Varun Suriyanarayana

PLASTIC ROADS – THE WAY AHEAD (A RESEARCH REPORT)

[49]

Varun Suriyanarayana Guided by Dr. Rajappan Vetrivel

Varun Suriyanarayana

CONTENTS RESEARCH QUESTION ............................................................................................................................. 3

ABSTRACT ............................................................................................................................................... 3

HOW ARE ROADS MADE? ...................................................................................................................... 4

COMPARISON OF TYPES OF ROADS IN USE TODAY .............................................................................. 5

Bitumen/Asphalt roads: ..................................................................................................................... 5

Tar road: ............................................................................................................................................. 5

Concrete Road: ................................................................................................................................... 6

WHAT ARE PLASTIC ROADS? .................................................................................................................. 6

TYPES OF PLASTICS USED IN PLASTIC ROADS ........................................................................................ 7

TWO PROCESSES USED IN THE CONSTRUCTION OF PLASTIC ROADS ................................................... 7

Wet Process: ....................................................................................................................................... 7

Dry process: ........................................................................................................................................ 7

CONSTRUCTION OF PLASTIC COATED BITUMEN ROAD ........................................................................ 8

SIGNIFICANT FEATURES OF THIS PROCESS ............................................................................................ 9

Durability ............................................................................................................................................ 9

Environmental advantage ................................................................................................................ 12

Economic advantage ........................................................................................................................ 14

Safety advantage .............................................................................................................................. 15

CONCLUSION ........................................................................................................................................ 15

BIBLIOGRAPHY ...................................................................................................................................... 17

Varun Suriyanarayana

RESEARCH QUESTION Should plastic roads be the preferred option in road construction for highly populated countries?

ABSTRACT Challenges are a way of life. From challenges arise the endeavour to find solutions. Two such challenges that countries with large populations face are effective disposal of plastic waste and establishing a road network that is economical and durable. On the face of it, it appears odd to bring up two matters, so different in nature, together. However, there is a solution that connects the two problems. Current methods adopted to deal with plastic waste disposal worldwide include use of landfills and incineration. Both methods are known to have environmental and safety concerns. Today the majority of roads are constructed using either bitumen, tar or cement. Each of these have their own merits and demerits. Another kind of road has been suggested: plastic road. This provides a solution to the problem of effective disposal of plastic waste at the same time increases the strength and durability of the road, addresses the environmental, economic and most importantly safety issue.

INTRODUCTION Our rapid advances in technology have done much to improve our quality of life and our

environment but in the process we have also produced a number of issues. Two such issues

are plastic waste disposal and establishing a road network which is both economical and

durable. Every year the world produces 275 million tonnes of non-recycled non-

biodegradable plastic waste. [6] The problem of disposing this plastic waste has been around

for several years and all the solutions that have been implemented on a large scale have

flaws, both environmental and economic. On the other hand, growth and development of

an economy has always been intrinsically dependent on transportation via a presence of a

reliable and extensive road network. Most developing countries often encounter problems

in the quality and durability of their roads and this in turn impacts the economy significantly.

India, a country with the second largest road network in the world with 4.7 million

kilometres of roads as of May 2, 2014, is no exception. [30]

Dr. R Vasudevan of the Thiaragar college of engineering in Madhurai, India came up with a

solution to build roads by integrating a fraction of plastic waste into the Bitumen and

aggregate mixture. His idea has been implemented in a number of places across India. The

first plastic road was laid in Kovilapatti of Tuticorin district on October 4th 2002. In order to

understand how they are a solution to today’s problems one must first understand what

they are and how they are built.[24] This paper will examine what a plastic road is, how it is

built, its environmental implications, economic impact and finally safety features.

Varun Suriyanarayana

WHAT ARE ROADS? According to the Organisation for Economic Co-operation and Development (OECD), a road

is a “Line of communication (travelled way) using a stabilized base other than rails or air

strips open to public traffic, primarily for the use of road motor vehicles running on their

own wheels.”

Pharaoh Cheops is believed to be credited with the building of the first road around 2500

BC. This road was 1000 yards long and 60 feet wide and led to the site of the Great Pyramid.

It was put in place for making the pyramid and later visiting it. With time, more and more

roads were made to promote trading.

