Question

Aconcrete mixture for a proposed building work is to be designed. A characteristic compressive strength of 25 MPa with 5% defective rate is specified for 28 days. The standard deviation may be taken based on a compressive strength results on specimens less than 20. A slump of 40 mm is required and the maximum w/c ration and the minimum cement content allowed are 0.7 and 200 kg/m3, respectively. The fine aggregate is uncrushed and the percentage passing sieve 600 Micro meter is 70%. The coarse aggregate is crushed gravel aggregate. Design the concrete mixture, using OPC of 42.5 MPa and assume that the relative density of SSD combined aggregates is 2.7 with maximum aggregate size is 20mm. The volume of the mix is 0.1 m3.

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Answer 1