The Dutch asphalt sector can reduce emissions by 30% to 60% by using biobased asphalt, in which the fossil bitumen has been replaced by lignin and other components from residual vegetable flows. That is what figures from Wageningen University indicate.
The potential savings are enormous because, in the Netherlands alone, 10 million tons of asphalt is produced annually, which contains 300 000 tons of bitumen.
Asphalt consists of pebbles, sand, and bitumen made from petroleum. All ingredients are mixed at high temperatures. Bitumen is used as a binder. It holds the stones in the asphalt mixture together and provides firmness.
But the road construction sector is looking for an alternative, such as lignin. This natural binder is frequently found in plants, trees, or straw and is available as a residual flow from paper and bioethanol production, among other things.
Less energy needed
An essential advantage of lignin is that it can fix carbon for a more extended period of time. As a result, less CO2 ends up in the atmosphere. Asphalt with lignin can also be made at lower temperatures.
The production temperature of traditional asphalt is between 160 and 180 degrees; with lignin, the temperature is 40 degrees lower. As a result, less energy is needed for production.
New calculations show that biobased asphalt, in which 50% of the fossil bitumen has been replaced by lignin, contributes to the avoidance of 85 to 170 kilotons (kt) of CO2 equivalent per year in 2050. With 100% replacement of bitumen, savings are expected to double.
Projected to the European market, with 11 million tons of bitumen used in asphalt per year, a CO2 reduction of up to 12 000 kt CO2 per year could be achieved.
This development represents a significant contribution to achieving European and global climate goals. The European Union has the ambition to reduce CO2 emissions by 55% in 2030 compared to 1990.
The Dutch sector organization Bouwend Nederland is enthusiastic about alternatives to bitumen. The organization calls clients and road authorities to accept asphalt with alternative binders to bitumen to accelerate the transition.
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