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In Marshall method of mix design, the coarse aggregate, fine aggregate, fines and bitumen having respective values of specific gravity 2.60, 2.70, 2.65 and 1.01, are mixed in the relative proportions (% by weight) of 55.0, 35.8, 3.7 and 5.5 respectively. The theoretical specific gravity of the mix and the effective specific gravity of the aggregates in the mix respectively are:
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- 2.42 and 2.63
- 2.42 and 2.78
- 2.42 and 2.93
- 2.64 and 2.78
Correct Option: A
Theoretical specific gravity of mix, GT
GT = w1 + w2 + w3 – w4
| + | + | + | |||||
| G1 | G2 | G3 | G4 |
| = | ||||||
| + | + | + | ||||
| 2.6 | 2.7 | 2.65 | 1.01 | |||
= 2.424
Effective specific gravity of aggregates in mix, GE
| GE = | (only fine + coarse) | |
| w1 + w2 |
| = | = 2.64 | |
| 55 |
