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DECEMBER 2017 | 17 PHOTOGRAPHY COURTESY MAXXON CANADA; CCMET INC. Concrete underlayment is ideal for smoothing concrete slabs or precast planks in new or renovation projects (it covers old floor coverings, including vinyl asbestos tile, can be poured from three inches deep to a featheredge, and has compressive strengths up to 4,000 psi). Beth Lee, business development and project manager for Maxxon, discusses an interesting trend that is gaining traction in the construction industry. "We spent the better part of the year studying acoustics in mass timber construction [for exam- ple cross laminated timber and nail laminated timber]. Often in mass timber con- struction the owner wishes to leave the ceiling exposed to showcase the beauty of the wood – and because of this exposure, impact sound and airborne sound can be a real problem for the people occupying the floor below." Lee goes on to say, "Normally, our gypsum underlayments are used for fire rat- ings in wood construction, but mass timber buildings can achieve a fire rating with- out a gypsum underlayment. However, the gypsum underlayments have proven to be terrific in mitigating impact and provide significant airborne sound control. A gypsum underlayment also encapsulates underlying sound control mats, which are used to control impact sound waves. "Meeting sound code requirements in mass timber construction when the ceiling is exposed is tricky. We recommend a robust system that includes a top of the line impact sound control system topped with a thick pour of gypsum underlayment. Also, be sure that the selected system is backed by acoustical testing to ensure it will meet code," says Lee. Finally, engineering and testing ensures that concrete maintains its status as a building material of choice for developers. Canadian Construction Materials Engineering & Testing (CCMET) has full-service concrete testing facilities through- out Western Canada, including 12 mobile concrete testing laboratories for remote locations. Its Metro Testing Laboratories division in Burnaby, B.C. employs over 80 materials engineers, technologists and technicians, specializing in mix design for concrete and asphalt. Marc Varty, director of business development and marketing for CCMET Inc. (better known as Metro Group), reports a new service that provides its clients with state-of-the-art concrete technology. "Metro staff have developed a maturity-based real-time concrete strength estimation system using up-to-date wireless and sen- sor technology for measuring the tem- perature and time history of concrete in order to evaluate the early strength of concrete," he says. "Reusable sen- sors are inserted into a concrete slab pour and tracked. Each sensor/probe is housed in a 'sleeve,' and easily extracted after use." The attractiveness of this system, which is currently being field-tested, is that it allows the site to review the temperature history of the concrete remotely and therefore determine the in-situ strength, allowing decisions to be made earlier for form removal. This allows for the potential significant labour cost savings by helping the site to call in the stripping crew when required, versus waiting for the strength test results from the lab or sacrificing/testing the limited concrete test samples too early. Another benefit is that "every concrete spot test conducted in Metro Vancouver requires a minimum of three cylinders a piece [as per CSA A23.2-14], each weighing about three kilograms, and considering there are well over 100 tests [300 cylinders] being conducted daily in this region, that amounts to a lot of cylinders to be recycled or disposed of, on the order of plus or minus 900 kilograms," says Varty. "Think of the environmental impact by reducing this disposal. I think in my lifetime we'll see cylinders being eliminated altogether." A Dura-Cap underlayment from Maxxon Canada. Metro Group concrete strength estimation system wireless box and sensor ready to install. 11:24 AM

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