
WLF
parameters showed Na
2
O linear term, mostly to
WLFB
.
Na
2
O i K
2
O also induced a signii cant inl uence on
FS
,
WLFT
, and
WLFB
in the terms containing another l ux, Fe
2
O
3
[26]. In the case of
WLF
parameters, CaO was more inl uential in relation to Na
2
O, TiO
2
, MgO,
Te m p a n d S i O
2
, but as the linear term. CaO content and some of the other
l uxes gained strong inl uences on
WLF
, and also SiO
2
from quartz and/
or clay minerals showed powerful impact, thus coni rming calcium sili-
cate formation. Firing temperature inl uenced
WLFT
, following the order
of importance: quadratic term of Temp, Al
2
O
3
xTemp, and linear term of
Temp. Laboratory tiles showed the highest sensitivity to i ring tempera-
ture, concerning weight loss, since the greatest specii c surface is exposed
to furnace conditions, above all sample shapes. Firing temperature mostly
inl uenced
WLFB
following the order of importance: linear term of Temp,
CaOxTemp, and SiO
2
xTemp. Weight loss depended on combined ef ects of
i ring temperature and CaO/SiO
2
contents, and it is being slightly increased
with them. Hollow blocks were also sensitive to i ring temperature, but less
than tiles, and its impact is also combined to the calcite and quartz con-
tent.
WLFC
is inl uenced by i ring temperature in the order: MgOxTemp,
TiO
2
xTemp, and linear term of temperature.
VMC
mostly depended on CaOxTemp, Al
2
O
3
xTemp, and SiO
2
xTemp.
h e i red material density mostly depended on carbonate content and i r-
ing temperature applied, but also on clay minerals content and densii ca-
tion abillity.
h e residual variance, marked as error in table 4.3, presents the model
disagreement with the experimental values (contributions of other mem-
bers that are not described in the SOP model). h e statistically signii cant
discrepancy between experimental data and results obtained using math-
ematical models, would show inadequacy of the developed model. All the
developed models showed statistically insignii cant deviation from the
experimental values of the model, which coni rmed their suitability. h e
coei cient of determination,
r
2
is also a share of output variability of the
system, which was calculated based on regression analysis. High
r
2
values
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