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Solidifying The Future Emerging trends shape the world of precast concrete by Robin Brunet A dvancements in precast concrete are completely changing the design and construction sectors. The use of precast concrete building elements have been proven to positively impact the bottom line. Precast systems help minimize cost with faster construction, lower maintenance and overall operating costs, and reduce the environmental impacts, while providing comfortable, safe buildings. Innovations dominate the precast realm too, thanks to developments such as computerized precision colour control, carbon fibre reinforcement (for ultralite panels) and prestressed open space trusses, which provide long spans but maintain the shallow floor depth of a flat plate system. Thus, companies such as The Prestressed Group – that has made the process of strengthening concrete's natural weakness with tension one of its specialties – can meet virtually any precast need, whether it is hol- lowcore plank and structural products (voided slabs, box beams, girders, double tees, beams, columns, walls and noise walls) or high-end architectural products. In fact, "precast concrete is the material of choice for many developers who seek durability, construction ef ficiency and pleasing visual esthetics," says Brian Hall, managing director, Canadian Precast/ Prestressed Concrete Institute (CPCI). "Our mem- bers are involved in some interesting projects," adds Hall. Take the recently opened ALT Hotel in Halifax for example; precast concrete mixed with imported black granite sand and charcoal was selected to pull off the building's sleek, dark exterior. Almost 3,000 square metres of architectural precast concrete was required for the 169-room hotel. The recent construction of the Toronto South Detent ion Cent re highlighted one impor t ant competitive benefit that precast concrete has over other structural materials; the cost effectiveness of selecting a system that would provide an architec- tural precast concrete finish on both the load bearing and the non-load bearing panels were integral to the structural system. Once the structural parameters were established, the architect (Zeidler Partnership) developed the final design of the interior spaces, addressing structural details that ultimately defined the overall character of the building. In particular, due to the nature of the facility, the owner wanted connections between the precast elements hidden wherever possible. During the engineering design process, The Prestressed Group and Stephenson Engineering developed many con- cealed and hidden types of connections. Organizations such as the Cement Association of Canada (CAC) have publicly expressed disappointment that some governments have officially endorsed wood as the building material of choice for all government buildings, and that the proposed building code change would increase the maximum height of wood buildings to six storeys, from the current limit of four. The CAC's counter-argument to wood proponents is a familiar but compelling one. CAC contends that the construction of five- and six-storey wood-frame buildings could present many safety concerns for Canadians. If these taller wood-frame buildings are included in the Building Code, Canada could see an increase in fires, putting more Canadians at risk. Manufacturers and builders continue to innovate and take advantage of the latest systems in order to differentiate themselves from the competition. Plus, companies like Ontario-based Res Precast Inc., that has over ten years' experience in the design, fabrication and erection of architectural precast concrete products, aggressively expand their exper- tise by involving themselves in the latest construction methods and techniques – for the simple reason that quicker turnarounds, greater project scope respon- sibility, high-quality products and competitive prices are routinely demanded of subcontractors by develop- ers and design-build specialists. Lafarge, a leader in product innovation, recently signed a partnership agreement with the U.S. start- up Solidia Technologies to industrialize an innova- tive technology that could reduce the environmental footprint of concrete. The technology allows lower carbon dioxide (CO2) emissions in the cement pro- duction process and involves the capture of CO2 in precast Solidia concrete. Overall, CO2 emissions could be reduced by up to 70 per cent. "The development of a new type of cement, Solidia, is significant because the manufac- turing process uses conventional cement kilns and existing precast batching/mixing equipment, as well as conventional aggregates. The major difference is that CO2 replaces water in the setting and curing process," says Don Zakariasen, director of market- ing at Lafarge Canada Inc. "Water is used for mixing and placing Solidia concrete but is not consumed in a hydration process." Curing does not require autoclaves or other specialized equipment. Zakariasen adds that not only does this pro- cess result in a dramatic reduction in CO2 emis- sions compared to conventional mixes, but "Solidia has a favourable cost of manufacturing because it's fired at a lower temperature. The finished product has a higher strength and permeability, and it sets in one day instead of 28 days. Plus, the colour is beige, not dark grey, which I'm sure will be attractive to many architects." Solidia Concrete, which was the brainchild of New Jersey-based scientists, is being manufactured for the first time in block, pipe and precast plant production in Alberta. "We need to ensure that it works on a com- mercial basis, but I have a strong feeling it will blow the socks off the industry overall," says Zakariasen. Embedded fi bre optics in the wall panels of the Simons Retail Store Anjou in Quebec create the sparkling effect. Made possible by Béton Préfabriqué du Lac (BPDL) precast concrete. Photo courtesy CPCI. APril 2014 /13 Precast Concrete p12-17Precast.indd 13 14-04-02 4:47 PM