Toronto-based Innocon Ready Mix Concrete has set a new North American volume record for a continuous self consolidating mix placement. Dispatching 510
Toronto-based Innocon Ready Mix Concrete has set a new North American volume record for a continuous self consolidating mix placement. Dispatching 510 truckloads from four Toronto-area plants, the producer delivered 5,500 yd. of Agilia brand SCC for the foundation of the $500 million, 55-story Four Seasons Yorkville Hotel.
Lasting about 13 hours, the late-2008 pour saw trucks feed the hoppers of a centrally located boom pump and five static placement pipes around the foundation perimeter. Placement peaked at about 525 yd./hour for mixes designed to reach 8,700-psi (60Mpa) compressive strength.
Agilia is a proprietary SCC of Lafarge North America, which also operates Innocon in a joint venture with Essroc Canada/Italcementi. The project bests the continuous SCC placement benchmark set by Chicago’s Prairie Material Sales in September 2005 for the foundation of the 92-story Trump International Hotel & Tower core Û 5,000 yd. in 24 hours.
While the use of SCC versus conventional mixes afforded contractors productivity gains through faster placement rates and reduced labor requirements tied to finishing ease, Innocon President John McCabe says the Trump Chicago pour did not factor into the way his company handed the Four Seasons job. We had done a couple of jobs somewhere around the 3,000-meter [4,000-yd.] mark, so we used our own methods Û ones we’d used before Û on the Four Seasons job, he says.
We went to the engineers and contractor with a proposal to use SCC for this large, predominantly reinforced concrete job, says McCabe. We showed them the details of our prior successes downtown and how we could coordinate such a big job with these space limitations. In the process, we convinced them to change a standard pour into an SCC job.
After two months of intensive planning and testing, the pour commenced early on November 29. Ready mixed was poured from 120 trucks from four plants in the Toronto area Û two central mixed facilities on Commissioners Street, another central mixed plant on Wilson Road, and one portable dry batch plant on Newkirk Road.
At the corner of Bay Street and Yorkville Avenue, the hotel and private residences are being developed by Bay Yorkville Development Ltd., a joint venture of Menkes Developments Ltd., Lifetime Urban Development Group, and Alcion Ventures. Menkes Construction Ltd. is building both the hotel and adjacent 26-story residential tower.
The day of the pour, six trucks pulled into locations around the site shortly before dawn. We had five pipes spaced out around the perimeter, set against the walls, explains McCabe. The concrete was poured into hoppers, which gravity fed the pipes and dumped into the foundation at various spots. By doing it this way, we get less noise since we don’t have pumps running and no pump trucks driving around. There was one pump on hand in case one of the pipes broke down.
We were able to lower the cost of the operation by not using many pumps, and it was safer, since we didn’t need as many workers or vehicles moving around at the foundation level. At most, I’d say there were 10-12 guys down there during the entire 13-hour pour. And, there’s no touching of the concrete until the very end. Construction on the Four Seasons is scheduled for completion in late 2011.
Developed at Lafarge S.A.’s Lyon, France, research lab and introduced first to European contractors, Agilia was unveiled in the North American market through Lafarge Canada Inc. in early 2000 and offered a mix design based on the latest-generation of superplastisizers. It is flowable enough to be self compacting and require no vibration. At the time, Lafarge officials noted that the material maintains set time and strength development characteristics similar to conventional mixes; places evenly amid heavy reinforcements; and, in structural and architectural applications, yields a smooth, bughole-free surface finish.
Agilia logged its first field application in North America at Wall Centre, a 48-story commercial and residential development in Vancouver, B.C. Agilia mixes were chosen for six 8-ft.-square, 20-ft.-tall outrigger columns on each of the tower’s first four floors. Since then, the SCC mix has been used in everything from casinos and dams to wind turbine bases and bridges.