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REVIEW PAPER
A Review on the Effect of Silica to Alumina Ratio, Alkaline
Solution to Binder Ratio, Calcium Oxide + Ferric Oxide
,
Molar
Concentration of Sodium Hydroxide and Sodium Silicate to Sodium
Hydroxide Ratio on the Compressive Strength of Geopolymer
Concrete
Ahmad Jan
1
&Zhang Pu
1
&Kashif Ali Khan
1
&Izhar Ahmad
2
&Ahmed Jawad Shaukat
1
&Zhang Hao
1
&Irshad Khan
1
Received: 1 December 2020 /Accepted: 24 April 2021
#Springer Nature B.V. 2021
Abstract
Recently, geopolymer concrete (GPC) has gained substantial consideration and commercial interest in the construction industry
owing to the superior mechanical and chemical properties in comparison with the ordinary Portland cement (OPC) that it brings
through the use of waste material and reduction in the CO
2
emission. Previous research Studies revealed that different ratios of
chemical oxide combination of the raw material (fly ash, rice husk ash, meta kaolin, sugarcane bagasse ash, GGBS etc.) strongly
affect the mechanical and durability properties of GPC. Nevertheless, findings concerning different ratios of Si/Al, alkaline
solution to binder, NaOH to Na
2
SiO
3
, combined percentage of Fe
2
O
3
+ CaO and molar concentration of NaOH are controversial
regarding the compressive strength of GPC. Therefore, in the light of literature, this study presents the investigation of the
compressive strength behavior against the different ratios of oxides and alkaline solution (i.e. Si/Al, alkaline solution/binder,
NaOH/Na
2
SiO
3
,Fe
2
O
3
+ CaO and NaOH molar concentration) present in the raw material used for the production of GPC. An
extensive data from previous research publications has been collected and trend of compressive strength for 7 and 28 days was
developed against different ratios of Si/Al, alkaline solution/binder, NaOH/Na
2
SiO
3
, in order to conclude a typical range for the
above mention parameters. It was concluded that compressive strength of GPC greatly depends on the variation in ratios of Si/Al,
alkaline solution/binder, NaOH/Na
2
SiO
3
,Fe
2
O
3
+ CaO and NaOH molar concentration. It was also concluded that the compres-
sive strength of GPC has been primarily affected by the ratio of Si/Al, alkaline solution/binder, NaOH/Na
2
SiO
3
and molar
concentration of NaOH.Besides, the oxides like CaO and Fe
2
O
3
although smaller in quantityin comparison with the alumina and
silicate oxides, have indicated a distinct influence on the compressive strength development.
Keywords Compressive strength .Geopolymer concrete .Alkaline activators .Oxide composition of source material .
Environmental degradation
1 Introduction
Concrete is comprehensively used construction material
across the globe and during the production of ordinary
Portland cement (OPC), a significant amount of energy is
consumed and simultaneously the emission of huge amount
of CO
2
into the atmosphere occurs. The CaCO
3
calcination
process discharges about 0.53 tons of CO
2
to the atmosphere
for the production 1 ton of OPC and if carbon fuel is utilized as
an energy source for the production of OPC, the additional
0.45 tons of CO
2
might be produced [1]. Consequently, for the
production of 1 ton of OPC, around 1 ton of CO
2
is released
into the atmosphere. Currently, 4.0 billion tons of cement is
produced annually by different countries across the globe with
agrowthrateof4%[2]. However, the utilization of OPC in
the construction industry cannot be avoided completely due to
the beneficial properties that it brings to the structures in
*Ahmad Jan
engr.ahmedjan36@gmail.com
1
Department of Civil Engineering, Zhengzhou University, 100 Kexue
Ave, Zhongyuan District, Zhengzhou, Henan, China
2
College of Civil and Transportation Engineering, Hohai University,
No. 1, Xikang Road, Nanjing 210098, China
Silicon
https://doi.org/10.1007/s12633-021-01130-3
comparison with other relative construction materials. The
alternative materials may also be useful to replace some part
of the OPC. A possible replacement could be the use of alkali-
activated binders which may be acquired from industrial waste
material rich in alumina-silicate oxides [3–5]. In this regard,
geo-polymer concrete (GPC) holds better chemical and me-
chanical properties [6,7] and may not only reduce the CO
2
production but also helps in consuming industrial and agricul-
tural wastes like fly ash, rice husk ash, bagasse ash, slag, red
mud, etc. In this manner, the degradation concerns of the
environment might be minimizes that occurs due to the dump-
ing processes of industrial wastes [8–10]. In 1979, Joseph
Davidovits started studying the GPC; however, his study
didn’t get proper attention in the early two decades but later
on substantial research investigations have been carried out in
this area and GPC has shown remarkable advantages due to its
better performance than the conventional concrete. Besides,
GPC is proved to be significant in reducing the CO
2
emission,
thus provided a solution to the researchers for increasing em-
phasis on energy conservation and global warming [11,12].
GPC is also termed as a green concrete that is produced by
alkaline activation of source material rich in alumina and sil-
icates. Alkaline activation is a chemical process, in which
material rich in alumina and silicate of natural or industrial
source might be converted into compacted cementitious struc-
ture after mixing with a highly alkaline solution like KOH or
NaOH and solvable silicates i.e. sodium silicate or potassium
silicate in gel, under suitable curing environments [12–18]. A
large quantity of agricultural waste, industrial by-product and
natural raw materials such as rice husk ash [19,20], fly ash
[19–21], palm oil fuel ash [22,23], slag [24,25], red mud [26,
27], sugarcane bagasse ash [28], hematite, barite and copper
[29,30], metakaolin [31,32], silica fume [33] and other such
material that are rich in alumina and silicates may be
employed as source materials for GPC production. The source
material employed for GPC passes through geo-
polymerization process in the presence of alkaline activators
and forms an amorphous to semi-crystalline structure with
chemical and mechanical properties similar to conventional
concrete or superior than conventional concrete.
In geopolymerization procedure, the Si and Al oxides pres-
ent in source material goes through a quick chemical reaction
in the presence of favorable alkaline conditions that yields an
amorphous to semi-crystalline polymers chain reaction and a
ring structure comprise of Si-O-Si and Si-O-Al bondings [34].
Primarily, the geopolymerization reaction is dependent upon
the capability of the aluminum ions that occurs either in four-
fold or six-fold coordination in inducing crystal structure and
chemical changes in silica backbone [35].
By using GPC, CO
2
emissions might be decreased and the
usage of OPC in the construction industry might be complete-
ly avoided. Besides, the utilization of waste materials from
industrial sector and agricultural sector along with the
minimization of CO
2
is very essential to solve the problems
regarding waste disposal and environmental degradation. On
the other hand, investigation of the mechanical properties of
the final product is necessary as these properties are the main
parameters in any type of concrete for deciding its superiority
and suitability over others.
Up till now, several investigations have been carried out on
the factors affecting the compressive strength of the GPC.
Previous research studies revealed that the compressive
strength properties of GPC is influenced by ratio and nature
of alkaline activator [24,36], molar concentration of alkaline
activator [37,38], curing time and temperature (ambient, ele-
vated) [20,33,39,40], type of source material and their cor-
responding chemical compositions [41], Si to Al ratio in the
mix proportion of geo-polymer matrix [31], mass ratio of al-
kaline solution to binder material [42], mass ratio of sodium
silicate to sodium hydroxide [43], ratio of water to geo-
polymer solids [44,45], state of sodium silicate (i.e. liquid
or solid) [46], SiO
2
to Na
2
O ratio in the geo-polymer matrix
[47,48], time of mixing and rest period before curing [44],
molar ratio of water to Na
2
O in the geo-polymer matrix [49],
cumulative percentage of CaO and Fe
2
O
3
[50]etc.
A large number of studies have been performed on the en-
hancement of compressive strength of GPC. Studies regarding
the influence of Si to Al ratio, alkaline solution to binder ratio,
CaO + Fe
2
O
3
, molar concentration of NaOH and Na
2
SiO
3
to
NaOH ratio on the compressive strength of GPC remains the
core interest. Still many of the research studies are controversial
regarding the effect of different oxide ratios, molar concentration
and Na
2
SiO
3
toNaOHratioonthecompressivestrengthofGPC.
The other parameters like curing temperature, methods and
mixing time etc. are manageable in the laboratory but the per-
centages of oxides present in the source material along with their
ratios are uncontrollable in GPC matrix, therefore, it is important
to conclude different oxide ratios, molar concentration and
Na
2
SiO
3
to NaOH ratio for the production of GPC in a scientific
manner. This review study is carried out to discuss the literature
results based on the findings related to Si to Al ratio, alkaline
solution to binder ratio, CaO + Fe
2
O
3
, molar concentration of
NaOH and Na
2
SiO
3
to NaOH ratio on the compressive strength
of GPC. Besides, from the literature, various oxides and alkaline
solution ratios for the selection of an individual or combination of
different material are also concluded.
2Methodology
Before describing and evaluating the effect of silica to alumina
ratio, alkaline solution to binder ratio, calcium oxide + ferric
oxide, molar concentration of sodium hydroxide and sodium
silicate to sodium hydroxide ratio on the compressive strength
of geopolymer concrete, a detailed bibliographic search of
related topics has been carried out and the data have been
Silicon
collected from various databases including Elsevier, Springer,
Scopus and ScienceDirect etc. After collection of data from
the past research studies, the data have been evaluated through
discussions, tables and graphs. Finally, concluding remarks
have been provided; the detailed methodology of the review
paper is shown in the Fig. 1.
