Nuns' Island bridge built with two special ingredients: love and crushed glass
MONTREAL -- A Nuns' Island Bridge is being held together partially by a special ingredient: crushed glass.
The Darwin Bridge may look like any other, but it may be the first in the world to incorporate recycled glass into its construction materials.
Etienne Cantin Bellemare, the City of Montreal's lead design engineer, estimated that the bridge contains the equivalent of 70,000 wine bottles.
But don't worry about punctured tires – the glass is ground into a powder, which is then added directly to the concrete measure. It's a technique developed at the University of Sherbrooke and was tested in 35 kilometres of sidewalk around Montreal.
“It performed very well. What we see with glass powder, it creates a concrete that is more resistant to compressive force but also to de-icing salt,” said Cantin Bellemare.
The engineer said he's confident the concrete in the bridge will outperform the regular variety and that there are environmental benefits as well.
“Cement is a very good material but at the same time, it's a very energy consuming material,” he said. “By replacing 10 per cent of the cement with glass powder for this project, we have been able to reduce the CO2 emission by 40 tonnes.”