College of Engineering Education

2nd Floor, B&E Building

Matina Campus, Davao City

Paper Review

Development of Sustainable Fiber Cement Boards

Utilizing Geopolymer Cement and Coconut Coir
Fiber

1. Introduction

In recent years, the construction industry has faced increasing pressure to adopt
sustainable practices that minimize environmental impact while maintaining the quality and
durability of building materials. Ordinary Portland Cement (OPC) is one of the most widely
used and traditional binders in construction materials. However, its high carbon footprint
and resource-intensive production process highlight the urgent need for alternatives. With
the rising global demand for greener solutions, geopolymer cement has emerged as a
viable alternative to Portland cement. This material is particularly noted for its reduced
carbon footprint, remarkable durability, sustainable material, and strong resistance to
environmental wear and tear.

In the Philippines, coconut farming produces 3.41 million metric tons of organic waste
annually. However, with limited technical and logistical resources, only about 5 to 10% of
these coconut husks are being recycled (Philippine Statistics Authority, 2023). Residues
of agricultural industry have become a preferred substitute to fiber in the production of fiber
cement boards. In the study of Budiman, I., et. Al (2021), coconut coir fiber holds significant
potential for a variety of uses, including its application in cement boards as a building
material. By utilizing coconut coir, a renewable and biodegradable fiber derived from these
husks, it is possible to not only improve the toughness and flexibility of fiber cement boards
but also address the pressing issue of agricultural waste.

This study will investigate the feasibility of geopolymer cement as a substitute for Ordinary
Portland Cement (OPC) in coconut coir fiber cement board. This research will explore the
mechanical properties, durability, and compatibility of the composite material. This will not
only contribute to the development in the sustainable construction industry but will also
address the agricultural waste management issues in the Philippines.

2. Literature Review

2.1. Natural Fibers in Cement Composites

The study of Rocha, D., et. al., (2022) highlights the growing use of natural lignocellulosic
fibers in cementitious composites, driven by their abundance, low cost, and ability to
enhance mechanical properties, with Brazil being a key producer. Natural fibers' lower
density and higher cellulose content make them suitable for such applications, with the
fiber-matrix interface playing a crucial role in determining composite performance.
Chemical and physical treatments can enhance this bond, improving the composite's
mechanical properties. The review underscores the importance of fiber treatment, optimal
fiber proportion, and the fiber-matrix interface, concluding that lignocellulosic fibers hold

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 significant potential for use in cementitious materials due to their low density and high
compressive strength.

2.2. Coconut Coir Fiber as a Material

In the study conducted by Budiman, I., et. al., (2020), the impact of coconut coir fiber (CCF)
on the physical and mechanical properties of cement boards was evaluated, with a focus
on the effects of pretreatment and fiber-to-cement ratio. The researchers found that
soaking CCF in hot water at a 1:3.25 ratio significantly enhanced the boards’ properties by
reducing hemicellulose and extractive content, leading to improved fiber-cement
compatibility. The study demonstrated that the fiber-to-cement ratio and hot water
pretreatment positively influenced properties such as density, moisture content, modulus
of rupture, and elasticity. These findings, which meet ISO 8335-1987 standards, concluded
that cement boards produced with hot water-treated CCF exhibit superior physical and
mechanical characteristics.

2.3. Geopolymer Cement

The study of Wong (2022) examines the durability of geopolymer concrete, highlighting its
robust performance across various metrics. It retains high compressive strength up to
400°C, with enhancements possible through fibers and nano-silica. The concrete also
demonstrates low to moderate chloride ion penetrability, influenced by aggregate type, mix
alkalinity, and fiber inclusion. Moreover, geopolymer concrete surpasses ordinary Portland
cement (OPC) concrete in acid resistance, due to the stability of its aluminosilicate binder,
and offers superior abrasion resistance, which can be improved with durable aggregates
and recycled materials. Its dense microstructure and stable chemical bonds further
underscore its durability.

3. Theoretical Framework (if available)

Not available.