HOW ARE ROADS MADE? Bitumen and Tar roads are laid in several stages. The land on which the road is to be built is

cleared of all vegetation. All rocks and stones are removed. Ditches, basins and fences are

installed to prevent erosion on the land that has been cleared. Then bulldozers and diggers

are used to mount soil and dirt onto the land. Drains made from concrete pipes are also

installed to ensure that rainwater does not flood the road. After this the road is graded or

levelled. This requires a combination of manpower and machines. In order to ensure that

the levelling is stable, concrete or limestone is used. This grading process is repeated before

a stone aggregate base layer is added. This aggregate consists of crushed stone or gravel or

granite. The layer is evenly placed and if the road is in a city, a gutter will be constructed

right after the stone aggregate is placed. After this the road is graded again. Then up to 4

layers of Bitumen are applied one at a time and the final touches on the drainage system

are made just before the final layer of Bitumen is added. After this the road is left to set. [1]

The Bitumen acts as a binding agent and seals the aggregate to form a smooth surface on

which vehicle can travel.

Concrete roads on the other hand require the concrete mix to be prepared in the ready mix

plant from where it is transported to the site where the road is to be laid. It is then poured

into a frame work that defines the final size and shape. Once poured the concrete must be

consolidated. This ensures that all air voids are removed and the concrete is evenly

distributed all over the framework including nooks and corners. This process is also referred

to as Compacting. This is followed by Finishing. Finishing provides the road with a smooth,

durable and appealing surface. The final step is Curing. This is ensuring that the concrete is

fully saturated while hardening. Once properly cured, the concrete develops the requisite

properties which make it stronger and more durable.

Varun Suriyanarayana

COMPARISON OF TYPES OF ROADS IN

USE TODAY There are 3 major types of roads that are used today. These are Bitumen/asphalt roads, tar

roads and concrete roads.

Bitumen/Asphalt roads: These roads are made using Bitumen and a stone aggregate. Two kinds of stone used are

gravel and granite. The Bitumen is a substance derived from crude oil. It is a hydrocarbon

that is semi-solid. It is obtained by refining heavy crude oil. It is the residue obtained by

fractional distillation which removes lighter fractions such as kerosene, naptha, gasoline and

diesel. 85% of the 102 million tonnes of Bitumen produced per year is used for paving[21].

Bitumen is obtained from crude oil, which is a depleting natural resource. The cost of

constructing these roads varies from 20 - 30 lakhs per kilometre (km) for a single lane.

However, very often these roads do not score high on strength and durability. They are

affected by weather conditions. In the summer, high temperatures cause Bitumen to

become soft which results in bleeding, rutting as well as segregation and finally breaking

down of the road. On the other hand in winter, low temperatures cause the road to become

brittle resulting in cracking, ravelling and unevenness, rendering the road unsuitable for use,

in the monsoon, when the rains are heavy the water enter the road creates potholes and

sometimes removal of the Bitumen layer. In mountainous and hilly places where

temperatures drop to below zero degrees, the freezing and melting of ice in the bituminous

voids causes the water to expand and contract. This damages the road. [27]Fuel or oil leakage

from vehicles can also cause damage. [23]

On the positive side, Bituminous roads cost around 25% less than concrete roads. They are

very easy to repair and they also score higher on safety as they have more skid resistance in

wet conditions, than concrete roads. The Bitumen used is recyclable, the process of laying

the road is carried out on site and since there is no industrial process required, it is simple

and convenient. Construction poses no risk. [23]

Tar road: Tar roads are largely similar to Bitumen roads except for the fact that tar is used instead of

Bitumen. Tar is similar to Bitumen in appearance in that it is black and sticky. Tar is

produced from coal. When coal is heated to high temperatures it forms coke and carbon

dioxide. Tar is a by-product. It was used as the binding agent but has over time been

replaced by refined Bitumen. [20]

Tar is obtained from coal, which is a depleting natural resource, the road does not perform

well in high temperature conditions. Tar does not lend itself to even levelling as a result fuel

efficiency of vehicles travelling on Tar roads is less. The biggest concern with the tar road

arises from the fact that it poses a cancer risk for those who work to construct it. [23]

Varun Suriyanarayana

On the positive side Tar roads cost 40% less than Bitumen, they also set quickly and take less

time to put in place. They are more durable than Bitumen roads and need less maintenance

than Bitumen roads and like Bitumen roads are easy to repair. They are somewhat rough

and hence have the highest skid resistance of the three types of roads. Tar is recyclable and

the road is not easily damaged by oil or fuel leakages from vehicles. [23]

Concrete Road: The concrete comprises of a mixture, an aggregate, water and chemical additives that may

be necessary to give it the desired properties. Once the concrete is mixed, it is transported

to the location where it will be used. At this location it will be poured on the framework that

reinforces it. After this it is consolidated to remove any air voids. Once this is done the

concrete is finished by smoothing it with a blade of sufficient width. Finally it is left to cure

and set. The concrete road is different from the others in that there is no stone aggregate

base used. There is a framework instead. [20]

