CIV8803: PET Fiber Reinforced Concrete Bridge - Design and Analysis

This report investigates the feasibility and design of a PET Fiber Reinforced Concrete Bridge, focusing on utilizing waste PET fiber to enhance concrete's properties and promote sustainability. The report covers various aspects, including the introduction and background of fiber-reinforced concrete, the concept and innovation behind using PET fiber, strength and durability requirements (compression strength, temperature resistance, collapse prevention, and resistance to moisture and UV radiation), the design and evaluation process (including design principles, stress analysis, load considerations, and seismic design), and application and maintenance considerations. The study highlights the potential benefits of PET fiber in improving concrete's tensile strength, ductility, and resistance to shrinkage while also addressing environmental concerns related to plastic waste disposal. The report provides a comprehensive overview of the design considerations and potential advantages of using PET fiber reinforced concrete in bridge construction.

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THE USE OF FIBRE WASTE IN CONCRETE FOR A SUSTAINABLE ENVIRONMENT
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Table of Contents
1. INTRODUCTION AND BACKGROUND...................................................................................................2
2. CONCEPT AND INNOVATION...............................................................................................................3
2.1 PET Fiber Reinforced Concrete Bridge.........................................................................................4
3. STRENGTH AND DURABILITY REQUIREMENTS.....................................................................................5
3.1 Compression Strength.......................................................................................................................5
3.2 Durability Requirements....................................................................................................................6
3.2.1 Temperature...............................................................................................................................6
3.2.2 Collapse......................................................................................................................................7
3.2.3 Moisture and UV radiation.........................................................................................................7
3.3 Fibers.................................................................................................................................................7
3.4 Resin..................................................................................................................................................9
3.5 Fabrication process............................................................................................................................9
4. DESIGN AND EVALUATION.................................................................................................................10
4.1 PET bottle fibre Reinforced Concrete Bridge...................................................................................11
4.2 Design Principles..............................................................................................................................12
4.3 STRESSES..........................................................................................................................................13
4.4 LOADS..............................................................................................................................................13
4.5 SEISMIC DESIGN...............................................................................................................................13
4.6 EVALUATION....................................................................................................................................14
5. APPLICATION, MAINTENANCE AND OTHER ISSUES...........................................................................15
6. REFERENCES......................................................................................................................................16

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1. INTRODUCTION AND BACKGROUND
The research and development of various approaches and materials in civil engineering are
aimed at determining the outcome in which the financial constraints, environmental preservation
or compatibility, and availability aspects are considered. Consequently, the construction material
selection should only be made after a thorough assessment of environmental preservation or
compatibility, durability in the structure, and long-term performance. Concrete is a composite
construction material composed of majorly water, cement, and aggregate (Shoeb & Chavan,
2016). Fibre waste such as wastes from natural fibers, synthetic fibers, glass fibers, and steel
fibers, can be used in concrete to control cracking caused by drying shrinkage and plastic
shrinkage.
The use of natural fibers in construction materials has taken place since ancient times through
strengthening of mortar with horse hair or use of straw in sun-dried mud brick. Fibers have been
applied in the reinforcement of construction concrete since time memorial. The asbestos fibers
were used in concrete in the 1900s. The concept of fibre-reinforcement and composite materials
became interesting topics in the 1950s (Ransubhe, 2018). Once the health risks related to
asbestos were revealed, there was a need to determine a replacement for the substances in
concrete and other construction materials. The synthetic, glass, and steel fibers were used in
concrete by the 1960s. The benefits of using fibers can assist in reducing the cost of building and
also conserving the environment through optimization of agricultural and plant waste.
Currently, concrete is the most exceedingly used materials in construction because of its high
compressive strength, low cost, and long service life. The major shortcoming of concrete
material is that it has low tensile strength. There is a need to improve the strength of concrete by
the construction industry by determining cost-effective materials to introduce into the concrete.