4. Comparison and Synthesis

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Table 1. Matrix of the relevant comparison and synthesis (please make this section in landscape orientation)
Title Objectives Theory Methodology Conclusion Knowledge Reference
Applied Gaps/Future Number
Works
The properties of This study aimed The study utilized Cement boards Try to increase the [1]
cement boards to determine the Ordinary Portland made with cement content or
reinforced with effect of giving Cement (OPC), coconut coir fiber try other mixes to
coconut coir fiber hot and cold coconut coir fiber showed the best study the strength
(Cocos nucifera) as water immersion (CCF), and properties when of the material.
building materials treatment on magnesium using a fiber-to-
coconut coir chloride (MgCl₂) as cement ratio of
fibers and the materials. CCF was 1:3.25 and
difference in a treated in three treating the fiber
weight ratio ways: no treatment, with hot water.
between coconut immersion in cold The increased
coir fibers with water for 24 hours, cement content
cement to the and immersion in improved
physical and hot water (100°C) bonding, and the
mechanical for 1 hour. The hot water
properties of the cement boards treatment
cement board. were made with enhanced the
varying ratios of mechanical
CCF to cement properties by
(1:2.75, 1:3.0, and reducing
1:3.25 by weight), hemicellulose
using water at 60% and extractives
of the cement's in the fiber.
weight and MgCl₂
at 2.5%. The
boards were
formed, cold-
pressed, and cured
for 28 days before
undergoing
physical and
mechanical testing

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 according to ISO
8335-1987
standards.
Coconut Fiber The objective of The study involved The paper Look for a [2]
Cement Panels as the study is to the fabrication of explored the use sustainable
Wall Insulation and develop a fiber fiber cement of organic fibers material
Structural cement composite samples in composites to substitute for
Diaphragm composite that using a enhance both cement.
can be applied to combination of compressive and
the interior or coconut husk bending
exterior of a fibers, rattan, pine strength, aiming
home and wood fibers, to improve the
provide both Portland cement, fly elasticity of wall
insulative and ash, and hydrated systems. Tests
structural lime. The thermal showed that
improvements. conductivity of adding wood
these composites waste fiber
was measured increased the
using a heat flux flexural strength
machine, while their of cement
flexural strength composites
was tested with an compared to
MTS universal control samples.
testing machine. However, the
Field tests were studies assumed
conducted in ideal conditions
Gujarat, India, to for load transfer
validate the lab between
results. masonry walls
Additionally, and composite
coconut coir fiber- cladding,
reinforced cement highlighting the
panels with varying need for further
fiber contents were research to
fabricated, and optimize
thermal mounting

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conductivity tests systems and
were performed understand force
using a Netzsch flow through
HFM 436 Lambda. connections.
The compressive Additional
strength of these studies are also
panels was also needed to
tested. Energy ensure the
simulations using waterproofing,
EnergyPlus v8.4 durability, and
were conducted to hydrothermal
evaluate the performance of
energy-saving coconut coir fiber
potential of the panels,
panels in different especially in
climate zones. colder climates,
Temperature data to prevent
was collected from internal damage.
data loggers Developing new
connected to mix
constructed wall compositions
samples in Bhuj, and fabrication
India. Further field methods could
tests in Gujarat, further improve
India, and Nepal the use of waste
were conducted to fibers in wall
validate lab results systems.
and gather
qualitative
perceptions of the
material. Surveys
and informal
interviews with
homeowners in
India and Nepal
were carried out to

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 understand the
product's aesthetic
and cultural appeal.
Coconut Fiber and The objective of The study This study The study found [3]
Pulverized Rice the study is to employed a explored the that rice husk-
Husk as Alternative investigate the quantitative, feasibility of coconut fiber
Ingredients in feasibility of experimental using rice husk- cement boards are
Constructing using coconut research design to coconut fiber not feasible in
Cement Board fiber and rice evaluate the cement boards terms of flexural
husk as effectiveness of rice as an alternative strength, but they
alternative husk and coconut material for can be
ingredients in fiber as ingredients constructing recommended for
making cement in alternative cement boards. interior purposes.
boards. cement boards. While these For future works,
Researchers used boards may not add more flexural
various tools and match the strength to the rice
followed flexural strength husk-coconut fiber
established of commercial cement board by
procedures for cement boards, adding
making and testing they could be a another material to
the cement boards, viable substitute it.
including flexural for gypsum
strength tests using boards. Among
a three-point the tested ratios,
bending setup. Ratio C showed
Three different the best
ratios of cement, performance in
coconut fiber, and terms of flexural
rice husk were strength,
tested, with the suggesting that
mixtures being sun- increasing the
dried, compacted, cement content
and then subjected enhances the
to strength tests. board's strength.
Data analysis The study's
involved calculating hypothesis