The concrete road has a higher cost of construction and takes much longer than a Bitumen

or tar road to put into place. The concrete is not recyclable. Even though it requires very

little maintenance the process of repair is a complex one, the damage section of the road

cannot be repaired in isolation, the entire slab has to be replaced. This makes the process of

repair cumbersome, more expensive as well as more time consuming than the Bitumen and

Tar roads. To add to this in wet conditions the road is unsafe and accidents can be caused by

skidding vehicles. [23]

On the positive side a concrete road is made using lime stone which is abundantly available

lasts up to 40 years. Even though it costs 25% more than Bitumen roads it is far more

durable than Bitumen roads and requires very little maintenance, this balances the fact that

more time and money are needed to build the concrete road. They can withstand extreme

heat, cold, rain, snow, and water logging. They are not affected by fuel leakages. Since they

do not suffer damage they increase fuel efficiency by 14 – 20%[27]. They are not affected by

fuel or oil leakages. Construction poses no risk as is the case in tar roads. [23]

The comparison indicates that the best option is the concrete road. However a fourth kind

of road was suggested by Dr Vasudevan in 2001 – The Plastic Road.

WHAT ARE PLASTIC ROADS? Traditionally the construction of a bitumen or tar road is initiated by laying a base layer of

aggregate. This aggregate comprises of crushed stone or gravel which is spread evenly over

the area that is to become a road. On top of this, up to 4 layers of Bitumen are applied.[1]

The plastic road requires the addition of 5-10% of plastic waste to heated aggregate for 30-

40 seconds before the addition of the heated Bitumen. The final road obtained was found to

be superior to the conventional road in a number of ways. This process effectively uses a

substantial amount of plastic waste. [2] This road, called a plastic road, is more durable, more

economical and environmentally beneficial. [3]

Varun Suriyanarayana

TYPES OF PLASTICS USED IN PLASTIC

ROADS The most commonly used plastics in this process are polyethylene, polystyrene, polyester,

and polypropylene. Polyethylene can be made in 3 different ways. Each of these 3 different

ways results in polyethylene with different properties. Hence each one is given a slightly

different name. Low density polyethylene is normally used to make plastic bags. High

density polyethylene is used to make plastic chairs, dustbins, bowls etc. Linear low density

polyethylene is used to make plastic sheets and wraps. Polystyrene is typically used in fast

food cartons and as insulation. Polyester (Polyethylene terephthalate) is mainly used as a

fabric for clothes. Polypropylene is used for clothing and is applied in radio controlled toy

planes. All of these plastics, upon incineration liberate large amounts of carbon dioxide and

water if sufficient oxygen is used, otherwise, carbon monoxide is produced along with

water. Polyvinylchloride (PVC) cannot be used because upon heating it can release dioxin

which is toxic gas[25].

TWO PROCESSES USED IN THE

CONSTRUCTION OF PLASTIC ROADS

Wet Process: In this process, the waste plastic is directly mixed with hot Bitumen at 1600C and this

mixture is then mixed using a mechanical stirrer. This mixture also contains additional

stabilisers and requires proper cooling. It is not popular because it requires huge

investments, larger plants and more equipment than the Dry Process. [26]

Dry process: First the plastic waste is collected, segregated and stored[2]. The segregation is done

because certain kinds of plastic like polyvinyl chloride (PVC) and flux sheets cannot be used

due to safety concerns[4]. The next step involves the cleaning of the plastic. This is necessary

because most of the plastic waste collected has been used for packaging (55% in India)[3]

and hence is likely to contain residual substances such as little bits of food which must be

removed. After this the plastic goes through the process of shredding which reduces it to

the correct thickness, 2-4mm. [2]

The aggregate is heated to around 1600C-1700C and then the plastic is added and after 30-

40s a uniform coating is observed. This coating gives it an oily look. The Bitumen is then

added and the mixture is thoroughly mixed before laying. The Bitumen is added at a

temperature of around 1550C - 1630C[2]. This temperature is carefully regulated to make

sure that the binding is strong[5]. The process is described by the diagram below.