Fig. 1 Flowchart of the
methodology used for the review
Silicon
3 Basis for Data Points
Extensive data from the past studies regarding the compres-
sive strength of GPC was collected in the current study.
Primary importance was given to the influence of Si/Al ratio,
alkaline solution to binder ratio, molar concentration of
NaOH, NaOH/Na
2
SiO
3
and cumulative percentage of
CaO + Fe
2
O
3
on the compressive strength of class-F fly ash-
based GPC. Later on, the literature study is comprehended to
compare the results of GPC through the use of various source
materials i.e. fly ash, ground granulated blast furnace slag
(GGBS), metakaolin, red mud in addition to the combination
of these source material.
3.1 Silica to Alumina Ratio
Davidovits [51] defined three different polysialates monomers
i.e. PS (polysialate), PSS (Poly-sialatesiloxo) and PSDS
(poly-sialate-disiloxo) which can be formed during the reac-
tion process of geopolymer concrete. The chemical formulae
of the monomers are as follows:
PS: -Si-O-Al-O-
PSS: -Si-O-Al-O-Si-O-
PSDS: -Si-O-Al-O-Si-O-Si-O-
The formation of monomers in GPC matrix is entirely re-
liant upon the ratio of Si to Al present in the source material.
The total Si to Al ratio should be in the range of 1.6–2.3, for
the formation of stable geopolymer gel [52,53]. The amor-
phous geopolymer structure was primarily proposed as PS (Si
to Al = 1), PSS (Si to Al = 2) and PSDS (Si to Al = 3), respec-
tively [54,55]. Low ratio (Si to Al ≤3) might yield brittle and
stiff GPC similar to cement and ceramics that may have 3-
dimensional cross-linked rigid network. On the other hand,
higher ratio (Si to Al >3) may yields adhesive GPC that may
have 2-dimensional network having a polymeric structure of
linear linkages [56]. This provides an indication about the
importance of SiO
2
and Al
2
O
3
composition, their ratios in
the source material and its impact on the mechanical strength
achieved in the final product of GPC. The Si to Al ratio can be
changed up to some level by changing the ratio of NaOH and
Na
2
SiO
3
however, the chemical composition of Si and Al
ratio primarily depend on the source material utilized for
GPC, which indicates that the final strength of GPC is
governed by SiO
2
and Al
2
O
3
compositions and their corre-
sponding ratios present in the source material. The type of
formation of chemical structure depends entirely on the per-
centage of Al
2
O
3
present in the source material [57]. Recently,
GPC has been proposed as a feasible technology by utilizing
by-product of waste material for tailings of mine, oil, and sand
[35]. These are mostly unpredictable sources of alumina and
silicate minerals, covering a significant range of Si and Al
ratios. Therefore, to obtain optimum compressive strength of
GPC, an attempt has been made in the current study for deter-
mining the optimum percentage level of SiO
2
and Al
2
O
3
in the
source materials and their corresponding ratios.
3.2 Alkaline Solution to Binder Ratio
Alkaline solution to binder ratio is a significant parameter
of GPC which considerably affects the compressive
strength of the GPC matrix. To develop GPC, a combina-
tion of NaOH, Na
2
SiO
3
or KOH and K
2
SiO
3
are exten-
sively utilized as an alkaline activator with the incorpora-
tion of source material [19,50].Thealkalineactivationof
source material (AASM) is a chemical process by which
the source material (fly ash, rice husk ash, metakaolin,
GGBS, etc.) rich in alumina and silicates is mixed with
a certain amount of highly alkaline solutions and then the
mixture is cured under a suitable temperature to make
solid materials (geopolymer concrete). The glassy compo-
nents of the source materials are transformed into well-
compacted cement [13,15,58–62]. From the last two
decades, significant development has been observed in
GPC due to its eco-friendly nature, excellent mechanical
properties, resistance against aggressive environment and
durability [63–65]. When sodium is used as an activator, a
three-dimensional reaction product gel (Na
2
O–Al
2
O
3
–
SiO
2
–H
2
O) is produced, adopting the OPC nomenclature.
The product of this gel is essentially dependable for the
mechanical strength and durability while secondary prod-
ucts are developed in the form of crystalline zeolites
[66–69]. Alkaline solution to binder ratio is a significant
parameter of GPC which affects the compressive strength
in same manner as w/c ratio effects the strength of OPC
[70,71]. Moreover, increasing the addition of alkaline
solution in the geopolymer matrix not only increases the
alkaline solution to binder ratio, it also increases the water
content, OH
−
ions and the quantity of alkaline cations
present in the geopolymer system. Ultimately, the increas-
ing quantity of alkaline cations and OH
−
amount would
significantly influenced the type and nature of
geopolymerization gel (N-A-S-H) and the zeolites devel-
oped through alkaline activation process [72]. Various
researchers reported that low alkaline solution to binder
ratios may develop densified microstructure of GPC
which would ultimately results in the improved mechani-
cal properties [73]. However, some researchers have indi-
cated that high alkaline solution to binder ratio has en-
couraging influence upon the mechanical strength [74].
Thus, an attempt has been made in this study to determine
the specific range of the alkaline solution to binder ratio
for the production of GPC having superior mechanical
and chemical properties.
Silicon
3.3 Cumulative Percentage of Calcium Oxide and
Ferric Oxide
Several research studies stated that the material having least
CaO percentage is ideal for GPC as compared to the source
material having high CaO percentage. The presence of high
percentage of CaO could affect the geopolymerization reac-
tion and can change the microstructure of the geopolymer
matrix [75–77]. On the other hand, some research studies
reported that material having a high percentage of CaO has
favorable impact on the compressive strength of the final
product (geopolymer matrix) [78,79]. Furthermore, it is dem-
onstrated that the source material having CaO more than 20%
could exhibit a very quick setting of geopolymer matrix which
is not recommendable for GPC [80]. The presence of CaO in
material used for GPC either in low or high percentage can
affect the geopolymerization reaction in addition to the com-
pressive strength and microstructure of the geopolymer matrix
[76]. Another main constituent of the oxide composition pres-
ent in the source material is Fe
2
O
3
that is used for the produc-
tion of GPC. Studies regarding GPC are generally based on
traditional source materials like metakaolin, fly ash, rice husk
ash and GGBS having less than 10% of Fe
2
O
3
. However,
recent research work revealed that source material with
Fe
2
O
3
percentage more than usually found in traditional
source materials might be activated in a suitable alkaline en-
vironment [81–83]. However, due to the restrictions of NMR
spectroscopy (method for microstructural analysis of
geopolymer matrix), there is still insufficient knowledge re-
garding the role of Fe
2
O
3
in GPC [84]. The current study
intends to examine the range of the cumulative percentages
of CaO and Fe
2
O
3
present in the source material for achieving
better performance of GPC.
3.4 Molar Concentration of Sodium Hydroxide
Molar concentration of sodium hydroxide (NaOH) plays a
significant role in the synthesis of geopolymerization gel in
GPC [85]. Geopolymerization gel is formed by the combined
reaction of Na
2
O, Al
2
O
3
,SiO
2
and H
2
O (N-A-S-H). In the
geopolymerization reaction, the Na
+
ions are used for
balancing the charges to form alumina and silicate networks
in the mixture [43,86]. By increasing the molar concentration
of NaOH, the solubility of alumina and silicate present in the
geopolymer mix also increases [87]. This ultimately results in
the higher compressive strength of the final product of GPC
[88]. A study [89] was performed on fly ash-based
geopolymer mortar in which the authors concluded that the
compressive strength of geopolymer mortar is dependent up-
on the molar concentration NaOH i.e. the higher molar con-
centration may lead to higher compressive strength. Another
study [14] was conducted on metakaolinite based GPC and
the authors stated that higher molar concentration of NaOH
solution delivers an improved dissolving capability to
metakaolinite and develop even reactive bond for the mono-
mer that subsequently increases the intermolecular bond
strength of the GPC. It was also demonstrated that the me-
chanical behavior of metakaolinite-based GPC activated with
a combined NaOH and sodium silicate (Na
2
SiO
3
) solution
may be significantly influenced by the NaOH molar concen-
tration. Increasing the molar concentration of NaOH, the ap-
parent density and mechanical properties of GPC were
increased.
3.5 Sodium Silicate to Sodium Hydroxide Ratio
The environmental concerns in regards with the manufactur-
ing process of OPC are fully recognized [90,91], the major
concern being the CO
2
emission to the environment. The GPC
was introduced by Davidovits that offers an alternate solution
in avoiding the environmental concerns [92,93]. The
manufacturing of GPC is same as that of conventional con-
crete. The production of GPC needs 75% to 80% by mass of
aggregate which are bounded together by geopolymer paste.
The paste is formed by the reaction of thealumina and silicates
present in the source material and the alkaline solution formed
by the combination of KOH and K
2
SiO
3
or NaOH and
Na
2
SiO
3
. A mixture of Na
2
SiO
3
or K
2
SiO
3
and NaOH or
KOH has been widely utilized as a source of activation mate-
rial for the fabrication of GPC [90,94,95]. The ratio of
Na
2
SiO
3
/NaOH is another significant factor in GPC which
has a vital role in the development of compressive strength
of geopolymer matrix. According to the data collected from
past studies (Table 1), the GPC produced purely from fly ash
as a source material has achieved the peak compressive
strength of 66.1 MPa while using Na
2
SiO
3
to NaOH ratio of
5.05 [96]. On the other hand, it was reported [97,98]that
while using Na
2
SiO
3
to NaOH ratio of 1.0, yielded highest
compressive strength of 70.2 MPa and 54.40 MPa respective-
ly, whereas Na
2
SiO
3
to NaOH ratio of 2.5 yielded in lower
compressive strength of 26.10 MPa [99]. In addition, the
Na
2
SiO
3
to NaOH ratio of 5.0 has given a compressive
strength of 26.70 MPa [96]. Based upon the above discussion,
different research studies suggests different ratios of Na
2
SiO
3
/
NaOH based on their findings and this disagreement is accept-
able because of the different source material and different
environmental conditions. The current study intends to exam-
ine the range of the Na
2
SiO
3
/NaOH ratios in the manufactur-
ing of GPC having enhanced mechanical properties.
