Ontario’s 400 series highways are changing colour.
Aecon Construction Materials Limited is using concrete — not asphalt — to pave a 10-kilometre stretch of the eastbound Highway 401 near London, Ont.
Since 2001, the Ministry of Transportation Ontario (MTO) has initiated an alternative bid (AB) process for freeway reconstruction contracts. Under the AB process, bidders prepare their construction bid based on either a rigid (concrete) or a flexible (asphalt) pavement design option.
“We chose to use concrete instead of asphalt, because it was a new opportunity that we feel is a more reoccurring item on many MTO contracts,” said Joe Tomlinson, contracts manager for concrete specialties with Aecon.
According to the MTO, during the design of the Highway 401 project between Union Road to Colonel Talbot Road, the ministry determined that both rigid and flexible pavement design options were feasible alternatives based on the scope of the project, constructability, service life and life-cycle costs.
As such, the ministry tendered the contract as an AB contract, giving bidders the option to bid on rigid or flexible pavement design options.
Of the 1,851 centreline kilometres of provincial 400 series highways, approximately 117 centreline kilometres are classified as concrete, which is 6.3 per cent of the total 400 series highway length, states the MTO. A centreline kilometre is one kilometre of the highway, including all driving lanes, the shoulders and even entrances.
Although paving highways using concrete isn’t always well received, there are some benefits to using the construction material, says Tomlinson.
Concrete roads have a much longer service life, less repair and rehabilitation requirements, and greater resistance to damage from cars and extreme weather. Concrete highways also have several environmental advantages over their asphalt counterparts.
Asphalt requires bitumen, a petroleum product that emits a lot of polluting gases during the paving process.
Concrete also has its disadvantages.
“Concrete can be very unforgiving,” says Tomlinson. “There are restrictions on being able to put traffic on it. It is also more sensitive to temperature and weather.”
Asphalt highways are better at remaining free from snow and ice. They also provide better traction and skid resistance for vehicles.
Using the proper equipment is important.
The equipment dealer who sold Aecon the Gomaco equipment, the Hot Mix and Aggregate Equipment Company of Canada Ltd. (HMA), also sells Roadtec equipment for asphalt paving.
“Our vision is to bring all paving knowledge together for two competing industries. This expertise in the paving industry allows us to supply superior services and products to both the concrete and asphalt industries,” says Brian Keveryga, general manager at HMA.
Aecon is pouring roughly 1,000 to 1,200 cubic metres of concrete each day. Trucks run a 40-minute loop beginning at a portable concrete plant that Aecon set up near the project site.
In order to complete the project, Aecon purchased a new Gomaco PS-2600 placer/spreader.
“We like the reliability of these machines, as well as the service and support we get from our local dealer, Hot Mix & Aggregate,” says Tomlinson.
“The purpose of the PS-2600 is to receive the loads from the trucks and control the amount of material ahead of the GP3 paver. This provides a constant, even head pressure and allows the GP3 paver to keep moving at a constant speed to achieve smoothness,” says Keveryga.
The PS-2600 features a Gomaco-designed conveyor system that is 1.5 metres wide by 6.7 metres long to catch the concrete from dump trucks with a drive capable of running 150 metres per minute, so trucks can unload quickly. Then, a 500-millimetre hydraulic, split, reversible auger moves the material across the machine’s spreading width of 9.75 metres. Hydraulically pressure-compensated sideplates provide edge control and a spreading depth up to 480 millimetres.
“The GP3 paver with G+ controls is unique in that it was purchased by Aecon for dual roles. First, it can pour barrier walls in the curb and gutter configuration and, second, it transforms into a road paver capable of paving up to nine metres wide. Both units are equipped for stingless operation in the future if required,” says Keveryga.
“The TC600 completes the process by putting in longitudinal lines in the finished concrete, a requirement set up in the MTO specifications as well the unit sprays curing agent on the finished slab.”
Aecon expects to complete the project by the end of November. Next spring, the company will begin preparations for paving the westbound lanes of that same stretch of highway.