Pozzolanas and pozzolanic materials

Developments in concrete construction mean that there are now a broader range of cementitious materials, than have traditionally been available, providing options for engineers to meet specific technical requirements. Pozzolanas and pozzolanic materials from natural deposits or industrial processes represent a group within this category. These include natural pozzolanas, fly ash (from coal-fired electricity generation), silica fume (from silicon/ferro-silicon manufacture) and others. This chapter considers these materials in detail, with initial consideration given to their physical and chemical properties, and reaction characteristics in cementitious systems. Thereafter, their influences on the properties of concrete, including fresh, mechanical, and chemical/physical aspects of durability are reviewed.