Meet the ice doctor who’s reviving the frozen science behind Canada’s secret weapon from WWII

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Meet the ice doctor who’s reviving the frozen science behind Canada’s secret weapon from WWII


EDMONTON—Arno Pronk bends slightly and prods the mound of rough, milky-looking ice with one finger, then nods approvingly.

The tall Dutch professor and a team of Alberta engineering students have been working outside since before dawn; mixing a slurry of water and paper together, pouring the resulting concoction into a wooden frame and smoothing it as it freezes.

Pronk is teaching the University of Alberta students to build ice beams, but the late February weather is moody. It’s just past noon and temperatures are threatening to rise above zero.

The scientist behind the latest pass at a kind of ice-based construction that dates back to a wild chapter in Canada’s wartime history sees great potential for reinforced ice known as pykrete as a tool for construction in climates ranging from the Arctic to Mars.

Credit: Jake Kondor/University of Alberta

Pronk, an assistant professor at Eindhoven University of Technology in the Netherlands estimates that his reinforced ice can be as much as three times stronger than regular frozen water. He says materials themselves are cheap and it’s good for the environment — clean up mostly involves letting it melt.

“It reinforces the ice, so it makes it three times stronger. Usually ice is very brittle, so it’ll break into pieces,” he explains, but adding fibre like paper or wood pulp makes it stronger and more pliable. The fibre also acts as an insulator, and ensures the ice doesn’t melt as fast.

The fibre used to create these ice beams is toilet paper, and bits of the cardboard roll are visible. It is, as one University of Alberta engineering student jokes, a slightly redneck way of building.

Arno Pronk, an assistant professor at Eindhoven University of Technology in the Netherlands, right, and University of Alberta student Jake Kondor check on a fortified beam of ice on Feb. 20, 2020.

“It’s very much like mixing concrete, except we don’t have a guideline,” laughs Jake Kondor. “So we kind of, you know, throw some paper here and throw some water here and let’s hope for the best.”

The next day, the team was again up early to remove the ice beams from their frames — though not totally frozen, both V-shaped beams were a little over six centimetres thick. The sun was just visible over the horizon as they propped up each beam with pieces of wood placed under the ends. Students took turns adding concrete blocks on top — creating a “point load,” to use the technical term — to determine how much weight each beam could hold.

Arno Pronk, right, and Jake Kondor show a cross section of an ice beam, a structure created by freezing a mixture of water and paper.

The skinnier beam takes 600 pounds before it crumbles, while the larger one takes 780 pounds before succumbing to the bricks.

“Not bad for ice if you ask me,” Kondor said.

While this is the first time some of these students have heard about fortified ice, Pronk isn’t the first to bring it to Canada. In fact, one of the first major attempts to fortify ice happened about 400 kilometres south west of Edmonton almost 80 years ago — in a top secret project during the Second World War.

It was 1942, and the war was still anyone’s game, when an eccentric scientist named Geoffrey Pyke hatched a plan to strike back at German U boats. The “mad, wild scheme,” which was signed off on by British Prime Minister Winston Churchill himself, involved an Alberta mountain lake and ice. A lot of ice.

During the war, the middle of the Atlantic could not be reached by planes on either side, and it became a fertile hunting ground for deadly German U Boats.

Pyke, described by one academic as an “eccentric British genius,” knew how difficult icebergs could be to destroy — international ice patrols had done their best to blow many to smithereens after one infamously sunk the Titanic. He became fixated on the idea of towing an iceberg into the war zone so planes could land on it — a kind of frozen aircraft carrier.

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According to a research paper published by Susan B.M. Langley in a scientific journal in 1986, even Churchill got on board, going so far as to dictate a “most secret” memo with his thoughts on how an ice airfield should be built.

The Canadian government was tasked with building a model — dubbed Project Habbakuk — to test the theory. Eventually Jasper’s Patricia Lake was chosen as the testing site. It was more private and had a convenient source of labour, in the form of a conscientious objectors camp made up of Mennonites and Doukhobors.

An artist's conception of Project Habakkuk, a top-secret Second World War project to create an aicraft carrier out of reinforced ice.

But the shortcomings of regular ice quickly became apparent, Langley writes. Most of the weight of icebergs are below the surface, for example, so any hunk of ice used for an airfield would also have a tremendous amount of mass below the surface, making it almost impossible to move around.

Although lake ice was used for the test model, it was decided that reinforced ice would be better for the eventual vessel, because it was strong, buoyant and could be hammered and sawed, but since it required more work than regular ice, it would increase costs. A man by the name of Dr. Herman Mark of Brooklyn had been experimenting with reinforcing ice, and decided that between four and 10 per cent of wood pulp in ice worked best. He named the resulting creation after Pyke — hence, Pykrete.

The eventual test vessel was a mass of ice with a wooden frame and a peaked roof. It featured an elaborate cooling system for the ice. A full sized vessel was estimated to cost half of a conventional aircraft carrier.

But while they were building, better long-range aircraft and radar were invented, and officials decided a flotilla of ice vessels would be impractical, according to Langley. By the summer of 1943, the project was dead.

As someone who has built a career out of Pykrete, Pronk commends Pyke for persuading the likes of Churchill to let him test the concept, but calls the idea of an Arctic ship built from Pykrete “quite strange.” He points out that, aside from the melting issues, you’d only be able to use a ship like Habbakuk in very cold waters, where navigating around actual icebergs would be a very real problem.

Pronk, who describes his job as something between an architect and a structural engineer, has spent much of his working life pushing the limits on what can be built with fibre-reinforced ice.

University of Alberta engineering students mix water and bits of paper together to create reinforced ice.

Considering Pronk grew up in the Netherlands with aggressively placid weather it’s notable that he has devoted his life to ice and sub zero temperatures and building structures that test the extremes.

But then, he says, laughing, he’s always been a romantic.

“I thought ice is nice, it has a feeling of Christmas,” he says simply. “It appealed to me.”

In 2014, he set the world record for the largest ice dome in Finland, with a geodesic design spanning 30 metres. It was built with the help of 50 volunteers from the Netherlands. The next year, he built a scaled and simplified version of Spain’s Sagrada Familia, also in Finland. In recent years, Plonk says he’s worked more in China.

A pykrete dome project undertaken by Dutch professor Arno Pronk. He set the world record for the largest ice dome in Finland, with a geodesic design spanning 30 metres.

Instead, he sees the future of building with ice in projects that need to be strong but can be hard to clean up, such as temporary foundations for drilling rigs. He also says it might have future applications, such as research on Mars, where the environment is very cold.

Dutch professor Arno Pronk helped create a pykrete ice version of Spain's Sagrada Familia in Finland.

Pronk said he hoped his project with Canadian engineering students introduce them to new possibilities in cold climates.





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