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Showing posts with label innovation. Show all posts
Showing posts with label innovation. Show all posts

Tuesday, November 1, 2016

City’s new pothole innovation could save thousands on road repairs

From May to August of this year, The City’s 14 asphalt hot boxes filled over 5,000 potholes. The hot boxes are a single-purpose piece of equipment, and can’t be used without an operator.

“Our crews started looking for a multi-functional piece of equipment,” says Roads Maintenance Manager Bill Biensch. “There were products on the market but they did not fulfill all our requirements.”

So instead, a City-specific design was created. With a focus on increasing utilization of City fleet, Fleet Services, in collaboration with Roads, designed a new slide hot asphalt carrier that can be slipped onto the box of Snow and Ice Control (SNIC) trucks. After about 350 hours of engineering time and 800 hours of manufacturing, Fleet Services developed a prototype asphalt hot box that would slip into the back of the truck was delivered.

“By using the SNIC trucks, which are parked in the summer, we turned these units into multi-purpose trucks that can be used year-round,” said Majid Asefi, Fleet Operations Manager. “This saves The City a significant investment in purchasing the additional chassis that was previously required.”

The redesigned unit, which was fabricated in-house at the Fleet Fabrication and Welding shop, also allows the Roads crews to use the recycled asphalt pulled up from construction zones. After collecting the asphalt, recycling it is a four-step process:

1. Apply emulsion (a liquid solution) to the asphalt carrier
2. Apply emulsion to the asphalt
3. Load the asphalt carrier with material
4. Bake at ~ 350 °F for 8-12 hours

After these four simple steps, the asphalt is ready to reuse!

Crews can let the material bake during peak traffic periods in the afternoon, then get back out on the roads in the evening to start filling potholes. The baking process can occur without an operator while crews attend to other maintenance work, which makes the machines even more efficient. Crews can recycle up to four tonnes of asphalt each time the cycle runs, at a total cost of just $29 per tonne. For every tonne recycled, we save $141.

The first trial used asphalt from manhole work in the southwest, which was re-purposed for a pothole in Charleswood. With a successful trial under their belts, crews are looking to turn more trucks into multi-purpose pieces of equipment. If two trucks could each recycle three tonnes of asphalt each day, crews could re-use almost 100 tonnes of asphalt every month, saving around $14,000.

As the temperature cools down, crews may soon switch to snow and ice control. To prepare for next year’s summer road work, Fleet Services has refined the initial design and is currently building six additional units.

For more information, visit the City’s Roads Maintenance program page.

Friday, October 23, 2015

Innovations in road construction: Summer 2015


A fibreglass grid is installed on Sarcee Trail S.W.
Calgary is a city of changing climates, which can cause some roadways to deteriorate more quickly than others. While asphalt is a durable and economical material when it comes to road construction, maintenance problems occur when cracks form within the base layers of the roadway and are reflected up into the top layers. These cracks form due to a number of reasons, including very low temperatures, the freeze-thaw cycle, moisture penetration and traffic fatigue.

To keep Calgarians on the move, this summer The City piloted a pair of new projects aimed at improving the service life of our roadways and reduce lifecycle costs.

The first of these projects was a fibreglass grid system. The grid is placed between the base layer and the top layer of the asphalt. The potential is that the fibreglass grid should decrease cracking that occurs over time on the top asphalt layer of the roadway, and the grid will also help strengthen high use roads to prevent ruts and fatigue cracks from forming.

A close-up of the fiberglass grid.
In this particular case, The City used a grid that was a composite (with a nonwoven polypropylene material) which will also serve as a protective barrier against moisture penetration. This major road rehabilitation, including the fibreglass grid and drainage improvements, was installed on a one kilometre section of northbound Sarcee Trail S.W. north of Richmond Road S.W. The grid was also installed on 101 Street S.W. between Highway 8 and 17 Avenue S.W.

The second pilot used this summer was fibre reinforced asphalt, which was installed on southbound Shaganappi Trail N.W. between 16 Avenue N.W. and 32 Avenue N.W. Small batches of synthetic fibre are added to asphalt during the mixing process. This helps to increase the structural capacity of the asphalt by making it stronger in turn creating a more durable asphalt top layer that is more resistant to daily wear and tear.

The City will continue to monitor both pilots over the course of their service life by comparing them with roadways of similar age and traffic counts.

For more information on The City of Calgary’s Roads Construction, visit Calgary.ca and search Roads Construction Division