Masonry Construction MCQ with answer and solution

Concept

Autoclaved aerated concrete (AAC) blocks are very light, with low strength and good insulation, so they are mainly used for non-load-bearing partition and infill walls.

Step-by-step solution

1. AAC blocks have a density of about 550–800 kg/m³, much lighter than bricks. 2. Their compressive strength is low, about 3–4.5 N/mm². 3. They reduce the dead load on beams and columns in framed buildings. 4. So they are mostly used for partition and infill walls. 5. Answer is (B).

Explanation

Lightweight aerated blocks are light and have low strength. They reduce the dead load on the frame of a building and give good heat and sound insulation. So they are mostly used for partition walls, not for heavy structural parts.

Why the other options are wrong

(A) Foundations need high strength and resistance to water; AAC is weak and absorbs water. (C) Load-bearing walls need higher strength; AAC is rarely used for them. (D) Shear walls are reinforced concrete walls that resist lateral loads, not block walls.

Shortcut

Lightweight block means low strength, so it is used for partitions.

Common mistake

Choosing load-bearing walls because AAC is sometimes used in low-rise load-bearing work, but its main use is partitions.