Varun Suriyanarayana

CONSTRUCTION OF PLASTIC COATED

BITUMEN ROAD

[32] [33]

Plastic waste collection Plastic waste is segregated

[35] [34]

Plastic waste is (shredded to 2-4mm Plastic waste cleaned and dried

[37] [36]

Stone aggregate heated to 1600C-1700C Shredded plastic added to

heated aggregate ‘ for 30-40s for

uniform coating

[39] [38]

Up to four layers of the mixture The Bitumen (temp. 1550C-

1630C) is then is laid rolled and cleaned ‘ added and mixed

with the coated aggregate

[40]

A final layer is added and rolled before being left to rest[2]

Varun Suriyanarayana

SIGNIFICANT FEATURES OF THIS PROCESS 1. Durability

2. Environmental advantage

3. Economic advantage

4. Safety advantage

Durability The normal Bitumen roads in India tend to break down very quickly. This to a large extent is

due to the high temperatures prevalent in some parts of the country. However even in the

best of conditions in India, roads often break down within 5 years. Dr. Vasudevan conducted

a number of tests which illustrate that the durability of the plastic road will be significantly

higher.[3]

Binding test

This test measures the bending strength and the compression strength of the mixture used

to make the road. Bending strength refers to the mixtures ability to resist deformation

under heavy load. Compression strength refers to the mixtures ability to resist forces that

attempt to compress or squeeze it. [48]

For this test the hot mixture was compacted using a compacting machine and then

compressed using a universal testing machine. The test was done for mixtures with 10%

20% and 25% plastic and the test was repeated using different plastics. The results illustrate

that the greater the proportion of plastic the greater the bending strength and the greater

the compression strength. For example with polyethylene the bending strengths were 325kg

340kg and 350kg at 10% 20% and 25% respectively while the compression strengths were

250 tonnes 270 tonnes and 290 tonnes respectively. [3]

Varun Suriyanarayana

Moisture absorption test

The moisture absorption test is done to determine the extent to which the aggregate

absorbs water. If the water absorption is high the road is likely to break down and develop

pot holes in the event of any water logging.

In order to determine how resistant the road is to water absorption a fixed mass of the

mixture was taken and immersed in water. After 24 hours the mixture was removed and

reweighed. The difference in mass was the mass of water absorbed. This was identified for

plastic concentrations of 0%, 1%, 2% and 3%. The moisture absorbed has been quoted as a

% of the mass of the mixture added. The results were 4%, 2% and 1.1% for 0%, 1% and 2% of

plastic added. For 3% plastic only negligible amounts of water were absorbed. This indicates

that the plastic makes the mixture less susceptible to moisture. [3]

Soundness test

This test measures the mixture’s resistance to weathering by conducting tests that simulate

weather cycles in an accelerated manner. The weathering occurs because when water

enters pores and voids in the mixture, the salts dissolved in the water, crystalize. When the

water evaporates more crystal is formed and this crystal causes the mixture to crack and

break. The freezing and thawing can cause the porous aggregate tends to disintegrate

prematurely.[47]

The test conducts 5 accelerated weathering cycles and measures the mass of the mixture

that was lost. The % mass lost should not exceed 12% when sodium sulphate solution is

used. Just like in the test for moisture, 0% 1% 2% and 3% plastic were used. The results

indicated that the % lost for the 0% plastic (plain aggregate) was 5% ± 1% but for 1%, 2%

and 3% plastic no mass loss was observed. This suggests that the plastic in the mixture

increases the mixture’s resistance to weathering. This could be explained by the fact that

the % voids in the mixture decreased as the % plastic increased. The values were found to

be 4%, 2.2% and 1% for 0%, 1% and 2% plastic while for 3% plastic no voids were observed. [3]

Varun Suriyanarayana

Aggregate impact test

The test is used to determine the aggregate’s resistance to fracturing. It measures the ability

of the road to resist impact or to measure how tough the road is. Continuous movement of

heavy vehicles on the road subjects them to nonstop impact causing it to disintegrate.

Often, to begin with, it resembles a crocodile skin before completely breaking down.

In order to measure this a sample of the mixture is taken and hit with a 14 kg hammer 15

times. The % of mass that becomes powdered should not exceed 30%. The powdered mass

will be identified as the mass passing through a 2.36mm sieve. The experiment was

conducted for 0%, 1%, 2 % and 3% of plastic and the results were found to be 25.4%, 21.2%,

18.5% and 17% respectively. This suggests that the plastic makes the mixture less

susceptible to fracturing in the event of a large force. [3]

Los Angeles abrasion test

The test used is the Los Angeles abrasion test. This test measures how resistant the

aggregate used in the road is to abrasion. Soil particles present in the tyres of the vehicles

and the on the road result in abrasion of the road as the vehicles move on the road. This

test measures whether the road aggregate is hard enough to withstand abrasion. [46] This is

measured by rubbing the mixture with steel balls. This is done by placing the mixture on a

