ABSTRACT
Portland cement concrete is one of the most widely used construction materials. As the demand for concrete as a construction material increases, so, too, does the demand for Portland cement. It is estimated that the production of cement will increase from about from 1.5 billion tons in 1995 to 2.2 billion tons by 2010 (Malhotra, 1999). On the other hand, climate changes due to global warming have become a major concern. Global warming is caused by the emission of greenhouse gases, such as carbon dioxide (CO2), into the atmosphere by human activities. Among the greenhouse gases, CO2 contributes about 65% of global warming (McCaffrey, 2002). The cement industry is held responsible for some of the CO2 emissions, because the production of 1 ton of Portland cement emits approximately 1 ton of CO2 into
Portland cement in concrete to address the global warming issues. These include the utilization of supplementary cementing materials such as fly ash, silica fume, granulated blast-furnace slag, rice-husk ash, and metakaolin, as well as the development of alternative binders to Portland cement. In this respect, the geopolymer technology proposed by Davidovits (1988) shows considerable promise for application in the concrete industry as an alternative binder to Portland cement. In terms of reducing global warming, the geopolymer technology could reduce CO2 emissions to the atmosphere caused by the cement and aggregates industries by about 80% (Davidovits, 1994).
