1. Is Concrete a Green Building Material? The Emergy and Environmental Impact…

2. What is Emergy? Phrase originally coined by Professor Howard T. Odom in 1986 “Emergy can be defined as the total solar equivalent available energy of one form that was used up and directly and indirectly in the work of making a product or service.” (Odom, 1996) Measured by scientific unit “Emjoule” “Embodied Energy,” established as a means to understand and evaluate the energy involved in the production and destruction of a particular material…

3. Concrete Production Patented in England by Joseph Aspdin in 1824, resembled Isle of Portland quarried Stone 75- 90 million tons of Concrete production per year in the last decade… (Portland Cement Ass.) Cement production involves the mixture of Limestone, clay/sand, bauxite, iron ore in a rotary cement kiln: –Kiln rotates slowly mixing contents progressively getting hotter to reach temperatures up to 2700° –Largest piece of moving industrial equipment in the world Concrete is made up of: 1.Portland Cement 12% 2.Sand 34% 3.Crushed Stone 48% 4.Water 6%

4. Emergy Efficiency It takes 2,300 to 3,500 pounds of raw materials to produce one ton (2,000#) of cement. Cement is the most energy intensive component of concrete and all industrial manufacturing processes, 92% of emergy in concrete Cement production takes about six million BTus for every ton of cement; includes direct fuel for mining and transporting raw materials…

5. Pro’s of Concrete Creates sustainable Sites Enhances energy performance Contains recycled material (fly-ash, slag cement, etc.) Cement kiln burn hazardous waste materials as fuel; high temp = complete combustion and decrease pollution… Manufactured Locally Builds durable structures LEED Certified as Green building material Utilizing concrete in commercial buildings offers up to 25 certification points.

6. Con’s of Concrete Concrete accounts for up to 67% by weight, 53% by volume of C&D Solid Waste…and only 5% avg. is recycled! ¾ Tons of C02 per ton of cement in the combustion of fossil fuel Additional CO2 released in calcining; turning limestone into lime Dust & Air pollution via Kiln; manufacturing, transportation, etc H2O pollution as high PH or Alkaline water toxic to marine wildlife… New add-mixtures increase chemicals within concrete to control; setting time, plasticity, pump-ability, water content, strength, and color. Despite the Alkalinity when wet, traditionally concrete is very safe and chem free…

7. Solutions and Recommendations Fly-Ash; reduce solid waste and reduce overall energy use as cement substitute –Increase concrete strength –Improve sulfate resistance –Decrease permeability –Increase overall workability of concrete Increase waste fuel used by Kiln; 50% Switch to lower CO2 fuels; Natural gas and Ag. Waste Utilize Pre-cast concrete structures to reduce dust and H20 pollution… Minimize the amount of concrete use by buildings and focus on the strategic use of the material to provide maximum structural support and minimal environmental degradation…

8. Sources http://www.buildinggreen.com “eMergy Evaluation” Howard T. Odom, Environmental Engineering Sciences, University of Florida, Gainsville. May 27, 1998. http://en.wikipedia.org/wiki/Emergy http://www.cement.org/buildings/gree n_leed.asphttp://www.cement.org/buildings/gree n_leed.asp http://www.usgbc.org/ “Emergy indices and ratios for sustainable material cycles and recycle options” M.T. Brown, Vorasun Buranakarn, July 2002.