4 Combination of Different Materials
The most utilized waste material in the manufacturing of GPC
is coal fly ash that is attributed due to the presence of high
amorphous alumina and silica content. The availability of fly
Silicon
ash worldwide and the key role in the geopolymerization re-
action gives a significant importance. The over-all fly ash
production throughout the globe is around 480 million tons
per annum while the entire quantity of OPC production is
around 4 billion tons [2,100].Basedonthesestatistics,
there is a huge gap within the production of coal fly ash
and OPC which would lead to the efficiency of GPC in
replacement of OPC. Hence, some new source materials
are required other than fly ash to reduce the gap and to
replace OPC in the future. In this regard, researchers de-
veloped GPC by the combination of different source ma-
terial i.e. fly ash + granulated lead smelter slag [101], fly
ash + RHA [102], fly ash + silica fume [103], fly ash +
metakaoline [104] and so on, for the purpose of overcom-
ing the present gap between the production of OPC and
fly ash and to solve the environmental problems related to
CO
2
emission and waste material disposal.
Recently, the researchers have examined the utilization of
different waste material in the production of GPC combining
with the fly ash, aiming to enhance the durability and mechan-
ical properties of GPC and at the same time, minimizing the
CO
2
emission for sustainable infrastructural development
[105].Pateletal.,[106] developed GPC while replacing fly
ash by rice husk ash and concluded that up to 15% replace-
ment of fly ash by RHA may increase the compressive
strength behavior. Another research was carried out by
Kusbiantoro et al., [107] and demonstrated that the replace-
ment of fly ash up to 7% by RHA provides an appropriate
condition of fast dissolution for the formation of silicate
monomer, which supports the development of aluminosilicate
solution in GPC matrix and make a denser geopolymer paste
that ultimately results in higher compressive strength.
Moreover, from the literature it is revealed that by using dif-
ferent source material in combination with fly ash, their basic
parameter (Si/Al, alkaline solution/binder, CaO + Fe
2
O
3
,mo-
lar concentration of NaOH and Na
2
SiO
3
/NaOH ratio) value
may remain in the typical range similar to fly ash-based GPC
[26,99].
5 Discussion
With the aim of determining the influence of Si/Al ratio,
alkaline solution/binder ratio, Na
2
SiO
3
/NaOH ratio, molar
concentration of NaOH, and the influence of combined
percentage of CaO and Fe
2
O
3
on the compressive strength
of GPC, the data has been collected from the literature
whichisgraphicallyshowninFigs.2,3,4,5and 6and
tabulated in Table 1.
Several researchers developed GPC by considering the dif-
ferent ratios of Si/Al ratio, alkaline solution/binder ratio,
Na
2
SiO
3
/NaOH ratio, molar concentration of NaOH, the ef-
fect of combined percentage of CaO and Fe
2
O
3
for the pur-
pose of studying the mechanical and chemical properties of
GPC [72–75,96–99,106–123]. The ratio of Si to Al is an
important factor of GPC which affect its compressive strength
[124,125]. Figure 2a and b represent the influence of Si to Al
ratio on the 7 and 28-days compressive strength of GPC.
Various Si to Al ratios have been defined and used for the
manufacturing of GPC having higher durability and enhanced
compressive strength. Pham (2020). [116] reported a high
compressive strength at Si to Al ratio of 2.5 from basalt-
based GPC. Nevertheless, Bignozzi et al. [96]reportedhigh
compressive strength at Si to Al ratio of 4 from fly ash-based
GPC. This controversy is appropriate because different re-
searchers have used different synthesizing conditions such as
type of alkaline solution, binding material, temperature and
curing time, etc. Moreover, in literature, the reactionary attri-
bute of silicate precursor on the development of N–A–S–Hgel
and mechanical behavior of geopolymers is not uniform.
Several researchers have demonstrated that with the addition
of silicates, the structural stability of geopolymers was
0
25
50
75
100
0246
htgnertSevisserpmoCsyaD7
Si to Al ratio
a
0
25
50
75
100
0246
28 Days Compressive Strength
Si to Al ratio
b
Fig. 2 aInfluence of Si/Al ratio on 7 days compressive strength, bInfluence of Si/Al ratio on 28 days compressive strength
Silicon
improved because of the development of Al–O–Si complexes
and long chained silicate oligomers within the geopolymers
[126,127].
The results of different alkaline solution to binder ratio and
Na
2
SiO
3
to NaOH ratios regarding the 7 and 28-days com-
pressive strength are shown in Figs. 3a, b and 6a, b respec-
tively. The figures have no evident and defined trend; howev-
er, the peak compressive strength of 66.1 MPa was reported at
Na
2
SiO
3
to NaOH ratio of 5.05 and an alkaline solution to
binder ratio of 0.52, at the age of 28 days [96]. One of the
studies [128] reported that by increasing the dosages of fly ash
and activator solution concentration, the compressive strength
enhances. This is owing to the increase in the amount of
NaOH that is commonly obligatory in the reaction of
geopolymerization. Moreover, compressive strength of
94.1 MPa was reported by keeping the ratio of Na
2
SiO
3
to
NaOH as 1 using basalt fiber-based GPC [116]. A similar
trend in the result was reported by Chindaprasirt et al.,
[129]. In his study, the author concluded that for optimum
compressive strength, the Na
2
SiO
3
to NaOH ratio should be
in the range of 0.67 to 1.00, which is quite different from the
literature related to GPC. This could be owed to the variability
of the Na
2
SiO
3
to NaOH ratio that interrupts the pH condition
of material and thus would have an influence upon the devel-
opment of compressive strength of GPC.
Figure 4a and b represent the effect of Fe
2
O
3
+ CaO on the
7 and 28-days compressive strength of GPC. From figures, it
can be determined that the GPC compressive strength in-
creases as the cumulative percentage of Fe
2
O
3
+CaO in-
creases as reported by Chindaprasirt et al., [129]. It can be
observed that a small increase in the cumulative percentage
of Fe
2
O
3
+ CaO can significantly affect the compressive
strength. Moreover, it can be concluded from Figures that
GPC made by source material having Fe
2
O
3
+CaO
0
25
50
75
0 0.5 1 1.5 2 2.5
htgnertSevisserpmoCsya
D
7
Alkaline solution to Binder Ratio
a
0
25
50
75
0 0.5 1 1.5 2 2.5
28 Days compressive Strength
Alkaline solution to Binder Ratio
b
Fig. 3 aInfluence of alkaline solution to binder ratio on 7 days compressive strength, bInfluence of alkaline solution to binder ratio on 28 days
compressive strength
0
25
50
75
100
0204060
htgnertSevisserpmoCsyaD7
Combined persentage of CaO & Fe2O3
a
0
25
50
75
100
0204060
28 Days Compressive Strength
Combined percentage of CaO & Fe2O3
b
Fig. 4 aInfluence of combined percentage of CaO and Fe
2
O
3
on 7 days compressive strength, bInfluence of combined percentage of CaO and Fe
2
O
3
on
28 days compressive strength
Silicon
percentages in the range of 8% to 20% yields better compres-
sive strength as compared to the source material having more
than 20% of Fe
2
O
3
+CaO.
Figure 5a and b represent the impact of NaOH concentra-
tion on the 7 and 28-days compressive strength of GPC. By
using 12-M NaOH solution, the compressive strength of 94.12
MPa was attained [116]. This is because of increasing the Na
+
ions in the geopolymer matrix which has a vital role in the
geopolymerization reaction. The Na
+
ions are utilized for sta-
bility of charges in the geopolymer mixture to form alumina
and silicate networks [43]. By increasing the NaOH solution
beyond the 12-M, the compressive strength was reduced and
the compressive strength of 34 MPa was attained for 18-M
concentration [108]. Similar result was reported by Palomo
et al., [61], that 12-M NaOH solution gives better strength as
compared to 18-M NaOH solution.
Moreover, from the Figs. 2a and 3a, it has been realized that
different compressive strengths were achieved for the same
molar ratios. For instance, at Si/Al ratio of 4 and alkaline solution
to binder ratio of 0.5, the resulting compressive strengths for
7 days decreases dramatically from as high as 43.26 MPa to as
low as 11.2 MPa [96,120]. In addition, it has been noticed from
the literature study that the main oxide composition present in
source material used for GPC are SiO
2
,Al
2
O
3
,CaOandFe
2
O
3
and their percentages may vary in different source material.
However, when GPC is produced by the combination of fly
ash + GGBS and fly ash + RHA etc., the parametric ratios (Si/
Al, alkaline solution/binder, CaO + Fe
2
O
3
, molar concentration
of NaOH and Na
2
SiO
3
/NaOH) will remain in the typical range of
ratio similar to fly ash-based GPC [112].
