Road Construction Project: Utilizing Plastic Waste Materials

This research paper proposes the use of plastic waste in road construction as a substitute for conventional bitumen, aiming to enhance road mechanical characteristics and reduce plastic waste disposal. The study investigates modifying waste plastics with bitumen to achieve a more water-resistant road surface with improved density, stability, and binding properties. It reviews techniques for applying plastic wastes in road construction, including the dry, wet, and basic processes. The research methodology involves primary research through case studies and interviews, as well as secondary research, to evaluate the suitability of plastic waste materials for road construction. The paper also reflects on the challenges and benefits of using plastic waste, highlighting its potential to address both waste management and road quality issues.

Road Construction Using Plastic Waste 1
ROAD CONSTRUCTION USING PLASTIC WASTE
A Research Paper on Construction By
Student’s Name
Name of the Professor
Institutional Affiliation
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Year/Month/Day

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Table of Contents
INTRODUCTION...........................................................................................................................................2
Aim and Objectives..................................................................................................................................3
Definition of Key Concepts......................................................................................................................3
Background..............................................................................................................................................4
RESEARCH METHODOLOGY.........................................................................................................................5
Primary Research.....................................................................................................................................6
Case Study...........................................................................................................................................6
Basic process.......................................................................................................................................6
Wet Process.........................................................................................................................................7
Dry Process..........................................................................................................................................9
Interviews............................................................................................................................................9
Secondary Research...........................................................................................................................10
LITERATURE REVIEW..................................................................................................................................10
PROJECT ANALYSIS....................................................................................................................................12
PROJECT REFLECTION................................................................................................................................14
CONCLUSION.............................................................................................................................................16
BIBLIOGRAPHY...........................................................................................................................................17
APPENDIX..................................................................................................................................................19

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INTRODUCTION
This research paper is a project proposal for the road construction using plastic waste
which is made entirely by the composites of plastics or plastic wastes. The growth in population,
technological, consumerism, and industrialization development have resulted in the uncontrolled
plastic waste accumulation. Proper disposal of waste is of great significance in both urban and
rural regions. This paper proposes the suitability of the plastic waste materials for the
construction of roads. The rate of plastic waste production has tremendously increased in
numerous countries globally in the past few decades. The amount of accumulating waste have
led to the problems with the disposal. The conventional methods of waste disposal have been
proved to be inefficient and hence there is a need of coming up with better ways of handling
these wastes.
The application of plastic wastes in the construction of roads is not something new in the
construction industries. Recent researches have proved that there are some hopes in terms of the
application of plastic waste in the construction of roads which are commonly referred to as
plastic roads. The plastic roads are expected to use the PET bottles, disposable cups, and carry
bags which are collected from disposal sites such as garbage sites and used as ingredients of the
construction materials. When the plastic wastes are mixed with bitumen, the plastics melt and
form an oily coat on top of the aggregate and the mixture is then placed on the surface of the
road like an ordinary tar during road construction.
Aim and Objectives
The main aim of this research paper is to propose the use of the plastic waste in the construction
of roads to replace the commonly used conventional bitumen so as to improve the mechanical
characteristics of the road and also reduce the disposal of waste plastics in the environment. The
research also seeks to review how the waste plastics can be modified together with bitumen so as

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to attain a more water resistant road surface, high density, stability, and better binding property.
The paper also seeks to develop the techniques that can be used during the application of plastic
wastes in the roads constriction (Aalbers, 2009).
Definition of Key Concepts
The key concepts involved in the proposal of the application of plastic waste in the
construction of roads include the plastic wastes, bitumen, plastic roads, aggregates, mechanical
characteristics, and bitumen-plastic-aggregates mixture. The plastic roads are roads that are made
entirely of plastic composites or plastic materials and are much different from the ordinary roads
which are normally made of asphalt and mineral aggregates. Bitumen is a composite material
and acts as a binding agent for the aggregates in the bituminous mixtures. Plastic wastes are non-
biodegradable materials which form the greatest percentage of the disposed of plastic wastes.
Plastics are materials with a single or more organic polymer of huge molecular weights and can
be categorized into thermoplastics, elastomers, and thermosets (Ahmed, 2009).
Background
More than 7.2 million tonnes of waste materials are generated and then disposed into the
environment yearly making the disposal of waste to be a major problem since approximately one
kilometre of the load is needed for the purposes of waste disposal yearly. Industries also dispose
of more than 150 million tonnes of waste materials that are hazardous yearly which are majorly
disposed of in an open section of the environment. Plastic wastes are one of the major
components of the solid waste which are disposed and available abundantly without proper
treatment. There has been an exponential increase in the municipal plastic wastes especially in
urban sectors which have been to the deterioration of the landscape beauty of these regions
(CHAKROBORTY, 2017).

