Building Materials - Engineering

Q1:

Portland pozzolana cement possesses

A higher resistance to chemical attack

B lower heat of hydration

C lower shrinkage on drying

D water tightness

E all the above.

ANS:E - all the above.

* Portland Pozzolona cement contain 20-30% of pozzolanic materials.
* Pozzolana is non-cementitious material themselves but they react with calcium hydroxide in presence of water at ordinary temperature and form compound that posses cementitious property.
* Pozzolana cement is produced either by grinding together portland cement clinker and pozzolana or by intimately or uniformly bleeding portland cement with pozzolana.

ADVANTAGES
* Higher resistance to chemical attack.
* lower heat of hydration.
* lower shrinkage on drying.
* Water Tightness.
* It has the higher ultimate strength.

DISADVANTAGE
* As compared to OPC it attains strength slowly.
* it needs a framework to be kept for longer periods.