Super sulphate cement is produced by inter-grinding granulated blast furnace slag with gypsum and a small share of Portland clinker. The respective proportions stated in the source are:
A{'text': '50 / 35 / 15 percent of total mass', 'label': 'A'}
B{'text': '70 / 25 / 5 percent of total mass', 'label': 'B'}
C{'text': '60 / 20 / 20 percent of total mass', 'label': 'C'}
D{'text': '80-85 / 10-15 / about 5 percent of total', 'label': 'D'}
Answer & Solution
Correct answer: D. {'text': '80-85 / 10-15 / about 5 percent of total', 'label': 'D'}
1. §1.8.1: super sulphate cement is 'a mixture of 80-85 percent granulated slag, 10-15 percent hard burnt gypsum and about 5 percent portland cement clinker.'
2. The fineness must be at least 4000 cm² per gm and the cement has low heat of hydration of about 45-50 cal/gm at 28 days.
_Source: IGNOU ET-522 Block-1 Unit-1 Cement, §1.8.1, p. 11_
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