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Citation: Kotsay, G.; Grabowski, P.
Properties of Geopolymers Based on
Metakaolin and Soda-Lime Waste
Glass. Materials 2023,16, 5392.
https://doi.org/10.3390/
ma16155392
Academic Editors: Miguel Ángel
Sanjuán and Valentina Medri
Received: 15 June 2023
Revised: 16 July 2023
Accepted: 26 July 2023
Published: 31 July 2023
Copyright: © 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
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4.0/).
materials
Article
Properties of Geopolymers Based on Metakaolin and
Soda-Lime Waste Glass
Galyna Kotsay * and Paweł Grabowski
Faculty of Civil Engineering, Mechanics and Petrochemistry, Warsaw University of Technology,
Lukasiewicza St. 17, 09-400 Plock, Poland; pawel.grabowski@pw.edu.pl
*Correspondence: galyna.kotsay@pw.edu.pl; Tel.: +48-243672111
Abstract:
The paper determines the properties of geopolymer pastes based on metakaolin and
soda-lime waste glass. The density, alkaline activity, strength and microstructure of the reference
geopolymer, as well as geopolymers with a 10%, 30% and 50% soda-lime waste glass content instead
of metakaolin, were tested. The experimental results indicate that the properties of the geopolymers
with waste glass largely depend on the ratio of the liquid to solid substance. Increasing the content
of waste glass causes an increase in the fluidity of the geopolymer paste, which in turn allows the
amount of water glass, i.e., an activator during the obtaining of geopolymers, to be reduced. On
the basis of the conducted tests, it was found that the strength of geopolymers can be increased by
adding up to 50% of soda-lime waste glass instead of metakaolin and by having a lower content of
water glass.
Keywords: soda-lime waste glass; geopolymer; paste; alkaline activity; dynamic viscosity; strength
1. Introduction
In the construction industry, innovative materials, in particular recycled materials, are
becoming increasingly important. A very valuable material for recycling is glass waste.
An important feature of glass is the possibility of it being repeatedly processed without
its properties changing. Glass recycling saves natural resources, reduces carbon dioxide
emissions into the atmosphere, and reduces the energy that is needed to produce new
products [
1
,
2
]. According to the FEVE association (European Federation of Glass Packaging
Manufacturers), in the European Union and Great Britain, 79% of glass was recycled
in 2020 [3]
and, by 2030, there is an aim to achieve a 90% recycling level of glass packaging.
The glass industry produces more and more glass, with the amount of glass waste also
increasing accordingly. Some of the waste is recovered and returned to the production
process of glass products. However, the amount of glass that can be reused in production
is limited due to the deterioration of the quality of the obtained products. Glass waste can
also be used for the production of fiberglass, mineral wool, abrasives or road paints [
4
].
However, to date, glass waste accounts for 7 to 10% of all the waste that is deposited
in landfills.
At present, more and more ways to reduce the amount of waste, as well as methods to
reuse it in accordance with the principles of sustainable development, are being sought.
There are many publications concerning the use of glass as an aggregate or non-clinker
component for cement [
5
–
13
]. The use of glass as an aggregate for mortar or concrete
reduces the strength of the obtained products as a result of the reduction in the adhesion
between the slurry and the glass aggregate. Moreover, the use of glass as a non-clinker
component of cement is also limited due to the high content of alkali in the waste glass,
which in turn causes an alkali–silica reaction (ASR) [
14
–
20
]. The potential use of glass cullet
as a non-clinker component of cement is not clear. Previous research [
21
–
25
] has proven
that the use of ground glass instead of cement had no negative effects on the properties of
cement after a long period of maturation. In turn, in [
26
–
30
], it was stated that the effect of
Materials 2023,16, 5392. https://doi.org/10.3390/ma16155392 https://www.mdpi.com/journal/materials
Materials 2023,16, 5392 2 of 12
glass on the expansion of the obtained products depends on the grain size of the ground
glass. The use of glass with a grain size of less than 300 microns can reduce the impact of
the expansion of ASR products. The authors of [
31
–
34
] proposed the use of waste glass
as an alkaline activator in combination with other waste materials, e.g., blast furnace slag
or fly ash.
When analysing the results of research concerning the possibility of using waste glass,
the largest disadvantage of glass in building materials made from commonly used cement
is the alkali content. This is why the use of glass cullet for geopolymers has been proposed
in scientific research [
35
–
44
]. Geopolymers are considered to be an alternative material to
cement and can be used for the production of prefabricated elements, structural elements,
adhesive mortars or insulating materials [
45
–
47
]. It is derived from an active aluminosilicate
material (called a precursor) and an activator. Metakaolin or industrial waste, such as fly ash,
blast furnace slag or ceramic brick, are often used as precursors [
48
–
52
]. In turn, alkaline
activators are used to dissolve precursors and to catalyse polycondensation reactions, as
well as to stabilize aluminium cations in tetrahedral coordination in order to make the
structure neutral. Water glass, NaOH or KOH bases, sodium or potassium sulphates, or
carbonates are used as activators [
46
,
53
–
55
]. Water glass, which is used the most often, is
considered to be the best activator because it introduces silicate ions into the solution. It
is worth noting that water glass is an air binder, but the use of water glass as an activator,
with a precursor, results in the obtaining of a geopolymer that is resistant to moisture
after curing.
A properly designed and synthesized geopolymer has very good mechanical and
physicochemical properties [
56
]. The binding and hardening mechanism of geopolymers
significantly differs from that of ordinary cement. The cement setting process is based on
the hydration reaction, whereas the geopolymer setting process is based on the polycon-
densation reaction [
46
]. As a result of polycondensation in the geopolymer, amorphous
or semi-crystalline groups of silicon and aluminium oxide tetrahedra are formed, which
are connected alternately by common oxygen atoms. The main difficulty in the synthesis
of geopolymers is the variability of the chemical and mineralogical composition of the
precursors. This results in a different activation process and a very diverse physicochemical
structure of geopolymers. Therefore, there are no clear guidelines for the mechanism
of geopolymerization.
Glass waste is a source of amorphous silica and alkalis, making them not only a
precursor but also an activator in geopolymers. However, the potential use of glass waste
as a substitute for conventional precursors is limited. In most studies, the optimal content
of glass waste as a precursor is up to 15% [
36
,
37
,
39
,
42
]. Therefore, the aim of this research is
to increase the content of soda-lime waste glass (SLWG) in metakaolin-based geopolymers.
2. Materials and Methods
Metakaolin produced by the firm Rominco Polska [
57
], soda-lime waste glass produced
by REWA [
58
] and glass water produced by Rudniki S.A. [
59
] were used as the main object
of the research. The chemical compositions and properties of the materials are shown in
Table 1. The real density and the Blaine specific surface test of materials were performed
according to the methods described in the standards [
60
,
61
]. Sodium hydroxide of 99%
purity by [62] was used to reduce the modulus of the water glass to M = 1.5.
