Men at the helm of affairs at Richie Bags and Fashions Pvt. Ltd., globally recognized manufacturer of jute and cotton handbags had all along been expressing their worries about the colossal collection of plastic carry bags that have choked our oceans and polluted the land mass. Since the discarded once used plastic carry bags can neither be destroyed nor serve any useful purpose, they pose a perilous threat to our very existence.
However, the worries harbored by the reputed company that helps restoration of the planet’s environment by manufacturing and marketing products made of eco-friendly biodegradable material such as jute and cotton may now rest in peace because scientists have recently invented a process in which plastic waste can be used extensively for construction of rural roadways, especially in developing countries of the world, thus reducing the impact of plastic pollution.
How it is done?
The following types of plastic waste are mostly used for 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.
However, PVC sheets or Flux sheets are not suitable for this purpose
Also, the waste plastic modifier should be free from dust and is to be shredded, preferably to 2-3 mm particle size. While authorities specified that the shredded waste plastic should pass through 3 mm sieve, Dr. Vasudevan (research scholar and pioneer in developing the technique) is of the opinion that it has to pass through 4.75 mm sieve and retained on 1 mm. This also indicates indirectly that the size of the shredded bitumen should normally be 2-3 mm for better spread and coating the aggregate.
How the road is laid (Dry process is suitable for isolated work)
It is suggested that the percentage of shredded waste plastic will be 8%, while the same is specified as 10% by Dr. Vasudevan. However you may adopt 8% as the optimum plastic content for blending the bitumen in the construction of plastic roads. T Bitumen of grades 60/70 or 80/100 can be used as binder as in case of conventional method.
The substance, however is then transferred to the mixing cylinder where it is heated to 1650c and is shifted to the mixing puddler (temperature monitored through IR thermometer). While transferring the hot aggregate into the puddler, measured quantity of shredded plastics is sprayed over the hot aggregate in course of few seconds (30 seconds). The sprayed plastic films melts and gets coated over the aggregate, thus forming an oily coating.
In the same way, the bitumen is to be heated to a maximum of 1600c in a separate chamber and kept ready (The temperature should be monitored to have good binding as also to prevent weak bonding). At the mixing puddler, the hot bitumen is added over the plastic coated aggregate and the resulted mix is used for road construction. The road laying temperature varies between 1100c to 1200c, while the roller used is within 8-ton capacity.
Plastic Road in Northeast
According to recent newspaper report, 1km road was constructed in the Nongkynjeng village in Meghalaya (West Khasi Hills division) by mixing shredded plastic waste with heated bitumen, technology detailed above that has made the road more durable and at the same time solved the plastic waste problem for good.
“We have used 470 kg plastic waste like polythene carry bags, plastic cups, chips packets and foam packaging for the road. The waste was collected from the district headquarters Nongstoin and Shillong which would have otherwise littered our roads. This is a cost-effective work as we spent only Rs 33 lakh for the 1km road. If all roads in Meghalaya are built using this technology, we can get rid of the plastic menace,” West Khasi Hills deputy commissioner Arunkumar Kembhavi told The Telegraph, adding that finesse and finishing of the road was as good as any National Highway