8. Chemical and Mechanical Properties of Geopolymers Made of Industrial By-Products Such as Fly Ash, Steel Slags and Garbage Melting Furnace Slags

Geopolymers are composite hard materials made by mixing solid (binders such as fly ash and slag) and alkaline liquid (activators such as NaOH and sodium silicate). Geopolymers have recently been developed to be used as a replacement for Portland cement concrete. Industrial by-products such as fly ash, steel making slags and garbage melting furnace slags can be used to create geopolymers in a process that emits less carbon dioxide than in the cement making process. This reduction in CO₂ emission is important because CO₂ is one of the substances known to contribute to global warming. In the future, further uses of these fly ash and slags must be explored. The chemical mechanism for hardening composite materials by mixing aluminosilicate binders, such as fly ash and slags with alkaline activators, such as liquid NaOH and sodium silicate, is known as a geopolymer reaction. The development of high compressive strength geopolymer using fly ash and slags will strongly contribute to the fields of construction, geotechnical engineering, and architecture. This paper describes the chemical and mechanical characteristics of geopolymers made of industrial by-products as binders mixing with a solution of NaOH and sodium silicate as activators.