Road repaving has got an upgrade. Now, three-dimensional scanning technology is being used to shave and pave stretches of highway in Canada.
The new technology provides an extremely precise, in-depth roadway profile to determine exactly how much asphalt needs to be stripped and replaced during the road repair process. Control System CA, with offices in Calgary, Alta., and Timmins, Ont., is the company behind the new tech. It has already been used to repave stretches of highway in the Sudbury and Orangeville areas in Ontario.
“We can identify all problematic areas and solve all problems before we start the milling,” said Vitek Obr, the firm’s chief technology officer and business development manager. “This process is very complicated, but it saves a lot of time in the field, which is significantly more expensive.”
Construction Time Reduced
Only the necessary asphalt is stripped during the road rehabilitation process, thereby reducing the construction time and waste. The process has the potential to slash construction time by 25 per cent, resulting directly in cost savings and lower carbon emissions.
The road is first scanned using proprietary technology. The data is relayed to scanning stations and provides operators with a 3D model of the roadway. The information then enables operators to see abnormalities in the pavement and identify any trouble areas where water pooling might occur.
The process does not require any surveying crews or specialists. A precise digital twin of the road is created, along with a computer model for milling and paving. The information is uploaded to a computer, which can control the hydraulic system of a milling machine and use precise GPS coordinates to set the milling depth in millimetres based on the terrain of the road.
Technology Trims Waste
Milling machines are traditionally set to take off a fixed depth of asphalt. However, the new system enables operators to adjust the amount of asphalt to be removed. This new approach produces less waste. Road crews can also more accurately calculate the exact quantities of materials they will need. At the same time, the technology avoids milling too deep, thus eliminating the risk of breaking through the pavement into the granular below.
The technology reduces milling depth in areas of a road that are already low, such as sunken culverts, ruts or potholes, and increases milling in higher points of the road. Having exact measurements enables pavers to improve the water drainage profile of roads and lay down a smoother surface.
“The milling machine knows exactly what is the correct milling depth in any road location, based on GPS horizontal position data,” Obr said.
Benefits to Remote Areas
There are several global players that produce 3D surveying equipment, but they mainly focus on selling hardware. The technology developed by Control Systems, on the other hand, can be used with other products available on the market.
According to Obr, the technology is especially useful for projects in remote locations, where recycled asphalt is in high demand.
Building a 3D model before milling enables contractors to adjust the milling profile to a specific client. For example, in a busy urban area where existing asphalt stockpiles are significantly full, the model could be adjusted to limit the recycled asphalt production. This way, both trucking costs and the resulting greenhouse gas emissions will be lowered.
The tech could also be used when working on airport runways. A runway could be milled using several machines at the same time so that the operation is finished quicker. The technology has already been used at Arlanda International Airport at Märsta, north of Stockholm in Sweden.
Future Looks Bright
In Canada, the technology was used on a seven-kilometre road rehabilitation project in Orangeville and saved 46 per cent of the asphalt from going to the dump. Last year, it was used on a five-kilometre stretch of Highway 17 near Sudbury, and the works finished days ahead of schedule.
The technology has been used on road rehabilitations in Norway, Sweden and Finland, as well as the Prague International Airport in the Czech Republic.
Obr says that road repair work is big business, and many regulations govern it. He is hopeful that more provinces and municipalities across Canada will begin adopting the requirement for 3D milling technology in their tender documents. Ontario’s Ministry of Transportation is currently working on new specifications for public road tenders that would require 3D milling on some thoroughfares.
“Contractors are limited by conditions in public tenders,” he said. “This seems to be a very positive development which brings many benefits mainly for regular people.”