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Per §8.5.1, freezing of water in fresh concrete is hazardous mainly because the ice lens formation causes:
A{'text': 'About 9 percent volume contraction during freezing', 'label': 'A'}
B{'text': 'About 9 percent volume increase, leading to permanent damage', 'label': 'B'}
C{'text': 'Less than 1 percent change, no damage', 'label': 'C'}
D{'text': 'Heat release that recovers strength', 'label': 'D'}
Answer & Solution
Correct answer: B. {'text': 'About 9 percent volume increase, leading to permanent damage', 'label': 'B'}
1. §8.5.1 reads: 'The ice lense formation in fresh concrete results in about 9% increase in volume and causes permanent damage to concrete and the structural integrity cannot be recovered even if the concrete is made to harden later at higher temperatures.'
2. Hence cold-weather concreting requires that the fresh concrete be maintained above 0°C.
_Source: IGNOU ET-522 Block-2 Unit-8 Durability of Concrete, §8.5.1, p. 73_
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