Industrial manufacturing has been the traditional economic driving force of Hamilton, Ont., so it is perhaps not surprising that the city has felt the effects of the economic downturn more than many of Canada’s urban centres. Fortunately, the city’s infrastructure program is right on target and is playing
a vital role in its future development.
Aggregates & Roadbuilding saw part of Hamilton’s infrastructure program at work on three separate roadbuilding projects earlier this year. In the city’s Sunninghill residential neighbourhood, work involved road resurfacing and selective sidewalk repairs on sixteen streets under public works contract PW-09-17 (H). Dan Lenko, construction contract inspector for this work, explains that the thickness of new asphalt depends on the condition of the existing pavement, the milling depth and the amount of padding needed to match new finished elevations. After milling, some streets have received 60 mm-80 mm of SP19 base asphalt followed by a 40 mm lift of SP12.5 surface mix. In other situations, effective surface rehabilitation can be achieved with a single surface lift. At Sharon Avenue, the crew of general contractor Rankin Construction was placing and compacting a single 80mm surface lift of SP12.5 mixture from the company’s Thorold hot mix asphalt plant.
|At Sharon Avenue in Hamilton, the crew of general contractor Rankin Construction placed and compacted a single 80 mm surface lift of SP12.5 mixture from the company’s Thorold hot mix asphalt plant.
Rankin’s paving train here consisted of a Caterpillar AP1000D paver followed by a Dynapac CC 432V double drum roller in the breakdown position and a Volvo PT-240R pneumatic roller in the secondary position. Once the asphalt had partially cooled, typically two to three hours later in hot weather, the CC 432V revisited the mat to complete finishing passes. Lenko is pleased with the results of this method and reports good pavement density results and driving smoothness for the finished mat. Target density figures are 92 per cent to 97 per cent and results of 93.5 per cent or better have being achieved.
Rankin foreman Dave Defrias added that the portability of the AP1000D wheel paver is an advantage in applications such as this where there are several paving locations relatively close to each other. The wheeled unit has maximum travel speed of 22 km/h and, unlike a track paver, can readily be travelled to the next paving location without using a float. The wheel configuration can also be an advantage in tight locations such as short radius corners where the wheel is less likely to scuff newly placed asphalt.
Cannon Street reconstruction
The Cannon Street reconstruction, the second job seen, was entirely different in nature to the residential resurfacing work. Cannon Street is one of Hamilton’s arterial traffic routes in the core area and the scope of work involved significant utility replacement as well as full depth reconstruction. Moreover, the general contractor was pressing hard to meet a road reopening deadline the following day after completing a considerable amount of work in less than three months. Valued at $4.5 million, the contract extended some 900m between Gage Avenue and Ottawa Street. Hamilton’s construction contract inspector on this contract, Don Putzig, explained that the scope of work included the replacement of a 300 mm water main and a 750 mm trunk main, as well as a new storm sewer down the road centre line to help alleviate pressure on the existing combined sewer.
|Coco Paving demonstrates echelon paving, an established technique to improve the longitudinal joint sealing and durability, on Fennell Avenue.|
|Echelon paving allowed adjacent asphalt lifts to be compacted at the same time on Fennell Avenue. A Caterpillar CB-534D split drum roller completes breakdown compactions on one lift while a Bomag 24RH pneumatic unit completes secondary compaction on the adjacent mat.
|Teamwork in action. D’Orazio Infrastructure Group’s concrete crew completes a concrete sidewalk on Hamilton’s Cannon Street.
|This Caterpillar PM-565B was milling 80 mm of old asphalt down to the original concrete on E41st Street, as part of the Sunninghill milling resurfacing and sidewalk repair program. The PM-565B was discharging reclaimed asphalt into a fleet of fifteen trucks, most of which were carrying the RAP back to Rankin’s Thorold asphalt plant.
|A Bobcat 864 with sweeper attachment clears RAP at Rankin Construction’s E41st Street milling operation.
On the day of Aggregates & Roadbuilding’s visit, the site was an impressive example of coordinated activity. At one location, the concrete crew of general contractor D’Orazio Infrastructure Group was completing one of the last sections of sidewalk, while at another location the paving crew of subcontractor Coco Paving was placing the final stretch of SP 19 base asphalt on Cannon Street’s westbound lane. In between, Hamilton Hydro was busy installing intersection traffic lights while another contractor was line painting. Elsewhere, additional D’Orazio crew members were placing and compacting sidewalk base material, on general site clean up or water spraying completed asphalt sections.
Putzig added that asphalt paving on this contract consisted of two 60 mm lifts of SP19 asphalt, to be followed in 2010 by a 40 mm lift of SP12.5 mixture. The time separation between base and surface asphalt placement is a precaution given the extensive utility replacement work done here and will give the pavement time to settle under traffic loading.
D’Orazio’s Sam Pignataro explained that the contractor was well on track to open two lanes to traffic by the following day, with related sidewalk, driveway and associated work to be completed later.
Pignataro added that the job was originally planned for completion in two separate sections for the north and south halves. Instead, D’Orazio adopted an aggressive construction schedule whereby both north and south sections would be completed at the same time and reopened by the stipulated contract date. In practice that meant all the utility replacement, reconstruction and paving work had to be completed between the project’s start date at the end of March and June 27, 2009.
D’Orazio’s site equipment fleet reflected the multiple demands on the contract. The excavator fleet included Caterpillar 365BL and John Deere 160C LC units, while a Gomaco GT3600 was utilized to completed concrete curb and gutter work. Material grading was completed by a John Deere 650J XLT dozer and compacted by Bomag BW177PDH-40 and BW Z130 units as well as a Caterpillar CB-214D. Materials handling duties were completed by Case 580 Super L, John Deere 310 SJ tractor loader backhoes and a Case 1845C skid steer.
Paving equipment utilized by subcontractor Coco Paving included a Caterpillar AP-1055B paver, Caterpillar CB-534D split drum roller and a 14,000 kg Bomag 24RH pneumatic unit. Detail compaction work around catch basins and edges was done by a Caterpillar CB-224D.
Fennell Avenue surfacing
The site visit to Hamilton’s Fennell Avenue found Coco Paving in action again, this time placing surface asphalt on another of Hamilton’s arterial routes after the previous placement of base asphalt. At this location, Coco was subcontractor to general contractor Wesroc Construction Limited and was utilizing two pavers in echelon to lay a 40 mm surface lift of SP12.5 asphalt. Echelon paving is an established technique to improve the sealing and durability of longitudinal joints by providing hot to hot mixture contact. This avoids the cold longitudinal joint that can result from long single lane paving followed some time later by the paving of the adjacent lift.
Here, hot mix asphalt from Coco Paving’s east Hamilton plant was paved by Caterpillar AP-655C and AP-1055B pavers while the compaction train included a Caterpillar CB-534D split drum roller in the breakdown position, a Bomag 24RH pneumatic unit in the secondary position and an additional Caterpillar CB-534D at the rear to finish the mat.
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