The rheological measurements (dynamic viscosity and fluidity) were conducted using
the IKA ROTAVICS me-vi. The geopolymer mixture was prepared in a mixer. The mixing
time was 3 min. The measurement of rheological parameters was conducted 15 min after
the completion of mixing the components. The temperature during the test was maintained
at a constant level of 20
◦
C. The reaction speed of the pastes was assessed on the basis of heat
measurements. Calorimeter Calmetrix I-Cal 2000 HPC was applied to determine the effect
of waste glass on the polycondensation reactions of metakaolin. The rate of heat evolution
was recorded for the pastes with a liquid-to-binder ratio equal to 0.5. Solid mixtures were
made from metakaolin and glass as partial metakaolin substitution. The amount of the heat
Materials 2023,16, 5392 3 of 12
released was monitored every 15 s for the 48 h. The rate of heat evolution was measured at
the isothermal condition (20 ◦C).
Table 1.
The chemical composition and basic properties of metakaolin, soda-lime waste glass and
water glass.
Materiałs
Oxides (wt %)
Density, g/cm3
Specific Surface, m2/g
SiO2
Al2O3
CaO + MgO
Na2Oeq
Fe2O3
TiO2
H2O
LOI
Metakaolin 52 41 0.30 1.40 1.3 0.7 - 1.1 2.50 20,000
Soda-lime waste glass (SLWG) 72 1.0 12.0 14 - - - - 2.43 3987
Sodium water glass (WG) 29 - - 9 - - 62 - 1.45 -
The specimens of pastes were made in moulds sized 20 mm
×
20 mm
×
20 mm. All
cuboids of pastes were taken out from the moulds after one day; then, part of the samples
were cured at 20
◦
C and part of the samples were stored at the 40
◦
C and 80
◦
C for 24 h.
The apparent density and the compressive strength tests were evaluated on a series of six
specimens. Samples were examined using hydraulic press with the 500 N/s force increase
rate. Apparent density tests were conducted according to [
60
]. Pieces of geopolymers after
the compression test were used for microstructure observations by SEM using a ZEISS EVO
10 with an acceleration voltage of 10.0 kV.
To determine the alkaline activity of geopolymers, distilled water was used as an
extractant with a ratio of the specimen surface to the extractant volume of 0.34 cm
−1
.
The alkaline activity of the paste was determined on a series of six specimens. For the
quantitative analysis of alkali content, a flame photometer FP902 (PG Instruments Limited,
Alma Park, Wibtoft, Leicestershire, UK) with an accuracy of
±
0.5% was used. The results
of the alkaline activity of specimens are presented in units of ppm/m2of paste.
3. Results and Discussion
The parameters of SiO
2
/Al
2
O
3
, Na
2
O/Al
2
O
3
and Na
2
O/SiO
2
are important when
designing geopolymers. Geopolymers with a polysialate-syloxo structure are believed to
have a higher strength and therefore, a molar ratio of SiO
2
/Al
2
O
3
ranging from 3.3 to 4.5 is
optimal [
39
,
63
,
64
]. In turn, the alkali content affects the solubility of aluminosilicates and
the stabilization of aluminium cations in tetrahedral coordination. Thus, when obtaining
geopolymers, Na
2
O/Al
2
O
3
ranging from 0.8 to 1.6 and Na
2
O/SiO
2
from 0.20 to 0.48 are
optimal. Many publications describe the influence of some parameters on the properties
of geopolymers [
46
,
63
,
64
], but to date, there is no clear answer regarding the relationship
between a given module and these properties. Geopolymers are still seen as a modern
material, despite the fact that they have been known for several decades.
In the research, two materials—metakaolin and glass waste—were used as the precur-
sor, whereas water glass with a constant molar ratio of SiO
2
/Na
2
O = 1.5 was used as the
activator. In the case of the reference geopolymer, 100% of metakaolinite was used as the
precursor, and in the other samples, metakaolin was replaced with 10%, 30% and 50% of
soda-lime waste glass. The liquid to solid ratio for the geopolymer reference, 10SLWG0.9,
30SLWG0.9 and 30SLWG0.9 samples, was 0.9. The composition of the samples is shown in
Table 2.
In metakaolin, the molar ratio of SiO
2
/Al
2
O
3
is 2.15, and the adding of an activator to
metakaolin increases this parameter to 3.23. Replacing 10%, 30% and 50% metakaolin with
SLWG that contains 70% SiO
2
also increases the molar ratio of SiO
2
/Al
2
O
3
from 3.53 to
7.15. Waste glass still contains 14% of alkali, and therefore the use of glass also acts as an
Materials 2023,16, 5392 4 of 12
activator and increases the Na
2
O/Al
2
O
3
and Na
2
O/SiO
2
parameters. The molar ratio of
the designed geopolymers is shown in Table 2.
Table 2.
Mixture compositions and molar ratio of the prepared geopolymer pastes with a liquid/solid
ratio of 0.9.
Sample Name
Mixture Composition (wt %)
Liquid/Solid
Molar Ratios
Metakaolin SLWG WG SiO2/Al2O3Na2O/Al2O3Na2O/SiO2
Geopolymer reference 100 0 90 0.9 3.23 0.79 0.24
10SLWG0.9 90 10 90 0.9 3.53 0.93 0.26
30SLWG0.9 70 30 90 0.9 4.83 1.33 0.28
50SLWG0.9 50 50 90 0.9 7.15 2.03 0.28
When comparing the molar ratio of the designed geopolymers to the optimal parame-
ters (according to literature data [
63
,
64
]), the use of 10% of SLWG instead of metakaolin
meets all the required parameters. In turn, the sample with 30% of SLWG only meets the
parameters of Na
2
O/Al
2
O
3
and Na
2
O/SiO
2
, whereas the sample with 50% of SLWG meets
the parameters for only Na2O/SiO2.
It is known that the geopolymerization process depends on the type of precursor, the
concentration of the activator, and the method of curing. In order to investigate how water
glass affects the dissolution of the precursor, calorimetric tests were first performed for
the “metakaolin and water glass” sample, and then for the “waste glass and water glass”
sample. Glass with different alkalinity was used for the study.
When adding metakaolin to water glass, the first stage involves the adsorption of
the water glass solution on the surface of the precursor, and then its dissolution, which is
associated with the release of heat. Figure 1a shows that, the greater the alkalinity of the
water glass (the molar ratio of Na
2
O/SiO
2
), the greater the solubility of the metakaolin.
The released heat increases exponentially with an increasing alkalinity of the activator. In
turn, the heat from the reaction of waste glass with water glass was ten times lower when
compared to the metakaolin (Figure 1b). It was observed that, for a given sample, the molar
ratio of the Na
2
O/SiO
2
activator (within the range from 0.5 to 0.7) increased the release of
heat, while in the case of higher alkalinity, no changes in heat were observed.
Materials 2023, 16, x FOR PEER REVIEW 5 of 13
(a)
(b)
Figure 1. Calorimetric results of the reaction: (a) metakaolin with water glass; (b) waste glass with
water glass.
Although the use of waste glass instead of metakaolin in geopolymers increases the
molar ratio of Na2O/Al2O3 and Na2O/SiO2, its activity, when compared to metakaolin, is
ten times lower. Therefore, the introduction of waste glass instead of metakaolin into ge-
opolymers causes a decrease in the reaction rate with an increase in the glass content (Fig-
ure 2). The introduction of soda-lime waste glass in the amount of 10% does not signifi-
cantly change the heat of hydration, while the introduction of 30% and 50% instead of
metakaolin reduces the total heat of hydration after 48 h to 24% and 38%, respectively.