6 Conclusions
This study considers different oxide and alkaline solution ra-
tios of source materials utilized for GPC production and their
0
25
50
75
100
0 2 4 6 8 101214161820
htgnertSevisserpmoCsyaD7
NaOH Molar Concetration
a
0
25
50
75
100
2 4 6 8 10 12 14 16 18 20
28 Days Compressive Strength
NaOH Molar Concetration
b
Fig. 5 aInfluence of NaOH molar concentration on 7 days compressive strength, bInfluence of NaOH molar concentration on 28 days compressive
strength
0
25
50
75
100
0246
htgnertSevisserpmoCsyaD7
Na2SiO3 to NaOH ratio
a
0
25
50
75
100
0246
28 Days Compressive Strength
Na2SiO3 to NaOH ratio
b
Fig. 6 aInfluence of Na
2
SiO
3
to NaOH ratio on 7 days compressive strength, bInfluence of Na
2
SiO
3
to NaOH ratio on 28 days compressive strength
Silicon
Table 1 Effect of Si/Al ratio, alkaline solution/binder ratio, CaO + Fe
2
O
3
, molar concentration of NaOH and Na
2
SiO
3
/NaOH ratio on the compressive
strength of GPC
Material Oxide
composition
(%)
Compressive
strength
SiO
2
/
Al
2
O
3
Alkaline solution/
binder ratio
Fe
2
O
3
+
CaO
NaOH Na
2
SiO
3
/
NaOH
Ref.
7 d 28 d
Class F-FA SiO
2
: 51.8
Al
2
O
3
: 27.8
Fe
2
O
3
:6.2
CaO: 4.6
27 NDA 1 0.50 10.77 8 NDA When the system contains
excess amount of alkaline
activator, the polysialte
reaction products tend to be
produced which is
irrespective of the starting
composition [72]
Dehydroxylated
white clay
SiO
2
: 58.8
Al
2
O
3
: 32.8
Fe
2
O
3
:1.7
CaO: 1.04
15 NDA 1 0.75 2.74 8 NDA
Class F-FA SiO
2
: 49.7
Al
2
O
3
: 24.6
Fe
2
O
3
: 12.7
CaO: 4.9
NDA 58.6 2.13 0.43 17.6 NDA NDA The fresh and hardened
properties are greatly affected
by morphology and origin of
the fly and as well as particle
size, alkaline metal content,
calcium content and
amorphous content [73]
SiO
2
: 59.9
Al
2
O
3
: 21.6
Fe
2
O
3
:4.7
CaO: 2.9
NDA 32.4 2.13 0.43 7.6 NDA NDA
SiO
2
: 50.1
Al
2
O
3
: 28.3
Fe
2
O
3
:4.0
CaO: 8.2
NDA 51.4 1.75 0.20 12.2 NDA NDA
SiO
2
: 61.4
Al
2
O
3
: 33.0
Fe
2
O
3
:1.1
CaO: 0.6
NDA 7.3 1.75 0.20 1.7 NDA NDA
Class F-FA SiO
2
:60.02
Al
2
O
3
:34.25
Fe
2
O
3
:1.2
CaO: 1.05
24 NDA 3.29 2.50 2.24 16 2.5 The compressive strength is a
function of alkaline solution
to binder ratio, Na
2
SiO
3
to
NaOH ratio and molar
concentration of NaOH [74]
Class F-FA SiO
2
: 49.4
Al
2
O
3
:29.23
Fe
2
O
3
:2.7
CaO: 6.6
9.7 26.7 3.48 0.45 9.34 8 5 The fresh and hardened
properties are effected by
fineness and mineralogical
properties rather than by
increasing the sodium silicate
solution [96]
SiO
2
: 48.2
Al
2
O
3
:25.01
Fe
2
O
3
:1.3
CaO: 15.2
11.2 66.1 4 0.52 16.5 8 5.05
Class C-FA SiO2: 25.9
Al2O3:12.3
Fe2O3:32.3
CaO:20.9
68.1 70.2 2.76 0.55 53.2 12 1 Na
2
SiO
3
/NaOH ratio highly
effect the mechanical strength
of GPC [97]
Class F-FA SiO
2
:45.23
Al
2
O
3
:19.95
Fe
2
O
3
:13.15
CaO: 15.51
42.92 54.40 4.55 0.5 16.31 15 1 With the usage of higher NaOH
concentration, the
compressive strength and
modulus of elasticity are
improved [98]
Class F-FA SiO
2
:50
Al
2
O
3
:28.25
Fe
2
O
3
: 13.5
CaO: 1.79
15.18 26.10 1.77 2.5 15.29 14 2.5 The addition FA in GGBFS may
improve the setting time and
compressive strength of the
GPC [99]
FA+ 10%,20%
,30% of GGBFS
SiO
2
:50
Al
2
O
3
:28.25
Fe
2
O
3
: 13.5
CaO: 1.79
+
SiO
2
:32.46
Al
2
O
3
: 14.3
Fe
2
O
3
: 0.61
CaO: 43.1
21.98 34.98 1.80 2.5 NA 14 2.5
28.20 45.28 1.84 2.5 NA 14 2.5
41.25 55.30 1.89 2.5 NA 14 2.5
Class F-FA SiO
2
:51.75
Al
2
O
3
:34.75
NDA 42.7 3 0.45 7.4 12 2.5 The optimal replacement level
of RHA with GGBFS is 5%
Silicon
Table 1 (continued)
Material Oxide
composition
(%)
Compressive
strength
SiO
2
/
Al
2
O
3
Alkaline solution/
binder ratio Fe
2
O
3
+
CaO
NaOH Na
2
SiO
3
/
NaOH
Ref.
7 d 28 d
Fe
2
O
3
:6
CaO: 1.4
at ambient curing and 15% at
a curing temperature of 70 °C
[106]GGBS SiO
2
:34
Al
2
O
3
: 14.3
Fe
2
O
3
:0.5
CaO: 39.7
NDA 48.8 5.19 0.45 40.2 12 2.5
Class F-FA SiO
2
: 51.7
Al
2
O
3
: 29.1
Fe
2
O
3
: 4.76
CaO: 8.84
44 50 3.53 0.41 13.6 8 2.5 The high temperature provides
an appropriate condition for
fast dissolution of the
monomers of silicate and
oligomer from RHA surfaces
that encourages the
development of
aluminosilicate solution in
geopolymer matrix [107]
Class F-FA SiO
2
:36.02
Al
2
O
3
:20.58
Fe
2
O
3
:15.91
CaO: 18.75
17 34 3.88 0.53 34.66 18 2.5 At SiO
2
/Al
2
O
3
ratio of 15.9,
highest compressive strength
was achieved. Fly ash was
more reactive than RHBA
[108]
Class F-FA SiO
2
:49.45
Al
2
O
3
:29.61
Fe
2
O
3
:10.72
CaO: 3.47
52.5 56.9 3.38 0.32 14.19 10 2.63 The compressive strength is
significantly increased by
increasing the MS from 0.75
to 1.0 and 1.25 owing to the
increment in the dissolution
of FA and rate of reaction
[109]
Class F-FA SiO
2
: 55.3
Al
2
O
3
: 25.8
Fe
2
O
3
:5.5
CaO: 2.9
42.9 44.8 4.13 0.5 8.4 12 1 The higher molarity of alkaline
activators has considerable
effect on th e early strength
[110]
Class F-FA SiO
2
: 51.3
Al
2
O
3
: 30.1
Fe
2
O
3
: 4.57
CaO: 8.73
52.26 53.08 3.49 0.5 13.3 12 2.5 Compressive strength and
workability increases with the
increase in the dosage of
superplasticizer [111].
Class F-FA SiO
2
:53
Al
2
O
3
:33
Fe
2
O
3
:4.2
CaO: 1.5
33.77 41.62 2.98 0.4 5.7 8 2 Replacement of FA with RHA
in different percentages has
not shown any positive sign
regarding the mechanical
properties [112]Class F-FA
+10% RHA
SiO
2
:53
Al
2
O
3
:33
Fe
2
O
3
:4.2
CaO: 1.5
+
SiO
2
: 82.7
Al
2
O
3
: 0.15
Fe
2
O
3
: 0.16
CaO: 0.55
32.4 39.16 NA 0.4 NA 8 2
Class F-FA SiO
2
:57.30
Al
2
O
3
:27.13
Fe
2
O
3
: 8.06
CaO: 0.03
46 NDA 4.17 0.4 8.09 14 2 The Compressive strength of
GPC increases while
increasing the curing
temperature, curing time, rest
time, concentration of NaOH
solution. Whereas, it reduces
while increasing the water to
geopolymer ratio and
admixture dosage [113]
Class C-FA SiO
2
:32.10
Al
2
O
3
:19.90
Fe
2
O
3
:16.91
CaO: 18.75
32.2 NDA 3.83 0.6 35.66 16 2.5 Corrosion and chloride
penetration of embedded steel
decreases with the increase in
NaOH concentration [114]
Class F-FA SiO
2
: 56.48 31 35.2 5.05 0.35 9.43 NDA 5.39
Silicon
corresponding influence on the compressive strength. From
the past studies, it was found that different ratios of Si to Al,
alkaline solution to binder, Na
2
SiO
3
to NaOH, molar concen-
tration of NaOH and combined percentages of CaO and Fe
2
O
3
Table 1 (continued)
Material Oxide
composition
(%)
Compressive
strength
SiO
2
/
Al
2
O
3
Alkaline solution/
binder ratio Fe
2
O
3
+
CaO
NaOH Na
2
SiO
3
/
NaOH
Ref.
