Which of the following equations is correct for the Pozzolanic reaction? (A) Ca(OH)2 + Reactive Superplasticiser + H2O = C-S-H (B) Ca(OH)2 + Reactive Silicon dioxide + H2O = C-S-H (C) Ca(OH)2 + Reactive Sulphates + H2O = C-S-H (D) Ca(OH)2 + Reactive Sulphur + H2O = C-S-H | GATE 2022

Question: Which of the following equations is correct for the Pozzolanic reaction? 

(A) Ca(OH)2 + Reactive Superplasticiser + H2O = C-S-H 

(B) Ca(OH)2 + Reactive Silicon dioxide + H2O = C-S-H 

(C) Ca(OH)2 + Reactive Sulphates + H2O = C-S-H 

(D) Ca(OH)2 + Reactive Sulphur + H2O = C-S-H 

GATE 2022

Solution:

The correct equation for the Pozzolanic reaction is:

(B) Ca(OH)2 + Reactive Silicon dioxide + H2O = C-S-H

In the Pozzolanic reaction, calcium hydroxide (Ca(OH)2) reacts with reactive silicon dioxide (usually present in the form of a pozzolan material such as fly ash or silica fume) in the presence of water (H2O) to form calcium silicate hydrate (C-S-H), which is a key component of cementitious materials such as concrete.

Therefore, option (B) is the correct equation for the Pozzolanic reaction.