Figure 2. Heat of hydration for the samples with the addition of soda-lime waste glass (SLWG).
The basic properties of geopolymers are their rheological properties. The use of a
geopolymer with an appropriate dynamic viscosity allows the aggregate to be encapsu-
lated, and a more homogeneous structure to be obtained. The viscosity results of the tested
samples are presented in Table 3, in which they are compared to that of a cement paste
with a standard consistency.
Table 3. Tests of viscosity in the case of the reference sample and the samples with 10%, 30% and
50% of SLWG.
Sample
Specifications
Density of Fresh Pastes,
g/cm
3
Dynamic Viscosity, Pa·s
Fluidity of Fresh Pastes, 1/Pa
Geopolymer reference
1.83
24.5
0.04
10SLWG0.9
1.84
5.57
0.18
0
50
100
150
200
250
300
0.2 0.4 0.6 0.8 1.0
Heat, J/ g metakaolin
Molar ratio Na2O/SiO2
0
5
10
15
20
25
0.2 0.4 0.6 0.8 1
Heat, J/g waste glass
Molar ratio Na2O/SiO2
0
20
40
60
80
100
120
140
160
0 5 10 15 20 25 30 35 40 45
Heat, J/g
Time , h
0% SLWG
10% SLWG
30% SLWG
50% SLWG
Figure 1.
Calorimetric results of the reaction: (
a
) metakaolin with water glass; (
b
) waste glass with
water glass.
Although the use of waste glass instead of metakaolin in geopolymers increases the
molar ratio of Na
2
O/Al
2
O
3
and Na
2
O/SiO
2
, its activity, when compared to metakaolin,
is ten times lower. Therefore, the introduction of waste glass instead of metakaolin into
Materials 2023,16, 5392 5 of 12
geopolymers causes a decrease in the reaction rate with an increase in the glass content
(Figure 2). The introduction of soda-lime waste glass in the amount of 10% does not
significantly change the heat of hydration, while the introduction of 30% and 50% instead
of metakaolin reduces the total heat of hydration after 48 h to 24% and 38%, respectively.
Materials 2023, 16, x FOR PEER REVIEW 5 of 13
(a)
(b)
Figure 1. Calorimetric results of the reaction: (a) metakaolin with water glass; (b) waste glass with
water glass.
Although the use of waste glass instead of metakaolin in geopolymers increases the
molar ratio of Na2O/Al2O3 and Na2O/SiO2, its activity, when compared to metakaolin, is
ten times lower. Therefore, the introduction of waste glass instead of metakaolin into ge-
opolymers causes a decrease in the reaction rate with an increase in the glass content (Fig-
ure 2). The introduction of soda-lime waste glass in the amount of 10% does not signifi-
cantly change the heat of hydration, while the introduction of 30% and 50% instead of
metakaolin reduces the total heat of hydration after 48 h to 24% and 38%, respectively.
Figure 2. Heat of hydration for the samples with the addition of soda-lime waste glass (SLWG).
The basic properties of geopolymers are their rheological properties. The use of a
geopolymer with an appropriate dynamic viscosity allows the aggregate to be encapsu-
lated, and a more homogeneous structure to be obtained. The viscosity results of the tested
samples are presented in Table 3, in which they are compared to that of a cement paste
with a standard consistency.
Table 3. Tests of viscosity in the case of the reference sample and the samples with 10%, 30% and
50% of SLWG.
Sample
Specifications
Density of Fresh Pastes,
g/cm
3
Dynamic Viscosity, Pa·s
Fluidity of Fresh Pastes, 1/Pa
Geopolymer reference
1.83
24.5
0.04
10SLWG0.9
1.84
5.57
0.18
0
50
100
150
200
250
300
0.2 0.4 0.6 0.8 1.0
Heat, J/ g metakaolin
Molar ratio Na2O/SiO2
0
5
10
15
20
25
0.2 0.4 0.6 0.8 1
Heat, J/g waste glass
Molar ratio Na2O/SiO2
0
20
40
60
80
100
120
140
160
0 5 10 15 20 25 30 35 40 45
Heat, J/g
Time , h
0% SLWG
10% SLWG
30% SLWG
50% SLWG
Figure 2. Heat of hydration for the samples with the addition of soda-lime waste glass (SLWG).
The basic properties of geopolymers are their rheological properties. The use of a
geopolymer with an appropriate dynamic viscosity allows the aggregate to be encapsulated,
and a more homogeneous structure to be obtained. The viscosity results of the tested
samples are presented in Table 3, in which they are compared to that of a cement paste with
a standard consistency.
Table 3.
Tests of viscosity in the case of the reference sample and the samples with 10%, 30% and 50%
of SLWG.
Sample Specifications
Density of Fresh Pastes, g/cm3Dynamic Viscosity, Pa·s Fluidity of Fresh Pastes, 1/Pa
Geopolymer reference 1.83 24.5 0.04
10SLWG0.9 1.84 5.57 0.18
30SLWG0.9 1.8 0.99 1.02
50SLWG09 1.72 0.14 6.94
Cement paste 2.06 2 0.5
The research showed that the introduction of soda-lime waste glass instead of metakaolin
significantly reduced the dynamic viscosity of the geopolymers when compared to the
reference geopolymer. The addition of 10% of SLWG reduced the dynamic viscosity by
five times
, while the addition of more than 30% of soda-lime waste glass caused its viscosity
to decrease significantly. The reduction in viscosity increased the fluidity of the geopolymer.
The introduction of more than 30% of soda-lime waste glass caused fluidity to increase
quickly, which in turn violated the continuity of the mixture’s structure and reduced
the cohesive forces in the material. When compared to the cement paste of a standard
consistency, the reference geopolymer had a much greater plastic viscosity. However, only
when 10% to 30% of soda-lime waste glass was introduced, instead of metakaolin, was the
fluidity comparable to that of the cement paste.
The effect of soda-lime waste glass and curing temperature on the bulk density is
shown in Table 4. In all the samples, after 7 days of thermal curing, the density was
reduced. This was associated with a decrease in the weight of the samples as a result of
water evaporation during the polycondensation reaction. The reference geopolymer had
the highest density due to the higher reactivity of metakaolin. Waste glass, when compared
to metakaolin, has a lower specific surface and activity, and therefore the introduction of
glass instead of metakaolin into geopolymers causes a decrease in their density.
Materials 2023,16, 5392 6 of 12
Table 4. Bulk density and the loss of density of the geopolymers at 7 days and 28 days.
