Citywide: paving the roads green

When Citywide flipped the switch at its cutting-edge Laverton asphalt plant in March last year, COVID-19 had just arrived in Victoria, and the prospects for the local economy – let alone the construction sector – were looking increasingly uncertain.

Fast forward 18 months and the company, which also runs a busy production facility in North Melbourne, is preparing to launch the eighth product under its flagship GreenPave green asphalt range to the market, with research and development going strong within the team.

Tim Ogun, Operational Improvement and Business Development Manager at Citywide Asphalt Group (CAG) says the recent diversification of the GreenPave range follows increased demand for ‘green asphalt’ products within the industry, as well as added capabilities with the launch of the company’s Laverton site.

CAG is a 50-50 joint venture between Citywide and Fulton Hogan, which was formed in 2016. The joint venture launched a new plant in Laverton using the Marini Asphalt Plant, a batch plant capable of producing a wide variety of asphalt mixes at up to 200 tonnes per hour.

The Laverton plant is also designed for low-emission production, using an efficient ‘blue smoke’ system that reduces both emissions and odours. The plant is also Melbourne’s first asphalt production facility powered by 100 per cent renewable electricity as part of the Melbourne Renewable Energy Project.

“Citywide has been industry-leading with the production of low-emission warm mix asphalt products from our North Melbourne facility for many years. But with the launch of our Laverton asphalt plant, we have been able to incorporate a wider range of environmentally friendly products into our asphalt mixes,” says Ogun, who has worked as project manager with Fulton Hogan for 15 years before moving to CAG in 2016.

“With Fulton Hogan’s full technical support, all of our new asphalt products are tested extensively in the labs. This has helped fast-track our research and development process to deliver products with higher recycled content,” he adds.

Having started with the GreenPave warm asphalt mix produced at Citywide’s North Melbourne plant for the past five years, the GreenPave range today incorporates seven other specialty products, each with a high percentage of recycled content.

Each of Citywide’s GreenPave products is identified with a suffix denoting the type of recycled product used within the mix. For example, the CR in GreenPave CR stands for crumbed rubber and the mix is manufactured using highly engineered crumbed rubber as binder

“Citywide has supplied its GreenPave CR for municipal projects in southwest Melbourne and on several other projects. After multiple applications, not a single defect has been recorded,” says Ogun.

GreenPave HR is another product in the range with a high content reclaimed asphalt pavement (RAP) mix. CAG can produce mixes with up to 40 per cent RAP content across both of its facilities, with the product registered with Victoria’s Department of Transport and already used across major projects in Victoria.

GreenPave G is manufactured by cold-injecting crushed glass into the manufacturing process to create a uniform blend of binder, reclaimed asphalt pavement (RAP), aggregate and glass.

One of the most notable products in the Citywide GreenPave range, according to Ogun, is GreenPave U, a dense-grade asphalt product that boasts the largest proportion of recycled materials in the GreenPave range.

“The GreenPave U product incorporates large quantities of RAP. It also uses glass as a partial sand replacement and has plastic additive in the form of processed consumer waste products. In addition to all of these, it incorporates slag – a by-product of steel manufacturing – to create a mix with over 55 per cent recycled content,” explains Ogun.

“We have already trialled GreenPave U in our yard, and it has shown significant improvement in the pavement’s skid resistance compared to conventional mixes. So, it’s a great product for areas like schools, community centres, or shopping strips that receive more pedestrian traffic than usual and need high skid resistance,” he adds.

GreenPave PB and GreenPave PA are Citywide’s plastic-based products, with GreenPave PB containing waste plastic sourced from the automotive industry dissolved into the binder and GreenPave PA using soft plastic from household packaging as a dry-mix additive.

Ogun says the Department of Transport (DoT) is currently looking at plastic mixes on a case by case basis and is in the early stages of getting involved in a potential certification process for asphalt mixes using plastic binders and additives, GreenPave PB and GreenPave PA have been welcomed by councils as alternative paving options for projects in their local areas.

“Councils across Victoria have a greater flexibility to choose innovative products that use alternative recycled mixes. Understandably, the DoT is usually slower at adopting specifications for alternative materials as they have a greater responsibility across bigger projects like national highways,” says Ogun.

“Within the councils themselves, some are more open to experimentation. For example, the City of Melbourne has used some of our plastic-based mixes over the past year, while the City of Wyndham has used our crumb rubber mixes in some of their projects.”

GreenPave Cold is another green product Citywide will be launching to the market soon. With a high RAP and glass content and bio-diesel as an additive to boost flexibility, Ogun says GreenPave Cold offers a green alternative for temporary road repairs and patchworks when cold asphalt mix is required.

Working with the industry

With such a wide range of green pavement products in its portfolio, Ogun says Citywide is prepared to flexibly meet the state’s needs for asphalt products. “One of the things Citywide is best known for is its flexibility,” says Ogun. “With our two plants located close to one another, we can adapt flexibly between all big and small projects and chop and change a fair bit to cater to a wide range of clients.”

In terms of expanding its product range in the coming years, Ogun says the GreenPave range has already fulfilled what the company intended to bring to the market, with some potential for expansion in the coming years.

“With the latest additions to the GreenPave range, we now have a very balanced mix to meet the sector’s needs for green asphalt products. As an evolving organisation, of course we will keep looking at areas where more recycled products can be incorporated in pavements and keep supporting the industry as interest for these products grows.”

Having spent over 20 years in the construction industry, with the last five years working closely with the pavement sector, Ogun observes that interest for green paving products is definitely increasing.

“The industry can be a bit slow to adapt to change, but over the past 20-30 years, interest has been gradually building up for products with higher recycled content. Today, there are very few projects anywhere in Victoria that use purely virgin products from a quarry with no recycled content,” he observes.

“What would be interesting to see, though, is for the larger road pavement projects to be able to incorporate specialty mixes with a variety of different recycled material, like GreenPave U. It will take more trials and demonstrations, but we are certainly on the right track.”