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 the modulus of testing confirmed
rupture and a significant
applying the Tukey- difference in
Kramer Multiple bending strength
Comparison Test to between the rice
compare the husk-coconut
bending and fiber cement
compressive board and
strength of the commercial
alternative boards cement boards,
with traditional supporting the
cement boards. potential for
The researchers further
followed safety development of
protocols and Ratio C.
based their data
interpretation on
standards from the
American Society
for Testing and
Materials and the
Indian Standard for
Fiber Cement.
A Review of the Use To provide a The study involves Incorporating More information [4]
of Coconut Fiber in comprehensive a review of existing coconut fibers about the physical
Cement review of the use research on the into cement- and chemical
Composites of coconut fibers properties and based materials characteristics of
and coconut fiber applications can reduce the coconut fibers.
textile mesh in of coconut fibers in environmental For future works,
cement-based concrete, including impact due to conduct more
materials, and to their mechanical their affordability, laboratories and
highlight their properties, availability, testings.
potential as a durability, and recyclability, and
sustainable sustainability. low density.
alternative to These fibers
synthetic fibers in improve the

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 construction physical and
materials. mechanical
properties of
cement
composites,
especially with
increased
elongation.
However, a
better
understanding of
the fibers'
physical and
chemical
characteristics is
needed for
broader
application. This
research
compared the
performance of
cementitious
matrices
reinforced with
coconut fibers
and textile
meshes, drawing
on existing
studies.
Comparative The primary The researchers The study Future studies can [5]
Analysis of the objective of this used a Universal concludes that explore other
Mechanical study is to Testing Machine CFB is a superior factors that affect
Properties of compare and (UTM) to test the material to CHB the cost-
Coconut Fiber analyze the compressive in terms of effectiveness of
Cement Board and mechanical strength of the compressive CFB and CHB,
properties of samples. The dead strength, but is such as labor

Page 8 of 20
Concrete Hollow CFB and CHB. load of the two more expensive. costs and
Blocks The researchers materials was The researchers environmental
aim to determine measured using an suggest that impact. Future
if CFB is a cost- industrial weighing CFB can be a studies may
effective and scale. The cost of cost-effective consider
sustainable both panels was and sustainable evaluating the
material in computed using material in samples using
construction and Microsoft Excel. construction and additional criteria,
an alternative to The methods used an alternative to using machines
CHB. in the study include CHB. and equipment to
cutting the Fiber The conclusions increase
Cement Board into of the study are productivity, and
rectangular boards, that CFB has producing a fresh
drilling a wood better batch of samples
support between compressive with different
the boards, pouring strength and concrete mix
cement mixture lower dead load ratios.
inside, and testing than CHB,
the compressive making it a
strength using the suitable
Universal Testing alternative for
Machine. panel systems,
despite its higher
cost.
Utilization of he objectives of The study used an The study Future studies [6]
Bamboo Fiber and the study were to experimental concludes that could investigate
Coconut Coir in the determine the research design, the utilization of the properties of
Production of physical and producing three bamboo fiber cement-bonded
Cement -Bonded mechanical experimental and coconut coir boards made with
Board properties of samples with three in the production different types of
bamboo and different fiber- of cement- natural fibers or
coconut coir fiber cement ratios. The bonded boards is explore the use of
cement-bonded samples underwent a viable additives to
board, several tests to alternative to improve the
specifically its determine their wood products, properties of the
density, water physical and with improved boards. The future

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absorption, mechanical physical and work
thickness properties. mechanical recommended
swelling, nail The methods used properties. includes
head pull- in the study are not The study standardizing the
through strength, explicitly described, concluded that production
and modulus of but it can be the addition of process, pursuing
rupture. inferred that the bamboo fibers to commercialization
researchers cement-bonded of bamboo and
conducted boards can coconut coir fiber
experiments to test improve their cement-bonded
the properties of properties, such boards, and
cement boards with as nail-head pull- promoting the use
varying through of agricultural
percentages of resistance and wastes in
bamboo fibers, modulus of construction
including thickness rupture, but may materials.
swelling, nail head also increase
pull-through their water
capacity, and absorption and
modulus of rupture. thickness
swelling.
The researchers
conclude that the
optimum
percentage
inclusion of
bamboo fiber is
3.2% (Mix
Design 3) due to
moderate
thickness
swelling and
water absorption
and exceptional
performance in
nail head pull-