Sample Bulk Density after 7 Days, g/cm3Loss of Density
after 7 Days, %
Bulk Density after 28 Days, g/cm3Loss of Density
after 28 Days, %
20 ◦C 80 ◦C 20 ◦C 80 ◦C
Geopolymer reference
1.71 1.58 7.6 1.62 1.54 4.9
10SLWG0.9 1.71 1.48 13.5 1.62 1.51 4.4
30SLWG0.9 1.67 1.48 11.4 1.64 1.51 2.5
50SLWG0.9 1.6 1.36 15.0 1.62 1.62 0.6
Increasing the curing temperature increases the rate of the polycondensation of
geopolymers, which in turn results in a decrease in their density. Thus, in the case of
the reference sample, when curing at a temperature of 80
◦
C, there was a reduction in
density of up to 8%. In turn, the thermal hardening of the samples with the addition of
soda-lime waste glass was characterized by a greater reduction in density—even up to
15% for the samples with a content of 50% of waste glass. The decrease in density was
associated with a greater water evaporation due to an increased porosity. Over time, after
28 days, when curing at 20
◦
C, a greater decrease in density was observed in the case of
the reference sample and the sample with the addition of 10% of SLWG, whereas for the
samples with a higher content of SLWG, the density was approximately the same as that
obtained after 7 days. By increasing the curing temperature after 28 days, the reference
sample (inversely) had a greater weight loss than the samples with the addition of SLWG.
The greater weight loss after the hardening of the sample can cause cracking.
The influence of soda-lime waste glass and temperature curing on the compressive
strength of geopolymers are presented in Figure 3. In the reference samples cured at 20
◦
C,
the strength reached 32 MPa at 7 days and increased at 28 days to 51 MPa. The temperature
increase in thermal curing accelerates the geopolymerization reaction; therefore, reference
samples at 50
◦
C reached a higher strength at 7 days and 28 days (45 and 55 MPa, respec-
tively). However, curing at 80
◦
C was observed to favour significant strength development
in the early ages to 71 MPa but decreased mechanical strength to 63 MPa at 28 days; this
reduction in strength was due to the formation of fissures caused by shrinkage.
Materials 2023, 16, x FOR PEER REVIEW 7 of 13
(a)
(b)
Figure 3. Compressive strength of the geopolymers at 7 days and 28 days.
Replacing metakaolin with 10% SLWG does not significantly change the strength of
the samples stored at room temperature and thermal curing at 50 °C. A decrease in
strength was observed for curing at 80 °C compared to the control samples. With 30%
SLWG instead of metakaolin, the strength does not change only for samples stored at room
temperature at 7 days. For the samples in question, no increase in strength was observed
after 28 days. Increasing the content to 50% SLWG, significantly falls geopolymer strength
after 7 days by 50% from the control sample values and strength falls after 28 days com-
pared to strength result tests after 7 days.
The reduction in the strength of geopolymers over time is related to the alkalinity of
the solution, which can cause the aluminosilicate gel to break down. It is known that an
excess of alkali destroys Si–O–Si stronger bonds, forming Si–O–Na species. For the tested
mixtures with 30% and 50% SLWG content, the compressive strength decreased due to
the excess of Na+ ions in the mixtures. According to the results of the alkaline activity of
the products, the amount of extracted sodium cations from a unit area increased 1.5 times
for the system with 30% SLWG content and four times with 50% SLWG content (Table 5).
However, the introduction of 10% SLWG instead of metakaolin slightly decreased the
amount of extracted sodium and potassium ions.
Relevant studies were conducted on the cement paste to compare the amount of ex-
tracted alkaline ions; the results are presented in Table 5. The data show that the cement
paste had a reverse extraction of alkali ions, more K+ extracted and the least amount of
sodium ion compared to geopolymers. It should be noted that the reference geopolymers
and 10 to 30% SLWG geopolymers have a lower total amount of extracted cations. Increas-
ing the SLWG content in the geopolymer to 50% increases the overall alkalinity for geo-
polymer compositions.
Table 5. The amount of extracted ions Na+ and K+ from the surface layers of the pastes.
Sample
Amount of Extracted, g/m
2
The Total Amount of Extracted
Cations, g/m
2
Na
+
K
+
Geopolymer reference
4.7
0.32
5.0
10SLWG0.9
3.4
0.25
3.7
30SLWG0.9
6.79
0.35
7.1
50SLWG0.9
18.62
0.78
19.4
Cement paste
0.97
7.47
8.4
The temperature increase in thermal curing accelerates the geopolymerization reac-
tion, so the reference samples decreased total amount extracted. The total amount of
32 31 34
16
45 47
39
21
71
66
51
29
0
10
20
30
40
50
60
70
80
0 10 30 50
Compressive strength at 7 days,
MPa
SLWG content, %
20°C
50°C
80°C
51 50
33
14
55 53
35
11
63
54
44
10
0
10
20
30
40
50
60
70
0 10 30 50
Compressive strength at
28 days,
MPa
SLWG content, %
20°C
50°C
80°C
Figure 3. Compressive strength of the geopolymers at 7 days and 28 days.
Replacing metakaolin with 10% SLWG does not significantly change the strength of
the samples stored at room temperature and thermal curing at 50
◦
C. A decrease in strength
was observed for curing at 80
◦
C compared to the control samples. With 30% SLWG instead
of metakaolin, the strength does not change only for samples stored at room temperature
at 7 days. For the samples in question, no increase in strength was observed after 28 days.
Increasing the content to 50% SLWG, significantly falls geopolymer strength after 7 days by
Materials 2023,16, 5392 7 of 12
50% from the control sample values and strength falls after 28 days compared to strength
result tests after 7 days.
The reduction in the strength of geopolymers over time is related to the alkalinity
of the solution, which can cause the aluminosilicate gel to break down. It is known that
an excess of alkali destroys Si–O–Si stronger bonds, forming Si–O–Na species. For the
tested mixtures with 30% and 50% SLWG content, the compressive strength decreased
due to the excess of Na
+
ions in the mixtures. According to the results of the alkaline
activity of the products, the amount of extracted sodium cations from a unit area increased
1.5 times
for the system with 30% SLWG content and four times with 50% SLWG content
(Table 5). However, the introduction of 10% SLWG instead of metakaolin slightly decreased
the amount of extracted sodium and potassium ions.
Table 5. The amount of extracted ions Na+and K+from the surface layers of the pastes.
Sample Amount of Extracted, g/m2The Total Amount of
Extracted Cations, g/m2
Na+K+
Geopolymer reference
4.7 0.32 5.0
10SLWG0.9 3.4 0.25 3.7
30SLWG0.9 6.79 0.35 7.1
50SLWG0.9 18.62 0.78 19.4
Cement paste 0.97 7.47 8.4
Relevant studies were conducted on the cement paste to compare the amount of
extracted alkaline ions; the results are presented in Table 5. The data show that the
cement paste had a reverse extraction of alkali ions, more K
+
extracted and the least
amount of sodium ion compared to geopolymers. It should be noted that the reference
geopolymers and 10 to 30% SLWG geopolymers have a lower total amount of extracted
cations. Increasing the SLWG content in the geopolymer to 50% increases the overall
alkalinity for geopolymer compositions.
The temperature increase in thermal curing accelerates the geopolymerization reaction,
so the reference samples decreased total amount extracted. The total amount of extracted
cations from the pastes’ surface vs. temperature geopolimiryzation are presented in Figure 4.
The reduction in the alkali extraction was also noted for the geopolymer from 10% SLWG.
An opposite situation is observed when increasing the waste glass content in geopolymer
to 30%, as the temperature increase in thermal curing accelerates the increased total amount
extracted, which proves that the alkali was not bound.
