Correct Answer - Option 2 : Shrinkage
Explanation:
Ordinary Portland cement:
Cement can be defined as the bonding material having cohesive & adhesive properties which makes it capable to unite the different construction materials and form the compacted assembly. Ordinary/Normal Portland cement is one of the most widely used types of Portland Cement. The name Portland cement was given by Joseph Aspdin in 1824 due to its similarity in color and its quality when it hardens like Portland stone. Portland stone is white grey limestone on the island of Portland, Dorset.
Portland Pozolona cement:
- This cement is produced by inter grinding the cement clinkers with 10 - 15 % of pozzolanic material.
- Pozzolanic material is essentially a siliceous compound that is itself does not possess any binding property, but when finely grinded reacts with lime released during the hydration of cement and results in the formation of a compound possessing binding property.
Effects of pozzolana in ordinary portland cement:
- Higher water tightness
- Low heat of hydration
- Reduces the cost
- Higher resistance against chemical attacks (Chloride & Sulphate)
- Higher resistance against volume change
- A slower rate of gain of strength
- Increases shrinkage
- Reduces permeability
- Reduces bleeding