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 through capacity
and modulus of
rupture tests.
Properties of Fiber The objective of Preparing fiber An inverse Future work could [7]
Cement Boards for the study is to cement boards with relation between explore other
Building Partitions investigate the varying fiber content and agricultural waste
physical and percentages of coir density was materials
mechanical fibers (5%, 10%, observed. substitute for
properties of fiber and 15%). The percentage coconut fibers.
cement boards Conducting density of water
with varying tests, water absorbed by the
percentages of absorption tests, boards
coir fibers. impact tests, and increased with
compressive an increase in
strength tests on fiber content.
the samples. The compressive
strength firstly
increased with
an increase in
fiber content up
to 10% and then
decreased.
An increasing
pattern in the
impact strength
was observed
with an increase
in fiber content.
Fiber cement
boards with 10%
and 15% fiber
content showed
effective drilling
characteristics.
Geopolymer Explore the The authors GPC is a Additional studies [8]
concrete as a effects of various reviewed many promising are needed to

Page 11 of 20
cleaner factors, such as databases, alternative to determine if
construction reinforcement including Scopus, PCC, with similar nanoparticles
material: An ratio, Science Direct, the or superior improve the
overview on compressive Web of Science, material workability of GC
materials and strength, and Research Gate, properties and or not. Further
structural fiber addition, on and Google structural research on the
performances the strength and Scholar, to identify performance, behavior of GPC
ductility of GPC a many studies on and reduced beams under
beams. the material carbon footprint various loading
properties and and energy conditions and
structural consumption. environmental
performance of GPC beams are exposures.
GPC. a viable Development of
Experimental alternative to design codes and
testing of GPC RCC beams, standards for the
beams with varying with similar use of GPC
reinforcement flexural behavior beams in
ratios, compressive and higher construction.
strengths, and fiber ductility and
additions. deflection
Finite element capacity.
analysis (FEA) and The specification
nonlinear finite codes for GPC
element (FE) beams can be
computer modeling predictably
to simulate the developed based
behavior of GPC on traditional
beams. RCC codes of
Comparison of the practice.
results with
traditional RCC
beams and codes
of practice.
Durability The objective of The study involves The study Future research [9]
Performance of the study is to a review of recent concludes that directions include
provide critical research on the geopolymer exploring the role

Page 12 of 20
Geopolymer insight into the durability of concrete is of thermal
Concrete: A Review recent progress geopolymer durable and insulating raw
in research on concrete, including resistant to heat, material such as
the durability of its compressive chloride fiberglass at
geopolymer strength at elevated penetration, acid enhancing the
concrete and to temperatures, attack, and residual
explore its chloride ion abrasion, and compressive
potential as a penetrability, acid that an optimal strength of
viable alternative resistance, addition of fibers geopolymer
to OPC concrete abrasion and ultra-fine concrete, and
in the resistance, and silica material assessing the
construction morphological and such as nano- long-term strength
industry chemical properties silica to development of
geopolymer geopolymer
concrete could concrete improved
enhance its with various types
residual of fiber and
compressive pozzolanic
strength additive
A comprehensive The objective of The review article The use of Future research [10]
review on the use of
this review is to compiles insights natural fibers as should focus on
natural fibers in provide a from numerous reinforcement for the development
cement/geopolymer comprehensive sources to aid concrete is a of effective
concrete: A step overview of the academia and the viable and treatment
towards use of natural construction sustainable processes and
sustainability fibers as industry in alternative to separation
reinforcement for developing eco- traditional techniques for
concrete, friendly materials. materials, with natural fibers.
highlighting their potential
benefits, optimal applications in
concentrations, the construction
and potential industry.
applications.
A Review on The objective of The review The review The review [11]
Natural Fiber- the review is to discusses various concludes that identifies the need
Reinforced provide an pre-treatment natural fibers for further