Materials 2023, 16, x FOR PEER REVIEW 8 of 13
extracted cations from the pastes’ surface vs. temperature geopolimiryzation are pre-
sented in Figure 4. The reduction in the alkali extraction was also noted for the geopoly-
mer from 10% SLWG. An opposite situation is observed when increasing the waste glass
content in geopolymer to 30%, as the temperature increase in thermal curing accelerates
the increased total amount extracted, which proves that the alkali was not bound.
Figure 4. The total amount of extracted cations from the pastes’ surface vs. temperature geopoly-
merization.
In order to reduce the amount of alkali in the samples, geopolymers with a lower
content of water glass were formed. The composition of the samples and the molar ratio
of the designed geopolymers are shown in Table 6.
Table 6. Mixture compositions and molar ratio of the prepared geopolymer pastes with a lower
liquid/solid ratio.
Sample Name
Mixture Composition (wt%)
Liquid/
Solid
Molar Ratios
Metakaolin SLWG WG SiO2/Al2O3 Na2O/Al2O3 Na2O/SiO2
Geopolymer reference
100
0.0
90
0.9
3.23
0.79
0.24
10SLWG0.8
90
10
80
0.8
3.53
0.84
0.24
30SLWG0.6
70
30
60
0.6
4.37
0.99
0.23
50SLWG0.5
50
50
50
0.5
6.04
1.40
0.23
The reduction in water glass in the samples with the SLWG reduced the molar ratios
of SiO2/Al2O3, Na2O/Al2O3 and Na2O/SiO2 when compared to the samples with a constant
ratio of liquid to substance (Table 6). When comparing the molar ratios of the geopolymers
with a lower content of water glass to the optimal parameters (according to literature
data), the use of 10% and 30% of SLWG instead of metakaolin meets all the required pa-
rameters, while the sample with 50% of SLWG meets only the Na2O/Al2O3 and Na2O/SiO2
parameters. For the tested systems, the density and amount of extracted alkalis, as well as
the strength of the evaluated systems, were tested. The test results are presented in Table
7.
Table 7. Tests results in the case of the reference sample and the samples with 10%, 30% and 50% of
SLWG.
Sample
Bulk Density after 7 Days,
g/cm
3
Compressive Strength, MPa
Amount of Extracted,
g/m
2
20 °C
80 °C
20 °C
80 °C
Na
+
K
+
Geopolymer reference
1.71
1.54
32.23
71
4.7
0.32
10SLWG0.8
1.76
1.62
36.95
64.66
3.24
0.2
0
2
4
6
8
10
20 50 80
The Total Amount of
Extracted Cations,g/ m
2
Temperature, oC
0% SLWG
10% SLWG
30% SLWG
Figure 4.
The total amount of extracted cations from the pastes’ surface vs. temperature geopolymerization.
In order to reduce the amount of alkali in the samples, geopolymers with a lower
content of water glass were formed. The composition of the samples and the molar ratio of
the designed geopolymers are shown in Table 6.
The reduction in water glass in the samples with the SLWG reduced the molar ratios
of SiO
2
/Al
2
O
3
, Na
2
O/Al
2
O
3
and Na
2
O/SiO
2
when compared to the samples with a
constant ratio of liquid to substance (Table 6). When comparing the molar ratios of the
Materials 2023,16, 5392 8 of 12
geopolymers with a lower content of water glass to the optimal parameters (according
to literature data), the use of 10% and 30% of SLWG instead of metakaolin meets all the
required parameters, while the sample with 50% of SLWG meets only the Na
2
O/Al
2
O
3
and Na
2
O/SiO
2
parameters. For the tested systems, the density and amount of extracted
alkalis, as well as the strength of the evaluated systems, were tested. The test results are
presented in Table 7.
Table 6.
Mixture compositions and molar ratio of the prepared geopolymer pastes with a lower
liquid/solid ratio.
Sample Name Mixture Composition (wt %) Liquid/Solid Molar Ratios
Metakaolin SLWG WG SiO2/Al2O3Na2O/Al2O3Na2O/SiO2
Geopolymer reference 100 0.0 90 0.9 3.23 0.79 0.24
10SLWG0.8 90 10 80 0.8 3.53 0.84 0.24
30SLWG0.6 70 30 60 0.6 4.37 0.99 0.23
50SLWG0.5 50 50 50 0.5 6.04 1.40 0.23
Table 7.
Tests results in the case of the reference sample and the samples with 10%, 30% and 50%
of SLWG.
Sample Bulk Density after 7 Days, g/cm3Compressive Strength, MPa Amount of Extracted, g/m2
20 ◦C 80 ◦C 20 ◦C 80 ◦C Na+K+
Geopolymer reference 1.71 1.54 32.23 71 4.7 0.32
10SLWG0.8 1.76 1.62 36.95 64.66 3.24 0.2
30SLWG0.6 1.77 1.58 45.00 73.82 2.9 0.22
50SLWG0.5 1.78 1.68 48.35 76.9 6.16 0.24
The reduction in water glass in the samples with the SLWG significantly changed
the properties of the geopolymers. It is known that the polycondensation process of
geopolymers is associated with the evaporation of water, and therefore the reduction in
water glass in the samples with the SLWG caused an inverse increase in density. When
the samples were cured at 80
◦
C, a slight decrease in their strength was observed for those
with 10% of SLWG. However, for the samples with the SLWG content from 30 to 50%, and
in the case of a lower liquid/solid ratio, an increase in strength was noted. The structure
of geopolymers with a reduced content of water glass is more compacted, as can be seen
from the results of testing the extracted sodium and potassium ions. Therefore, in the
30SLWG0.6 sample (Table 6), the amount of extracted alkalis halved when compared to the
30SLWG0.9 sample (Table 2). In turn, in the case of the 50SLWG0.5 sample, the reduction
in extracted alkalis decreased by three times. Changes in the strength with regards to the
content of water glass correlated with the microstructure of the samples of the obtained
geopolymers. Figures 5and 6show the microstructure of the geopolymers that were cured
at room temperature.
The geopolymer polycondensation process is associated with water evaporation and
can cause micro-cracks in products during curing. The SEM microscope tests confirm the
influence of liquid/solid ratio on the microstructure of the tested pastes. In the geopolymer
pastes with a higher liquid/solid ratio of 0.9 (samples: geopolymer reference, 10SLWG0.9;
30SLWG0.9 and 50SLWG0.9—Figure 5), microcracks, which were formed as a result of
shrinkage of the products of the polycondensation reaction, were found. In addition, in
the case of the 50SLWG0.9 sample with a soda-lime waste glass content of up to 50%, the
structure was the least homogeneous and the least compact, which was also confirmed
by the results of the tests on the viscosity and strength of the geopolymer paste. In
turn, the pastes that contained a lower liquid/solid ratio of 0.8, 0.6 and 0.5 did not have
microcracks and instead had a largely homogeneous gel structure (samples: 10SLWG0.8;
30SLWG0.6; 50SLWG0.5—Figure 6). However, in all samples with the soda-lime waste glass,
Materials 2023,16, 5392 9 of 12
particles were identified that did not undergo complete reaction and were surrounded by a
geopolymeric matrix. This will be the subject of further research and publications.