1.70mm sieve inside a rotating drum. A fixed number of steel balls were rotating in circular

fashion at a rate of 30-33 rpm until 500 revolutions had been completed. The mixture was

placed at a particular point on the circumference such that as each steel ball passed it

rubbed the mixture. The % mass passing through the sieve should be less than 30%. The

experiment was conducted for 0%, 1%, 2%, 3% of plastic and the % mass passing through

the sieve were found to be 37%, 32%, 29% and 26% respectively. This suggests that the

Varun Suriyanarayana

plastic coating improves the resistance to abrasion significantly and is essential in order to

bring it below the 30% value. [3]

Environmental advantage Our daily lives are inundated by the use of several products containing plastic in some form

or the other. Its annual production amounts to over 275 million tonnes globally and India

alone as a consumer accounts for over 11 million tonnes[6]. Although it is non-biodegradable

most of it is recyclable. The recycled products are even more environmentally harmful than

the first time manufactured ones. This is because every time plastic is recycled it is subject

to high intensity heat causing it to deteriorate and add to environmental pollution[2]. The

need of the moment is to find an effective way to deal with this non-biodegradable waste.

The Plastic Road is one such solution.

The environmental advantage of plastic roads arises from the fact that it uses plastics that

would otherwise be disposed through environmentally harmful means. One of the

acceptable methods of dealing with plastic waste all over the world is incineration.

Incineration, simply put is, the burning of plastics in the presence of oxygen. However often

incinerators used are not manufactured keeping in mind the recommended standards and

guidelines. As a result when we burn plastics, in an attempt to dispose them, highly toxic

0%

5%

10%

15%

20%

25%

30%

35%

40%

0.0% 0.5% 1.0% 1.5% 2.0% 2.5% 3.0% 3.5%

%Plastic used

Percentages for various tests against plastic used

Abrasion

Moisture absorption

Soundness

Impact value

Voids

%

obtained

for each

test

Varun Suriyanarayana

emissions are released. These include Carbon Monoxide, Chlorine, Hydrochloric Acid,

Dioxin, Furans, Amines, Nitrides, Styrene, Benzene, 1, 3- butadiene, CCl4, and Acetaldehyde.

These emissions cause air pollution[2] resulting in acid rain, death of various animals and

contribute to the greenhouse effect thereby magnifying global warming. Furthermore the

incineration requires energy and this energy inevitably ends up coming from fossil fuels

burnt elsewhere. Therefore, the impact of incineration, on the environment is twofold. The

burnt plastic harms the environment as do the fuels burnt to produce energy for the

burning of the plastics. To compound matters, the process of incineration produces an ash.

This contains toxic heavy metals like lead and cadmium. If not kept in strong airtight

containers, these may leach into surroundings[7]. It has also been suggested that

incineration can cause monsoon failure or drought[26]. The usage of plastic is particularly

significant because approximately 1 million carry bags are used to lay 1km of road. This

translates into 1.125 tonnes of plastic per km of single lane road[4]. Furthermore, the dry

process does not result in the burning of plastics- they are only heated[3]. Because the

plastics are not burnt 3 tonnes of carbon dioxide per km of road is not liberated into the

atmosphere[4]. The 2500 km of road that has been laid in India this way has saved over 2500

tonnes of plastic waste and this in turn has meant that 7500 tonnes less of CO2 has escaped

into the atmosphere. This in turn reduces the effect of global warming[3].

Another popular method is the disposal of the plastic waste into specifically built up landfills however, landfills are not a problem free solution either. Plastics disposed in the landfills are impermeable and this means that the indiscriminate disposal of plastic waste makes land infertile. To make matters worse these plastics contain lead and cadmium pigments. These pigments are additives that are usually found in LDPE, HDPE and PP. They are toxic in nature and prone to leaching[2]. The chlorinated plastic waste in landfills tends to contaminate the surrounding space with harmful chemical which can find their way into groundwater. The water in turn harms all living organisms who consume it[8]. In case of other kinds of plastics micro-organisms in the landfill speed up their biodegradation. The biodegrading plastics release methane, a gas which is known to have an adverse effect on global warming[9]. For every 1km of plastic road constructed, 1.125 tonnes of plastic waste does not end up in a landfill. This in turn will reduce the size/area of the landfills required for disposal of municipal solid waste. The more the municipal solid waste, the larger the area that is required for its disposal. Every time a new landfill is created a space is identified and cleared of all vegetation and along with the vegetation the existing ecosystem is either disturbed or destroyed.

