Per §10.5, the CHARACTERISTIC compressive strength of concrete is defi…

Question

Per §10.5, the CHARACTERISTIC compressive strength of concrete is defined as the strength below which:

Accepted Answer

C. {'text': 'Not more than 5 percent of test results fall', 'label': 'C'}

1. §10.5 (and §10.3 grade designation paragraph): 'characteristic strength indicates that value of strength below, which not more than 5 per cent of test results are expected to fall.'
2. The target mean strength is then ftarget = fck + 1.65σ for the Indian Standard 5% risk factor.
_Source: IGNOU ET-522 Block-3 Unit-10 Concrete Mix Design, §10.5, p. 10_

Answer

{'text': 'Exactly half of all test results fall', 'label': 'A'}

Answer

{'text': 'Not more than 25 percent of test results fall', 'label': 'B'}

Answer

{'text': 'All test results must fall by definition', 'label': 'D'}