The new asphalt, called GemGroReflection, – Municipality of Groningen Reflection – has a number of advantages. For example, it is produced at 130 degrees instead of the usual 160 degrees, which saves both CO2 emissions and energy consumption. “The asphalt also wears less, so less maintenance is needed,” says Alderman Mirjam Wijnja.

Over time, white stones become visible in the asphalt, which reflects light better. “Then you can also dim the street lights, which of course also makes a difference in terms of energy consumption,” says Wijnja.


According to expert Richard Gosselink from Wageningen University, this is an interesting development. “Of course, we all want to move towards lower CO2 emissions and that’s one of the possibilities,” he says. “Because it’s light-colored asphalt, shadows and outlines are easier to see. I think it’s safer for road users.”

The new type of asphalt has another advantage: because it whitens slowly due to wear, the asphalt retains less heat. And it allows the environment to cool faster, explains Ronald Rossman. He is a technical specialist in roads for the municipality and the inventor of asphalt.

Solution against heat stress

“Did you know that black asphalt can reach 50 to 60 degrees Celsius in hot weather? On a very hot day, it can get even hotter. You don’t want to walk on it barefoot,” says Rosman.

“With GemGroReflection, the nights become cooler. After all, the heat doesn’t have to go away, because the surface temperature is lower. This benefits everyone’s sleep in the summer,” he expects.


Researcher Gosselink sees possibilities of using Groningen’s invention in his own research. He has been involved in “biobased” asphalt for years: as a senior biorefinery researcher at Wageningen Food & Biobased Research, he is researching a sustainable alternative to bitumen – the fossil raw material used as an asphalt binder.

“You can replace bitumen with lignin. This substance is found in trees, reed and straw, for example,” says Gosselink. “Lignin remains in large quantities in the paper industry.” By using lignin, a CO2 reduction of 35 to 70% can be achieved on a ton of asphalt, according to the researcher.

Is it the Holy Grail rather than the asphalt of Groningen? “No, I think we should look for a combination of all current developments. What would it mean, for example, if we also started working with clear rock and a bio-based asphalt binder for sustainability asphalt?”

Free recipe

The GemGroReflection recipe is in any case free. “Everyone has an interest in reducing CO2 emissions and limiting heat stress”, explains Alderman Wijnja. The new asphalt now covers a small part of the citybut: “All the asphalt we lay in the future will be this new asphalt.”