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An attempt has been made in various investigations to determine the effect of introducing waste
materials such as waste plastic bottles, empty waste tins, soft drink caps, and lathe waste so as to
improve the strength of concrete shows positive results (Karanth, et al., 2017). The use of PET
fiber waste not only improve the durability, shrinkage, and toughness of concrete but also
provides the extra benefit of resource preservation and waste reduction.
2. CONCEPT AND INNOVATION
Currently, there has been numerous research on the use of innovative material in concrete to
improve the characteristics. The major problem in the present world is the disposal of waste
since the majority of these wastes are non-biodegradable. Therefore, researchers have introduced
a new method of reusing the fiber wastes materials which some may be non-degradable. The
most common wastes are referred to as PET or POLYETHYLENE TERPHTHALATE which is
acquired from a huge quantity of water bottles used as water bottles and soft drink containers. It
is approximated that in 2008, 2,400,000 tons of plastic jars and bottles were disposed of. 10% of
the plastic bottles manufactured yearly across the world and disposed into the water bodies and
70% of the disposed of wastes settle under the water bodies according to the UN.
The rate of recycling of waste plastic bottles is as low as 13% where they are converted into
products such as new containers, playground equipment, decks, carpeting, and clothing. Concrete
is a mixture of water, coarse aggregate, fine aggregate, and cement. Concrete plays a significant
role in the development of highways, bridges, industrial structures, buildings, and infrastructure
(Lei & Ozbakkaloglu, 2016). Currently, concrete is the most exceedingly used materials in
construction because of its high compressive strength, low cost, and long service life. The major
disadvantage of concrete material is that it has low tensile strength. Presently, the construction
industry is in need of determining cost-effective materials to improve concrete strength. An

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attempt has been made in various investigations to determine the effect of introducing waste
materials such as waste steel powder, empty waste tins, soft drink caps, and lathe waste so as to
improve the strength of concrete.
Some of the innovations that have been implemented to increase the strength of concrete include
the addition of both short and long fiber, the introduction of pre-compression through the pre-
stressing method, addition of resins and chemicals, introduction of numerous layers of wire
mesh, and introduction of steel reinforcement. However, these techniques do not improve the
tensile strength of concrete but the basic properties of concrete are improved by adding small
fibers to the material. The tensile strength of concrete can be improved by introducing fibers.
2.1 PET Fiber Reinforced Concrete Bridge
By introducing PET fiber into the concrete during bridge construction, it provides high tensile
strength and high ductility but minimizes the workability. Fiber wastes from plastic drink bottles,
cement bags, disposable glasses, polythene bags, and water bottles can be used as construction
materials to improve the properties of concrete such as shrinkage, impact strength, and flexural
strength (Kien, et al., 2018). The use of fiber waste not only improve the durability, shrinkage,
and toughness of concrete bridge but also provides the extra benefit of resource preservation and
waste reduction.

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Figure 1: Conceptual drawing of PET Fiber Reinforced Concrete Bridge (Iskhakov & Ribakov,
2013)
3. STRENGTH AND DURABILITY REQUIREMENTS
3.1 Compression Strength
The compression strength of PET Fiber Reinforced Concrete Bridge is the most common test
performed for acceptance of concrete. Despite strength is not normally a suitable indicator of the
durability of concrete, most concrete will need a minimum level of compression strength for the
purposes of structural designs regardless of the application. Concrete can have a variety of
compressive strength for a total cementitious content or a given w/cm. For every set of materials,
there is a unique relationship between fibre-cement and strength ratio (Tosun, et al., 2012). The
compression strength can range from 4000, 5000, and 6000 psi depending on the type of
reinforcement used in the cement mixture. For this PET Fiber Reinforced Concrete Bridge, the
strength requirements are shown below:
In Tension:
 Total fracture energy: 30,000 – 20,000 J/m
 Modulus of rupture, design characteristic: 15 MPa
 Modulus of rapture, Mean Test Results: 39 – 25 MPa
In Compression:
 Ductile softening behaviour than other high-strength concrete
 Design Young’s Modulus: 47GPa
 Design Strength: 160 – 140 MPa
 Mean compression strength: 185 – 175 MPa
 Durability design requirements of fiber reinforced concrete
compared with ordinary concrete (Várdai, 2017)
The tensile strength of the fibre reinforced concrete and the behaviour after cracking depend
highly on the quantity and type of fiber crossing the crack.

