The goal of Bangladesh's extensive road network, which consists of about 85,000 km of paved roads and motorways, is to promote economic activity and facilitate travel. Unfortunately, the road system currently has very limited service life. By modernizing the pavement design approaches with the relevant local and international studies, maintenance can be greatly enhanced.
Some of these studies demonstrate that, in addition to environmental benefits, the use of waste plastics in bitumen-wearing course of road pavements can greatly increase road serviceability.
Although it may seem innovative in Bangladesh, the concept has been used for many years in many other nations, including India. In order to boost their strength, bitumen and sand or stone are typically mixed with polymer plastics to create plastic roadways.
According to Bangladeshi experts, building plastic roads in Bangladesh is not only feasible but also a solution to the nation's ongoing issue with crumbling streets and roads.
The creation of an acceptable infrastructure design technique is required for the long-term enhancement of the road system in Bangladesh. Due to restricted and abandoned research attempts, Bangladesh has historically been unable to develop an indigenous design.
Bangladesh still needs to build its road pavements using extrapolation charts and catalogs created in other nations. This frequently results in either expensive overdesigns or premature failures of the pavements.
In Bangladesh, flexible bitumen-surfaced pavements are the most common. Multiple unbound layers of progressively stronger materials are included in this type's higher layers. The materials employed in the lower levels fulfill the criteria for strength and are readily available from local sources.
However, the “base” and surfacing materials utilized in the crucial top two layers are inappropriate. Softer brick aggregates are typically employed in foundation layers due to a lack of stone aggregates, while surfacings are typically provided with thin bitumen layers due to a lack of funding.
Because of these weak upper layers' inability to withstand the forces brought on by traffic overload and unfavourable environmental variables, pavements eventually disintegrate before they should.
Can Bangladesh build plastic roads?
According to experts, building plastic roads could offer a potential answer to the nation's protracted issues with maintaining roads. In subtropical climes like Bangladesh's, bitumen-paved roads are susceptible to heat and humidity throughout the summer and during the monsoon, which is why they frequently have cracks and potholes.
Traditional bitumen roads, according to VolkerWessels, are unstable, unreliable, and they release more than 1.6 million tons of carbon dioxide into the environment each year.
Alternately, plastic roads have a much lower carbon impact than conventional road construction. Additionally, paving asphalt roads takes three times as long as paving plastic ones. The Civic Aviation Authority of Bangladesh (CAAB) has been utilizing a similar technique to build new runways at the airports in Dhaka, Cox's Bazar, and Sylhet after being inspired by the plastic road idea.
Processing of the plastic
Experts have described the wet procedure as being very straightforward and smooth for building roads. Many businesses in the nation today sell liquid plastic that can be diluted with bitumen. Only a facility with machinery would be required to combine the two components.
Shredded plastic is less expensive, while liquid plastic is more expensive. If the liquid plastic was imported, the price would rise even higher. Recently, the Indian government built roads using dry technology, which is anticipated to save construction costs by 50%.
But because of its simplicity, along with also strengthening roads, Bangladeshi experts advise utilizing the wet technique. A few restrictions were stated; it would be challenging to manage the entire process by gathering trash plastic in one location. Furthermore, if the wet procedure was employed, substantial funding as well as technology would be required to complete the project.
Road of waste plastics
India's Bangalore and Mumbai City Corporations are pioneers in the use of waste plastic in road building. A scheme to build 150 km of waste plastic-bituminous roads is being carried out in Bangalore. In Mumbai, a small-scale trial road was built in 2004, and work is currently being done on a larger trial road.
The Central Road Research Institute (CRRI), an Indian organization, has given its approval to the technology used to use shredded plastic trash in road construction. The use of the technology has been encouraged by the success in Delhi, Surat, Hyderabad, and other places. The technique of using plastic shreds has also been used in Canada and Brazil.
Are plastic roads cost-effective?
It depends on how and from where you get your plastic. The biggest cost savings are actually twofold. The cost savings will come from the price difference between the cost of bitumen and the cost of the plastic, which, according to research, should be between 8 and 10% of the plastic content of plastic-bitumen roads. If we can find a source of waste plastic that is inexpensive or free, the amount we could save compared to the price of bitumen could be significant.
Second, there are maintenance cost reductions because roads created with plastic added are demonstrating significantly greater durability and resilience to water. On the amount of those savings, I haven't discovered any reliable information.
We can also take into account the value of preventing plastic from ending up in landfills, waterways, and other environmental areas. The greatest disadvantage, in my opinion, would be if people considered this an “acceptable” use for plastic and kept making it rather than gradually eliminating it. Elimination of plastic is what would be most beneficial for the environment.
While plastic roads were first used in India in 2000, they have been in use in Europe since the 1970s. Now is Bangladesh's chance to make history by following suit.
Bishal Basu is a freelance contributor and works at Rupali Bank Limited.