Issue link: http://digital.canadawide.com/i/178290
Standards Association (CSA) cement and concrete standards, is referenced in the 2010 National Building Code of Canada (NBCC), and has been approved for use in B.C., Manitoba, Ontario, Quebec and Nova Scotia. The manufacture of EcoCemPLC, a recently introduced PLC, can result in up to a 10 per cent reduction of CO2 emissions, compared to normal Type GU Portland cement, according to Lehigh Cement product literature. "In 12 months, we expect it to be the dominant cement supplied for the industry in B.C. Acceptance has been very good," says Brad Pope, manager for ly ash and technical services at Lehigh Cement, a division of Lehigh Hanson Materials Ltd. EcoCemPLC's performance pro ile is almost identical to that of standard GU cement, but with a possible advantage at the front end. "It has about ive per cent greater strength at three days. At 28 days, it's the same as GU," says Pope. He says that Lehigh has several precast clients for EcoCemPLC. PLC use appears likely to increase across North America, with U.S. standards bodies like ASTM preparing to adopt PLC, Pope says. Besides sustainability, esthetics and staying within budget were central to a refurbishment project for Hamilton City Hall (HCH) where precast was used to match the building's original white marble. The refurbishment is highlighted as a project of the month on the CPCI website. Esthetics, budgets and also ef iciency are very much front and centre for some hospital P3 projects that Res Precast has been involved with recently. Sandwich precast panels were based on molds using form liners so that the exteriors of the panels looked like brick. "The advantage of this approach is you get to mimic any kind of look that you're after, for example, brick," says Joe Di Leo, president and CEO of Res Precast. In the case of one recent project, a design for a building that was to have a traditional brick face was converted to a design that would use a precast envelope instead – "With a full brick appearance in terms of relief and form, with the use of form liners. These [panels] can be stained to any colour. This has been the biggest movement in precast here in Ontario," says Di Leo. At a slightly higher cost, these panel systems can accommodate soap brick (typically real brick cut in half), which are speci ied by some architects. At the same time, the appearance of a control or expansion joint can be incorporated in the brick's design pattern to conceal any 'panel effect.' Di Leo notes that both types – stained relief or real brick – can bene it from the form liner system that Res Precast uses. Besides better thermal inertia than a conventional brick cladding, precast systems like this have all the bene its of precast, shop-based manufacture. The tight quality control of the shop environment for precast is critical for some projects that Armtec has been making precast components for, says Ken Pensack, director for engineered structures at Armtec, Paci ic region. "There must be good conductivity in some components and absolute zero chance of electrical conductivity in others. This could only happen in a shop where you have absolute quality control," he says. Steel ibre, a reinforcement technology developed about 10 years ago, but not used widely yet, recently saved labour time on projects involving precast tunnel liners. "Because there were uneven sections, it's more dif icult to fabricate conventional reinforcement. The use of steel ibre eliminated a fair amount of labour-intensive work," says Pensack. From the perspective of some specialty irms, like Sanderson Concrete Inc., which makes site furnishings, custom and architectural precast products, not a lot has changed in the last decade, says Jan Antorp, president of Sanderson. But, he says, "The continual improvement of admixtures has helped us make better concrete." ■ APRIL 2012 p.12-19Precast concrete.indd 17 /17 3/26/12 2:16:39 PM