Road Science and EnviroNZ, solve a growing waste plastic problem

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Road Science and EnviroNZ, solve a growing waste plastic problem

10 June 2018

Road Science and EnviroNZ are committed to ensuring our future generations continue to enjoy this incredibly beautiful country. Which is why we have formed a partnership to investigate the use of glass and plastic recoverable materials in New Zealand’s roading products. EnviroNZ has long been recognised as New Zealand’s most environmentally responsible waste management and resource recovery company.

EnviroNZ dedicates substantial investment and resources to ensure they are delivering innovative and sustainable solutions that meet the highest environmental standards. Road Science is New Zealand’s leading designer and supplier of bitumen, specialty pavement solutions and technical services. Road Science promotes change through harnessing creative potential to deliver new and innovative solutions to the pavements industry.

The partnership between the two entities will bring meaningful products to the civil construction industry that benefit New Zealand communities through smarter re-use of waste streams. Road Science and EnviroNZ are excited about their newly formed partnership, and we look forward to delivering innovative waste repurposing solutions in the near future.


New Plymouth District Council recently approached Road Science about their growing waste plastic problem. The local authority had an existing partnership with EnviroNZ and together with Road Science the organisations have come up with a ground-breaking solution - Plas Mix.


Plas Mix is in essence raw shredded plastic that goes into asphalt. Road Science laboratories have gone to great effort to identify the optimum plastic mix and the actual size needed for a successful product. It is then laid and paved in the same way a traditional asphalt.


“The creation of Plas Mix is a collaboration between two commercial companies actively working together to solve significant local and global waste minimisation issues. The team are tasked with developing a meaningful outcome that can successfully repurpose waste plastic while not compromising the integrity of the pavement solutions.” Murray Robertson, General Manager, Road Science.


“Main benefits of using recycled plastic in roading is that it prevents waste going to landfill or ending up on our beaches or in our rivers and oceans. It also eliminates the need to transport and ship these materials thousands of kilometres overseas for processing, which significantly reduces our carbon footprint.” Glen Jones, Commercial Manager at EnviroNZ.


A secondary benefit found in testing was that the performance of asphaltic road surfacing was actually enhanced by adding the plastic, especially in the areas of waterproofing and rutting.


The first large scale trial of Plas Mix was delivered last month in New Plymouth. This was the first example in New Zealand, where plastic has been used to surface a public road. The trial consumed 500 kilograms of hard plastic waste in 100M2 of road. This is equivalent plastic waste to what 1,2000 people would generate in one week.


The common types of hard plastics included containers for margarine, yogurt, cottage cheese, butter, and bottles for cleaning products such as Jif, dishwasher powder bottles, polystyrene packing, and coloured juice bottles.


“Road Science is committed to providing innovative solutions for technical and business challenges facing the New Zealand roading market. Developing practical and cost effective solutions to sustainability challenges remains front and centre for our team. Reducing solid waste from entering landfills, while reducing our carbon footprint and providing high quality cost effective outcomes is a challenging yet motivating assignment for us. Darcy Rogers and his technical development team are doing a fantastic job and highlighting the world-leading capability that this country has.” Murray Robertson, General Manager, Road Science.

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