Geosynthetics MCQ with answer and solution

Concept

Coir is a natural fibre that is elastic, light and tough, but it is biodegradable, so its service life is limited.

Step-by-step solution

1. Coir is a natural fibre from coconut husk. It is used for ropes, mats and geotextiles. 2. It is elastic and resilient, so it resists dynamic or impact loading. 3. It is light in weight, so it is easy to carry and handle. 4. Being natural and biodegradable, it decays in soil and water within a few years. 5. So a long service span is NOT its property. Answer is (D).

Explanation

Coir fibres are elastic, light and tough, so they handle dynamic loads and are easy to carry. But coir is a natural, biodegradable material, so it decays with time. Its service life is shorter than synthetic materials.

Why the other options are wrong

A: coir is tough and resilient, so it resists dynamic loading. B: coir is light, so it is easy to carry. C: coir has good elasticity.

Shortcut

Natural fibre means biodegradable, so it does not have a long service span.

Common mistake

Thinking coir lasts long because it decays more slowly than jute. It is still short-lived compared to synthetic geosynthetics.