Construction World May 2017

Five major benefits of concrete There are at least five major benefits in designing and building with concrete: versatility, attractive appearance, cost-effectiveness, structural integrity, and sustainability, says Bryan Perrie, MD of The Concrete Institute (TCI).

“Concrete is changing the face of South Africa’s landscape. One only has to consider the high number of truly impressive structures competing for the 2017 Concrete Society of Southern Africa’s Fulton Awards to see how many cutting-edge architects and engineers are making concrete their material of choice,” Perrie states. He says concrete’s versatility is the material’s first major positive factor. “As requests for changes are common in any construction project, the design flexibility of concrete allows the contractor to accommodate design changes after the process has begun. “As for aesthetic appeal, the range of colours and textured finishes available in concrete is amazing. Mixing and matching colours and textures provide a spectrum of design possibilities. Concrete textures can resemble smooth, high-polished granite or exposed aggregates with a rugged feel. As natural stone becomes inaccessible or the costs prohibitive, concrete is a natural alternative for recreating traditional finishes in a cost-effective way.” Perrie says speed has become a top priority in building. “When designing with concrete, there is no delay as concrete is readily available. Earlier start-up means better cash flow for owners and developers. It also could mean getting the jump on rainy seasons. “Should office tenant requirements include sound transmission control, the natural mass of concrete floor and wall systems provides both acoustical important structural advantage of concrete. On average, the construction of concrete buildings will allow one additional floor to be created for each 10 stories of traditional building height, resulting in more rentable resistance and vibration control. “Shallower floor systems are an

space for buildings of similar size. When faced with height restrictions, concrete construction is a key consideration and could represent initial construction cost savings and additional income generation.” Perrie says advanced construction techniques, such as ‘ flying formwork systems’ , increase the speed of floor construction. As a concrete frame progresses upward, workers on the completed floors below can proceed with interior partitions, exterior finishing, electrical, mechanical and plumbing systems. “Concrete construction assists in energy efficiency; a major consideration in the life cycle cost analysis. “With concrete cladding panels, a great range of finishes and textures are available. Precast panels are extremely durable, weather resistant, offer superior air tightness, increased sound attenuation and thermal properties and are inherently fire resistant. Concrete claddings permit fast enclosure of the structure, allowing other trades to start sooner, cutting construction time, and reducing wall thickness to maximize rentable space.” Perrie adds that due to its longevity and ease of construction, concrete is often the most economical choice for engineered structures. Load-bearing concrete exterior walls serve not only to enclose the buildings, but to carry roof and wind loads, eliminating the need to erect separate cladding and structural systems. “When it comes to energy efficiency, most concrete is produced locally, reducing fuel requirements for handling and transportation. Once in place, concrete offers significant energy savings over the lifetime of the structure. The mass of a concrete structure makes it a thermal reservoir with the ability to store large amounts of energy. This thermal mass

ABOVE: Precast concrete panels offer wide design possibilities as well as important economic and practical advantages on building sites. BELOW: The sky is the limit for designers when creating structures with concrete. Pictured: an innovative concrete roof in Tenerife, Canary Islands.

allows concrete to help maintain a relatively steady interior temperature. “Finally, concrete is an inert material that is easily recyclable. Old concrete that has reached the end of its service life can be reused as aggregate for new concrete mixtures. The addition of industrial by- products such as fly ash, silica fume and blast furnace slag make concrete less permeable while incorporating materials that would otherwise be deposited in landfill sites,” Perrie concludes. 

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CONSTRUCTION WORLD MAY 2017