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Per §7.2, water-cement ratios above approximately 0.38 (with full hydration) tend to produce concrete that:
A{'text': 'Has zero capillary voids in the paste', 'label': 'A'}
B{'text': 'Has capillary voids in the hardened paste', 'label': 'B'}
C{'text': 'Has higher 28-day strength than mass concrete', 'label': 'C'}
D{'text': 'Cannot be fully compacted by vibration', 'label': 'D'}
Answer & Solution
Correct answer: B. {'text': 'Has capillary voids in the hardened paste', 'label': 'B'}
1. §7.2 (Water/Cement Ratio): 'water cement ratio above 0.38 will produce capillary voids: higher the water cement more the capillary voids.'
2. With w/c below 0.38 there are no capillary voids but some cement remains unhydrated.
_Source: IGNOU ET-522 Block-2 Unit-7 Strength of Concrete, §7.2, p. 42_
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