pozzolaneja

Pozzolan is a siliceous and aluminous material which, in itself, possesses little or no cementitious value. However, in finely divided form and in the presence of moisture, it chemically reacts with calcium hydroxide at ordinary temperatures to form compounds possessing cementitious properties. The most common natural pozzolans are volcanic ash and pumice. Artificial pozzolans include fly ash, silica fume, and metakaolin.

The pozzolanic reaction is a pozzolanic reaction. This reaction is a chemical process that occurs when a pozzolanic material reacts with calcium hydroxide (also known as slaked lime) in the presence of water. The result is the formation of calcium silicate hydrate (C-S-H) gels and calcium aluminate hydrate (C-A-H) gels. These gels are similar to those formed during the hydration of Portland cement and contribute to the strength and durability of the hardened material.

Pozzolans are often used as a partial replacement for Portland cement in concrete mixtures. This substitution can offer several advantages, including improved long-term strength, increased resistance to sulfate attack and alkali-silica reaction, and reduced heat of hydration. The use of pozzolans can also contribute to sustainability by reducing the amount of Portland cement needed, which has a significant carbon footprint. The specific benefits and performance characteristics depend on the type and amount of pozzolan used.