What is pozzolana used for?

Uses of Portland Pozzolana Cement Used in hydraulic structures, marine structures, construction near the sea shore, dam construction etc. Used in pre-stressed and post-tensioned concrete members. Used in masonry mortars and plastering. As it gives better surface finish, it is used in decorative and art structures.

Why is pozzolana added to cement?

What does a pozzolan do in the concrete? A. Pozzolans reduce bleeding because of fineness; reduce the maximum rise in temperature when used in large amounts (more than 15\% by mass of cementitious material) because of the slower rate of chemical reactions; which reduce the rise in temperature.

What is pozzolana in civil engineering?

The modern definition of pozzolana encompasses any volcanic material (pumice or volcanic ash), predominantly composed of fine volcanic glass, that is used as a pozzolan. …

What do you understand by pozzolana?

Definition of 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.

Where is pozzolana found?

Diatomite and other pozzolans Other well-known sources of natural pozzolana include the Santorin earth of Greece and the trachytic ‘tuffstein’ (ground to ‘trass’) from the Rhineland and Bavaria. Suitable volcanic deposits are also exploited in many other places including the USA, former USSR, Japan and New Zealand.

Is pozzolana a cement?

properties. Pozzolanic cements are mixtures of portland cement and a pozzolanic material that may be either natural or artificial. The natural pozzolanas are mainly materials of volcanic origin but include some diatomaceous earths. Artificial materials include fly ash, burned clays, and shales.

Is sand a pozzolan?

Other Pozzolans The term “pozzolans” has extended to man-made aggregates and powders that have a similar hydraulic effect when blended with lime. Sand which has been quarried (pozzolana) requires one-fourth its weight of lime, while river sand or sea sand requires one third.

What are the advantages of pozzolanic materials?

The advantages of using pozzolans in concrete include the following: (1) material cost reduction when a part of the cement is replaced by pozzolans, which are low cost (with some of them being natural or industrial by-products/wastes) and pollution free; (2) environmental cost reduction in relation to reducing the …

Is pozzolana a mineral?

It is the natural or artificial mineral material with pozzolana which can be divided into the blended materials with hydrous silicic acid, alumina-silica glasses, and calcined clay and others based on its chemical components and mineral structures.

How is pozzolana made?

pozzolana, also spelled pozzuolana, hydraulic cement perfected by the Romans and still used in some countries, traditionally made by grinding a material of volcanic origin (the pozzolan) with powdered hydrated lime.

Who invented pozzolana?

the Romans
Although the Romans typically are credited with inventing pozzolana based cement, there is archeological evidence that the Greeks were using their own pozzolana from the eruption at Thera (Santorini) for water cisterns as early as 600 B.C. as well as for methods of wall construction only later adopted by the Romans.

What are the advantages and disadvantages of pozzolana?

Portland pozzolana cement (PPC) has following advantages when concrete is in its fresh state.

• Workability.
• Bleeding.
• Pumpability.
• Setting Time & Finishability.
• Compressive Strength & Rate of Strength Gain.
• Modulus of Elasticity.
• Bond of Concrete to Steel.
• Heat of Hydration.