First publishedin World Highways
Enfield in North London is trialling MacRebur's three bitumen additives which is manufactured from waste plastic
At last some good news about plastic waste: road authorities around the world are starting to use it in their roads - Kristina Smith reports
Enfield Council in North London became the latest authority to use asphalt mixes modified with waste plastic on its roads. The council announced in February that it has successfully resurfaced a section of Green Dragon Lane, a busy road carrying buses and cars, and that tests showed that it was performing well
“We all have a responsibility to step up our efforts to help the environment by recycling more, upcycling and responsibly sourcing materials,” said Enfield Council’s Cabinet Member for Environment, Cllr Daniel Anderson. “Enfield Council is delighted with this road trial and hope we can use more of the product across the borough to help divert plastics from landfill and reduce the carbon footprint for road construction.”
Enfield is following in the footsteps of UK authorities in Cumbria, Dumfries and Galloway and Northumbria, using technology from a Scottish start-up company called MacRebur. The council has now secured funding from London-wide authority, Transport for London, to carry out further trials at bus stops around the borough. And there’s interest from outside the UK too; MacRebur trials are planned in the Middle East and North America this year.
Enfield laid test patches using each of MacRebur’s three additives, MR6, MR8 and MR10. MR6 has been designed to increase a mix’s mechanical strength and decrease deformation. “You would use it somewhere like the slow lane of a motorway or at bus stops,” said Graham Reid who, along with Toby McCartney and Nick Burnett, founded MacRebur. “There is also a lot of interest from hot countries because it raises the softening point of the bitumen.”
MR10 increases flexibility and resistance to fatigue and cracking at low temperatures, suitable for colder climates. MR8 has been designed simply as a bitumen replacement. It costs less than bitumen, whereas the other two additives cost more.
“We brought MR8 to the market purely due to feedback from customers who wanted slight improvements but a polymer that was cheaper than bitumen,” said Reid.
The inspiration for MacRebur, which has received financial backing through start-up investment site Seedrs, came from McCartney who says that his technology was inspired by watching people put plastic bags into potholes in India and then burn them to make road repairs.
However, waste plastics have been used in a much more scientific way in India for nearly 20 years. Brothers K Ahmed and Rasool Khan set up KK Plastic Waste Management in Bangalore at the turn of the century, working with academics from Bangalore University, and laid their first waste plastic road in 2002. As manufacturers of plastic bags, through KK Polyflex, they have an understanding of the technology – and also a social conscience about finding ways to make use of the waste their products produce.
The Khan’s technology has been patented and certified by the Centre for Transportation Engineering and the Central Road Research Institute and the Indian Congress has published a code to cover the hot and cold blending of the plastics waste additive at hot mix plants, IRC SP: 98-2013
Since then KK Plastic Waste Management has laid over 3,000km of road in Bangalore city, using 15,000tonnes of waste which have been converted into its KK Poly Blend. The additive is added at a proportion of 8% of the bitumen.
According to the company, its roads typically have a two-year-longer life than those laid with conventional mixes, and often more. Adding the blend increases the Marshall stability, flow value and strength of the bitumen and also the fatigue life and tensile strength by three times, according to KK Plastic Waste Management.
The additive is now considered tried and tested technology. “There are roads that we laid ten years ago that are still in good condition,” said Khan, who is passionate about ridding the world of what he calls the “plastic menace”.
KK Plastic Waste Management uses plastics that cannot otherwise be recycled such as multilayer plastic used for food packaging and plastic bags. “We can use any sort of polyethylene material,” said Khan.
The company buys the waste from ragpickers – people who collect recyclable material from rubbish dumps - and manually segregates it. It also has an agreement with a number of larger producers of waste such as schools, groups of apartments and NGOs. Having sorted and cleaned the waste plastic, the company creates KK Poly Blend by shredding it into flakes using exclusively designed machinery.
Now many other authorities in India are trialling or using plastic waste in their roads. At the same time as Enfield Council was announcing its trial, the Pune Municipal Corporation was doing the same. Following on from six successful pilot projects in 2016 and 2017, it is planning to team up with a chemical company and an environmental company to use the technology on 25 roads around the area.
Pune says that it will be using plastic bags and polyurethane packing to create the additive. Commonly used packaging materials include polyethylene terephthalate (PET or PETE), polyvinyl chloride (PVC), polypropylene (PP), and high and low density polyethylene (HDPE and LDPE).
The first PlasticRoad will be laid as a cycle lane later this year
MacRebur will not reveal the ingredients of its waste-derived pellets and flakes. “We use quite a variation of waste plastics,” said Reid. “We use different patterns of mixes that we know work. We know what polymers work and – perhaps more importantly - we know which polymers don’t work.”
Reid claims that their attention to content is what sets them apart from other companies who produce similar products. Its approach seems to be promising. As well as upcoming trials with four other local authorities in the US, and with Heathrow airport on one of its runways, the company has trials in Bahrain, Abu Dhabi, Saudi Arabia, Australia, Canada and the US.
MacRebur claims that for every tonne of bitumen replaced with its pellets or flakes, 1tonne of CO2 is saved when materials production alone is considered. Taking reduced maintenance requirements into account, this figure would be higher, it says.
Both MacRebur and KK Plastic Waste Management say that roads modified with their products can be recycled at the end of their lives, just as you would do a with a road laid with a standard mix.