Materials 2023, 16, x FOR PEER REVIEW 9 of 13
30SLWG0.6
1.77
1.58
45.00
73.82
2.9
0.22
50SLWG0.5
1.78
1.68
48.35
76.9
6.16
0.24
The reduction in water glass in the samples with the SLWG significantly changed the
properties of the geopolymers. It is known that the polycondensation process of geopoly-
mers is associated with the evaporation of water, and therefore the reduction in water
glass in the samples with the SLWG caused an inverse increase in density. When the sam-
ples were cured at 80 °C, a slight decrease in their strength was observed for those with
10% of SLWG. However, for the samples with the SLWG content from 30 to 50%, and in
the case of a lower liquid/solid ratio, an increase in strength was noted. The structure of
geopolymers with a reduced content of water glass is more compacted, as can be seen
from the results of testing the extracted sodium and potassium ions. Therefore, in the
30SLWG0.6 sample (Table 6), the amount of extracted alkalis halved when compared to
the 30SLWG0.9 sample (Table 2). In turn, in the case of the 50SLWG0.5 sample, the reduc-
tion in extracted alkalis decreased by three times. Changes in the strength with regards to
the content of water glass correlated with the microstructure of the samples of the ob-
tained geopolymers. Figures 5 and 6 show the microstructure of the geopolymers that
were cured at room temperature.
(a)
(b)
(c)
(d)
Figure 5. Microstructure for sample with a liquid/solid ratio of 0.9: (a) geopolymer reference; (b)
10SLWG0.9; (c) 30SLWG0.9; and (d) 50SLWG0.9.
(a)
(b)
(c)
Figure 6. Microstructure for samples with a lower liquid/solid ratio: (a) 10SLWG0.8; (b) 30SLWG0.6;
and (c) 50SLWG0.5.
The geopolymer polycondensation process is associated with water evaporation and
can cause micro-cracks in products during curing. The SEM microscope tests confirm the
influence of liquid/solid ratio on the microstructure of the tested pastes. In the geopolymer
pastes with a higher liquid/solid ratio of 0.9 (samples: geopolymer reference, 10SLWG0.9;
30SLWG0.9 and 50SLWG0.9—Figure 5), microcracks, which were formed as a result of
shrinkage of the products of the polycondensation reaction, were found. In addition, in
the case of the 50SLWG0.9 sample with a soda-lime waste glass content of up to 50%, the
Figure 5.
Microstructure for sample with a liquid/solid ratio of 0.9: (
a
) geopolymer reference;
(b) 10SLWG0.9; (c) 30SLWG0.9; and (d) 50SLWG0.9.
Materials 2023, 16, x FOR PEER REVIEW 9 of 13
30SLWG0.6 1.77 1.58 45.00 73.82 2.9 0.22
50SLWG0.5 1.78 1.68 48.35 76.9 6.16 0.24
The reduction in water glass in the samples with the SLWG significantly changed the
properties of the geopolymers. It is known that the polycondensation process of geopoly-
mers is associated with the evaporation of water, and therefore the reduction in water
glass in the samples with the SLWG caused an inverse increase in density. When the sam-
ples were cured at 80 °C, a slight decrease in their strength was observed for those with
10% of SLWG. However, for the samples with the SLWG content from 30 to 50%, and in
the case of a lower liquid/solid ratio, an increase in strength was noted. The structure of
geopolymers with a reduced content of water glass is more compacted, as can be seen
from the results of testing the extracted sodium and potassium ions. Therefore, in the
30SLWG0.6 sample (Table 6), the amount of extracted alkalis halved when compared to
the 30SLWG0.9 sample (Table 2). In turn, in the case of the 50SLWG0.5 sample, the reduc-
tion in extracted alkalis decreased by three times. Changes in the strength with regards to
the content of water glass correlated with the microstructure of the samples of the ob-
tained geopolymers. Figures 5 and 6 show the microstructure of the geopolymers that
were cured at room temperature.
(a) (b) (c) (d)
Figure 5. Microstructure for sample with a liquid/solid ratio of 0.9: (a) geopolymer reference; (b)
10SLWG0.9; (c) 30SLWG0.9; and (d) 50SLWG0.9.
(a) (b) (c)
Figure 6. Microstructure for samples with a lower liquid/solid ratio: (a) 10SLWG0.8; (b) 30SLWG0.6;
and (c) 50SLWG0.5.
The geopolymer polycondensation process is associated with water evaporation and
can cause micro-cracks in products during curing. The SEM microscope tests confirm the
influence of liquid/solid ratio on the microstructure of the tested pastes. In the geopolymer
pastes with a higher liquid/solid ratio of 0.9 (samples: geopolymer reference, 10SLWG0.9;
30SLWG0.9 and 50SLWG0.9—Figure 5), microcracks, which were formed as a result of
shrinkage of the products of the polycondensation reaction, were found. In addition, in
the case of the 50SLWG0.9 sample with a soda-lime waste glass content of up to 50%, the
Figure 6.
Microstructure for samples with a lower liquid/solid ratio: (
a
) 10SLWG0.8; (
b
) 30SLWG0.6;
and (c) 50SLWG0.5.
4. Conclusions
This study determined the effect of soda-lime waste glass on the properties of geopoly-
mer pastes based on metakaolinite. Based on the results of this study, the following
conclusions may be drawn.
The viscosity tests revealed that the introduction of sodium–calcium waste glass
instead of metakaolin significantly reduces the dynamic viscosity of geopolymers com-
pared to the reference geopolymer. The decrease in viscosity enhances the fluidity of the
geopolymer, thereby allowing for a reduction in the amount of water glass.
The reduction in water glass in the samples with soda-lime waste glass markedly
altered the properties of the geopolymers. The structure of geopolymers with a diminished
water glass content exhibited a higher compaction, as evidenced by the results of the
extracted sodium and potassium ion testing.
Introducing 30% and 50% of soda-lime waste glass instead of metakaolin in samples
with a liquid-to-solid ratio of 0.9 resulted in a decrease in the compressive strength of the
geopolymers compared to the reference geopolymer. However, the geopolymer containing
30% and 50% soda-lime waste glass at a liquid-to-solid ratio of 0.6 and 0.5, respectively,
exhibited the highest compressive strength compared to the reference geopolymer.
Author Contributions:
Conceptualization, G.K.; methodology, G.K.; formal analysis, G.K.; investi-
gation, G.K. and P.G.; writing—original draft preparation, G.K.; writing—review and editing, G.K.
and P.G.; visualization, G.K.; funding acquisition, G.K. and P.G.; supervision, G.K.; validation, G.K.;
resources, G.K.; project administration, G.K. All authors have read and agreed to the published
version of the manuscript.
Materials 2023,16, 5392 10 of 12
Funding:
This paper was co-financed by the research grant of the Warsaw University of Technology
supporting the scientific activity in the discipline of Civil Engineering and Transport.
Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Not applicable.
Data Availability Statement:
The data presented in this study are available upon request from the
corresponding author.
Acknowledgments:
This publication was co-financed at the Faculty of Civil Engineering, Mechanics
and Petrochemistry, Warsaw University of Technology.
Conflicts of Interest: The authors declare no conflict of interest.
References
1. Rafał, P. Recykling odpadów szklanych. ´
Swiat Szkła 2006,7–8, 68–69.
2. Ku´snierz, A. Stłuczka szklana. Kłopotliwy odpad czy cenny surowiec? ´
Swiat Szkła 2011,1, 40–43.
