What are pozzolans give at least five examples?

Typical pozzolans include:

• metakaolin.
• silica fume.
• fly ash.
• slag.
• VCAS (vitrified calcium alumino-silicate)

What do you mean by pozzolana?

: finely divided siliceous or siliceous and aluminous material that reacts chemically with slaked lime at ordinary temperature and in the presence of moisture to form a strong slow-hardening cement.

What are natural pozzolans?

Natural pozzolans include rocks of volcanic origin (e.g. vitreous rhyolites from the Rocky Mountains in the USA or German and Turkish trasses), as well some sedimentary clays and shales. Some may be used as they are, while others undergo a process of thermal activation (e.g. calcined clays).

What is pozzolana and what is its significance?

The just-mentioned action of pozzolan is of quite significance as it reduces the corrosion of iron in concrete mixtures thereby increasing the life of concrete structures. In conventional concrete, alkaline Portland cement is mainly used. This cement upon drying leads to the development of pores, voids, and cracks.

Which is the best definition of a pozzolan?

Pozzolan. Definition: a siliceous or silico-aluminous material that will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds having cementitious properties (there are both natural and artificial pozzolans).- A pozzolan is a siliceous or siliceous…

What makes a pozzolan a cementitious material?

A pozzolan is a siliceous or siliceous and aluminous material that in itself possesses little or no cementitious value but will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds having cementitious properties.

What are the benefits of a natural pozzolan?

In natural pozzolans, they are finding an exceptional solution backed by quantifiable data and the test of time—over two millennia of hard evidence. Natural pozzolans are sustainable, highly effective, and best of all, performance-consistent pour after pour. See also: Frequently Asked Questions SOURCE NATURAL POZZOLANS

How are pozzolans different from other refractory materials?

Pozzolans are a different type of refractory materials. They are naturally available and consist of very fine particles of siliceous and aluminous materials that in presence of water react with Ca (OH)2 to form cementitious materials [7].