Plastic waste that lies around or in garbage disposal bins can find its way into the stomachs

of animals and birds who source their food from such places. The toxins in the plastics once

inside the bodies of the animals and birds cause intense suffering and pain. They can even

cause death. Additionally they become a part of the food chain and indirectly affect even

those who have not actually consumed any plastic. Plastic roads can definitely reduce and

perhaps eventually eliminate this suffering.

Varun Suriyanarayana

Roads are made with Bitumen. Bitumen is a hydrocarbon derived from crude oil. Replacing a

percentage of Bitumen with plastic means reducing the amount of Bitumen required,

resulting in reduced net oil consumption and the amount of oil that extracted. This brings

down the negative effects of oil extraction and ensures oil reserves will last longer, thereby

giving us more time to figure out alternative ways to meet our fuel needs. Methane is a gas

that can be released by the Bitumen upon heating. Although the resultant greenhouse

effect methane has is lesser than that of CO2, this is because the concentration of CO2 in the

atmosphere is greater than the concentration of methane in the atmosphere. In fact, the

negative effects of one molecule of methane are significantly more than one molecule of

CO2.

The plastic roads, because they are less susceptible to damage and breaking down, provide better mileage and decrease fuel consumption resulting in reduction of greenhouse gases generated by the vehicles.

Economic advantage The merits of the plastic road are not merely environmental. They have a considerable financial impact as well. The cost of construction of roads decreases considerably with the use of plastic. Since 10 %– 15% of Bitumen is replaced by plastic, the cost benefit is sizeable. According to Dr. Vasudevan’s report, the construction of 10m2 of road costs nearly Rs. 4 lakhs. The integration of plastic reduces the cost by Rs. 25000. This translates to over 6% savings on the construction of the road. There is no additional time required for the construction of the road as compared to the Bitumen road. The equipment used is also the same. The resulting road is superior to the Bitumen road. It requires far less maintenance because the road is much more durable and can last for up to twice as long as normal roads and is resistant to most factors that cause a road to break down. This means that less material, labour and time is required to service the road thereby allowing for resources to be diverted towards the expansion of infrastructure instead of maintaining the existing one.

[3] In countries like India, a lot of goods and people are transported by road and the trucks and buses used for this purpose contribute significantly to the economic growth of the country. If the roads are better, vehicles do not experience undue stress resulting in premature wear and tear which in turn reduces the cost of transportation. Better quality roads also translate into better fuel efficiency. This directly impacts the cost of transportation of the goods and their prices. Improved fuel efficiency implies lower fuel consumption. This reduction in fuel consumption results in less imports and hence savings for both the government and the people. Better quality roads translates into less time spent on the road, reduced fatigue caused by driving and commuting and resultant increased efficiency and productivity. Plastic waste which was earlier considered worthless rubbish, created environmental trouble and had to be disposed of at a cost suddenly becomes a valuable means of generating revenue. Rag pickers and small entrepreneurs can segregate the waste, shred the waste and sell it to the road construction industry in huge quantities. In order to utilise

Varun Suriyanarayana

plastic waste, it is required to be collected from various sources. The possibility of securing an income from plastic waste collection prompts the uneducated and unemployed to become rag pickers, waste plastic segregators or cleaners and seek employment in waste plastic shredding houses. In some countries, carbon credit can be sold. Since the road industry and plastic waste disposal industry would now emit far less carbon, they could sell their extra carbon credits to others thereby earning themselves a financial benefit. This in turn could be used to benefit the community at large by being donated to charities or being used constructively for infrastructural improvements. The carbon tax would also be lower Dr. Vasudevan has even gone so far as to suggest that if this idea were to be implemented

on a national scale, India would need to import plastics from other countries. Instead of

importing, India could charge other countries for helping them with the disposal of their

plastic waste thereby creating another source of income.

Safety advantage Plastic roads when compared with Bitumen roads have been proven to be more durable.

Susceptibility to cracks, abrasion, weathering and pot holes is considerably reduced. It has

an improved load bearing capacity and skid resistance. When compared to concrete roads

they have better skid resistance in wet conditions. Since no toxic emissions occur in the

process of road making, plastic waste is disposed in a safe and hazard free manner. All this

means is that there is less wear and tear of vehicles, reduced driver fatigue leading to lesser

accidents and improved safety.

