Z. Giergiczny, Silesian University of Technology, Gliwice, Poland

 Fly ash is a by product of hard or brown coal combustion process. Owing to the size of spherical particles (similarly to cement), its chemical and mineral composition as well as the activity, fly ash is widely used in cement and concrete production.

Properly used fly ash has a positive effect both on properties of concrete mixture and concrete itself. It allows the production of high-quality concrete in economical and ecological way. The addition of fly ash to cement (or concrete) composition indicates the reduction of cement clinker content, thus, lower CO2 emission and preservation of non-renewable natural resources.