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Layer by layer, metre by metre

Building a new road is expensive, time-consuming and difficult

Nathan VanderKlippe
Northern News Services

Yellowknife (Aug 09/02) - It's a sunny day, and Henry Larabie is outside, hosing off his massive pickup truck. This could be any day, really, since for the past few years Larabie has had to wash his truck almost every day.

It's one of the hazards of living in a house on Highway 3, which has for decades been a wicked cauldron of dust and mud and flying stones.

Guy Guilbault, another person living on the road, has to replace his windshield two or three times a year.

But things are looking up. The retired miner doesn't have to haul out the hose as often any more, because his house is right at the end of a new stretch of road being built by RTL Enterprises.

The new road is wider, straighter and more solidly built than the old one. Better yet, it won't be gravel for long. When RTL finishes up its work on 8.5 kilometres just outside of Yellowknife, Larabie may be washing his truck even less, since the road will sport a freshly chip-sealed surface.

RTL's work fits into a grander scheme that will see a fresh surface for the entire length of Highway 3 in the next few years. Construction crews have been at work for the past three years upgrading the road, which has proven a deep wellspring of complaint from its users.

Department of Transportation officials are right now reviewing proposals to redo another stretch of the road, from kilometres 271-293.

The GNWT has paid $6 million for 8.5 kilometres just outside of Yellowknife, $12 million for 15 kilometres near Rae, and is expecting to pay about $15 million for the 21 kilometres under review.

"Things are slowly improving," said Bernard Cassidy, the acting director of highways for the department of transportation. "It takes a while, but we're getting there"

In the past, the road has been bumpy enough to cause damage to vehicles and dusty enough to make driving dangerous. Its narrow stretches and tight turns have made it perilous to pass, and transport trucks haven't made things any safer.

It's already a far cry from where it was 30 years ago, said Cassidy.

"We used to have to tow people through on floats by bulldozers (after it rained)," he said. "The mud was so deep you just couldn't drive through it."

And now, at about a million dollars a kilometre, the GNWT is slowly replacing every kilometre of the stretch between Yellowknife and Rae. In many areas, that requires blazing a brand new trail to make it wider, flatter and easier to drive.

Starting in the air

To build a new roadway, you have to start in the air. Route planners begin their work by studying aerial photographs, sketching out a possible location for the road.

The preliminary plan is followed by an actual road-walk, as road designers hike the location of the road and take notes on the various geographic features that will help or hinder its construction.

"You're trying to look for the least-cost approach," said Henry Murzyn, general manager of Nishi-Khon/SNC-Lavalin, which has done road design for two segments of Highway 3.

The Precambrian shield in the Northwest Territories makes for an excellent road bed, since it's about as solid as rock gets. But its toughness also makes it expensive to level out.

The rule of thumb is that you need about 1-1.3 kilograms of explosives to dislodge one cubic metre of rock. To build one kilometre of road, you have to blast about 40,000 cubic metres of rock.

So road designers get into a balancing act. The object is to match a solid road with an equal dispersion of resources. So the height of a road through a rock plateau is balanced against how much of the blasted rock will be needed to fill a bog or some muskeg.

"Ideally if you can balance cut and fill, that's probably the best solution," said Murzyn.

Once the route is chosen, the actual work begins. Everything depends on location, but the basic design of the road is always the same. Workers spread out layer after layer of rock and stone, gradually using smaller-sized material as they get closer to the top.

In muskeg and water, the first layer is a "geotextile fabric," basically a massive sheet of cloth designed to prevent muck and small stones from getting up into the road's base of large rocks - thereby slowing the amount that the road will shift.

The road-builder's biggest enemy is road movement. For example, a chip-sealed surface can last a decade, but usually frost and settling crack the smooth roadtop, and repair work needs to start after only three years.

That's the reason the NWT uses chip-seal, which is a layer of oil covered by two layers of rock and pressed together. Asphalt is a much thicker topping, but also much more expensive - and road movement destroys it just as easily.

"The road is going to move, so you might as well use the cheaper thing, because then you can do it again," said Norm Kelly, an engineer for Pelly Construction which this summer finished up a 15-kilometre stretch of road near Rae.

The chip-seal does make a much more comfortable driving surface, but it doesn't do much for maintenance costs. The price for upkeep for gravel compared to chip-seal is basically a wash.

The work requires a lot of money, a lot of men and a lot of heavy machinery. Crews use dozers, hydraulic excavators, packers, loaders, graders, water trucks, rock trucks and gravel trucks, along with their own rock crushers to make gravel.

Even with large crews crushing rock 24 hours a day, construction still proceeds at a plodding one kilometre per month.

The upside, though, is that despite the length of time needed to finish off the whole road, the number of kilometres of gravel is diminishing. In fact, one of the tasks left to do for the GNWT is to change the sign warning motorists of 60 kilometres of narrow, winding roads.

So far, enough money has been allocated that by next summer only 30 kilometres of gravel should remain. After that, only time - and budgets - can predict how long before drivers can cruise on an uninterrupted stretch of paved road all the way to Yellowknife.