3.
The EU Packaging and Packaging Waste Regulation (PPWR): How Glass can Support the EU’s Circular Economy Ambition.
Available online: www.feve.org (accessed on 1 June 2023).
4. Sordo´n-Kulibaba, B. Zagospodarowanie odpadów szklanych. ´
Swiat Szkła 2008,7–8, 46–49.
5.
Zanwar, A.B.; Patil, Y.D. Utilization of waste glass powder as a cementitious material in concrete. In Proceedings of the IOP
Conference Series: Materials Science and Engineering, Tamil Nadu, India, 4–5 December 2020; Volume 1070, p. 012040. [CrossRef]
6.
Patel, D.; Tiwari, R.P.; Shrivastava, R.; Yadav, R.K. Effective utilization of waste glass powder as the substitution of cement in
making paste and mortar. Constr. Build. Mater. 2019,199, 406–415. [CrossRef]
7.
Szewczenko, W.; Kotsay, G. Alkaline Activity of Portland Cement with Additives of Waste Glass. Materials
2021
,14, 1346.
[CrossRef]
8.
Kotsay, G.; Brzóska, A. Effect of Borosilicate Glass Wastes and Synthetic Silica on Cement Products Properties. Chem. Chem.
Technol. 2021,15, 312–318. [CrossRef]
9.
Tamanna, N.; Tuladhar, R. Sustainable Use of Recycled Glass Powder as Cement Replacement in Concrete. Open Waste Manag. J.
2020,13, 1–13. [CrossRef]
10.
Sharifi, Y.; Houshiar, M.; Aghebati, B. Recycled glass replacement as fine aggregate in self-compacting concrete. Front. Struct. Civ.
Eng. 2013,7, 419–428. [CrossRef]
11.
Liu, T.; Qin, S.; Zou, D.; Song, W. Experimental investigation on the durability performances of concrete using cathode ray tube
glass as fine aggregate under chloride ion penetration or sulfate attack. Constr. Build. Mater. 2018,163, 634–642. [CrossRef]
12.
Park, S.B.; Lee, B.C.; Kim, J.H. Studies on mechanical properties of concrete containing waste glass aggregate. Cem. Concr. Res.
2004,34, 2181–2189. [CrossRef]
13.
Jani, Y.; Hogland, W. Waste glass in the production of cement and concrete—A review. J. Environ. Chem. Eng.
2014
,2, 1767–1775.
[CrossRef]
14. Shevchenko, V.V. ASR effect in glasses used as additives to Portland cement. Glas. Phys. Chem. 2012,38, 466–471. [CrossRef]
15.
Jiang, Y.; Ling, T.-C.; Mo, K.H.; Shi, C. A critical review of waste glass powder—Multiple roles of utilization in cement-based
materials and construction products. J. Environ. Manag. 2019,242, 440–449. [CrossRef] [PubMed]
16.
Kotsay, G.; Szewczenko, W. Extraction of Alkalis from Silicate Materials PART 2—Crystalline Silicate Materials. Materials
2022
,
15, 6059. [CrossRef] [PubMed]
17. Shevchenko, V.; Kotsay, G. Alkaline Factor in Cements with Glass Powder. Chem. Chem. Technol. 2017,11, 99–104. [CrossRef]
18.
Zhu, H.; Chen, W.; Zhou, W.; Byars, E.A. Expansion behaviour of glass aggregates in different testing for alkali-silica reactivity.
Mater. Struct. 2009,42, 485–494. [CrossRef]
19.
Sobolev, K.; Türker, P.; Soboleva, S.; Iscioglu, G. Utilization of waste glass in ECO-cement: Strength properties and microstructural
observations. Waste Manag. 2007,27, 971–976. [CrossRef]
20.
Park, S.-B.; Lee, B.-C. Studies on expansion properties in mortar containing waste glass and fibers. Cem. Concr. Res.
2004
,
34, 1145–1152. [CrossRef]
21.
Szydłowski, J.; Szudek, W.; Gołek, Ł. Effect of temperature on the long-term properties of mortars containing waste glass powder
and ground granulated blast furnace slag. Cem. Wapno Bet. 2021,26, 264–278. [CrossRef]
22.
Gołek, Ł.; Szudek, W.; Bł ˛adek, M.; Ci˛eciwa, M. The influence of ground waste glass cullet addition on the compressive strength
and microstructure of Portland cement pastes and mortars. Cem. Wapno Bet. 2020,25, 480–494. [CrossRef]
23. Nagrockien˙
e, D.; Barkauskas, K. Utilization of Waste Glass Powder in Cement Mortar. Environ. Sci. Proc. 2021,9, 25.
24.
Grdi´c, D.Z.; Topliˇci ´c- ´
Curˇci´c, G.A.; Grdi´c, Z.J.; Risti´c, N.S. Durability Properties of Concrete Supplemented with Recycled CRT
Glass as Cementitious Material. Materials 2021,14, 4421. [CrossRef] [PubMed]
25.
Aliabdo, A.A.; Abd Elmoaty, A.E.M.; Aboshama, A.Y. Utilization of waste glass powder in the production of cement and concrete.
Constr. Build. Mater. 2016,124, 866–877. [CrossRef]
Materials 2023,16, 5392 11 of 12
26.
Idir, R.; Cyr, M.; Tagnit-Hamou, A. Use of fine glass as ASR inhibitor in glass aggregate mortars. Constr. Build. Mater.
2010
,
24, 1309–1312. [CrossRef]
27.
Serpa, D.; Santos Silva, A.; de Brito, J.; Pontes, J.; Soares, D. ASR of mortars containing glass. Constr. Build. Mater.
2013
,
47, 489–495. [CrossRef]
28.
Sharifi, Y.; Afshoon, I.; Firoozjaei, Z.; Momeni, A. Utilization of Waste Glass Micro-particles in Producing Self-Consolidating
Concrete Mixtures. Int. J. Concr. Struct. Mater. 2016,10, 337–353. [CrossRef]
29.
Schwarz, N.; Cam, H.; Neithalath, N. Influence of a fine glass powder on the durability characteristics of concrete and its
comparison to fly ash. Cem. Concr. Compos. 2008,30, 486–496. [CrossRef]
30. Shayan, A.; Xu, A. Value-added utilisation of waste glass in concrete. Cem. Concr. Res. 2004,34, 81–89. [CrossRef]
31.
Ibrahim, K.I.M. Recycled waste glass powder as a partial replacement of cement in concrete containing silica fume and fly ash.
Case Stud. Constr. Mater. 2021,15, e00630. [CrossRef]
32.
Zhang, L.; Yue, Y. Influence of waste glass powder usage on the properties of alkali-activated slag mortars based on response
surface methodology. Constr. Build. Mater. 2018,181, 527–534. [CrossRef]
33.
Gołek, Ł. Glass powder and high-calcium fly ash based binders—Long term examinations. J. Clean. Prod.
2019
,220, 493–506.
[CrossRef]
34.
Parghi, A.; Shahria Alam, M. Physical and mechanical properties of cementitious composites containing recycled glass powder
(RGP) and styrene butadiene rubber (SBR). Constr. Build. Mater. 2016,104, 34–43. [CrossRef]
35.
