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In the context of provisions relating to durability of concrete, consider the following assertion: Assertion (1): As per IS 456-2000, air entrainment to the extent of 3% to 6% is required for concrete exposed to marine environment. Assertion (2): The equivalent alkali content (in terms of Na2O equivalent) for a cement containing 1% and 0.6% of Na2O and K2O respectively, is approximately 1.4% (rounded to 1 decimal place). Which one of the following statements is correct?

In the context of provisions relating to durability of concrete, consider the following assertion: Assertion (1): As per IS 456-2000, air entrainment to the extent of 3% to 6% is required for concrete exposed to marine environment. Assertion (2): The equivalent alkali content (in terms of Na2O equivalent) for a cement containing 1% and 0.6% of Na2O and K2O respectively, is approximately 1.4% (rounded to 1 decimal place). Which one of the following statements is correct? Correct Answer Assertion (1) is FALSE and Assertion (2) is TRUE

As per clause 8.2.2.3 of IS 456-2000, entrained air percentage of 3 to 6% is required to resist freezing and thawing i.e. not meant for marine environment.

∴ Assertion 1 is wrong.

Equivalent alkali content in terms of Na2O = + 0.685

                                                                   = 1 + 0.685 × 0.6 = 1.41 %

Hence, Assertion 2 is correct.

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