Concrete Offers Myriad Advantages
Due to its durability, versatility, aesthetic appeal, cost-effectiveness and availability, concrete is changing the face of South Africa’s landscape with cutting-edge architects and engineers increasingly making concrete their material of choice.
Here, Bryan Perrie, MD of The Concrete Institute, (TCI) deals with the benefits of the world’s oldest and most popular building material:
Due to its longevity and ease of construction, concrete is often the most economical choice for engineered structures. Load-bearing concrete exterior precast or tilt-up 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.
Lower energy costs:
The energy efficiency of a structure is a major consideration in the life cycle cost analysis. Concrete construction can minimise the overall building height to shorten vertical runs of mechanical and electrical systems and reduce the exterior surface area to be enclosed and insulated.
Insulated concrete buildings with a medium to high level of thermal mass are characterised by their inherent ability to store thermal energy, and then release it several hours later when needed.
Once the design has been selected, there is generally pressure to get a project started. More and more organisations are making speed a priority, particularly high technology companies and rapidly growing firms. When such businesses decide to construct a new facility, they are often overburdened and already behind schedule. With concrete designs, there is no delay in getting started as concrete is readily available from many locations across South Africa. A concrete structure can be well underway using in-situ concrete before final plans are complete. Precast/prestressed concrete can also help reduce construction time and on-site labour costs by taking advantage of pre-fabrication of standard and custom structure segments.
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.
Generating revenue faster:
Faster construction means reduced carrying costs and faster revenue generation. This facilitates more timely pay back of financing charges and faster revenue generation for the developer/owner.
The design flexibility of concrete allows the contractor to accommodate design changes after the process has begun.
Design and colours:
Limited only by a designer’s imagination, the breadth of designs, colours and textured finishes available in concrete today is unrivalled. Mixing and matching colours and textures provides a spectrum of design possibilities.
Concrete textures can resemble smooth, high-polished granite or gutsy, exposed aggregates with a rugged feel. Other possibilities include tumbled cobblestone, brick, cultured limestone, slate, flagstone or river rock.
Stamping and scoring:
As natural stone becomes inaccessible or the costs rise prohibitively, concrete is a natural alternative for recreating traditional finishes in a cost-effective way. Besides being widely available and less expensive than quarried stone, cement-based cultured stone is easier to match and install. This makes it popular even in places where quantities of quarried stone are available.
Reduced sound transmission:
Containing sound within the walls of a structure is critical in today’s highly competitive environment. Should the tenant requirements include sound transmission control, the natural mass of concrete floor and wall systems provides both acoustical resistance and vibration control.
Creative wiring options:
Thin concrete floor structures facilitate the use of raised floor systems used where the wiring is run in the space below.
More floors per structure:
Shallower floor systems are an important structural advantage of concrete. On average, the construction of concrete buildings will allow one additional floor to be created for each 10 storeys of traditional building height, resulting in more rentable 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. Longer spans:
Post-tensioning reinforced concrete beams and slabs allow for longer floor spans with fewer columns to plan around. This offers flexibility in architectural layout and even more usable space. Increasingly, concrete is setting the standard for space planning and utility infrastructure.
Concrete is often left exposed on interior walls due to its aesthetic appeal, durability and inherent fire-resistance.
Ideal for strict specifications:
A major advantage of concrete construction for engineered structures is the material’s properties of density and mass. Lateral stiffness, or resistance to horizontal movement, make concrete the product of choice when constructing tall buildings where high winds or seismic conditions are considerations. This lateral stiffness also means that occupants of concrete towers are less able to perceive building motion.
Most concrete is produced locally, minimising 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 significant thermal reservoir with the ability to store large amounts of energy. In hot months, concrete walls and floors absorb the interior heat during the day, then radiate warmth back into the space at night. The same principle holds true for cooling. This thermal inertia allows concrete to help maintain a relatively steady interior temperature.
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.