Roads & Paving
Highway 69 drives north
Province’s highway construction program
January 23, 2009 By Andy Bateman
An Ontario contractor is playing a key role in the province’s highway construction program.
|Fowler Construction’s paving train on Highway 69 just north of Parry Sound.|
In August 2005, the Northern Ontario Highways Strategy was released, setting out the first ever five-year, $1.8 billion program for the province’s northern highways. Central to the strategy is the four-laning of Highways 11 and 69, two arterial routes connecting the province’s heavily populated southern areas with the north. Fowler Construction Company is playing an important role in the development of both highways by supplying aggregates, asphalt and construction services from company operations.
On Highway 69, the overall four-laning of Highway 69 is scheduled for completion by 2017. Gordan Rennie, regional issues advisor for the Ministry of Transportation’s (MTO) northeastern region, explains that all four-laning construction on Highway 69 south of Parry Sound is now complete, with the last 8 km section through the Wahta First Nation completed at end of August 2008. North of Parry Sound, there are currently three projects underway south of Sudbury, three north of Parry Sound and a S-curve realignment south of Highway 637. Aggregates & Roadbuilding saw Fowler’s team working as paving subcontractor to the Bot Construction Group on MTO contract 2005 5009. MTO details indicate that this $60.46 million, four-year job covers a 6.3 km stretch of Highway 69 and is scheduled for completion at the end of July 2009.
|The Caterpillar AP1055D paver was equipped with a 10-20B Extend-A-Mat screed and MOBA sonic averaging ski.|
|Fowler’s compaction train included a|
Bomag BW174AD tandem vibratory ride on roller equipped with Asphalt
Manager in the breakdown position followed by a Bomag 24R pneumatic
roller in the secondary position. The BW174AD also finished the mat.
|Secondary and tertiary crushing at the McDougall Quarry was completed by a new Raptor Excel 400 cone crusher (left) and a Symons 66-in cone crusher (right). |
Senior road construction inspector Steve Ferrante explains that the new pavement includes 150 mm of Type 2 Granular B base material and 150 mm of Granular A base. Hot mix asphalt includes two 50 mm lifts of SP 19 binder course followed by a 40 mm lift of SP 12.5 FC1 surface mix, with the latter to be paved by others under a later contract. The first 50 mm lift of binder course is two lanes or 7.5 m wide for the mainline paving. The second 50 mm binder lift is 12 m wide guardrail to guardrail, including the 3 m wide right shoulder and 1.5 m wide left shoulder.
On site, a Caterpillar grader and Bomag BW211D-3 single-drum compactor prepared the granular base ahead of the paving crew to remove any remaining tire marks or other anomalies. The asphalt paving itself was much more involved than one might expect on a mainline paving job, due in part to the staging between various sections. Asphalt foreman Corey Brooks described the job as a “jigsaw puzzle”, with work on this particular stretch including a tapered section in preparation for a crossover between the northbound and the southbound lanes.
Just a short distance north of the crossover, the paving crew also had to match the first lift of binder course with the lift already in place on the deck of a new bridge. This situation arose because, as Brooks explains, the activities of bridge waterproofing and mainline paving coincide only on rare occasions. In this case, the bridge deck’s waterproofing membrane had been placed some time earlier and protected (with asphalt) in accordance with contract conditions. Brooks adds that the second binder lift would be paved continuously across the top of the bridge, once the approach first lift and the existing bridge first lift had been matched. Even then, there was another twist in the paving sequence as the bridge had to be paved with the 12.5 FC1 surface mix before it could be opened to live traffic. This requirement recognised the risk of early ice formation on open bridge spans and the higher skid resistance of the surface mix compared to the binder courses. To meet this requirement, the paving crew place the surface lift across the span, extending it 30 m either side of the bridge span and notching it into the upper binder lift. When the rest of the surface asphalt is subsequently placed on the mainline either side of the bridge, the 30 m extensions mean that the horizontal joints between bridge and mainline 12.5 FC1 mix will be some distance from the bridge and not affected by any differential settlement between the bridge deck and bridge abutment fill.
