Sustainable Building Materials for a Greener Tomorrow
Precast concrete contributed to green building practices in significant ways
Strong and Durable - The lower water-cement ratios possible with precast concrete mean it can be extremely durable.
Energy Efficient - The thermal mass of concrete allows the shifting of peak heating and cooling loads in a structure to help reduce mechanical-system requirements.
Less Waste - Factory-made in a controlled environment means little to no waste at the plant and then also reduces waste and debris on site.
Adapt - Load-carrying capacities, optimized cross-sections, and long spans possible with precast concrete members help eliminate redundant members.
Reuse - Concrete readily accommodates recycled content.
Strong and Durable
The primary ingredient of concrete- sand, gravel, and cement, are all mineral-based. When mixed with water, the cement chemically reacts to create a crystalline matrix with high compressive strength. This matric binds the sand and gravel together, creating concrete.
Unlike other construction materials that can rust, rot, or otherwise degrade when in the presence of moisture, concrete can actually get stronger if there are unhydrated cement particles available to react with the water!
The thermal mass of precast concrete absorbs and releases heat slowly, shifting air conditioning and heating loads to allow smaller, more efficient heating, venting, and air conditioning (HVAC) systems. Insulation is often used in architectural panels and sandwich wall panels to increase thermal efficiency, with continuous insulation in walls being possible.
The result savings are significant - up to 25% on heating and cooling costs!
The financial payback of a green building practice is measured in the operating and maintenance savings over time offsetting the initial costs of sustainable features. In the case of a precast building, costs can be countered during the construction process when you are able to reduce the HVAC systems due to continuous insulation.
Adapt & Reuse
Precast Concrete structures have the flexibility for many adaptive reuse possibilities.
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 also be reused in other applications.
Precast Concrete structures also can be manipulated to fit other needs. The flexibility to rearrange components means that walls could be added or removed to create a different space. For example, an precast concrete abandoned shopping mall was adapted to be a school with classrooms and offices.
Precast concrete is also friendly to downcycling, in which building materials are broken down because it comes apart with a minimum amount of energy and retains its original qualities. Breaking down old panels to become concrete aggregate in a new mix for future buildings.
Precast concrete's in-place performance can improve when several common industrial by-products are added. Fly ahs, slag, and silica fume, which would otherwise go into landfills, can be incorporated into concrete as supplementary materials. These by-products can also reduce the amount of cement that is used in concrete. Reinforcement is typically made from recycled steel. Insulation and connections within the precast concrete also contain recycled content.