Page 13 of 20
Geopolymer and overview of the methods aimed at have the research on the
Cement-Based natural fiber improving potential to be durability of fiber-
Composites modification mechanical and used as reinforced
strategies to physical properties sustainable geopolymers for
enhance fiber of natural fibers, reinforcement in indoor and
hydrophobicity including chemical cement and outdoor
and physico- agents, geopolymer applications, as
chemical hornification, composites, but well as the
interactions at hydrothermal, and further research application of
the fiber–matrix heat treatments. is needed to animal fibers as
interface of address the reinforcement in
cement and limitations and cement and
geopolymers challenges geopolymer
composites. associated with composites.
their use.
Effect of Plant Fiber The objective of The study reviews The study The study [12]
on Early Properties the study is to recent studies on concludes that suggests that PFs
of Geopolymer review recent the early properties the addition of can be pretreated
studies on the of PFRGs, PFs to GPs can with chemical
early properties including their improve their modification to
of plant fiber- rheological early flexural solve the
reinforced properties, early strength but can problems
geopolymers strength, and early also have an associated with
(PFRGs). shrinkage and adverse effect on their use in
deformation the early geopolymers.
properties. performance of
Microscopic composites,
analysis of the early mainly on the
reaction process of fluidity of
GPs is also used to mixtures. The
understand the workability loss
structure and of different types
formation of fiber-
mechanism of the reinforced GP
early reaction of mixtures is
PFRGs. affected by fiber

Page 14 of 20
 type, aspect
ratio, and
content in the
mixture.
Utilization of The objective of The study involved The geopolymer Future research [13]
Industrial By- the study was to a literature review technique is should focus on
Products/Waste to review the use of of various industrial helping to resource
Manufacture industrial waste/by-products develop low- augmentation
Geopolymer waste/by- and their chemical cost, policies for
Cement/Concrete products as composition, sustainable, and geopolymer
sustainable mechanical desired supporting
building properties, mechanical industrial waste,
materials, durability, financial strength developing a
specifically benefits, and construction complete standard
geopolymer sustainability materials, code for
cement/concrete, aspects in reducing the geopolymer, and
and their producing environmental investigating the
mechanical geopolymer burden. The use effect of
properties, cement/concrete. of industrial influencing factors
durability, waste/by- on compressive
financial benefits, products as strength.
and sustainability sustainable
aspects. building
materials has
considerable
potential to fulfill
sustainable
construction
material
demands.
The Nature of The objective of The study uses a The study Future studies [14]
Coconut Fibre Fly the study is to combination of concludes that could investigate
Ash-Based investigate the sodium silicate and the use of the long-term
Mechanical use of coconut sodium hydroxide coconut fibre as durability of the
Geopolymer fibre as a natural as an alkaline a natural fibre in geopolymer
fibre in activator, with fly geopolymer mortar composites

Page 15 of 20
 geopolymer ash as the base mortar and the potential
mortar material. The composites can environmental
composites, material used in this improve impacts of using
examining the study includes compressive and coconut fibre as a
effects of fibre sand, fly ash, flexural strength, natural fibre.
length and sodium silicate, and that the fibre
percentage on sodium hydroxide, length and
compressive and water, and coconut percentage have
flexural strength. fibre. The coconut a significant
fibre is treated with impact on the
immersion in a 5% strength of the
NaOH solution for 6 composite.
hours, washed The study
clean, and dried at concludes that
room temperature the fibre length
before being cut and NaOH
into 10 mm, 20 mm, concentration
and 30 mm lengths. have a
The study uses a significant effect
combination of on the
experimental and compressive
analytical methods, strength and
including flexural strength
compressive of fly ash-based
strength tests, geopolymer
flexural strength mortar. The
tests, and SEM optimal fibre
analysis. length is 30 mm,
and the optimal
NaOH
concentration is
16 M.
Setting time of The objective of The study uses a The study Future studies [15]
coconut fiber ash- this study is to mixture of CFA concludes that could investigate
based geopolymer investigate the precursors and two the use of CFA the long-term
binder effect of coconut types of alkaline precursors with a durability and

Page 16 of 20
fiber ash (CFA) activators, namely high proportion mechanical
precursors and NaOH (SH) and of mixed P/A and properties of
two types of Na2SiO3 (SS), with SS/SH results in geopolymer
alkaline varying ratios of faster bonding binders produced
activators on the precursor to times. The using CFA
beginning and activator and amount of silica precursors and
ending binding alkaline activator and alumina in alkaline activators.
times of solutions. The CFA is sufficient
geopolymer specimens are cast to cause rapid
binders. in a Vicat ring and hardening.
the setting time test
is conducted
according to the
SNI 2049:2015
standard.

Page 17 of 20
5. Conclusion

Related studies on coconut fiber cement boards and geopolymers concrete highlight the
potential compatibility of the two materials for sustainability and enhanced performance of the
fiber cement boards. This study could not only help the durability of the material, but it also helps
minimize the impact on our environment.