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Majority of the current roads have the bituminous base and granular base. The large-scale
production of plastics seems to be the cheapest and effective raw materials in the road
construction due to the industrial revolution. Currently, all the vital sectors in the economy
beginning with communication, building construction, electrical, electronics, automobile,
packaging, and agriculture have revolutionized through the application of plastic materials.
Plastic is a material that is non-biodegradable and has been proved to have the ability to remain
on the surface of the ground for over 4500 years without being degraded. The plastic materials
also cause health hazards when improperly disposed into the environment after being used
(Chandra, 2012).
There have been numerous researches which seek to investigate the application of waste
plastics in the road construction since the plastic roads have been proved to be better compared
to the ordinary bitumen. The researches have proved that when the waste plastics are used in
coating the aggregates of the bituminous mixture, their results show better performance
characteristics. The application of plastic waste helps in the improvement of the slip resistance
and abrasion of the road surface substantially and also enables satisfaction in the slipping tensile
strength of the mixture (Davim, 2014).
RESEARCH METHODOLOGY
This section explains the research methods of the proposed plastic waste in the road
construction. The methodology is the collected system within which the theories upon which the
research is conducted or research is conducted. The chapter in addition to evaluating the
strategies of the research also clarifies the selection of the researchers to progress his studies by
descriptive case study. It is also to find out among others by interviewing and observing the
application of plastic waste in the road construction. Further, the research seeks to explain the

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circumstances why the conventional road construction methods are still common despite the
availability of plastic raw materials and also the costly nature of bituminous substances (Davim,
2014).
By this, the researchers strive to unravel evidence as a supplement to theory-based
practice. The case study is expected to illuminate the real-life circumstances which in itself can
offer leads to further theories. The chapter further summaries the techniques of data collection,
research approach, method, and strategies. There are three methodologies that can be used in this
research on the application of plastic waste in the road construction experimentally, these
methodologies include the dry process, basic process, and wet process (Development, 2013).
Primary Research
Case Study
There have been numerous experiments conducted to investigate the possibilities of using
the plastic waste materials in the construction of roads. According to the researchers who
performed these experiments, the waste plastics are the major problems facing any economy and
also the deterioration of road quality was noted to be of great concern. The increased number of
road users and the poor quality of construction materials can also be the reason for them to
conduct the research. In the investigations, the autoclaved plastic waste in the form of shredded
syringes was used and then prepared with the traditional mixture of bitumen. Better performance
was noted for the case of asphalt concrete after conducting the loss of stability test and stability
test and the conclusion made was that the waste plastics can be used as binder materials
effectively in the construction of roads (Dhir, 2010). The following are some of the processes
that can be adopted during the experimental setup to investigate the application of plastic waste
in road construction:

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Basic process
In the basic process, the first process carried out is the segregation process where the plastic
wastes are collected from numerous sources such as dumping sites and then separated from other
categories of solid wastes. During this process, the maximum thickness observed is the 60
Microns. The next process is the cleaning process where the collected plastic waste materials are
cleaned and then tried and then shredded in the next process of shredding. During shredding, the
cleaned plastic materials are cut or shredded into smaller pieces after being mixed together
(Ekolu, 2014). The figure below shows the shredding process of cleaned plastic waste materials:
Figure 1: Shredding of waste plastic materials (Forrest, 2014)
The last process is the collection of the waste plastic materials having 2.36mm after which the
collected plastic waste can be mixed with heated aggregates.
Wet Process
In the wet process, the waste plastic materials are ground and then shredded into power.
8% or 6% of these grounded plastics are mixed with the bitumen. The plastics will increase the
melting point of the bitumen and make the road to retaining its flexibility during the periods of
winter resulting in a longer lifespan of the road. The application of the shredded plastic wastes
acts as a strong agent of binding for the tar resulting in a long lasting asphalt. By mixing the
bitumen with shredded plastic, there will be an increase in the ability of the bitumen to sustain
high temperature. The plastic waste should be mixed and melted together with bitumen in a

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specific ratio (Hebel, 20). The figure below shows the process flowchart of the plastic coated
bituminous mix road:
Figure 2: The process flow chart of the plastic coated bituminous mix road (Hossain,
2017)
The blending of bitumen and waste plastics will take place when the temperature of
45.5oC is attained and the mixture will retain its stability even if the temperature reaches 55oC.
The numerous tests that have been performed show that bituminous concrete mixture prepared
by the bitumen binder treated. It was noted that there was a significant improvement in the
Marshall Stability value of the mixture which was two times higher value compared to the
ordinary or untreated bitumen. The major advantage of this process is that this approach can be
used for recycling plastic waste materials of any shape, size, and type. There are numerous
disadvantages of this wet process is that only a maximum percentage of waste plastics can be
added around 8%, there is need for additional cooling since improper addition of bitumen may