7 d 28 d
Al
2
O
3
:20.34
Fe
2
O
3
: 6.61
CaO: 2.82
Alkaline solution to binder ratio
of 0.35, GPC possesses better
durability and mechanical
properties as compared to
other various ratios [115]
Rice husk ash SiO
2
:90
Al
2
O
3
: 0.46
Fe
2
O
3
: 0.43
CaO: 1.10
21.50 38.33 1.1 NDA 1.53 12 1 Basalt fibers had a positive
influence on fiber-matrix
transition zone as a result
compressive strength,
flexural strength, initial
setting time, final setting time
and bulk density increases
[116]
Basalt
Fiber
SiO
2
:46.5
Al
2
O
3
:13.4
Fe
2
O
3
:0.79
CaO:31.4
73.12 94.12 2.5 NDA 32.19 12 1
Sugar cane
bagasse ash
SiO
2
: 66.7
Al
2
O
3
: 9.24
Fe
2
O
3
: 1.53
CaO: 10.07
18 21.5 NDA 0.35 11.58 12 2.5 The combination of SBA and PP
composite can provide
alternative ways to achieve
sustainable GPC [117]
Metakaolin SiO
2
: 52.8
Al
2
O
3
: 43.7
Fe
2
O
3
:0.6
CaO: –
36.8 NDA 2 0.89 0.6 NDA NDA The compressive strength of
GPC at different Si to Al
ratios depends upon the
development of N-A-S-H gel,
instead of the silicate
derivatives or zeolitic nuclei
[118]
Class F-FA SiO
2
: 43.7
Al
2
O
3
: 21.0
Fe
2
O
3
: 22.5
CaO: 4.85
52 65 5.1 0.12 27.35 NDA NDA Significant change has been
observed in compressive
strength by changing
SiO
2
/Al
2
O
3
from 4.0 to 6.0
[119]
Class F-FA SiO
2
:56.01
Al
2
O
3
: 29.8
Fe
2
O
3
: 3.58
CaO: 2.36
43.26 48.2 4 0.50 5.94 NDA NDA SEM and XRD results shows
formation of a new
amorphous alumina-silicate
phase i.e. hydroxysodalite
and herschelite which may
affect the development of
compressive strength [120]
Class F-FA SiO
2
:55.15
Al
2
O
3
:30.85
Fe
2
O
3
: 3.15
CaO: 2.45
44.36 NDA 4 0.3 5.6 12 NDA The compressive strength and
microstructure of GPC is
dependent on alkaline
content, silica content and
water to binder ratio [121]
kaolin clay SiO
2
: 52.3
Al
2
O
3
: 39.8
Fe
2
O
3
: 1.29
CaO: 1.75
29 40 2.8 0.51 3.04 NDA 2 The kaolin based geopolymer
concrete will be competitive
to the cement concrete [122]
Class F-FA+Copper Slag
+ Crusher dust
SiO
2
:50.47
Al
2
O
3
:28.76
Fe
2
O
3
:4.3
CaO: 0.81
+
SiO
2
:10.98
Al
2
O
3
: 2.35
Fe
2
O
3
:37.41
CaO: 0.67
NDA 67.8 5.004 0.38 NA 14 2.4 Investigation on inclusion of
copper slag to fly ash based
geopolymer and their design
parameters [123]
Where, NDA, no data available; FA ,flyash;GPC, geopolymer concrete; RHA, rice husk ash; SBA,sugarcanbaggasash;PP, polypropylene; GGBFS,
ground granulate blast furnace slag; NA, not applicable
Silicon
used in GPC has a significant impact on the compressive
strength. Thus, special attention is required while selecting
the above-mentioned ratios to be used for the production of
GPC. Besides,while achieving higher compressive strength, it
is very essential to find out the optimum level of each ratio.
The ratio of Si to Al, alkaline solution to binder, Na
2
SiO
3
to
NaOH, the molar concentration of NaOH, used in geopolymer
concrete should be in the range of 1–5.2, 0.2–2.5, 1–5.4, 8–18
and combined percentage of CaO and Fe
2
O
3
should not be
more than 10 to 25%. As SiO
2
and Al
2
O
3
are the two main
oxides of source material and their ratios predominantly gov-
ern the formation of geopolymerization gel which ultimately
affects the compressive strength. Thus, knowledge of typical
ranges of oxide compositions in the source material employed
for GPC is of prime importance. It can be concluded from the
literature studies that SiO
2
and Al
2
O
3
intherangesof40to
65% and 20 to 35% respectively, would result in higher com-
pressive strength in case of fly ash-based GPC but for other
material it may varies. The typical range of various parameter
and oxides ratio is extremely important in choosing the correct
source materials to be used for GPC when different source
materials are available. The authors encourage further studies
regarding, the mix design of GPC, based on the oxide ratios
and alkaline solution ratios in order to know a fixed range of
these parameters for a fixed value of compressive strength just
like in ordinary concrete mix design.
Acknowledgments I wish to record my deep sense of gratitude and
thanks to my Ph.D. supervisor Dr. Zhang Pu, professor, civil department,
Zhengzhou University P.R. China for his keen interest and guidance
during the writing of this review article.
Authors Contributions All authors whose names appear on the submis-
sion made substantial contributions to the conception, analysis, interpre-
tation of data and writing/revision of the article.
Data Availability The data used to support the findings of this study are
included within the article.
Declarations
Consent to Participate Not applicable.
Consent for Publication Not applicable.
Conflict of Interest The authors declare that there is no conflict of
interest.
References
1. Lawrence CD (2003) The production of low-energy cements.
Lea’s Chemistry of Cement and Concrete:421–470
2. U.S. Geological Survey (2014). Mineral commodity summaries
2014. Mineral Commodity Summaries. https://doi.org/10.3133/
70100414
3. Gjorv OE (1989) Alkali activation of a Norwegian granulated
blast furnace slag. In: Proc. third international conference on FA,
silica fume, slag, and natural Pozzolans in concrete, Trondheim,
Norway, pp. 1501–1518
4. Philleo RE (1989). Slag or other supplementary materials? In:
Proceedings of the third international conference on FA, silica
fume, slag, and natural Pozzolans in concrete, Trondheim,
Norway, pp. 1197–1208
5. Amran YHM, Alyousef R, Alabduljabbar H, El-Zeadani M
(2020) Clean production and properties of geopolymer concrete;
a review. J Clean Prod 251:119679. https://doi.org/10.1016/j.
jclepro.2019.119679
6. Razak S, Zainal FF, Shamsudin SR (2020) Effect of porosity and
water absorption on compressive strength of Fly ash based
Geopolymer and OPC paste. IOP Conference Series: Materials
Science and Engineering 957:012035. https://doi.org/10.1088/
1757-899x/957/1/012035
7. Bellum RR, Muniraj K, Madduru SRC (2020) Exploration of
mechanical and durability characteristics of fly ash-GGBFS based
green geopolymer concrete. SN Applied Sciences 2(5). https://doi.
org/10.1007/s42452-020-2720-5
8. Verma M, Dev N (2020) Sodium hydroxide effect on the mechan-
ical properties of flyash-slag based geopolymer concrete. Struct
Concr 22. https://doi.org/10.1002/suco.202000068
9. Madani H, Ramezanianpour AA, Shahbazinia M, Ahmadi E
(2020) Geopolymer bricks made from less active waste materials.
Constr Build Mater 247:118441. https://doi.org/10.1016/j.
conbuildmat.2020.118441
10. Silva G, Kim S, Bertolotti B, Nakamatsu J, Aguilar R (2020)
Optimization of a reinforced geopolymer composite using natural
fibers and construction wastes. Constr Build Mater 258:119697.
https://doi.org/10.1016/j.conbuildmat.2020.119697
11. Sandanayake M, Gunasekara C, Law D, Zhang G, Setunge S,
Wanijuru D (2020) Sustainable criterion selection framework for
green building materials –an optimisation based study of fly-ash
Geopolymer concrete. Sustain Mater Technol 25:e00178. https://
doi.org/10.1016/j.susmat.2020.e00178
12. Silva PD, Sagoe-Crenstil K, Sirivivatnanon V (2007) Kinetics of
geopolymerization: role of Al2O3 and SiO2. Cem Concr Res
37(4):512–518. https://doi.org/10.1016/j.cemconres.2007.01.003
13. Duxson P, Fernández-Jiménez A, Provis JL, Lukey GC, Palomo
A, van Deventer JSJ (2006) Geopolymer technology: the current
state of the art. J Mater Sci 42(9):2917–2933. https://doi.org/10.
1007/s10853-006-0637-z
14. Wang H, Li H, Yan F (2005) Synthesis and mechanical properties
of metakaolinite-based geopolymer. Colloids Surf A Physicochem
Eng Asp 268(1–3):1–6. https://doi.org/10.1016/j.colsurfa.2005.
