GATE 2022 CE (CE2) – Question 64
It is given that an aggregate mix has 260 grams of coarse aggregates and 240 grams of fine aggregates. The specific gravities of the coarse and fine aggregates are 2.6 and 2.4, respectively. The bulk specific gravity of the mix is 2.3. The percentage air voids in the mix is ____________. (round off to the nearest integer)
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Correct answer: 8
Explanation
Solid aggregate volume is $260/2.6+240/2.4=200$ cm³. With total mass 500 g, theoretical no-air specific gravity is 500/200=2.5.
Air-void fraction is $1-G_{bulk}/G_{theoretical}=1-2.3/2.5=0.08$. **Answer: 8%**.