Recent months saw an impressive entry by bagged dry mix producers into the green building market. Predictably, perhaps, California is the home of several operators that have entered the field in force: A Buddy Rhodes joint venture with Palo Alto-based Clean Concrete Technologies offers 90 percent recycled-content dry mix. Further down the coast, Rapid Set products developed by CTS Cement Manufacturing Corp., Cypress, received the Home Depot Eco Options Seal of Approval.
Contracting with dry mix suppliers, San Francisco-based Buddy Rhodes Concrete Products and Clean Concrete Technologies jointly announced availability of Buddy's Ultra Green Concrete, a bagged product comprising 90 percent recycled and by-product materials. Clean Concrete Technologies' patented formula reduces the amount of portland cement used in the mix and achieves 50 percent embodied energy savings over traditional concrete, reportedly without sacrificing strength or durability. Product developers emphasize that Buddy's Ultra Green Concrete is suitable for any traditional concrete job and can be obtained from authorized western U.S. distributors.
We have searched a long time to find a concrete mix that meets our green product criteria, notes producer Buddy Rhodes, an early purveyor of decorative precast. Clean Concrete Technologies' formula meets our criteria in all respects: We were most impressed with its strength and crack resistance. Plus, it finishes much better than common concretes and carries colors very well.
The Buddy Rhodes Concrete Products/Clean Concrete Technologies partnership to provide packaged concrete under an arrangement with toll blenders, e.g., Basalite, parallels a late-2006 joint venture teaming the resources of Quebec-based pigment and admixture supplier Interstar Corp. with those of California concrete artisan Fu-Tung Cheng. Prompted by growing demand for distinctive concrete counter tops, the principals noted, that initiative served to expand the Cheng Concrete Counter top line of packaged products sold online and through U.S. building supply retailers.
Among Rapid Set cement products recently placed on Home Depot's Eco Options list were several CTS offerings for concrete repair and new slabs Û Cement All, Mortar Mix, and Concrete Mix. The Home Depot Eco Options program, which enables customers to identify products of lesser environmental impact, requires that all brands receiving its seal of approval offer one or more of the following benefits: sustainability, forest conservation, energy efficiency, healthy home environment, clean air, and/or water conservation.
Eco Options listing of Cement All, Mortar Mix, and Concrete Mix followed a Scientific Certification Systems (SCS) evaluation of Rapid Set claims based on U.S. Environmental Protection Agency guidelines for Environmentally Preferable Products (EPP), mandating that items in question meet or exceed environmental performance of a typical offering in the same product category throughout its life-cycle and without significant environmental trade-offs. In the building materials category, Rapid Set was chosen due to a 32?36 percent smaller carbon footprint on a pound-by-pound basis than portland cement, because production of the former consumes less limestone and fossil fuels. Additionally, SCS determined that Rapid Set meets EPP requirements regarding raw materials extraction and processing, packaging materials, product use, and disposal and transportation.
SOUTH AFRICA DRY MIX PRODUCER NAILS CO2 FACTOR
Former Holcim Ltd. affiliate AfriSam Cement, Africa, has developed a logo to indicate the relative carbon footprint of its cement and concrete products. Clearly visible to end users, the quantity of CO2 emissions associated with each material's production and transportation will be illustrated on all AfriSam cement bags via a thermometer insignia indicating emissions compared to the world average of 890 g/kg cited by Cembureau. Characteristics of low CO2 cement typically include low fuel consumption; high mineral content, e.g., fly ash and ground granulated blast furnace slag or a combination thereof within standard requirements; and, low clinker content.
For each of its major cement types, AfriSam developed a CO2 footprint worksheet, thus calculating the CO2 associated with production of one kg of cement. The AfriSam model takes into account specific types of direct and indirect emissions, as well as the effects of interplant transportation. In cement production, the company notes, roughly 60 percent of CO2 emissions can be attributed to decarbonation of limestone during the manufacturing process and 40 percent to fuel combustion. Interplant transportation emissions come into play where cement is processed at more than one facility.
Overall, total emissions determining a product's carbon footprint reflect a cradle to gate approach, where the end point is the factory gate at which the cement is finally sold. The initiative is based on the Greenhouse Gas Protocols developed by the World Resources Institute and the World Business Council for Sustainable Development.