01.016
15. Xu H, Van Deventer JSJ (2002) Geopolymerisation of multiple
minerals. Miner Eng 15(12):1131–1139. https://doi.org/10.1016/
s0892-6875(02)00255-8
16. Buchwald A, Hohmann M, Posern K, Brendler E (2009) The
suitability of thermally activated illite/smectite clay as raw mate-
rial for geopolymer binders. Appl Clay Sci 46(3):300–304. https://
doi.org/10.1016/j.clay.2009.08.026
17. Krivenko PV, Kovalchuk GY (2007) Directed synthesis of alka-
line aluminosilicate minerals in a geocement matrix. J Mater Sci
42(9):2944–2952. https://doi.org/10.1007/s10853-006-0528-3
18. Bajpai R, Choudhary K, Srivastava A, Sangwan KS, Singh M
(2020) Environmental impact assessment of fly ash and silica
fume based geopolymer concrete. J Clean Prod 254:120147.
https://doi.org/10.1016/j.jclepro.2020.120147
Silicon
19. Pacheco-Torgal F, Castro-Gomes J, Jalali S (2008) Alkali-
activated binders: a review. Part 2. About materials and binders
manufacture. Constr Build Mater 22(7):1315–1322. https://doi.
org/10.1016/j.conbuildmat.2007.03.019
20. Nazari A, Bagheri A, Riahi S (2011) Properties of geopolymer
with seeded fly ash and rice husk bark ash. Mater Sci Eng A
528(24):7395–7401. https://doi.org/10.1016/j.msea.2011.06.027
21. Hajjaji, W., Andrejkovičová, S., Zanelli, C., Alshaaer, M., Dondi,
M., Labrincha, J. A., & Rocha, F. (2013). Composition and tech-
nological properties of geopolymers based on metakaolin and red
mud. Mater Des (1980-2015), 52, 648–654. doi:https://doi.org/10.
1016/j.matdes.2013.05.058
22. Giasuddin HM, Sanjayan JG, Ranjith PG (2013) Strength of
geopolymer cured in saline water in ambient conditions. Fuel
107:34–39. https://doi.org/10.1016/j.fuel.2013.01.035
23. Yusuf MO, Megat Johari MA, Ahmad ZA, Maslehuddin M
(2014) Strength and microstructure of alkali-activated binary
blended binder containing palm oil fuel ash and ground blast-
furnace slag. Constr Build Mater 52:504–510. https://doi.org/10.
1016/j.conbuildmat.2013.11.012
24. Oh JE, Monteiro PJM, Jun SS, Choi S, Clark SM (2010) The
evolution of strength and crystalline phases for alkali-activated
ground blast furnace slag and fly ash-based geopolymers. Cem
Concr Res 40(2):189–196. https://doi.org/10.1016/j.cemconres.
2009.10.010
25. Aydın S, Baradan B (2012) Mechanical and microstructural prop-
erties of heat cured alkali-activated slag mortars. Mater Des 35:
374–383. https://doi.org/10.1016/j.matdes.2011.10.005
26. He J, Jie Y, Zhang J, Yu Y, Zhang G (2013) Synthesis and char-
acterization of red mud and rice husk ash-based geopolymer com-
posites. Cem Concr Compos 37:108–118. https://doi.org/10.1016/
j.cemconcomp.2012.11.010
27. Boskovic I, Vukcevic M, Zejak R (2015). The influence of the
amorphous SiO2 content on the characteristics of red mud based
geopolymers. Third International Conference on Advances in Bio-
Informatics and Environmental Engineering - ICABEE 2015.
https://doi.org/10.15224/978-1-63248-078-1-89
28. Rehman SKU, Imtiaz L, Aslam F, Khan MK, Haseeb M, Javed
MF, Alabduljabbar H (2020) Experimental investigation of NaOH
and KOH mixture in SCBA-based Geopolymer cement compos-
ite. Materials 13(15):3437. https://doi.org/10.3390/ma13153437
29. Chen Y, Zhang Y, Chen T, Zhao Y, Bao S (2011) Preparation of
eco-friendly construction bricks from hematite tailings. Constr
Build Mater 25(4):2107–2111. https://doi.org/10.1016/j.
conbuildmat.2010.11.025
30. Ahmari S, Zhang L (2012) Production of eco-friendly bricks from
copper mine tailings through geopolymerization. Constr Build
Mater 29:323–331. https://doi.org/10.1016/j.conbuildmat.2011.
10.048
31. Duxson P, Mallicoat SW, Lukey GC, Kriven WM, van Deventer
JSJ (2007) The effect of alkali and Si/Al ratio on the development
of mechanical properties of metakaolin-based geopolymers.
Colloids Surf A Physicochem Eng Asp 292(1):8–20. https://doi.
org/10.1016/j.colsurfa.2006.05.044
32. Pelisser F, Guerrino EL, Menger M, Michel MD, Labrincha JA
(2013) Micromechanical characterization of metakaolin-based
geopolymers. Constr Build Mater 49:547–553. https://doi.org/
10.1016/j.conbuildmat.2013.08.081
33. Liu Y, Shi C, Zhang Z, Li N, Shi D (2020) Mechanical and frac-
ture properties of ultra-high performance geopolymer concrete:
effects of steel fiber and silica fume. Cem Concr Compos 112:
103665. https://doi.org/10.1016/j.cemconcomp.2020.103665
34. Dimas D, Giannopoulou I, Panias D (2009) Polymerization in
sodium silicate solutions: a fundamental process in
geopolymerization technology. J Mater Sci 44(14):3719–3730.
https://doi.org/10.1007/s10853-009-3497-5
35. Davidovits J (2014) Geopolymer Chemistry and Applications,
Geopolymer Institute, Third ed 8
36. KomljenovićM, BaščarevićZ, BradićV (2010) Mechanical and
microstructural properties of alkali-activated fly ash geopolymers.
J Hazard Mater 181(1–3):35–42. https://doi.org/10.1016/j.
jhazmat.2010.04.064
37. Reddy DV, Edouard JB, Sobhan K, Rajpathak SS (2011)
Proceeding of 36th conference on 11 OUR WORLD IN
CONCR. & STRUCT., Singapore
38. Xie Z, Xi Y (2001) Hardening mechanisms of an alkaline-
activated class F fly ash. Cem Concr Res 31(9):1245–1249.
https://doi.org/10.1016/s0008-8846(01)00571-3
39. Ridtirud C, Chindaprasirt P, Pimraksa K (2011) Factors affecting
the shrinkage of fly ash geopolymers. Int J Miner Metall Mater
18(1):100–104. https://doi.org/10.1007/s12613-011-0407-z
40. Yahya Z, Abdullah M, Hussin K, Ismail K, Razak R, Sandu A
(2015) Effect of solids-to-liquids, Na2SiO3-to-NaOH and curing
temperature on the palm oil boiler ash (Si + Ca)
Geopolymerisation system. Materials 8(5):2227–2242. https://
doi.org/10.3390/ma8052227
41. Gunasekara MPCM, Law DW (2014) 23rd Australasian Conf. on
the Mechanics of Struct. And Mater., Byron Bay, Australia, 113-
118
42. Sukmak P, Horpibulsuk S, Shen SL (2013) Strength development
in clay–fly ash geopolymer. Constr Build Mater 40:566–574.
https://doi.org/10.1016/j.conbuildmat.2012.11.015
43. Sathonsaowaphak A, Chindaprasirt P, Pimraksa K (2009)
Workability and strength of lignite bottom ash geopolymer mor-
tar. J Hazard Mater 168(1):44–50. https://doi.org/10.1016/j.
jhazmat.2009.01.120
44. Matthew SJ, Mary UC (2015). World of coal ash conference
www.worldofcoalash.org
45. Hardjito, D., & Rangan, B.V. (2005). Development and properties
of low-calcium Fly ash-based Geopolymer Concr. Res. Report GC
46. Kong DLY, Sanjayan JG (2008) Damage behavior of geopolymer
composites exposed to elevated temperatures. Cem Concr
Compos 30(10):986–991. https://doi.org/10.1016/j.cemconcomp.
2008.08.001
47. Gao K, Lin KL, Wang D, Hwang CL, Shiu HS, Chang YM,
Cheng TW (2014) Effects SiO2/Na2O molar ratio on mechanical
properties and the microstructure of nano-SiO2 metakaolin-based
geopolymers. Constr Build Mater 53:503–510. https://doi.org/10.
1016/j.conbuildmat.2013.12.003
48. Ghanbari M, Hadian AM, Nourbakhsh AA (2015) Effect of pro-
cessing parameters on compressive strength of Metakaolinite
based Geopolymers: using DOE approach. Procedia Mater Sci
11:711–716. https://doi.org/10.1016/j.mspro.2015.11.047
49. Khale D, Chaudhary R (2007) Mechanism of geopolymerization
and factors influencing its development: a review. J Mater Sci
42(3):729–746. https://doi.org/10.1007/s10853-006-0401-4
50. Xu H, Van Deventer JSJ (2000) The geopolymerisation of
alumino-silicate minerals. Int J Miner Process 59(3):247–266.
https://doi.org/10.1016/s0301-7516(99)00074-5
51. Davidovits J (1991) Geopolymers. J Therm Anal 37(8):1633–
1656. https://doi.org/10.1007/bf01912193
52. Palomo A, Glasser F (1992) Chemically-bonded cementitious ma-
terials based on metakaolin, British ceramic. Transp J 91(4):107–
112
53. Van Jaarsveld JGS, Van Deventer JSJ, Lorenzen L (1997) The
potential use of geopolymeric materials to immobilise toxic
metals: part I. theory and applications. Miner Eng 10(7):659–
669. https://doi.org/10.1016/s0892-6875(97)00046-0
54. Davidovits, J. (1982). The need tocreate a new technical language
for the transfer of basic scientific information. Transfer and
Exploitation of Scientific and Technical Information
Silicon
Luxembrourg, Commission of the European Communities, 7716,
42 (2007) 729–746
55. Liu X, Wu Y, Li M, Jiang J, Guo L, Wang W, Duan P (2020)
Effects of graphene oxide on microstructure and mechanical prop-
erties of graphene oxide-geopolymer composites. Constr Build
Mater 247:118544. https://doi.org/10.1016/j.conbuildmat.2020.
