Concrete today is considered by many modern engineers and architects to be a more efficient and effective alternative to steel when it comes to the creation of buildings, ranging from low-rise apartments to neck-breaking skyscrapers. Thanks to the rapid growth and development of the world's major metropolises and growing cities, concrete today has become one of the most important building materials to date. According to the World Business Counsel for Sustainable Development (WBCSD), “it has become the most consumed substance on earth, replaced only by water, with three tonnes per person used each year” (World). This enormous demand for concrete makes the cement industry one of the largest producers of carbon dioxide in the world, accounting for approximately 5% of all human-caused pollution. “For every ton of cement used, approximately one ton of carbon dioxide is released into the atmosphere” (World). The cause of this problem is the increasing world population and the growing demand for land and energy. Its effect is that, as the population continues to increase, it forces builders and developers to meet the quota of creating unlimited amounts of infrastructure in a limited, resource-filled world. Knowing this, a proposed and widely shared solution is to produce concrete in an environmentally friendly manner, incorporating more demolished concrete, waste from past projects and other recycled aggregates. “Green” construction is the concept of constructing homes and buildings that we need today without depleting resources for future generations” (Balogh) As a subsidiary, the concept of incorporating recycled concrete began as the beginning of a environmental response of the “green building” theory to the growing demand and...... middle of paper... delay. (2009). Retrieved from http://www.nationalslag.org/blastfurnace.htmCase histories. (2011). Retrieved from http://www.concreterecycling.org/histories.htmlCobiax. (2010, January). Intuition. Retrieved from http://www.cobiax.ch/downloads/english/Cobiax_Insight_E.pdfGreen concrete. (2011). Excerpt from example http://www.concreteideas.com/green-concreteProject. (2010, January). Retrieved from http://www.cobiax.ch/downloads/french/projects/other_countries/Projektbeispiel_Nationalstadion_Warschau_PL_e.pdf Recycled materials in concrete reduce CO2 emissions and landfill use. (2011). Retrieved from http://www.greenconcrete.info/recycled.htmlWorld Business Council for Sustainable Development. (2002, July). The cement sustainability initiative. Retrieved from http://www.wbcsd.org/DocRoot/1IBetslPgkEie83rTa0J/cement-action-plan.pdf