Home ›› 13 Sep 2022 ›› Front
Officials involved in road construction is mulling over a plan to use plastic waste to construct better, more durable and cost-effective roads.
They are opting for the idea as road side waste dumping is reducing the lifespan of pavements.
They said using plastic waste would help strengthen roads and solve the country’s long-standing waste management problem simultaneously.
Rutting and stripping are the two major distresses that reduce the life of flexible pavement while overloading, excessive rainfall and water-logging further aggravate the distresses.
If the bitumen is modified with plastic polymer it would provide better binding capacity and improve the characteristics of pavement reducing rutting and some other distresses, said officials of the Roads and Highway Department (RHD).
The World Bank in a publication in 2021 reported that the average per capita plastic consumption in European countries is more than 100 kg - much higher than in Bangladesh.
However, Bangladesh is suffering as there is no proper solid waste management in place.
Plastic wastes are being released into roadside drain, water bodies. Plastics after degrading over time turns into micro plastics (commonly defined as less than 5 mm in diameter) and flows into water bodies which ultimately contaminates foods posing significant human health risks.
What is the work progress?
Many countries in Europe have been constructing plastic roads since 1970s, while India took its first initiative in 2000 and has already constructed over 33,796 kilometers of plastic roads.
Dr Md Abdullah Al Mamun, Additional Chief Engineer, Technical Services Wing of RHD who is leading the effort in Bangladesh, told this newspaper recently that they were working on developing standard specifications, design protocol, test protocols and construction protocol in the prevailing weather and traffic loading condition first.
“We also need to know the types of plastics being dumped in different areas,” he said.
A research team of the University of Texas at Arlington in the USA is working with the RHD to characterize (composition) solid waste in the country.
Characterization of 17 (seventeen) roadside solid waste dumping
sites across Bangladesh has been completed. The process of developing standard specification is in advance stage, he said.
Test protocol and construction protocol are in the final stage and there is a plan to roll out the organized trial immediately in different locations depending on variable climate condition, hazard exposure and traffic loading patterns, he said.
He said the team is working on different grades of plastic including Polyethylene Terephthalate (PET or PETE), High-Density Polyethylene (HDPE), Polyvinyl Chloride (PVC or Vinyl), Low-Density Polyethylene (LDPE), Polypropylene (PP) and Polystyrene (PS or Styrofoam).
“We will find out the ways of using some of these types with construction materials including bitumen.
We believe, we can use different kinds of plastic waste at different layers of roads,” he said.
For example, polythene can be used for slope protection of roads instead of woods. It can also be used for aggregate coating for flexible pavement construction, the RHD official explains.
As the RHD wants to sustain the technology they need to develop a test protocol, design protocol, construction protocol and a business model first.
“We want to include this in the road construction tender specifications. There is no point in going for a pilot project and stopping somewhere
if we cannot mainstream that for countrywide use finally,” said Abdullah Al Mamun.
RHD convened several meetings with representatives from relevant stakeholders like City Corporations, LGED, Department of Environment (DoE), Bangladesh Standards and Testing Institution (BSTI), Bangladesh University of Engineering and Technology (BUET), Bangladesh Council of Scientific and Industrial Research (BCSIR), development partners and multinational corporate houses over the issues, officials said.
The business model to collect garbage
Using plastic in road construction is rather a segment of the holistic solution of solid waste management, where a business model will complement the whole process to attain the objective of circular economy.
Currently a low volume of waste mainly PETE and some other plastics are recycled in a low volume and there is a secondary recycle market in the country.
Since currently the waste cannot be collected and characterized at source, a group of poor people collect waste to be recycled from the dustbin, road side dumping locations and other dumping sites which are very unhygienic, said the RHD official.
“So we opted for a business model that would include the Extended Producer Responsibility (EPR) mentioned in the Waste Management Regulations - 2021.”
This regulation also compels producers to recycle a minimum percentage of post-consumer products including plastic, he said.
There will be an automatic value chain when road construction will need huge amount of plastic waste.
There will be collectors, bulk sellers who will do their part for money. Also, there could be a system. For example, a beverage company can offer an incentive for its customers to return plastic bottles after consuming, he added.
Some international conglomerates have already shown interest to be a part of the RHD initiative. They offered the RHD to use the plastic waste they produce after collecting through incentive.
“We may issue them a certificate that their certain percentage of waste has been recycled as a compliance of EPR,” the official explained.
After establishing a proper system, the government may include plastic roads in construction tender contract specifications with an incentive.
If a contractor uses 10 per cent plastic in the road, they can be offered a discount.