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3.2 Durability Requirements
When it comes to the durability of concrete, the design requirements should not only depend on
air entrainment, minimum cementitious content, maximum concrete-fibre ratio, and minimum
compression strength. There are suitable methods of quantifying the durability requirements. The
shrinkage and low permeability are two characteristic performance of concrete that can lengthen
the life service of the bridge that is subjected to the extreme conditions of exposure (Yamaguchi,
et al., 2011). The fiber reinforced concrete is expected to exhibit exceedingly high resistance to
aggressive agents because of the absence of capillary porosity.
Durability requirement properties of the bridge:
 Water absorption: 2.5kg/m2
 Abrasion coefficient: 1.3
 Chloride ion diffusion: 2x10-8 mm2/s
 Microporosity: <1%
 Total porosity: 2-6% (Correia, et al., 2014)
3.2.1 Temperature
The temperature around the area where the PET Fiber Reinforced Concrete Bridge will be
situated is expected to affect the durability and the materials used in the construction of the
bridge. However, the PET fibre reinforcement is expected to improve heat resistance of the
bridge from high environmental temperature or fire outbreak but such high temperatures may
affect the performance of the bridge (Magalhães & Fernandes, 2015).
3.2.2 Collapse
When it comes to the durability of the PET Fiber Reinforced Bridge, there is the possibility that
the bridge may collapse as a result of those factors caused by natural calamities such as flooding
and seismic activities, or defects during the construction process (Neverkovica & Korjakins,
2014). The design of the bridge should be able to support various loads ranging from heavy and

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wide loads in all weather conditions. The construction materials used should have sufficient
strength to prevent buckling and stresses.
3.2.3 Moisture and UV radiation
The moisture and UV radiation extremely affect the performance of the PET Fiber Reinforced
Concrete Bridge by initiating cracks and damaging the fiber composites in the construction
material. Therefore, there is need of checking the construction materials to prevent any future
failures of the bridge (Jue, 2012). The long-term durability of the bridge is affected by the UV
radiations and moisture around the bridge.
3.3 Fibers
The tensile strength of concrete that will be used in the construction of the bridge above can be
improved by PET bottle fibre. The use of fiber waste from PET bottles not only improve the
durability, shrinkage, and toughness of concrete but also provides the extra benefit of resource
preservation and waste reduction. The PET fiber use is the concrete mix have been acquired after
an expensive and long process from the waste bottles and then divided into fiber length required.
Figure 2: PET bottle fibers (Welle, 2013)
Some of the properties of the PET bottle fibers include:
 Elongation: 64.7%
 Tensile strength of the fiber: 178.78 MPa

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 Aspect ratio: 69.
By the use of the compressive testing machine, Young's modulus, flexural strength, split tensile
strength, and compressive strength. The flexural strength, split tensile strength and compressive
strength of the PET bottle fibre reinforced concrete are shown in the table below:
Table 1: Flexural strength, split tensile strength and compressive strength of the PET bottle fibre
reinforced concrete (Correia, et al., 2014)
It can be seen that the value of flexural strength, split tensile strength and compressive strength
increases with increase in the time of curing. The increase in split tensile strength shows that the
interaction between concrete matrix and fibers. Since the flexural strength is the ability of a
material to resist deformation under load by increasing the deformation of flexural strength of the
structure will also minimize (Lachance, et al., 2016). The Young's modulus of the PET bottle
fibre reinforced concrete increases with an increase in the fibre content.
3.4 Resin
By reinforcing concrete with PET bottle fibre it provides its high tensile strength and high
ductility but minimizes the workability. The workability of PET bottle fibre reinforced concrete
can be improved by the used resin known as Superplasticizer (Mahmoud, et al., 2010).
Superplasticizer is a chemical admixture improves the workability of the construction material.
This resin is based on naphthalene and is recommended highly for high ultimate and early