118544
56. Reddy MS, Dinakar P, Rao BH (2016) A review of the influence
of source material’s oxide composition on the compressive
strength of geopolymer concrete. Microporous Mesoporous
Mater 234:12–23. https://doi.org/10.1016/j.micromeso.2016.07.
005
57. Rao F, Liu Q (2015) Geopolymerization and its potential applica-
tion in mine tailings consolidation: a review. Miner Process Extr
Metall Rev 36(6):399–409. https://doi.org/10.1080/08827508.
2015.1055625
58. Fernández-Jiménez A, Palomo A (2005) Composition and micro-
structure of alkali activated fly ash binder: effect of the activator.
Cem Concr Res 35(10):1984–1992. https://doi.org/10.1016/j.
cemconres.2005.03.003
59. Zhang F, Zhang L, Liu M, Mu C, Liang YN, Hu X (2017) Role of
alkali cation in compressive strength of metakaolin based
geopolymers. Ceram Int 43(4):3811–3817. https://doi.org/10.
1016/j.ceramint.2016.12.034
60. Xie J, Wang J, Rao R, Wang C, Fang C (2019) Effects of com-
bined usage of GGBS and fly ash on workability and mechanical
properties of alkali activated geopolymer concrete with recycled
aggregate. Compos Part B 164:179–190. https://doi.org/10.1016/j.
compositesb.2018.11.067
61. Palomo A, Grutzeck MW, Blanco MT (1999) Alkali-activated fly
ashes. Cem Concr Res 29(8):1323–1329. https://doi.org/10.1016/
s0008-8846(98)00243-9
62. Shi C, Jiménez AF, Palomo A (2011) New cements for the 21st
century: the pursuit of an alternative to Portland cement. Cem
Concr Res 41(7):750–763. https://doi.org/10.1016/j.cemconres.
2011.03.016
63. Fernandez-Jimenez A, García-Lodeiro I, Palomo A (2006)
Durability of alkali-activated fly ash cementitious materials. J
Mater Sci 42(9):3055–3065. https://doi.org/10.1007/s10853-
006-0584-8
64. Palomo A, Blanco-Varela MT, Granizo ML, Puertas F, Vazquez
T, Grutzeck MW (1999) Chemical stability of cementitious mate-
rials based on metakaolin. Cem Concr Res 29(7):997–1004.
https://doi.org/10.1016/s0008-8846(99)00074-5
65. Fernández-Jiménez A, Monzó M, Vicent M, Barba A, Palomo A
(2008) Alkaline activation of metakaolin–fly ash mixtures: obtain
of Zeoceramics and Zeocements. Microporous Mesoporous Mater
108(1–3):41–49. https://doi.org/10.1016/j.micromeso.2007.03.
024
66. Provis JL, Lukey GC, van Deventer JSJ (2005) Do Geopolymers
actually contain Nanocrystalline zeolites? A reexamination of
existing results. Chem Mater 17(12):3075–3085. https://doi.org/
10.1021/cm050230i
67. Villaquirán-Caicedo MA (2019) Studying different silica sources
for preparation of alternative waterglass used in preparation of
binary geopolymer binders from metakaolin/boiler slag. Constr
Build Mater 227:116621. https://doi.org/10.1016/j.conbuildmat.
2019.08.002
68. Barbosa VF, MacKenzie KJ, Thaumaturgo C (2000) Synthesis
and characterisation of materials based on inorganic polymers of
alumina and silica: sodium polysialate polymers. Int J Inorg Mater
2(4):309–317. https://doi.org/10.1016/s1466-6049(00)00041-6
69. Fernández-Jiménez A, Palomo A (2003) Characterisation of fly
ashes. Potential reactivity as alkaline cements☆. Fuel 82(18):
2259–2265. https://doi.org/10.1016/s0016-2361(03)00194-7
70. Provis JL, Yong CZ, Duxson P, van Deventer JSJ (2009)
Correlating mechanical and thermal properties of sodium
silicate-fly ash geopolymers. Colloids Surf A Physicochem Eng
Asp 336(1–3):57–63. https://doi.org/10.1016/j.colsurfa.2008.11.
019
71. ZUHUA Z, XIAO Y, HUAJUN Z, YUE C (2009) Role of water
in the synthesis of calcined kaolin-based geopolymer. Appl Clay
Sci 43(2):218–223. https://doi.org/10.1016/j.clay.2008.09.003
72. Ruiz-Santaquiteria C, Skibsted J, Fernández-Jiménez A, Palomo
A (2012) Alkaline solution/binder ratio as a determining factor in
the alkaline activation of aluminosilicates. Cem Concr Res 42(9):
1242–1251. https://doi.org/10.1016/j.cemconres.2012.05.019
73. Van Jaarsveld JGS, van Deventer JSJ, Lukey GC (2003) The
characterisation of source materials in fly ash-based geopolymers.
Mater Lett 57(7):1272–1280. https://doi.org/10.1016/s0167-
577x(02)00971-0
74. Joshi, S.V., & Kadu, M.S. (2012). Role of alkaline activator in
development of eco-friendly fly ash based geo polymer concrete.
International Journal of Environmental Science and Development,
417–421. https://doi.org/10.7763/ijesd.2012.v3.258
75. Lloyd N, Rangan B (2010) 2nd Int. Conf. on Sustainable Constr.
Mater. & Technol, Ancona, Italy
76. Vaidya S, Diaz E, Allouche E (2011) World of coal ash (WOCA)
Denver USA
77. Puligilla S, Mondal P (2013) Role of slag in microstructural de-
velopment and hardening of fly ash-slag geopolymer. Cem Concr
Res 43:70–80. https://doi.org/10.1016/j.cemconres.2012.10.004
78. Chindaprasirt P, De Silva P, Sagoe-Crentsil K, Hanjitsuwan S
(2012) Effect of SiO2 and Al2O3 on the setting and hardening
of high calcium fly ash-based geopolymer systems. J Mater Sci
47(12):4876–4883. https://doi.org/10.1007/s10853-012-6353-y
79. Wongpa J, Kiattikomol K, Jaturapitakkul C, Chindaprasirt P
(2010) Compressive strength, modulus of elasticity, and water
permeability of inorganic polymer concrete. Mater Des 31(10):
4748–4754. https://doi.org/10.1016/j.matdes.2010.05.012
80. Diaz EI, Allouche EN, Eklund S (2010) Factors affecting the
suitability of fly ash as source material for geopolymers. Fuel
89(5):992–996. https://doi.org/10.1016/j.fuel.2009.09.012
81. Gomes KC, Torres SM, de Barros S, Barbosa NP (2008)
ETDCM8- 8th seminar on experimental techniques and Design
in Composite Materials
82. Gomes KC, Torres SM, de Barros S, Barbosa NP (2009). in: Solid
Mechanics in Brazil 09 edited by H. S. C. Mattos, M. Alves,
Associação Brasileira de Engenharia e Ciências Mecânicas. 2
83. Komnitsas K, Zaharaki D (2009) in: Structure, processing, prop-
erties and industrial applications PART II: Manufacture and prop-
erties of geopolymers, edited by J. Provis and Jannie S.J. van
Deventer, CRC Press, Woodhead Publishing Ltd, Oxford 343
84. Gomes KC, Lima GST, Torres SM, de Barros SR, Vasconcelos
IF, Barbosa NP (2010) Iron distribution in Geopolymer with fer-
romagnetic rich precursor. Mater Sci Forum 643:131–138. https://
doi.org/10.4028/www.scientific.net/msf.643.131
85. Puertas F, Martı nez-Ramı rez S, Alonso S, Vázquez T (2000)
Alkali-activated fly ash/slag cements. Cem Concr Res, 30(10),
1625–1632. https://doi.org/10.1016/s0008-8846(00)00298-2
86. Wang Y, Liu X, Zhang W, Li Z, Zhang Y, Li Y, Ren Y (2020)
Effects of Si/Al ratio on the efflorescence and properties of fly ash
based geopolymer. J Clean Prod 244:118852. https://doi.org/10.
1016/j.jclepro.2019.118852
87. Gasteiger HA, Frederick WJ, Streisel RC (1992) Solubility of
aluminosilicates in alkaline solutions and a thermodynamic equi-
librium model. Ind Eng Chem Res 31(4):1183–1190. https://doi.
org/10.1021/ie00004a031
88. Safari Z, Kurda R, Al-Hadad B, Mahmood F, Tapan M (2020)
Mechanical characteristics of pumice-based geopolymer paste.
