FAQ

Is precast concrete different from other types of concrete?

Precast concrete is different because it is made in a factory by highly experienced personnel who apply stringent quality-control measures. In the factory environment, precasters are able to achieve consistency in temperature and moisture and low water cement ratios that are not possible in field-fabricated concrete. Precast concrete can easily attain strengths of 5000 psi to 7000 psi or more, with densities that minimize permeability.

Is precast concrete energy-efficient?

The thermal mass of precast concrete absorbs and releases heat slowly, shifting air conditioning and heating loads to allow smaller, more efficient heating, ventilating, and air conditioning (HVAC) systems. Insulation is often used in architectural panels and sandwich wall panels to increase thermal efficiency, with continuous insulation (ci) in walls being possible. The resulting savings are significant up to 25% on heating and cooling costs.

Can precast concrete members be reused?

Precast concrete members are unique in that they are individually engineered products that can be disassembled. Designers can easily plan future additions to buildings, because the precast concrete components can be rearranged. Once removed, precast concrete members may be reused in other applications. Precast concrete is also friendly to down cycling, in which building materials are broken down, because it comes apart with a minimum amount of energy and retains its original qualities. An example of down cycling would be the use of crushed precast concrete as aggregate in new concrete or as base materials for roads, sidewalks, or concrete slabs.

Is precast concrete a green building material?

Precast concrete contributes to green building practices in significant ways. The low water cement ratios possible with precast concrete -0.36 to 0.38- mean it can be extremely durable. The thermal mass of concrete allows shifting of heating and cooling loads in a structure to help reduce mechanical-system requirements. Because precast concrete is factory-made, there is little waste created in the plant (most plants employ exact batching technologies) and it reduces construction waste and debris on site, reducing construction IAQ concerns. The load-carrying capacities, optimized cross sections, and long spans possible with precast concrete members help eliminate redundant members, and concrete readily accommodates recycled content.

How does precast concrete contribute to LEED-NC rating points?

Precast concrete:

• Minimally disrupts the site (area and time).
• Reduces damage to drainage paths and natural habitats.
• Increases open area when multi-level parking structures are used.
• Reduces the heat-island effect because of concrete's light color.
• Improves energy efficiency and thermal comfort.
• Reuses and recycles formwork, keeping materials out of the landfill.
• Can be reused or recycled.
• Can use waste and recycled materials such as slag, fly ash, and silica fume.
• Is generally made from materials that are extracted and manufactured regionally.
• Does not off-gas, and does not need to be sealed or Painted.