Disadvantages of Plastic Bitumen

As far as using plastics in constructing new roads and highways, this is nothing new. Recently, studies have shed light onto the usage of plastic waste in road construction, specifically, plastic roads. Plastic roads primarily make use of plastic grocery bags, PET bottles and disposable cups reclaimed from landfills as a main ingredient for the necessary construction material. When these materials are mixed with molten bitumen, the plastics dissolve to create an oily coating over the aggregate and then the concoction is spread over the surface of the road in a fashion similar to using tar.

What exactly is Plastic?
Plastic is a material that comes in a wide variety of synthesized or semi-synthesized organic amorphous solids which are utilized in the manufacturing of industrial and consumer products. They are almost always polymers which contain high molecular mass and sometimes they’ll include various other substances to enhance certain attributes like malleability, rigidity, strength, translucency etc. or sometimes just to reduce cost. Monomers of plastic can either be natural or they can be synthesized organic compounds.

In society and the world, grocery bags which have been thrown away pose huge problem. They can obstruct and clog drainage ways leading to flooding, animals have been known to choke on them as have small children, the create unsightly clutters wherever they are found.

They can be found lying across fields where they prevent germination of new plant life and obstruct natural rainwater from soaking into the soil. The process of recycling plastics results in the release of noxious fumes which pollute the atmosphere, also this process as an effect on the plastic molecules itself which only allows this to be done to it three to four times before rendering it ineligible for recycling in the future.

What are Waste-Plastic Roads?
Roads which has been constructed with plastic waste material, best known as Plastic Roads, have been found to work better than their traditional counterparts which were constructed with conventional bitumen. The Indian Center for Plastics in the Environment (ICPE) have been advocating the usage of plastic waste in the construction of asphalt roads. They have tried a few test roads which were paved successfully by combining bitumen with the plastic waste. The plastics which were used in this experiment were mostly grocery store bags, bottles, and disposable cups reclaimed from dumps and landfills. They were mixed with heated bitumen to form a coating similar to tar which was then spread over the aggregate to act like tar.

The problems were:
0.Disposing of the plastic waste proved to be a major problem
0.It is not biodegradable
0.Incineration of plastic waste releases toxic gases and cause atmospheric pollution
0.Finding a way to incorporate it into bitumen based solutions to be applied to road construction required lab tests to be conducted. The studies found that the plastic waste actually enhanced certain properties of the mixture.
0.The conclusion was that the benefits of using the plastics with the bitumen provided a better solution for its disposal that was beneficial.

The advantages associated with the use of plastic in road construction
0.An increased Marshall Stability Value making it stronger.
0.Increased resistance from rainwater and water stagnation.
0.Resistance to potholes and stripping.
0.Better binding and bonding within the mixture.
0.Less rutting and raveling due to a reduced pore rate in the aggregate.
0.Elimination of UV radiation effects
0.An overall increase in strength by 100%
0.Increased load bearing capability.
0.For every Kg of plastic used a Kg of bitumen is saved.
0.Decreased costs for building the roads
0.Decreased maintenance costs.
0.Increase in the amount of waste plastic disposed by re-purposing it.
0.Increased employment in the labor division.

Nowadays, plastic waste treatment is mostly dangerous to the environment as a lot of the plastic is incinerated resulting in toxic gasses being released in the atmosphere. With an effective way to manage the collection, separation and processing of plastic waste, the environmental damages can be mitigated by eliminating the waste from our streets. We can have international standardized roads and pavements which are litter free. Here are economic advantages which would accrue to various communities if the plastic road project is implemented on a world wide scale.

Normal households and other units package all garbage and trash in plastic bags and dispose of them. The plastics which are not biodegradable act as a container around the trash preventing it from being converted into compost. At present, only 20% of the MSW converts into compost. This can be increased by 80-85% which would be incredible, and possibly more if we implement a systematic management of the plastic waste.

One of the first areas that would immediately benefit is the agricultural sector. Which at present, 20% of MSW is converted into compost. By converting this to 80-85% when the plastic from the MSW is segregated, farmers can directly purchase the compost from MSWM after the plastic is separated.

The accumulated benefits to the National Economy would include
–Improved status of the environmental
–Generation of employment
–Increased agricultural efficiency

When the lifespan of a road is doubled, then the savings that accumulate in the nations budget are in thousands of crores. Separation of the plastic from the MSW at the municipal yard involves the application of resources, the cost of which runs into crores of rupees. This is a substantial amount of savings.

The Central Government’s annual allocation and disbursement of funds into roads and highways is around 35 thousand crores. Laboratory tests and real-time simulations have shown that the life expectancy of a plastic polymer road compared to a normal road is no less than 100% more in addition to the savings accrued at the central level, every state Municipal Solid Waste Management would save crores of rupees by eliminating the plastic segregation process at its yards.

Disadvantages of plastic roads
1.During the cleaning process toxics which were present in the co-mingled plastic waste could start leaching.
2.During the road construction process the presence of chlorine will release noxious HCL gas.
3.After the road laying It is opined that the first rain could trigger leaching. As the plastics will merely form a sticky layer, (mechanical abrasion).
4.The components of the road, once it has been laid, are not inert.

This generation of waste plastics is increasing everyday. The major polymers, mostly  polyethylene, polypropylene, and polystyrene exhibit an adhesion property in their molten state and since plastics will increase the melting point of the bitumen, then, the usage of waste plastics in pavement could be one of the best applications and easy ways to dispose of waste plastics.

The use of this technology not only increased the strength of the road but also increased the road’s life span as well as created a source of income. Plastic roads would be a boon for India’s hot and extremely humid climate, where temperatures frequently cross 50°C, and torrential rains create havoc, leaving most of the roads with big potholes. It is hoped that in future we will have stronger, more durable and environmentally friendly roads that can relieve the earth from all these types of plastic waste.

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