Question

For reinforced concrete structures to be constructed along sea coast minimum grade of concrete should be
1. M15
2. M20
3. M30
4. M25

Answer 1

Correct Answer - Option 3 : M30

Explanation:

As per IS 456:2000, table 5,

Minimum M30 should be used for construction in sea weather conditions.

Minimum quantity of cement content needed in 1m3 of reinforced concrete which is exposed to sea weather conditions is 320 kg.

For Reference:

Environment	Exposure Conditions	Minimum Grade of concrete	Minimum Cement Quantity (kg/m3)
Mild	Concrete surfaces protected against weather or aggressive conditions, except those situated In coastal areas.	M20	300
Moderate	Concrete exposed to condensation and rain Concrete continuously under water	M25	300
Severe	Concrete completely immersed in seawater Concrete exposed to a coastal environment	M30	320
Very Severe	Concrete in contact with or buried under aggressive subsoil/groundwater.	M35	340
Extreme	The surface of the member in the tidal zone. Members in direct contact with liquid/ solid aggressive chemicals.	M40	360