Introduction:
Pozzolana is a finely divided material that is added to concrete to improve its properties. It is a natural or artificial material that reacts with calcium hydroxide in the presence of water to form compounds that possess cementitious properties. The use of pozzolana admixtures in concrete has several advantages.

Improved Workability:
Pozzolana admixtures improve the workability of concrete by reducing the water content required to achieve a desired level of consistency. This is achieved through the lubrication of the cement particles, which reduces friction and allows for easier movement of the particles. The result is a more workable mix that can be easily placed and compacted.

Reduction in Heat of Hydration:
Pozzolana admixtures also reduce the heat of hydration of concrete. Heat of hydration is the heat generated during the chemical reaction between cement and water. Excessive heat can cause thermal cracking in concrete, which can reduce its strength and durability. Pozzolana admixtures reduce the amount of cement required in the mix, which in turn reduces the heat generated during the hydration process.

Increased Resistance to Sulphate Attack:
Pozzolana admixtures also increase the resistance of concrete to sulphate attack. Sulphates are present in soil and groundwater, and can react with the cement in concrete to form compounds that cause expansion, cracking, and ultimately, degradation of the concrete. Pozzolana admixtures react with the sulphates to form stable compounds that do not cause expansion or cracking.

Conclusion:
In conclusion, the addition of pozzolana admixtures to concrete has several advantages, including improved workability, reduction in heat of hydration, and increased resistance to sulphate attack. These properties make pozzolana admixtures a valuable addition to concrete mixes in many different applications.