At Ceco Concrete, sustainability is something we strive to integrate into each and every project we construct. We view sustainability related to construction as designing and building a structure with the least amount of embodied energy possible that will perform at a high level and “live” with the structure’s occupants for the longest possible period, with the smallest carbon footprint and least amount of maintenance.
The Concrete Sustainability Hub at the Massachusetts Institute of Technology (MIT) has done some exciting work related to concrete sustainability. A recent white paper on life cycle analysis concludes that a concrete structure will most often show an advantageous life cycle when compared to a steel frame. This is largely due to the fact that the embodied energy of concrete is only 1.3 mj/kg as compared with structural steel at 32 mj/kg.
Furthermore, according to studies from MIT and PCA, a concrete frame will benefit from 5% to 9% energy savings versus a steel frame in an office application. The energy savings inherent in the thermal mass of a concrete frame can significantly decrease a structure’s carbon footprint and operating costs, and it can be multiplied by integrating structural and mechanical systems to introduce hybrid or fully hydronic heating & cooling systems and passive ventilation. This is an approach we have vetted with our industry mechanical and structural engineering partners to build higher-performing healthcare and office buildings.
Following are some potential strategies to consider when reviewing concrete sustainability related to LEED or Green Globes certification in the early stages of your next project:
- Increased energy efficiency via less structural volume and more thermal mass.
- No fireproofing or corrosion protection is required; concrete can be left exposed.
- Concrete has natural Solar Reflective Index (SRI) of 30+, and the addition of lighter fly ash or slag content can increase this.
- Recycled content, such as Class C or F fly ash, silica fume or slag, can be added to reduce the carbon footprint of cement.
- Concrete materials will always be local, and 51% more labor is required of a concrete frame than a steel frame.
- Daylighting is more easily attained via thinner floor-to-floor heights and high natural SRI if exposed.
- Crews may recycle construction waste by using organizations, such as reefball.org, or by building bollards or barricades.
- Crews can use Forest Stewardship Council (FSC)-certified plywood on concrete formwork.
- Recarbonation process (Ca(OH)2+CO2=CaCO3+H2O) proves reduction in carbon footprint.
- Life Cycle Analysis (ID credit).
- Biolube or other organic form-release agents can be used.
- Exposed concrete is possible.
- Including Ceco in sustainable solutions for environmental value analysis and early team charettes can help.