4 days ago
Pilot scheme cutting roadwork emissions by over 50%
Repairing and maintaining roads is, like most construction activity, a carbon-intensive activity.
One estimate puts the annual emissions from the asphalt paving industry in the EU at 14 million tons CO2 equivalent or 0.35% of the bloc's total emissions.
The Irish road network is one of the most extensive, per head of population, in Europe and every local authority has an annual programme for repair and resurfacing.
Monaghan County Council has been pioneering a new technique which can cut carbon emissions from roadworks by more than 50%.
Engineer Kevin West says the pilot project, funded by the Department of Transport, is already showing results.
"We have upgraded over 26km of local and regional roads using this type of material with an estimated carbon savings of 644 tons, which is equivalent to approximately 340 diesel vehicles for one year," Mr West said.
The first saving comes from recycling old asphalt scraped off roads before they are resurfaced.
At a plant where the old material is being mixed with virgin product, Robin Hutchinson, a Director with TH Moore Contracts, explains how the process has been honed to reduce emissions at every step.
"One is transport, this is a mobile batching plant. So you can situate the plant where the material is ... and you try and base it all around, where the next site is, that's a whole circle.
"Also, there's no heat generated, so less energy is used. A traditional hot mix, or warm mix, you burn kerosene to create heat, to heat the stone, to add the bitumen to create the hot mix, whereas this is just using a completely cold mix, adding emulsion bitumen, which is cold, straight onto the lorry and out to the job," Mr Hutchinson explains.
The plant has been set up at a council yard beside the N2 Dublin to Derry road and is a few kilometres away from the section of the road where the old asphalt was planed off.
When combined into the new product, it is being used to upgrade a local road just a few hundred metres from the site.
The pilot, which started in 2020, has now been extended to Cavan and Louth and the process was used for a greenway in Cork.
Monaghan County Council's Chief Executive Robert Burns says: "It's showing it can be replicated, it can be extended to other areas and I think if this pilot proves successful, I think it offers enormous potential to manage our road networks right across the country".
"And particularly rural networks, which are much more challenging because we have a larger number of local roads around the country that need to be maintained, and for many local authorities, that's a major challenge," he added.
The potential financial savings of the process have not yet been realised as its at pilot stage, which means it is operating at a small scale and repeated tests are carried out on the roads where it is used.
The tests add to the cost, but Kevin West says they show the new greener type of asphalt performing as well as the more conventional sort.
"The main test we would have done would be in Lough Egish, that would have been on a heavily trafficked regional road with a high volume of HGVs.
"That's done now three years, and there's been no deterioration in that road whatsoever," he says.
Robert Burns is confident that if the lower carbon asphalt goes mainstream, it will save money as well as emissions.
"If you look at it again from a common sense point of view, if you're cutting down on the use of energy, you're cutting down on the use of emissions, shorter haul routes, you're not heating up the hot mix like you would traditionally. So that will cut costs," Mr Burns says.
He says those efficiencies should allow local authorities to do more.
"We can actually maintain more road, actually get more bang for our buck, I think this is where this initiative is really going to come out on its own," Mr Burns says.
There are still some stages to go through before this way of doing things can go mainstream.
The new type of asphalt produced will have to be certified as meeting national standards for use on roads and the capacity for this type of production will have to be built up.
Hot mix asphalt still retains the advantage that it is ready for traffic once it has cooled. The cold mix product requires at least twenty-four hours to gain sufficient strength.
It would be too disruptive to close sections of a national road for days at a time so that could limit the lower carbon asphalt to local and regional roads.
However, Mr Burns says the pilot shows real carbon savings are available.
"It is very timely, because we know from a recent EPA report that we're not on a on the right trajectory for reducing our emissions by 2030, around 23% I think, and we need to get 51% this initiative offers huge potential to reduce emissions in a relatively short time frame, if it's adopted … nationwide," he says.