Badanoiu, A.I.; Al Saadi, T.H.A.; Stoleriu, S.; Voicu, G. Preparation and characterization of foamed geopolymers from waste glass
and red mud. Constr. Build. Mater. 2015,84, 284–293. [CrossRef]
36.
Hao, H.; Lin, K.-L.; Wang, D.; Chao, S.-J.; Shiu, H.-S.; Cheng, T.-W.; Hwang, C.-L. Utilization of solar panel waste glass for
metakaolinite-based geopolymer synthesis. Environ. Prog. Sustain. Energy 2013,32, 797–803. [CrossRef]
37.
Luhar, S.; Cheng, T.-W.; Nicolaides, D.; Luhar, I.; Panias, D.; Sakkas, K. Valorisation of glass waste for development of Geopolymer
composites—Mechanical properties and rheological characteristics: A review. Constr. Build. Mater.
2019
,220, 547–564. [CrossRef]
38.
Vafaei, M.; Allahverdi, A.; Dong, P.; Bassim, N. Acid attack on geopolymer cement mortar based on waste-glass powder and
calcium aluminate cement at mild concentration. Constr. Build. Mater. 2018,193, 363–372. [CrossRef]
39.
Alvarenga, C.D.B.C.S.; Sales, R.D.B.C.; Caldas, R.B.; Cetlin, P.R.; Aguilar, M.T.P. Use of glass waste in the production of metakaolin-
based geopolymer submitted to room temperature and thermal curing. Ambiente Construído 2022,22, 147–160. [CrossRef]
40.
Toniolo, N.; Rincón, A.; Roether, J.A.; Ercole, P.; Bernardo, E.; Boccaccini, A.R. Extensive reuse of soda-lime waste glass in fly
ash-based geopolymers. Constr. Build. Mater. 2018,188, 1077–1084. [CrossRef]
41.
Cyr, M.; Idir, R.; Poinot, T. Properties of inorganic polymer (geopolymer) mortars made of glass cullet. J. Mater. Sci.
2012
,
47, 2782–2797. [CrossRef]
42.
Torres-Carrasco, M.; Puertas, F. Waste glass in the geopolymer preparation. Mechanical and microstructural characterisation.
J. Clean. Prod. 2015,90, 397–408. [CrossRef]
43.
Vafaei, M.; Allahverdi, A. High strength geopolymer binder based on waste-glass powder. Adv. Powder Technol.
2017
,28, 215–222.
[CrossRef]
44.
Siddika, A.; Hajimohammadi, A.; Mamun, M.; Alyousef, R.; Ferdous, W. Waste Glass in Cement and Geopolymer Concretes: A
Review on Durability and Challenges. Polymers 2021,13, 2071. [CrossRef]
45.
Abbas, R.; Aly, M.; Ghorab, H.Y. Spoiwo geopolimerowe z pra ˙
zonej gliny o umiarkowanej zawarto´sci kaolinu. Cem. Wapno Bet.
2019,24, 33–44.
46. Davidovits, J. Geopolymer Chemistry & Applications, 5th ed.; Institut Geopolymere: Saint-Quentin, France, 2020.
47.
Nietupski, A.; Bołtryk, M.; Pawluczuk, E.; Kalinowska-Wichrowska, K.; Spodzieja, S. Propozycja wykorzystania betonów
geopolimerowych do prefabrykatów o podwy˙
zszonej izolacji cieplnej. Mater. Bud. 2022,1, 36–39. [CrossRef]
48.
Hamdi, N.; Ben Messaoud, I.; Srasra, E. Production of geopolymer binders using clay minerals and industrial wastes. Comptes
Rendus Chim. 2019,22, 220–226. [CrossRef]
49.
Foˇrt, J.; Novotný, R.; Vejmelková, E.; Trník, A.; Rovnaníková, P.; Keppert, M.; Pommer, V.; ˇ
Cerný, R. Characterization of
geopolymers prepared using powdered brick. J. Mater. Res. Technol. 2019,8, 6253–6261. [CrossRef]
50.
Zar˛ebska, K.; Zabierowski, P.; Gazda-Grzywacz, M.; Czuma, N.; Baran, P. Fly ash-based geopolymers with refractoriness
properties. Clean Technol. Environ. Policy 2022,24, 2161–2175. [CrossRef]
51.
Perera-Mercado, Y.; Hedayat, A.; Tunstall, L.; Clements, C.; Hylton, J.; Figueroa, L.; Zhang, N.; Bolaños Sosa, H.G.; Tupa, N.;
Yanqui Morales, I.; et al. Effect of the Class C Fly Ash on Low-Reactive Gold Mine Tailing Geopolymers. Polymers
2022
,14, 2809.
[CrossRef]
52.
Atabey, ˙
I.˙
I.; Karahan, O.; Bilim, C.; Ati¸s, C.D. Very high strength Na
2
SiO
3
and NaOH activated fly ash based geopolymer mortar.
Cem. Wapno Bet. 2020,25, 292–305. [CrossRef]
53.
Duxson, P.; Fernández-Jiménez, A.; Provis, J.L.; Lukey, G.C.; Palomo, A.; van Deventer, J.S.J. Geopolymer technology: The current
state of the art. J. Mater. Sci. 2007,42, 2917–2933. [CrossRef]
54.
Palomo, A.; Krivenko, P.; Garcia-Lodeiro, I.; Kavalerova, E.; Maltseva, O.; Fernández-Jiménez, A. A review on alkaline activation:
New analytical perspectives. Mater. Construcción2014,64, e022. [CrossRef]
55.
Provis, J.L.; van Deventer, J.S.J. Geopolymers: Structures, Processing, Properties and Industrial Applications; Elsevier: Amsterdam,
The Netherlands, 2009.
Materials 2023,16, 5392 12 of 12
56.
Słomka-Słupik, B. Resistance of geopolymers to chemical aggression. Literature study. Ochr. Przed Korozj ˛a
2022
,1, 10–24.
[CrossRef] [PubMed]
57.
Available online: https://astra-polska.com/produkt/dodatki-mineralne/pucolanowe/astra-mk-40/ (accessed on 1 June 2023).
58. Available online: https://pph-rewa.pl/produkt/kulki-szklane/ (accessed on 1 June 2023).
59. Available online: http://www.zchrudniki.Com.Pl (accessed on 1 June 2023).
60.
PN-EN 1936:2010; Natural stone test methods—Determination of Real Density and Apparent Density, and of Total and Open
Porosity. Polski Komitet Normalizacyjny: Warsaw, Poland, 2010.
61.
PN-EN 196–6:2019; Cement Testing Methods—Part 6: Determination of Grinding Degree. Polski Komitet Normalizacyjny:
Warsaw, Poland, 2019.
62. Available online: http://chempur.pl (accessed on 1 March 2023).
63.
Khale, D.; Chaudhary, R. Mechanism of geopolymerization and factors influencing its development: A review. J. Mater. Sci.
2007
,
42, 729–746. [CrossRef]
64.
Sikora, S.; Skowera, K.; Hynowski, M.; Rusin, Z. Formation of geopolymeric materials properties depending on the molar
modules of SiO2/Al2O3and SiO2/Na2O. Cem. Wapno Bet. 2022,27, 115–125. [CrossRef]
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