08-08-2014, 12:12 PM
Presentation Transcript
[attachment=66741]
INTRODUCTION
INTRODUCTION Plastic use in road construction is not new. Recent studies in this direction have shown some hope in terms of using plastic-waste in road construction i.e., Plastic roads. Plastic roads mainly use plastic carry-bags, disposable cups and PET bottles that are collected from garbage dumps as an important ingredient of the construction material. When mixed with hot bitumen, plastics melt to form an oily coat over the aggregate and the mixture is laid on the road surface like a normal tar road.
What is Plastic?
What is Plastic? A plastic material is any of a wide range of synthetic or semi-synthetic organic amorphous solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass and may contain other substances to improve perfo- -rmance and/or reduce costs. Monomers of plastic are either natural or synthetic organic compounds
Strewn across fields, they block germination and prevent rainwater absorption by soil. Recycling plastic by melting releases fumes, and is only possible 3-4 times. Toxic contents might leach into recycled water pots or water-pipes. Shredded plastic is a great additive for tar roads. Discarded thin-plastic carry-bags are a menace. In town they clog drains, cause flooding, choke animals that eat them and are unsightly.
ADVANTAGES OF PLASTIC ROAD
ADVANTAGES OF PLASTIC ROAD Use higher percentage of plastic waste. Reduce the need of bitumen by around 10%. Increase the strength and performance of the road. Reduce the cost to around Rs. 5000/Km. of single lane road. Generate jobs for rag pickers. Develop a technology, which is eco-friendly . 100% improvement in fatigue life of roads. Reduced penetration and ductility, a higher softening point, less rutting and cold cracking. 18
Plastic Wastes used in process
The following types of waste plastic can be used in the construction of rural roads:
• Films ( Carry Bags, Cups) thickness up to 60micron (PE, PP and PS)
• Hard foams (PS) any thickness
• Soft Foams (PE and PP) any thickness.
• Laminated Plastics thickness up to 60 micron (Aluminum coated also) packing materials used for biscuits, chocolates, etc.,
• Poly Vinyl Chloride (PVC) sheets or Flux sheets should not be used in any case
Process Step
Plastics waste (bags,cups,thermocole) made out of PE,PP and PS cut into a size between 2.36mm and 4.75mm using shredding machine, (PVC waste should be eliminated).
Characteristics of the process
Easy process without any new machinery
Simple process without any industry involvement
In situ process
Use of lesser % of bitumen and thus savings on bitumen resource
Use of plastics waste for a safe and eco-friendly process
Both Mini Hot Mix Pland and Central Mixing Plant can be used
Only aggregate is polymer coated and bitumen is not modified
Use of 60/70 and 80/90 bitumen is possible
No evolution of any toxic gases like dioxin
Fly ash can also be used to give a better performance
Roads from plastic waste
S.S. Verma
These columns of ICJ offer an opportunity to the engineering fraternity to express their views on the current practices in design, construction and management being followed in the industry. To share your opinion with our readers, you may send in your inputs in about 1500 words via e-mail to editor[at]icjonline.com
The debate on the use and abuse of plastics vis-à-vis environmental protection can go on, without yielding
results until practical steps are initiated at the grassroots level by everyone who is in a position to do something
about it. The plastic wastes could be used in road construction and the field tests withstood the stress and
proved that plastic wastes used after proper processing as an additive would enhance the life of the roads
and also solve environmental problems. The present write-up highlights the developments in using plastics
waste to make plastic roads. Plastic is everywhere in today’s lifestyle. It is used for packaging, protecting, serving, and even disposing of all kinds of consumer goods. With the industrial revolution, mass production of goods started and plastic seemed to be a cheaper and effective raw material. Today, every vital sector of the economy
starting from agriculture to packaging, automobile, building construction, communication or infotech has
been virtually revolutionised by the applications of plastics. Use of this non-biodegradable (according to
recent studies, plastics can stay unchanged for as long as 4500 years on earth) product is growing rapidly and
the problem is what to do with plastic-waste. Studies have linked the improper disposal of plastic to problems
as distant as breast cancer, reproductive problems in humans and animals, genital abnormalities and even a
decline in human sperm count and quality. If a ban is put on the use of plastics on emotional grounds, the real
cost would be much higher, the inconvenience much more, the chances of damage or contamination much
greater. The risks to the family health and safety would increase and, above all the environmental burden would
be manifold. Hence the question is not ‘plastics vs no plastics’ but it is more concerned with the judicious use
and re-use of plastic-waste
Plastics roads
Plastic use in road construction is not new. It is already in use as PVC or HDPE pipe mat crossings built by
cabling together PVC (polyvinyl chloride) or HDPE (high-density poly-ethylene) pipes to form plastic
mats. The plastic roads include transition mats to ease the passage of tyres up to and down from the crossing.
Both options help protect wetland haul roads from rutting by distributing the load across the surface. But
the use of plastic-waste has been a concern for scientists and engineers for a quite long time. Recent studies in
this direction have shown some hope in terms of using plastic-waste in road construction i.e., Plastic roads.
A Bangalore-based firm and a team of engineers from R. V. College of Engineering, Bangalore, have developed
a way of using plastic waste for road construction. An initial study was conducted in 1997 by the team to test
for strength and durability. Plastic roads mainly use plastic carry-bags, disposable cups and PET bottles
that are collected from garbage dumps as an important ingredient of the construction material. When mixed
with hot bitumen, plastics melt to form an oily coat over
Comparison
The durability of the roads laid out with shredded plastic waste is much more compared with roads with asphalt
with the ordinary mix. Roads laid with plastic waste mix are found to be better than the conventional ones. The
binding property of plastic makes the road last longer besides giving added strength to withstand more loads.
While a normal 'highway quality' road lasts four to five years it is claimed that plastic-bitumen roads can last
up to 10 years. Rainwater will not seep through because of the plastic in the tar. So, this technology will result
in lesser road repairs. And as each km of road with an average width requires over two tonnes of polyblend,
using plastic will help reduce non-biodegradable waste. The cost of plastic road construction may be slightly
higher compared to the conventional method. However, this should not deter the adoption of the technology as
the benefits are much higher than the cost. 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. Already, a kilometrelong test-track has been tested in Karnataka using this
technology. The government is keen on encouraging the setting up of small plants for mixing waste plastic and
bitumen for road construction. It is hoped that in near future we will have strong, durable and eco-friendly
roads which will relieve the earth from all type of plastic-waste.
Conclusion
Plastics will increase the melting point of the bitumen. The use of the innovative technology not only strengthened
the road construction but also increased the road life as well as will help to improve the environment and
also creating 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 near future we will have strong, durable and eco-friendly roads which will relieve
the earth from all type of plastic-waste.