Cement Testing MCQ with answer and solution

Concept

The soundness test checks for later expansion of cement due to free lime and magnesia. For OPC, Le Chatelier expansion must not exceed 10 mm.

Step-by-step solution

1. The soundness test checks for harmful expansion caused by free lime (CaO) and magnesia (MgO). 2. Le Chatelier apparatus measures expansion in mm. 3. For OPC of all grades (33, 43, 53), the limit is 10 mm. The autoclave test limit is 0.8%. 4. So the answer is 10 mm. Answer is A.

Explanation

Unsound cement expands after setting and causes cracks. The Le Chatelier test measures this expansion. For 53-grade OPC (IS 12269), the expansion should not be more than 10 mm.

Why the other options are wrong

8 mm, 15 mm and 5 mm are not the code limits. The limit for OPC is 10 mm by Le Chatelier and 0.8% by the autoclave test.

Shortcut

Le Chatelier = 10 mm, Autoclave = 0.8% (same for all OPC grades).

Common mistake

Mixing up the 10 mm Le Chatelier limit with the 0.8% autoclave limit, or thinking the limit changes with grade.