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Per §4.12, Category B superplasticizers are chemically known as:
A{'text': 'Sulphonated Melamine Formaldehyde (SMF)', 'label': 'A'}
B{'text': 'Sulphonated Naphthalene Formaldehyde (SNF)', 'label': 'B'}
C{'text': 'Modified Lignosulphonates (LS)', 'label': 'C'}
D{'text': 'Polyhydroxylated polymer / acid-amide / polysaccharide mix', 'label': 'D'}
Answer & Solution
Correct answer: B. {'text': 'Sulphonated Naphthalene Formaldehyde (SNF)', 'label': 'B'}
1. §4.12 lists four superplasticizer categories: Category A — SMF; Category B — Sulphonated Naphthalene Formaldehyde (SNF) condensate or its sodium salt; Category C — Modified lignosulphonates; Category D — Polyhydroxylated polymer or mix of acid-amides and polysaccharides.
2. SMF and SNF are typically used at 0.5 to 1.5 percent by weight of cement.
_Source: IGNOU ET-522 Block-1 Unit-4 Admixtures, §4.12, p. 53_
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