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strength and increasing workability of concrete (Vinayagam, 2012). For the bridge design
requirements, the dosage of superplasticizer used is 0.8% by weight of cement.
3.5 Fabrication process
The fabrication process of PET bottle fibre Reinforced Concrete Bridge is fairly simple. The
process starts with the preparation of cement which involves the mixing of materials such as
alumina, silica, and limestone and then preheated and calcines. The cement is then mixed with
ingredients such as water, PET bottle fibre, Superplasticizer, water, and aggregates. The
aggregate is generally crushed rocks or course such as granite or limestone, together with a fine
aggregate like sand. PET bottles used in the concrete mix are acquired from the wastes and then
cut into the fibre length required (Chun, et al., 2013). The circular fibers are most preferred due
to their high performance compared to the lamellar ones since they provide a higher adherence of
concrete-fibre also for high stress. The circular fibers acquired through perpendicularly cutting
waste bottles to their longitudinal axis. The workability of PET bottle fibre reinforced concrete is
then improved by the adding resin known as Superplasticizer into the mixture and then water.
The operation of mixing is done through stirring or rotation to blend other ingredients until
uniformity is attained.
4. DESIGN AND EVALUATION
By introducing PET fiber into the concrete during bridge construction, it provides high tensile
strength and high ductility but minimizes the workability. The workability of PET bottle fibre
reinforced concrete can be improved by the used resin known as Superplasticizer. The use of
PET fiber waste during the Bridge construction not only improve the durability, shrinkage, and
toughness of concrete bridge but also provides the extra benefit of resource preservation and
waste reduction (Fangwen, et al., 2015). The design considerations of PET bottle fibre

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Reinforced Concrete Bridge also considers the factors that the PET bottle fibre used for fibre
Reinforced Concrete must not be of other waste materials such as natural fibers, synthetic fibers,
glass fibers, and steel fibers. In case there is any additional processed waste PET glass fiber to be
made, then it should be collected from dumped sites and processed before mixing with the
concrete.
Plastic Drink Bottles
Cement Bags
Polythene Bags
Water Bottle
Empty Waste Tins
Soft Drink Caps
Table 2: PET bottle fibre for PET Fibre Reinforced Concrete Bridge (Shen, et al., 2010)
PET bottle fibre materials are prepared using Superplasticizer which is a chemical admixture that
improves the workability of the concrete matrix. The major characteristics of PET bottle fibre
that are required to ensure the required criteria of Reinforced Concrete Bridge are met are shown
in the table below:
Characteristics Performance
Elongation 64.7%
Tensile strength 178.78 MPa
Aspect ratio 69.
Water absorption >2.5
Flexural strength >40MPa
PET bottle fibre content 25wt%
Table 3: PET bottle fibre physical characteristics (Grimaldi, et al., 2013)
4.1 PET bottle fibre Reinforced Concrete Bridge
Design considerations for PET Fibre Reinforced Concrete Bridge are as follows:

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Width and Flow of River: The width of the river affects the bridge construction. In case the width
of the river is less, then the bridge will be cheaper and economical to design and build. If the
river is very wider, then this will mean that the dimensions of the bride will be wider and extra
materials will be required as well as cost. The bridge construction is also affected by the flow of
the river. In case the velocity of river flow if lower than a specific value, the silting will take
place and may affect the bridge foundation. The flow of the river influences the foundation of the
bridge.
Seismic and Geotechnical data: Research should be done to determine the factors like
earthquake sensitivity and the soil liquefaction of the region. The bridge should be designed to be
earthquake resistant to reduce the possibility of damage and collapse. The base isolation
techniques and seismic retrofitting are the current technologies that can be applied to assist in
reducing the impacts of earthquakes and seismic activities (Khan, et al., 2014).
Loads: The anticipated loads of the bridge should be considered during the design. The dead load
involves the combination of weight of the dead materials used and the superstructure. The
weights should be determined during bridge design and the weight of the decking materials
determined for both lightweight and normal concrete matrix.
4.2 Design Principles
PET bottle fibre Reinforced Concrete Bridge must not be located across rivers with the irregular
flow of water since such flows may cause problems during the process of construction and
maintenance. The selected section of the river where the bridge should be positioned across the
river where the flow is smooth without cases of flooding are rear and the river is straight at the
downstream or upstream. Flooding may also affect the foundation and decking materials of the