In the world of green building, innovation and measurement criteria are quickly developing side-by-side. Green rating systems and customer demands are evolving, and challenging concrete producers and contractors to keep up or be left out. While associations help members stay current with educational materials and seminars, there is still some confusion about sustainable concrete construction.
Navigating the maze of sustainable terminology and documentation takes significant time and resources, which are luxuries many concrete producers can't afford. Fortunately, producers are not alone. Collaboration with designers, contractors, and materials suppliers is the new green trend in the concrete industry.
Many entries in THE CONCRETE PRODUCER's GreenSite Awards highlighted such partnerships. These projects show how a team approach can improve concrete's sustainable contribution, beyond simply meeting specifications for recycled or locally sourced materials.
From the ground up
In Orlando, Fla., Tarmac America teamed with BASF and contractor Dewitt Custom Concrete to make a new subdivision a greener place to live. The producer used BASF's Eco-Efficiency Analysis tool to quantify the environmental benefits of its Green Crete Concrete.
They determined Green Crete reduces the amount of CO2 emissions by 18% and uses 10% less energy per yard than a standard residential concrete mix.
Tarmac asked Orlando-based Dewitt to help identify the best application for Green Crete. The contractor suggested pouring two test slabs in the Lake Forest neighborhood, and was pleased with the results. The mix, which contains 50% fly ash by weight of the total cementitious content, had good workability and a smooth finish. Its balance of the high-range water reducer Glenium 7500 and slump retaining admixture, Rheotec Z-60, eliminated the need for adding water at the jobsite.
In addition to easier placement, Green Crete's high strength, low shrinkage, and long-term durability has resulted in the partners' commitment to using it for every slab in the neighborhood.
BASF also worked with Eastern Concrete Materials, based in Elmwood Park, N.J., to develop two high-strength mix designs for columns in New York's One World Trade Center building. The concrete included substantial amounts of fly ash, slag, and high-range water reducers to exceed performance targets. The project is the 2010 GreenSite Readers' Choice winner.
Home green home
The owners and designers of the Melone Residence in Edgartown, Mass., wanted to make the 7100-square-foot home a model of energy efficiency. They chose a concrete composite deck system as the structure's “backbone” for its durability and efficiency. The deck's long interior spans created large open spaces with a relatively thin floor.
The concrete contractor, Trademark Services, of Vineyard Haven, Mass., suggested that the engineer specify macropolymeric structural fibers instead of traditional steel and rebar reinforcement. This reduced the amount of energy-intensive materials used in the home.
The contractor worked with concrete producer Goodale Construction Co., of Vineyard Haven, to ensure that the minimal concrete waste was 100% recycled in ready-to-fill forms or as aggregate. This contributed to the project's LEED waste management requirements.
Thanks to the team's close collaboration, the home has earned Energy Star's Home Energy Rating Systems (HERS) index of - 5 (a net zero energy home would have a HERS Index of 0; the home is actually an energy producer). The Melone Residence has earned the U.S. Green Building Council's LEED Gold rating, and may also meet requirements for LEED Platinum.
For full descriptions and photographs of all GreenSite Award entries, visit www.greensiteawards.com.