Excess of silica in brick earth results in

Definition: Silica is a key component of brick earth that influences the strength and durability of bricks. However, its excess can negatively impact the quality of bricks.

Step 1: Understanding the role of silica:

Optimal amount: Silica in the right proportion (about 50-60%) provides strength and prevents shrinkage.

Excess silica: When silica content is too high, it prevents proper bonding between particles, leading to weak bricks.

Step 2: Evaluating the options:

Cracking and warping of bricks: Usually caused by rapid drying or improper burning, not excess silica.

Loss of cohesion: Excess silica reduces the binding property of clay, making the bricks brittle and weak.

Enhancing the impermeability of bricks: Impermeability is affected by the proportion of clay and firing temperature, not directly by excess silica.

Step 3: Since high silica content leads to poor cohesion, the correct answer is Loss of cohesion (Option B).