Khan, who has been contacted about his technology by people from all over the world, believes that all those involved in the manufacture and use of plastic need to work together to turn waste plastic into a resource rather than a nuisance.
“We need the cooperation of all the big stakeholders,” he said. “Too many big companies are not bothered about their responsibilities. We produce so much waste plastic – two to three thousand tonnes every day in India. It is not reasonable to think that we can stop using plastic all together, but if we use waste plastic properly in roads, we can solve the problems of the world.”
Inventors in the Netherlands have headed in another direction when working out how to use waste plastic in roads.
Anne Koudstaal and Simon Jorritsa of asphalt and road construction company KWS, part of the VolkerWessels group, have come up with the concept of PlasticRoad, a prefabricated road made from 100% recycled plastic. It comes in modules or sections with hollow spaces beneath the surface to accommodate water or other utilities.
KWS has been working in partnership with Total and Wavin, which makes plastic piping, to develop the concept further with all three investing in the R&D. A trial project, a city bicycle lane, was due to start at the end of last year but, according to a spokesperson is now more likely to start mid-2018.
“It will be a real cycle lane in a real city, which means that there are certain licences and permits that have to be sorted out,” said a spokesperson, who would not reveal which city is involved.
According to KWS, the benefits of the PlasticRoad are that they weigh less than a traditional asphalt road, they last three times as long, require less maintenance and provide better use of space due to the hollow cavities for services. However, details such as how the modules will be fixed together, remain secret until the trial project is completed and unveiled.
Bitumen in Africa: secure supply and quality issues are on the agenda
Global energy and commodity agency Argus held its latest Argus Africa Roads conference in Dar es Salaam, Tanzania from the 6th to 8th March this year. Focused on the markets of South, Central and East Africa, the conference showed that there is huge potential for road building on the continent, but – as ever – there is unpredictability too.
“We do see some more positive signs this year, partly because of the recovery in oil and commodity prices,” said Keyvan Hedvat, Europe/Africa Editor for the Argus Bitumen market report. “There is also more urgency on the part of some countries to get things moving. But it depends very much on politics: which governments are coming in, what deficits they inherit, what they have to spend and where that money goes.”
The three-day conference kicked off with a technical focus day, chaired by Andrew Cooper, research director at Cooper Research Technology. “The main issue discussed at the workshop was specifications and having the right systems in place to check and test the products,” said Hedvat. “We talked about pooling resources, potentially to create regional laboratories that would be able to test the products coming in.”
Speakers on the second and third days included representatives from road authorities in Mozambique, Tanzania, Kenya and Namibia. One of the common themes to emerge from these speakers, said Hedvat who chaired days two and three, is the need to attract external funding to help enable some of the bigger projects to go ahead.
Public Private Partnerships (PPPs) are still a rarity in this region, although the conference did hear from one PPP of sorts. Barbara Mommen, CEO of Maputo Corridor Logistic Initiative spoke of how public and private organisations have come together to try to develop a transport corridor between Swaziland and South Africa to Mozambique and the Port of Maputo.
Andrew Patterson, regional president, Africa for Bechtel told delegates about the $2.9 billion project it has won from the Kenyan government to build the 500km-long Nairobi to Mombasa expressway. Due to start on site in late 2018 or early 2019, the road will be the first of its kind in Kenya and reduce the journey time between the two locations from over 10 hours to under four hours.
One topic which comes up at every conference right now is the potential impact on bitumen supply of the new bunker fuel rules that will come into force from 1st January 2020, says Hedvat. The International Maritime Organisation has ruled that all ships should have a maximum of 0.5% sulphur in their fuels. As a result, some refineries are either upgrading their technology to produce lower sulphur products, using lighter crude oils that do not lead to bitumen production or closing down altogether.
“People are worried that there will be less availability of bitumen,” said Hedvat. “On the other hand, there are some companies such as Shell who have committed to bitumen. Everyone wants to know what the impact on fuel oil, the supply of bitumen, and the price of bitumen will be but no one can predict what will happen. It creates uncertainty.”
Potholes patched around the world
Strassmayr, which makes specialist road repair equipment, sold 40% more machines in 2017 compared with 2016. The Polish company became part of Massenza in 2016 and has been growing its distribution network since then, with the two companies able to share distributors and partners.
According to CEO Ryszard Sowa, Strassmayr sold machines to seven new countries: Sweden, France, Morocco, Algeria, Nigeria and Myanmar last year. Its best seller everywhere is the Pothole Patcher Strassmayr STP 1008/6000, which it supplies in two versions: manually operated and remotely operated, using a joystick.
The Pothole Patcher contains all the materials and equipment needed to make repairs, reducing time spent going to and from depots and reducing wasted materials. “What is very interesting is that this type of machine is as popular in developed countries such as Germany, France and the US, as in countries that are looking to introduce road repair technology for the first time,” says Sowa.
Strassmayr’s home market, where the brand has been established for 60 years, remains its strongest but that could change, says Sowa. “Like most producers of road building and road repairing machinery, we are paying more and more attention to countries in Africa and Asia, because they could become the biggest markets in the future,” he says.
This year Strassmayr will be targeting several new markets in the Middle East, Africa and Europe. It will also be working with engineers at Massenza to produce slurry seal repair technology for the first time. “We haven’t worked with this technology before so it will be a big challenge. But by working in cooperation with specialists at Massenza, we are confident we will meet the task,” said Sowa.