“Green Concrete”

The Conco Companies recently completed the massive, continuous mat pour for the Salesforce Tower that is currently under construction in downtown San Francisco.  The job required approximately 12,000 cubic yards of concrete, and was enough concrete to fill almost four Olympic size swimming pools.  We are pleased to report that the foundation was poured using “green concrete”, which is concrete produced from recycled materials and generates lower CO2 emissions as compared to conventional concrete. 

While concrete is recognized as an excellent creative and effective sustainable building material, a conventional cubic yard of concrete contains by weight approximately 10 percent of cement.  CO2 emissions occur during the production of the cement, and for each ton of cement produced; it creates about 0.9 tons of CO2 emissions. 

To produce the cement used in concrete, it requires heating pulverized limestone, clay, and sand to 1,450 °C with coal or natural gas.  As a result in 2009, it was reported that five percent of all carbon dioxide emissions throughout the world were a result of producing 2.8 billion metric tons of cement.

“Green concrete” is defined as concrete that uses other material as a partial or complete replacement for cement or fine or coarse aggregates, and the substituted material can be waste or residual products obtained from manufacturing industries.  The goal of creating a greener concrete is to help reduce greenhouse gas emission, to reduce the use of natural resources such as limestone, shale, clay, natural river sand, natural rocks, and to recycle waste materials that would otherwise end up in landfills.  Today there are many people researching a variety of methods in order to create cements that do not produce as high of an amount of CO2 emissions. 

The Conco Companies are the foremost supplier of concrete services for the Western U.S. We have built a reputation on superior concrete formwork, reinforcing, place and finish, shotcrete and other ancillary services that benefit from our vast experience.  Our four regional offices serve California, Colorado, Oregon, Washington, and Nevada. 

Source:2.technologyreview.com/article/418542/tr10-green-concrete/