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Download PDF Blending plastic waste with bitumen in laying tarmac could increase road durability, drastically reduce maintenance costs; help save the environment and save the country Tk 1507.60 crore in maintenance cost a year.
Experts said this during a roundtable discussion held at the Dhaka Sheraton Hotel yesterday.
Less cracks and potholes will develop on roads and recycling of plastic waste would reduce the amount of hazardous non-biodegradable materials in the environment, they said.
“The technology can save the country Tk 1507.60 crore a year in road maintenance,” said SM Shafiqul Alam, executive engineer of Roads and Highways Department (RHD), presenting the keynote paper at the discussion.
Bangladesh Transport Foundation (BTF) and Practical Action, an international NGO, jointly organised the discussion on the findings of Bangladesh University of Engineering and Technology (Buet) laboratory tests and a study conducted by a team of planners, engineers and development administrators of BTF.
With BTF Chairman Kamaluddin Chowdhury in the chair, the discussion was addressed by experts from RHD, Buet, University of Asia Pacific and different government agencies.
The Local Government Engineering Department (LGED) implemented this new method of road surfacing in three roads back in 2005-06 using crammed rubber polymers. The trials show that the roads had 84 percent, 57 percent and 15 percent less cracks, depressions and ravelling respectively than conventionally-constructed roads, Shafiqul said.
Highly volatile and low quality bitumen, thin layer of surfacing, moisture pollution and soft brick aggregates make roads vulnerable and modified bitumen can bind the layers better, the experts said.
Materials used in the upper two layers, base and surfacing, of three-layer roads are not suitable for Bangladesh considering the climate and traffic load. The thin bituminous surface cannot deal with the traffic load and the weather.
Bitumen and plastic originate from petroleum and are thermoplastic in nature. They help good bonding, said Shafiqul adding that plastic waste can be used instead of virgin plastic, which is costly.
Citing performance tests conducted by India’s Central Road Research Institute, the roundtable was told that the life of roads was doubled and the roads became more resistant to water damages when they were constructed by mixing plastic waste with bitumen.
The technology was successfully implemented in Canada, Brazil, and the Indian cities of Bangalore, Mumbai, and Chennai.
Due to widespread use of plastic bags, bottles and containers, substantial amount of plastic waste is available in Dhaka and other cities of the country.
“We will need 1 lakh tonne of plastic waste a year and we can easily collect 1.5 lakh tonnes every year,” the RHD executive engineer said.
The RHD maintains about 21,571 km of highways and regional and district roads while the LGED maintains about 78,105 km of roads in upazila- and union-parishad levels.
The Dhaka City Corporation is going to undertake a project to try the technology on 0.5 km of road in Jatrabari, Shafiqul told The Daily Star.
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