Silicon
Resour Conserv Recycl 162:105055. https://doi.org/10.1016/j.
resconrec.2020.105055
89. Hardjito D, Cheak CC, Lee Ing CH (2008) Strength and setting
times of low calcium Fly ash-based Geopolymer mortar. Mod
Appl Sci 2(4). https://doi.org/10.5539/mas.v2n4p3
90. Hardjito D, Wallah SE, Sumajouw DMJ, Rangan BV (2005) Fly
ash-based Geopolymer concrete. Aust J Struct Eng 6(1):77–86.
https://doi.org/10.1080/13287982.2005.11464946
91. Shah SP, Wang K (2009) Development of ‘green’cement for
sustainable concrete using cement kiln dust and Fly ash,
International Workshop on Sustainable Development and
Concrete Technology, 15–23
92. Davidovits J (1999) Chemistry of Geopolymeric systems, termi-
nology in: proceedings of 99 international conference. eds. Joseph
Davidovits, R. Davidovits & C. James, France
93. Davidovits J (1994, October) Properties of geopolymer cements.
In First international conference on alkaline cements and concretes
(Vol. 1, pp. 131-149). Kiev State Technical University, Ukraine:
Scientific Research Institute on Binders and Materials
94. Rangan BV (2008) in: Low-calcium, fly-ash-based geopolymer
concrete, concrete construction engineering handbook, Taylor
and Francis Group, LLC, 1–19
95. Bondar D, Lynsdale CJ, Milestone NB, Hassani N,
Ramezanianpour AA (2011) Effect of type, form, and dosage of
activators on strength of alkali-activated natural pozzolans. Cem
Concr Compos 33(2):251–260. https://doi.org/10.1016/j.
cemconcomp.2010.10.021
96. Bignozzi MC, Manzi S, Natali ME, Rickard WDA, van Riessen A
(2014) Room temperature alkali activation of fly ash: the effect of
Na 2 O/SiO 2 ratio. Constr Build Mater 69:262–270. https://doi.
org/10.1016/j.conbuildmat.2014.07.062
97. Malkawi AB, Nuruddin MF, Fauzi A, Almattarneh H,
Mohammed BS (2016) Effects of alkaline solution on properties
of the HCFA Geopolymer mortars. Procedia Engineering 148:
710–717. https://doi.org/10.1016/j.proeng.2016.06.581
98. Rattanasak U, Chindaprasirt P (2009) Influence of NaOH solution
on the synthesis of fly ash geopolymer. Miner Eng 22(12):1073–
1078. https://doi.org/10.1016/j.mineng.2009.03.022
99. Nath P, Sarker PK (2014) Effect of GGBFS on setting, workabil-
ity and early strength properties of fly ash geopolymer concrete
cured in ambient condition. Constr Build Mater 66:163–171.
https://doi.org/10.1016/j.conbuildmat.2014.05.080
100. Feuerborn HJ (2005, November). Coal ash utilisation over the
world and in Europe. In Workshop on environmental and health
aspects of coal ash utilization (Vol. 5)
101. Albitar M, Mohamed Ali MS, Visintin P, Drechsler M (2015)
Effect of granulated lead smelter slag on strength of fly ash-
based geopolymer concrete. Constr Build Mater 83:128–135.
https://doi.org/10.1016/j.conbuildmat.2015.03.009
102. Nuaklong P, JongvivatsakulP, Pothisiri T, Sata V, Chindaprasirt P
(2020) Influence of rice husk ash on mechanical properties and fire
resistance of recycled aggregate high-calcium fly ash geopolymer
concrete. J Clean Prod 252:119797. https://doi.org/10.1016/j.
jclepro.2019.119797
103. Okoye FN, Durgaprasad J, Singh NB (2016) Effect of silica fume
on the mechanical properties of fly ash based-geopolymer con-
crete. Ceram Int 42(2):3000–3006. https://doi.org/10.1016/j.
ceramint.2015.10.084
104. Wang YS, Alrefaei Y, Dai JG (2020) Influence of coal fly ash on
the early performance enhancement and formation mechanisms of
silico-aluminophosphate geopolymer. Cem Concr Res 127:
105932. https://doi.org/10.1016/j.cemconres.2019.105932
105. Fairbairn EMR, Americano BB, Cordeiro GC, Paula TP, Toledo
Filho RD, Silvoso MM (2010) Cement replacement by sugar cane
bagasse ash: CO2 emissions reduction and potential for carbon
credits. J Environ Manag 91(9):1864–1871. https://doi.org/10.
1016/j.jenvman.2010.04.008
106. Patel YJ, Shah N (2018) Development of self-compacting
geopolymer concrete as a sustainable construction material.
Sustainable Environment Research 28(6):412–421. https://doi.
org/10.1016/j.serj.2018.08.004
107. Kusbiantoro A, Nuruddin MF, Shafiq N, Qazi SA (2012) The
effect of microwave incinerated rice husk ash on the compressive
and bond strength of fly ash based geopolymer concrete. Constr
Build Mater 36:695–703. https://doi.org/10.1016/j.conbuildmat.
2012.06.064
108. Songpiriyakij S, Kubprasit T, Jaturapitakkul C, Chindaprasirt P
(2010) Compressive strength and degree of reaction of biomass-
and fly ash-based geopolymer. Constr Build Mater 24(3):236–
240. https://doi.org/10.1016/j.conbuildmat.2009.09.002
109. Law DW, Adam AA, Molyneaux TK, Patnaikuni I, Wardhono A
(2014) Long term durability properties of class F fly ash
geopolymer concrete. Mater Struct 48(3):721–731. https://doi.
org/10.1617/s11527-014-0268-9
110. Ryu GS, Lee YB, Koh KT, Chung YS (2013) The mechanical
properties of fly ash-based geopolymer concrete with alkaline ac-
tivators. Constr Build Mater 47:409–418. https://doi.org/10.1016/
j.conbuildmat.2013.05.0
111. Nuruddin F, Demie S, Memon FA, Shafiq N (2011) Effect of
superplasticizer and NaOH molarity on workability, compressive
strength and microstructure properties of self-compacting
geopolymer concrete. World Acad Sci Eng Technol 75
112. Parthiban D, Vijayan DS, Sanjay Kumar R, Santhu AP, Abraham
Cherian G, Ashiq M (2020) Performance evaluation of Fly ash
based GPC with partial replacement of RHA as a cementitious
material. Materials today: proceedings, 33, 550–558 33:550–
558. https://doi.org/10.1016/j.matpr.2020.05.244
113. Vora PR, Dave UV (2013) Parametric studies on compressive
strength of Geopolymer concrete. Procedia Engineering 51:210–
219. https://doi.org/10.1016/j.proeng.2013.01.030
114. Chindaprasirt P, Chalee W (2014) Effect of sodium hydroxide
concentration on chloride penetration and steel corrosion of fly
ash-based geopolymer concrete under marine site. Constr Build
Mater 63:303–310. https://doi.org/10.1016/j.conbuildmat.2014.
04.010
115. Chi M (2017) Effects of the alkaline solution/binder ratio and
curing condition on the mechanical properties of alkali-activated
fly ash mortars. Sci Eng Compos Mater 24(5):773–782. https://
doi.org/10.1515/secm-2015-0305
116. Pham TM (2020) Enhanced properties of high-silica rice husk ash-
based geopolymer paste by incorporating basalt fibers. Constr
Build Mater 245:118422
117. Akbar A, Farooq F, Shafique M, Aslam F, Alyousef R,
Alabduljabbar H (2021) Sugarcane bagasse ash-based engineered
geopolymer mortar incorporating propylene fibers. Journal of
Building Engineering 33:101492. https://doi.org/10.1016/j.jobe.
2020.101492
118. Wan Q, Rao F, Song S, García RE, Estrella RM, Patiño CL, Zhang
Y (2017) Geopolymerization reaction, microstructure and simula-
tion of metakaolin-based geopolymers at extended Si/Al ratios.
Cem Concr Compos 79:45–52. https://doi.org/10.1016/j.
cemconcomp.2017.01.014
119. Atmaja L, Fansuri H, Maharani A (2011) Crystalline phase reac-
tivity in the synthesis of fly ash-based geopolymer. Indian J Chem
11(1):90–95. https://doi.org/10.22146/ijc.21426
120. Thakur RN, Ghosh S (2009) Effect of mix composition on com-
pressive strength and microstructure of fly ash based geopolymer
composites. ARPN Journal of Engineering and Applied Sciences
4(4):68–74
Silicon
121. Ghosh K, Ghosh P (2012) Effect of synthesizing parameters on
compressive strength of flyash based geopolymer paste. Int J
Struct Civ Eng 1(8):1–11
122. Abbas R, Khereby MA, Ghorab HY, Elkhoshkhany N (2020)
Preparation of geopolymer concrete using Egyptian kaolin clay
and the study of its environmental effects and economic cost.
Clean Techn Environ Policy 22(3):669–687. https://doi.org/10.
1007/s10098-020-01811-4
123. Khan KA, Raut A, Chandrudu CR, Sashidhar C (2021) Design
and development of sustainable geopolymer using industrial cop-
per byproduct. J Clean Prod 278:123565. https://doi.org/10.1016/
j.jclepro.2020.123565
124. Bondar D (2013, August) Geo-polymer concrete as a new type of
sustainable construction materials. In Proceedings of the Third
International Conference on Sustainable Construction Materials
and Technologies (ICSCMT) (pp. 18–21)
125. Nath SK, Kumar S (2020) Role of particle fineness on engineering
properties and microstructure of fly ash derived geopolymer.
Constr Build Mater 233:117294. https://doi.org/10.1016/j.
conbuildmat.2019.117294
126. McCormick AV, Bell AT, Radke CJ (1989) Multinuclear NMR
investigation of the formation of aluminosilicate anions. J Phys
Chem 93(5):1741–1744. https://doi.org/10.1021/j100342a015
127. Lee WKW, van Deventer JSJ (2002) Structural reorganisation of
class F fly ash in alkaline silicate solutions. Colloids Surf A
Physicochem Eng Asp 211(1):49–66. https://doi.org/10.1016/
s0927-7757(02)00237-6
128. Sathia, R., Babu, K.G., & Santhanam, M. (2008, November).
Durability study of low calcium fly ash geopolymer concrete. In
The 3rd ACF international conference-ACF/VCA (Vol. 2008).
Indian Institute of Technology Madras Chennai, India
129. Chindaprasirt P, Chareerat T, Sirivivatnanon V (2007)
Workability and strength of coarse high calcium fly ash
geopolymer. Cem Concr Compos 29(3):224–229. https://doi.
org/10.1016/j.cemconcomp.2006.11.002
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