KRS.Narayan, Business Leader, Carbon Abatement Initiatives & Economic Intelligence Reliance Industries
Advantages & DisadvantagesDue to their low cost, ease of manufacturing, versatility, and imperviousness to moisture, plastic is being used in a wide range of products from food packaging, healthcare, automotive, and appliances to electronic and space science, so much so, that demand for plastics has surpassed the demand of alternative materials. In volume terms, demand for plastics has surpassed that of steel and is set to overtake that of paper. The current global demand is estimated to be 350 million tons and is likely to surge ahead of the GDP growth rate in the future.
However, these advantages have also posed major challenges in management of post-consumer wastes that have inundated land, water bodies, and impacted both flora and fauna in the environment. Due to the prevailing linear economy model of “make-use-dispose” and low rate of recycling, which is prevalent in the world today, plastic waste has ended up in landfills and oceans, creating environmental pollution.
Possible SolutionsOne way to reduce plastic pollution is to enhance the recycling rate of plastics. While 80-90% of traditional materials like steel is recycled, global recycling rate for plastics is estimated to be around 10%. In India, the recycling rate is relatively much higher at 60% as estimated by the Central Pollution Control Board (CPCB). Plastics, even after being discarded, have a great value which when recycled can bring huge yields and earnings. This encourages the concept of circular economy wherein it is not “make-use- dispose” but “make-use-recycle”.
The key requisite for efficient recycling is segregated waste. Technically, all plastics can be recycled but due to the high levels of contamination and some difficult-to-recycle packaging film structure, alternative methods of material or energy recovery options are more viable.
One of the most viable “end-of-life” applications of difficult-to-recycle plastic waste is the time-tested use in construction of road. India is a pioneer in development of this technology which allows us to consume discarded, post-consumer, non-recyclable flexible packaging films in building roads by substituting 10% of bitumen with plastic waste, thus creating a value addition to non-recyclable plastic. Other solutions for safe disposal of plastic waste are waste to energy/fuel etc.
TechnologyIn the technology of waste to road, plastic waste is collected and segregated by waste management companies whose machines shred the waste to approx. 2.36mm to 4.75mm with thickness less than 60μ. In the hot mix plants used, the shredded plastic waste is dispersed on the conveyer belt carrying the aggregates and then transferred to the mixing chamber where the aggregates are uniformly coated with the plastic waste films within 30-60secs at a temperature of 165°C. The aggregates are later mixed with bitumen and the resulting mix is used for road construction. The road is laid at a temperature between 110°C - 120°C.
The road constructed with plastic waste helps us to substitute 10% of bitumen with waste plastic thereby reducing the bitumen resource and also reducing the cost of construction due to price delta between bitumen and waste plastic. This technology ensures enhanced durability, higher resistance to deformation, increased resistance to water induced damage, and improved stability and strength. The first road was laid in Chennai in Tamil Nadu in 2002 (Jambulingam Street) and the advantages of this technology have been proved.
RIL’s pilot study at Nagothane Manufacturing Division, MaharashtraReliance Industries adopted this technology and has recently laid approx. 30 kms of road in Nagothane, Maharashtra. In the methodology adopted, the waste was collected from households and offices and brought to the facility, where it was separated into dry and wet waste.
The shredded post-consumer non-recyclable flexible plastic waste was also procured from recyclers associated with the solid waste management facility set up by Reliance Industries at their Nagothane Township. The most important check point was to ensure quality of the plastics.
During the laying of the road and subsequent tests, possible savings of bitumen content was observed and quality of road was found good after one season of heavy rainfall of over 400 cms.
CRRI StudyAfter performance observation of the road laid with ReRouteTM, a study was initiated at CSIR – CRRI New Delhi for a comprehensive evaluation of the product to seek approval for accreditation from IRC.
Summary of CRRI Report on ReRoute™
- Addition of MLP based waste plastic improves stability value of mix which results in increase in strength of the mix.
- Due to addition of plastic waste the flow value increases, resulting in improvement in the workability.
- The MLP based waste plastic mixes showed better performance in terms of ITS, MIST, Resilient Modulus and Creep than the control mixes.
NIT – Warangal: Field evaluation on the performance of ReRouteTM roads at Nagothane (2023) after 4 ½ years of performance (4 seasons of rainfall of approx. 400 cms per annum)
NIT-Warangal was entrusted with the evaluation of the roads constructed at Nagothane and compare the performance with normal roads without ReRouteTM. The tests comprised of taking core samples, bitumen extraction, check of surface evenness, rutting, reflective cracking, FWD, and also collect data through NSV- network survey vehicle.
- ReRouteTM Roads were found to have higher resistance to moisture compared to roads constructed without ReRouteTM as seen in the bitumen content of both the roads after 4.5 years of performance.
- ReRouteTM Roads have more ITS (Indirect Tensile Strength) compared to roads constructed without ReRouteTM.
Photos of ReRouteTM Road after 4 ½ years at Nagothane
ConclusionsIn order to find sustainable pathways to create wealth from waste, a circular economy approach is found to be very effective. This is done by identifying the most difficult-to-recycle multilayered waste plastic and adopting stringent QA/QC standards of collection, segregation, shredding and packing of the waste for use in bitumen road construction, which is already facing serious issues of durability especially during and after every monsoon season. A considerable amount of money is spent on repeated maintenance of such roads. A solution to mitigate and save costs is to use ReRouteTM. So let us build better roads and create a sustainable environment.
AcknowledgementsI wish to thank the immense contribution of my mentor, Dr.Ashish Lele, Director, CSIR-NCL-Pune for his valuable knowledge, guidance & support in identifying the right type of Multilayered Waste Plastics for road construction and initiating this project, and Dr.Ambika Behl, Sr.Principal Scientist & former HoD, Flexible Pavements Division, CSIR-CRRI-New Delhi for her vast knowledge on road construction using Waste Plastics and conducting comprehensive testing & evaluation of the ReRouteTM product supplied by Reliance Industries.
Business Leader-Carbon Abatement Initiatives & Economic Intelligence, Member-National Centre of Excellence in Carbon Capture and Utilisation (NCoE-CCU)-IIT-Bombay Hon.Member-IC-IMPACTS-India Canada Research Centre of Excellence, Resource Member-MoHUA (Swachh Bharat Mission) Govt. of India