Fowler’s paving train consisted of a Roadtec SB 2500 Shuttle Buggy feeding Caterpillar AP1055D and AP650B pavers working in echelon. The AP1055D paver was equipped with a 10-20B Extend-A-Mat screed and MOBA sonic averaging ski while the 650B was equipped with an 8-16B screed. Behind the pavers, a Bomag BW174AD tandem vibratory ride on roller equipped with Asphalt Manager was in the breakdown position followed by a Bomag 24R pneumatic roller in the secondary position, with the BW174AD also finishing the mat. Ken Duguid, a roller operator with some 15 years of experience, adds a user’s perspective on the 174AD, noting that the machine is both big enough for mainline paving and manoeuvrable enough for commercial work. The display of asphalt surface temperature is a useful tool for operators, indicating, for instance the need to keep tighter to the paver should the asphalt be cooler than normal. The unit’s operational panel also indicates the EVIB value (related to asphalt density) and so helps determine the number of passes required. The ability to run all day on two water fill-ups and one fuel fill-up is also popular with operators, while the crabbing facility allows wide passes to be made on straight sections or long radius curves when finishing the mat. This particular 174AD is Duguid’s second unit, following 1,500 uneventful hours on a first machine.
Aggregates and hot mix asphalt for the highway 69 paving contract were supplied from the McDougall granite quarry of Fowler Materials located some 2 km east of Parry Sound. In operation, the quarry’s stationary aggregate plant was fed well-fragmented shot rock by a Caterpillar 988G wheel loader on load and carry duty. The plant’s Pioneer 3546 primary jaw was equipped with a pedestal-mounted Teledyne TM Series breaker of 1500 ft-lb capacity to break oversize when required. Material from the jaw was then conveyed past both the secondary and tertiary crushers to a Tyler 7 x 20 double deck screen. There, material larger than 75 mm retained on the screen’s top deck was conveyed via a feed bin to a new Raptor Excel 400 cone crusher while minus 75 mm plus 19 mm material was conveyed to a Symons 66-in cone crusher. Product from both crushers was returned to the screen for further size separation. Meanwhile,19 mm minus material passing the screen’s lower deck was conveyed forward to a feed bin where it was directed either to a Granular A product stockpile or the operation’s separate wash plant.
As part of the government’s $30-billion Re New Ontario infrastructure plan, the highways strategy is described as critical to the economic prosperity of the entire province, especially the North where more than $32 billion worth of minerals, wood, paper and other products are produced and shipped each year. In addition, 11 million tourists visited Northern Ontario in 2003, spending an estimated $1.7 billion.
The Ministry of Northern Development and Mines establishes and manages the budget for the annual highways’ program and works jointly with the Ministry of Transportation (MTO) to identify program priorities. The MTO is responsible for delivering the construction program and maintaining the highway system.
At the wash plant, a Dillon 6 x15 triple deck wet screen separated the Granular A feedstock to produce washed 19 mm clear sized stone, HL1 (minus 16 mm plus 4.75 mm) and minus 4.74 mm screenings. The screenings were directed down a chute to a 914 mm diameter GreyStone dewatering screw before being stockpiled as manufactured (crushed stone) sand. Lime slurry, an anti-stripping agent, was metered into the wash plant’s product streams from a nearby tank and pump system.
The aggregate production process at McDougall demonstrated several operating principles designed to maximize production efficiency and minimise operating costs. At the front end, the primary crusher was located near the face to avoid the use of haul trucks and connected by relatively long field conveyors to the secondary plant. Additional sections of field conveyor could be added as the quarry face moved to keep the primary load and haul distance low. In addition, the use of a single screen to perform material size separation from all three crushing stages was a departure from the multiple screen set-ups more commonly seen. On the control side, the plant had recently switched over to a wireless system which has worked well since its installation and is reported to be a significant improvement over the previous cable network.
McDougall Quarry hot mix asphalt plant
The Stansteel Asphalt Plant Products portable hot mix plant in the McDougall Quarry had four cold-feed bins, from which feed passed over a scalping screen and up an inclined conveyor belt. The scale on the belt monitored changes in the material feed rate as well as total tonnage, allowing a consistent asphalt cement content to be maintained in the final mixture. With this plant design, the process of drying and heating the cold feed was isolated from the mixing process by utilising separate dryer and mixer drums. Once the cold feed has reached the required temperature in the dryer drum, it was transferred to the mixing drum where asphalt cement, RAP and returned fines were added as required. RAP was supplied directly to the mixer drum via an RAP feed bin and conveyor belt. This separation of drying and mixing avoided any direct contact between the burner flame and either asphalt cement or RAP to increase production rates and reduce smoke emissions. Finished product from the mixer drum was stored in an 85 tonnes capacity Dillman Equipment silo.
Fowler last appeared in Aggregates & Roadbuilding Magazine as a finalist in the MTO’s Paver of Year awards for quality work on Highway 141 between Rousseau and Bent River in Muskoka.
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