Why Precast Concrete?

Why should you even consider precast concrete over steel or half a dozen of other building materials you’ve used before and you’re perfectly comfortable with?

Well, for starters, how about durability, aesthetics and quality? Then of course there’s timeline, budget, site size and location. And let’s not forget sustainability and maintenance. The fact is, we’ve not come across a building project challenge yet that can’t be solved with precast concrete or prestressed concrete. So why precast concrete?

Durability

Precast concrete is highly resistant to impact, corrosion, weathering, abrasion and other ravages of time, which reduces maintenance and operating costs. A low water/cement ratio combined with good compaction and curing in a controlled factory environment ensures a dense, highly durable concrete.

Safety

Precast concrete is non-combustible with built-in fire-resistant capability. It creates a safe envelope that helps protect people, equipment and the building itself. And it may also be helpful in reducing property insurance premiums

 

Aesthetics

Precast concrete provides the designer with an unlimited architectural vocabulary of expression. It is incredibly responsive to the designer’s needs, as it can be shaped in a cost-effective manner. The only limits are imagination and creativity. Design flexibility is possible in both colour and texture by varying aggregate and matrix colours, size of aggregates, finishing processes and depth of exposure.

Quality

Precast concrete components are produced under strict, factory-controlled conditions to ensure the highest quality in the desired shapes, colours and textures along with applicable tolerances. The pre-caster inspections focus on the process by which the units are produced, as well as the plant’s general operation. Precast pays off for owners and architects because it produces fewer worries about on-site discovery of units out of tolerance, connection details that are incorrectly cast or mismatched finishes from panel to panel. It also minimizes the need for continuous inspections, again saving the project money.

Sustainability

Thermal-efficient precast concrete building systems with continuous insulation offer a number of sustainability benefits during the construction process and long after the building has been completed. Precast can help increase building’s sustainability by reducing its embodied energy and assist in contributing to GREENSTAR LEED® points in several ways. Precast concrete’s ability to store energy and dampen the effect of temperature change on heating and cooling systems which may save a considerable amount of energy over the long term and can result in significant cost savings as well.

Sustainability

“Sustainability is meeting the needs of the present generation without compromising the needs of future generations. In other words, sustainability is our capacity to endure. As an industry. As a society. And as a people. We do this by making the most of our resources and by recycling and reusing materials whenever possible in a responsible and efficient manner.”

Through thermal efficiency, recycled content, local materials, minimal waste and more, we help enhance each building’s sustainability and assist in contributing to GREENSTAR and LEED® points, Energy Star ratings and Green Globes assessments.

The embodied energy of a building is equal to all the processes associated with creating that building. From the mining of raw materials to manufacturing, transportation and installation, Metromont incorporates a number of practices in order to help minimize the embodied energy of each project we work on.

A typical total precast building solution contains 25-35% recycled content. Of this, post-consumer content accounts for 20-25%, while pre-consumer content accounts for 5-10%.

Offsite Manufacturing and Minimal Waste

Since precast concrete building systems are manufactured in a controlled environment, we minimize building material waste along with construction site noise and dust. Typically, less than 2% waste is created and up to 95% of that waste is reclaimed and/or recycled into other products.

Water Recycling and Aggregate Reclaiming

Recycling of all concrete slurry water and reclaiming of aggregates is becoming common in concrete manufacturing facilities. This type of commitment to sustainable manufacturing is not only saving a precious resource, it can decrease the water bill by more than 70%.

Reduced Materials

Integrated design allows for a substantial reduction in material consumption and use. For example, a full bed depth brick utilizes five times the raw material of thin brick. By using non-corrosive C-GRID® carbon fibre reinforcing in Double Tees, there is reduced weight by up to 8%. Additionally, perimeter steel columns and fire proofing can be eliminated by utilizing the load carrying capacity of a fully composite, thermal efficient precast wall panel. The integrated design utilizes less material, costs less, is extremely durable and it can provide aesthetically pleasing architecture.

Materials with Recycled Content

Numerous materials with recycled content are used in precast concrete components. From rebar and steel mesh, to form liners, insulation and fly ash. Fly ash is the waste by-product of burning coal in electrical power plants. Generally, 15-20% of burned coal takes the form of fly ash. At one time, most fly ash was landfilled, but today a significant portion is used in concrete. Typically, pre-casters incorporate between 15-35% of fly ash in most structural products if allowed by specifications.

The Bottom Green Line

Everyone has their own unique set of motivations for incorporating sustainability into their buildings. Some are following codes. Others are following trends. While others still are leading the way for new and innovative initiatives. One thing connects them all, and that’s the appreciation of the significant cost benefits that can be achieved across the life cycle of the building. Much of this savings comes from the fact that concrete has the ability to store energy and dampen the effect of temperature change on heating and cooling systems. This is known as Thermal Mass Effect. The cost benefits to owners include:

  • Long-term energy savings – less energy to heat or cool a structure;
  • Smaller investment in HVAC equipment;
  • Off-peak energy used due to lag in peak demand;

When you consider that 65% of the electricity generated is used to heat, cool and operate buildings, and that 30% of greenhouse gas emissions are from buildings, this reduction has a significant financial and environmental impact.



Author: Nic
Dr Nicholas Mills is the Structural Director of NRM Consultants. Founded in Mandurah WA in 2017, he will continue to provide expert engineering advice and excellent structural service to their clients and whatever project they undertake.

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