CONCLUSION The plastic road is worthy of serious consideration particularly for countries with a large

population because the volume of their plastic waste and the extent of their road

construction is bound to be far more than that of countries with less population. What is

important to note is that the implementation of this technology is totally devoid of any

complication and additional investment. The process is easy and does not require new

machinery, industrial involvement or infrastructural investment. The entire process can be

implemented at the site where the road is to be laid. Since 10-15% Bitumen is replaced by

plastic, Bitumen resources are saved and plastic waste is utilised in an environment friendly

manner. This process can be conducted using both the mini hot mix plant and the central

mix plant and if both are available both can be used to speed up the road construction. Both

60/70 and 80/90 grade Bitumen can be used. During the entire process, no toxic gases like

dioxin are released because dioxin requires chlorine which is not present in any of the

plastics used. Polyvinyl chloride cannot be used for this reason. Furthermore, fly ash, a

difficult to dispose residue from incineration, can be integrated into the mixture as an

additional binding agent. [5]

By adding plastic to roads the resultant road is transformed. Unlike normal roads which do

not survive in extreme conditions, plastic roads are far more resistant to extremes in heat,

Varun Suriyanarayana

cold and rain. They are stronger, more durable and require less maintenance. This road is a

viable alternative for places with bad road access e.g. hills. It can help to improve national

infrastructure and enable supply to and from those areas to be more efficient, thereby

resulting in an improved quality of life for those people who live in the hills and benefits the

economy in general. [27]

The benefit of a plastic road lies not so much in the fact that the Bitumen road becomes

more durable and stronger but in the fact that it appears to provide us with an effective

solution to a potentially deadly problem of plastic waste disposal, a problem that the world

faces. Additionally, it helps to save fuel and Bitumen both of which are obtained from a

rapidly depleting natural resource, the crude oil. For the moment it does seem like an ideal

option. However it would be prudent to keep in mind that the world uses 85 million tonnes

of Bitumen to make its roads, even if this were to decrease by 10-15%, we will run out of

Bitumen and indeed crude oil in the near future. [21]

In India plastic road technology is being implemented, increasingly. On a small scale, certain

parts of India like Jamshedpur have converted to 100% plastic roads and proudly claim to be

a plastic waste free town. The scope of this technology is enormous and its benefits,

numerous - nevertheless on a large scale, the plastic road is a relatively localised

phenomenon, and it is being implemented extensively, mainly, in some parts of South India.

If this technology’s full potential is to be realised it has to be implemented on a national and

eventually on a global scale. In order to do this, awareness has to be increased at every level

and there have to be significant efforts made by the department of road transport,

government, environmentalists as well as educational institutions.

Thus plastic roads are indeed the need of the hour for developing countries with large

population, where the demand for improved road network and the problem of plastic waste

disposal is never ending. This solution though good, can by no means be a permanent one.

The fact remains that, neither the problem of plastic waste disposal nor the need for roads

is going to vanish, but Bitumen eventually will. Alternative technology to build roads is

already available but what happens to the ever increasing amount of plastic waste? Perhaps

it is time to begin looking for ways to extend the application of this technology into other

directions. In fact, Dr. Vasudevan has already taken the first steps in this direction. He has

used plastic waste to create Plastone, an interlocking block made with gravel and plastic.

Plastone is strong enough to withstand 300 tonnes of weight, along with the ability to

prevent water penetration. This can be used as an alternative for laying roads as well as for

household and industrial flooring. [28] This means, the technology is versatile and it can,

possibly be applied extensively to modify existing materials used for other infrastructural

construction. This would ensure effective plastic waste disposal and give us materials with

better durability, greater environmental advantage, economic advantage and above all

safety.

Varun Suriyanarayana

BIBLIOGRAPHY [1] http://www.ehow.com/info_8645892_stages-road-construction.html 14 June 2014

[2] http://beed.nic.in/htmldocs/pdf/management_plasticwaste.pdf 15 June 2014

[3] http://www.ajer.org/papers/v2(11)/A02110113.pdf 13 June 2014

[4] http://pmgsy.nic.in/WM_RR.pdf 12 June 2014

[5] http://tce.edu/chemistry/process.html 14 June 2014

[6] http://timesofindia.indiatimes.com/business/india-business/Plastic-per-capita-

consumption-to-double-in-5-years/articleshow/26588672.cms 15 June 2014

[7] http://www.ecoants.com/wasteincineration.html 15 June 2014

[8] Aggarwal,Poonam; (et al.) Interactive Environmental Educatiaon Book VIII. Pitambar

Publishing. p. 86. ISBN 8120913736

[9] Biello, David (June 5, 2011). "Are Biodegradeable Plastics Doing More Harm Than Good?".

