Strength of Concrete MCQ with answer and solution

Concept

Concrete is strong in compression, so it is good for bridge piers, arches, decks and foundations that carry heavy loads.

Step-by-step solution

1. Check each option. Is it an advantage for a bridge? 2. High compressive strength lets concrete carry heavy loads safely. This is an advantage. 3. Low durability is a weakness, not an advantage. 4. Low tensile strength is a weakness. Steel is added to cover it. 5. Low thermal conductivity does not matter much for bridges. 6. So the answer is (A).

Explanation

Bridges carry very heavy dead loads and moving loads. Concrete has high compressive strength, so it carries these loads well in piers, abutments, arches and decks. With steel reinforcement or prestressing, it also handles tension.

Why the other options are wrong

B: Low durability is a weakness. Good concrete is actually durable. C: Low thermal conductivity is useful in buildings for insulation, not a main reason to use concrete in bridges. D: Low tensile strength is a weakness. It needs steel to fix it.

Shortcut

Choose the only positive property. 'Low durability' and 'low tensile strength' are weaknesses.

Common mistake

Choosing low thermal conductivity because it sounds like a good property. It is not relevant for bridges.