Determination of Specific Gravity of Fine Aggregate

Specific gravity of fine aggregate (sand) is the ratio of the weight of given volume of fine aggregates to the weight of equal volume of water. The specific gravity of sand is considered to be around 2.65.

AIM:

To determine specific gravity of a given sample of fine aggregate.

Apparatus:

·         Balance,

·         Oven,

·         Pycnometer,

·         A tray of area not less than 32cm²,

·         Well-ventilated oven,

·         Taping rod,

·         Filter papers and funnel, etc.

FIGURE:

 

Procedure:

1. Take about 500g of sample and place it in the pycnometer.
2. Pour distilled water into it until it is full.
3. Eliminate the entrapped air by rotating the pycnometer on its side, the hole in the apex of the cone being covered with a finger.
4. Wipe out the outer surface of pycnometer and weigh it (W)
5. Transfer the contents of the pycnometer into a tray, care being taken to ensure that all the aggregate is transferred.
6. Refill the pycnometer with distilled water to the same level.
7. Find out the weight (W1).
8. Drain water from the sample through a filter paper.
9. Place the sample in oven in a tray at a temperature of 100ºC to 110º C for 24±0.5 hours, during which period, it is stirred occasionally to facilitate drying.
10. Cool the sample and weigh it (W2).

CALCULATION:

Apparent specific gravity = (weight of dry sample/weight of equal volume of water )

= W2/(W2- (W-W2))

Conclusion / Result:

Specific gravity of fine aggregate =………………….


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