Scientific American.

[10] Daniel D. Chiras (2004). Environmental Science: Creating a Sustainable Future. Jones &

Bartlett Learning. pp. 517-518. ISBN 0763735698

[11] Knight 2012

[12] Derraik 2002

[13] http://en.wikipedia.org/wiki/Low-density_polyethylene 16 June 2014

[14] http://en.wikipedia.org/wiki/Low-density_polyethylene 16 June 2014

[15] http://en.wikipedia.org/wiki/High-density_polyethylene 16 June 2014

[16] http://en.wikipedia.org/wiki/Polypropylene#Applications 16 June 2014

[17] Complete Chemistry for Cambridge IGCSE

[18] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1009718/pdf/brjindmed00129-0032.pdf

19 June 2014

[19]https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/07_1_CINCINNATI_01-63_0055.pdf 19 June 2014

[20]http://iti.northwestern.edu/cement/monograph/Monograph2_3.html 19 June 2014

[21] http://www.eurobitume.eu/Bitumen/what-Bitumen 17 June 2014

[22] http://www.brighthubengineering.com/concrete-technology/45858-concrete-roads-vs-

asphalt-roads/ 17 June 2014

[23] http://pmgsy.nic.in/downloads/10janjun06_eng.pdf 17 June 2014

Varun Suriyanarayana

[24] http://www.thehindu.com/news/cities/Madurai/indian-roads-congress-clears-code-for-

plastic-road/article5477350.ece 3 July 2014

[25] http://www.thehindu.com/todays-paper/tp-national/tp-tamilnadu/another-big-leap-for-

green-chemistry/article2335034.ece 4 July 2014

[26]http://prezi.com/ld0d8x5slwjs/presentation-on-plastic-roads/ 4 July 2014

[27] http://www.nbmcw.com/articles/roads/18259-types-of-pavements-used-in-road-

construction.html 4 July 2014

[28] http://timesofindia.indiatimes.com/city/madurai/Professors-unique-product-can-solve-

plastic-menace/articleshow/20709066.cms 5 July 2014

[29]http://stats.oecd.org/glossary/detail.asp?ID=4005 7 July 2014

[30] http://indiainbusiness.nic.in/newdesign/index.php?param=industryservices_landing/367/2 7 July

2014

[31]http://www.triplenine.org/articles/roadbuilding.asp 7 July 2014

[32]http://saferenvironment.files.wordpress.com/2008/10/plastic_waste.jpg 7 July 2014

[33]http://upload.wikimedia.org/wikipedia/commons/7/76/TriagemDeLixo.jpg 7 July 2014

[34]http://media.newindianexpress.com/plastic-

recycle.jpg/2013/07/25/article1700282.ece/alternates/w620/plastic-recycle.jpg 7 July 2014

[35]http://tce.edu/chemistry/step1b.jpg 7 July 2014

[36] http://tce.edu/chemistry/step3.jpg 8 July 2014

[37]http://www.featurepics.com/online/Stone-Aggregate-821672.aspx 7 July 2014

[38] http://tce.edu/chemistry/step4a.jpg 8 July 2014

[39]http://www.thehindubusinessline.com/opinion/columns/mohan-murti/ppp-model-for-

infra-push/article4140548.ece 8 July 2014

[40]http://4.bp.blogspot.com/-jWfafPeYpZ4/TzHuhJAFd7I/AAAAAAAAA9Q/QCQBySL-

GjU/s1600/plastic-Bitumen+road.jpg 8 July 2014

[41] http://www.pavementinteractive.org/article/rutting/ 8 July 2014

[42] http://cthousegop.com/2014/03/ct-pothole-patrol/ 8 July 2014

[43] http://www.tehamacountypublicworks.ca.gov/Operations/images/ac_cracking.jpg 8 July

2014

[44] http://cnx.org/content/m42215/latest/Figure_14_02_04.jpg 8 July 2014

[45] http://rescoplastics.com/tough-problems-easy-solutions 8 July 2014

[46] http://theconstructor.org/building/building-material/determination-of-los-angeles-

abrasion-value/1361/ 14 July 2014

Varun Suriyanarayana

[47] http://www.civil.iitb.ac.in/tvm/1100_LnTse/404_lnTse/plain/plain.html 14 July 2014

[48] http://www.toolingu.com/definition-500120-83821-compression-strength.html 15 July

2014

[49] http://www.ecoearthcare.com/storyd.asp?sid=144&pageno=1&isection=Eco 25 July

2014