Breedon Aggregates re-lays A90 in tyre-derived rubberised tarmac trial
Breedon Aggregates reports that it has successfully completed the first major UK trial of a kind of asphalt made partly from recycled tyres on behalf of Transport Scotland. Following the trial in Scotland, the firm will now begin to market the new material, to be called Breedon Polymer R+, from its 18 asphalt plants throughout Scotland and England.
In late April a short stretch of the A90 dual carriageway between Perth and Dundee was resurfaced with the material and a recently-completed ‘grip test’ on the surface has now confirmed its viability. This stretch of road is one of the busiest in Scotland, carrying around 35,000 vehicles a day. Over the next few months the material will be closely monitored against a number of key performance criteria, including skid resistance. According to the company, the early indications are “very encouraging.”
Unlike previous attempts at using rubber in asphalt, which usually involved trying to melt the rubber completely before mixing it with stone and bitumen, Breedon Aggregates has used technology from Danish company Genan which enables it to incorporate rubber particles directly into the binding agent. This is achieved at lower temperatures, with lower levels of emissions, apparently bringing environmental benefits. LCA (Life Cycle Assessment) studies show that for every ton of scrap tyres used for rubber modification of bitumen and asphalt, 1.1 tons of CO2 emissions are saved compared with incineration of the tyres (for example, in cement kilns).
How the trial came about
Breedon Aggregates is the UK’s largest independent aggregates business, with 26 quarries, 40 ready-mixed concrete plants and 18 asphalt plants in England and Scotland. It reports reserves and resources totalling nearly 200 million tonnes and employs around 800 people.
The new product, Breedon Polymer R+, is produced using a proprietary elastomer bitumen and asphalt modifier developed by Genan, the world’s largest tyre recycling company. Breedon Aggregates has a partnering agreement with Genan to promote the modifier in the UK.
Genan’s recycling technology is used to separate scrap tyres into their basic components: rubber powder and granulate, steel and textile. The rubber powder is then mixed with a semi-crystalline polyoctenamer to produce a bitumen and asphalt modifier. It is this modifier which Breedon has used to produce its new Breedon Polymer R+ surfacing material. Following an exploratory visit to Genan’s plant in Germany, Breedon carried out extensive tests on the modifier in its central laboratory and set out to design a special thin surfacing material appropriate for Britain’s roads.
Following preliminary trials, Breedon concluded that a very high performance thin surfacing material incorporating the new rubber modifier could be produced in volume that would bring significant installation and performance benefits on Britain’s roads. A Technical Submission was made to Transport Scotland through Breedon’s associate company, BEAR Scotland (which manages a sizeable proportion of Scotland’s trunk road network) for a formal trunk road trial of the new material. “This could transform our approach to road surfacing in the UK,” said Alan Mackenzie, chief executive of Breedon Aggregates Scotland. “Our industry has been trying for years to successfully incorporate recycled rubber into asphalt, without much success. Thanks to this new technology, which we are partnering with Genan to promote in the UK, we can help change that.”
“We’ll be drawing on a readily-available recycled raw material, reducing the proportion of expensive stone and bitumen in the mix and cutting the amount of gases and fumes produced, so it’s an all-round win for us and for our customers.”
Transport Scotland (TS) commented: “We are pleased that industry has identified this opportunity and developed an alternative surfacing material for use on the trunk road network. This adopts a sustainable approach in making the best use of resources available, by re-using an abundant waste material and thereby reducing the use of oil-based bitumen products. TS will continue to work collaboratively with the industry under the auspices of the TS Pavement Forum and we look forward to the continued success of this initial trial.”
Related news:
Comments