References

[1] I. Budiman et al., “The properties of cement boards reinforced with coconut coir fiber
(Cocos nucifera) as building materials,” IOP Conference Series Earth and
Environmental Science, vol. 762, no. 1, p. 012074, May 2021, doi: 10.1088/1755-
1315/762/1/012074.
[2] A. Brose, J. Kongoletos, and L. Glicksman, “Coconut fiber cement panels as wall
insulation and structural diaphragm,” Frontiers in Energy Research, vol. 7, Mar. 2019,
doi: 10.3389/fenrg.2019.00009.
[3] J. J. A. Calixto et al., “COCONUT FIBER AND PULVERIZED RICE HUSK AS
ALTERNATIVE INGREDIENTS IN CONSTRUCTING CEMENT BOARD,”
International Journal of Innovation and Industrial Revolution, vol. 6, no. 16, pp. 95–
109, Mar. 2024, doi: 10.35631/ijirev.616007.
[4] F. R. B. Martinelli, F. R. C. Ribeiro, M. T. Marvila, S. N. Monteiro, F. Da Costa Garcia
Filho, and A. R. G. De Azevedo, “A review of the use of coconut fiber in cement
composites,” Polymers, vol. 15, no. 5, p. 1309, Mar. 2023, doi:
10.3390/polym15051309.
[5] C. I. Jr. P. Lugay, D. T. Suacoco, M. L. Go, K. M. Espiritu, and M. N. Elamparo,
“Comparative Analysis of the Mechanical Properties of Coconut Fiber Cement Board
and Concrete Hollow Blocks,” IEOM Society International, Mar. 2023, doi:
10.46254/an13.20230472.
[6] C. M. E. Andales, L. M. Animas, Ma. J. D. Dalit, C. W. P. Noriega, and J. J. F. Famadico,
“UTILIZATION OF BAMBOO FIBER AND COCONUT COIR IN THE PRODUCTION
OF CEMENT--BONDED BOARD,” Deleted Journal, vol. 5, no. 2, pp. 76–92, Dec. 2019,
doi: 10.51200/jbimpeagard.v5i2.3271.
[7] https://www.ripublication.com/ijaer18/ijaerv13n10_161.pdf
[8] H. U. Ahmed et al., “Geopolymer concrete as a cleaner construction material: An
overview on materials and structural performances,” Cleaner Materials, vol. 5, p.
100111, Sep. 2022, doi: 10.1016/j.clema.2022.100111.
[9] L. S. Wong, “Durability Performance of Geopolymer Concrete: A review,” Polymers,
vol. 14, no. 5, p. 868, Feb. 2022, doi: 10.3390/polym14050868.
[10] J. A. Abdalla et al., “A comprehensive review on the use of natural fibers in
cement/geopolymer concrete: A step towards sustainability,” Case Studies in
Construction Materials, vol. 19, p. e02244, Dec. 2023, doi:
10.1016/j.cscm.2023.e02244.
[11] M. Camargo, E. A. Taye, J. Roether, D. T. Redda, and A. Boccaccini, “A review on
Natural Fiber-Reinforced Geopolymer and Cement-Based composites,” Materials, vol.
13, no. 20, p. 4603, Oct. 2020, doi: 10.3390/ma13204603.
[12] C. Lv et al., “Effect of plant fiber on early properties of geopolymer,” Molecules, vol. 28,
no. 12, p. 4710, Jun. 2023, doi: 10.3390/molecules28124710.

Page 18 of 20
[13] N. M. Azad and S. M. S. M. K. Samarakoon, “Utilization of industrial By-Products/Waste
to manufacture geopolymer Cement/Concrete,” Sustainability, vol. 13, no. 2, p. 873,
Jan. 2021, doi: 10.3390/su13020873.
[14] R. Zulfiati, N. Saloma, and Y. Idris, “The nature of coconut fibre Fly Ash-Based
mechanical geopolymer,” IOP Conference Series Materials Science and Engineering,
vol. 807, no. 1, p. 012041, Mar. 2020, doi: 10.1088/1757-899x/807/1/012041.
[15] I. N. S. Widnyana, I. M. a K. Salain, I. N. Sutarja, and I. B. R. Widiarsa, “Setting time of
coconut fiber ash-based geopolymer binder,” IOP Conference Series Earth and
Environmental Science, vol. 1117, no. 1, p. 012001, Dec. 2022, doi: 10.1088/1755-
1315/1117/1/012001.

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