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result in air pockets on road, there is need of powerful mechanical systems, and also the process
is time-consuming during blending (Hunter, 2013).
Dry Process
In this dry process, hot bitumen of temperature 160oC is mixed with the hot stone
aggregate of temperature 170oC and then the mixture is used for laying of roads. The aggregates
are selected on the grounds of their moisture absorption capacity, porosity, and strength as per
the IS coding. The bitumen is selected on the grounds of its viscoelastic property, penetration
value, and binding property. The aggregates after being coated with waste plastics improve its
quality in terms of the soundness, moisture absorption, and voids in the surface. The plastic
coating reduces the porosity and assists in improving the performance and quality of the
aggregate in the flexible road (Khatib, 2009).
Some of the advantages of the dry process include lack of toxic gases evolution at the
optimum temperature of 180oC, can be performed in all types of climatic conditions, no
degradation of roads even after 5 years after construction, coated aggregates have higher
strength, bitumen bonding increases, no new equipment is needed, doubles the binding property
of the aggregates, it is possible to use plastics more than 15%, and also there is an easy coating
and the temperature needed is similar to the road laying temperature. The major disadvantage of
the dry process is that the process is only applicable to plastic waste materials (McNally, 2016).
Interviews
The key stakeholder was contacted after being identified through formal phone calls and emails.
The questions for the interviews were based on the conducted primary research on the
application of plastic wastes from the construction of roads. The quantitative and qualitative

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information collected through semi-structured and structured interviews during the field visit
were analyzed and transcribed subsequently (Qingli, 2018).
Secondary Research
The secondary research involved visiting the construction sites and interacting with the
stakeholders and participants involved in the road construction using the plastic wastes. The aim
of the secondary research was to gather quantitative and qualitative data together with the
supporting documents (Siddique, 2009).
LITERATURE REVIEW
The two major types of plastics include the thermosetting plastics and thermoplastic
plastics. The thermoplastic plastics include Polystyrene, Polypropylene, High-Density Poly
Ethylene, Poly Vinyl Chloride, Low-Density Poly Ethylene, and Polyethylene Terephthalate.
These types of plastics can be recycled. The thermosetting plastics include multilayer plastics,
metallized plastics, polyurethane, urea formaldehyde, silicon, phenolic formaldehyde, melamine
formaldehyde, ester, epoxy, and alkyd. Some of the ways in which the mismanagement of the
plastics is a threat to the environment include:
 Some unhygienic wastes are hazardous to the environment
 May hinder the landfill operations when garbage mixed with waste plastics
 The emission of polluting gases when burning the garbage containing plastics
causing air pollution
 Filthiness in public places and choking of drainage systems as a result of littering
(Tchobanoglous, 2009)
One of the ways of waste plastics management is through using them as construction materials
for roads and pavements which serves the two purposes of resolving the environmental issues as
a result of the increase in waste plastics and also the durability and stability of the roads. One
must be familiar with the specific properties of materials and the processes involved in the

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construction of roads so as to understand the role of waste plastics in construction
(Tchobanoglous, 2010). The figure below shows the differences between the stone aggregate
with plastic and without plastic according to the test results:
Figure 3: Properties of aggregate improved by the plastic coating (Tukker, 2011)
Bitumen plays a significant role in binding the aggregates together by coating the aggregates
hence strengthening the road. Nevertheless, because of the high cost and poor resistance of
water, there is a need for high bitumen quality at low cost. This can be attained by the
modification of bitumen by the use of additives such as rubber and plastics. Some of the various
categories of aggregates used in road construction as shown in the figure below:
Figure 4: Types of aggregates used for the construction of roads (Tukker, 2011)

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Since the construction of plastic roads is the relatively new idea in the construction
sector, the process of construction may vary depending on the type of Construction Company.
There are numerous applications of the disposed of plastic materials and the first step in the
construction of roads include the management and collection of the plastic components from the
disposal sites. The plastic materials that can be used in the construction of these roads are
majorly composed of post-consumer products like product packaging. Some of the commonly
used types of plastics in packaging include low and high-density polyethene, polypropylene, and
polyethylene terephthalate. These plastic wastes are first sorted from other solid waste products
and then cleaning, drying, and shredding processes can be carried out (Wainwright, 2010).
PROJECT ANALYSIS
This section analyzes the anticipated problems with the data collection, identification of
the analytical tools for solving problems such as faulty questionnaires, interviewer bias, and
triangulation of data. Some of the participants are expected to refuse to speak against their
organisation especially on the negative aspects regarding their organizations. The method of
qualitative research does not permit complete determination of the problem examined. There is
also the challenge of social desirability which denotes that the respondent provides the most
conventional response socially to the questions instead of the complete truth. There is also need
of educating the examiners and the time allocated for the interview sessions is expected to the
financial disadvantage during the process of data collection since it is difficult for the workers to
spare time during working hours (Wainwright, 2010).
There are also likely to the problems relating to translations since some respondents use
certain expressions and languages which may be differently interpreted in English. These are
because there are numerous international construction companies working in the country and