STANTARD
- IS2386 (Part3) 1963.
DEFINITION
- Specific gravity is defined as the ratio of the mass of a given volume of the substance to the mass of an equal volume of water.
APPARATUS
- Balance of capacity 10 kg’s, sensitivity to 50 gram and of such a type and shape as to permit the basket containing the sample to be suspended from the beam and weighed in water.
- Oven thermostatically controlled with capacity up to 250°C.
- Wire basket of not more than 6.3 mm mesh or a perforated container of convenient size preferably chromium plated and polished, with wire hangers thickness not less than 1 mm.
- A stout watertight container in which the basket may be freely suspended
- Two dry soft absorbent clothes each not less than 650 cm2
PROCEDURE
- Take representative sample of aggregates not less than 2 kilograms.
- Wash the sample thoroughly to remove finer particles and dust.
- Remove the water and place the aggregates in the wire basket and immersed in distilled water at a temperature of 22° to 32°C with a cover of at least 5 cms of water above the top of the basket.
- Immediately after immersion, remove the entrapped air from the sample by lifting the wire basket 25 mm above the base of the tank and allowing to drop 25 times at a rate of about one drop per second.
- Allow the basket and aggregates completely immersed during the operation and for a period of 24 ± 1/2 hours.
- After the completion of the specified period of time remove the basket with the sample jolt 25 times and weigh (A1) in water at a temperature of 22 to 32°C .
- Remove the basket and the aggregates from the water and allow to drain for a few minutes, after which gently empty the aggregate from the basket.
- Retain the empty basket to the water, jolt 25 times and weigh (A2) in water.
- Surface dry the aggregates with the cloth, transferring it to the second dry cloth.
- Spread the sample not more than one stone deep on the cloth, and least exposed to the atmosphere away from direct sunlight or any other source of heat for not less than 10 minutes or until it appears to be completely surface dry.
- Weigh the aggregates (B) and keep in the oven maintained at a temperature of 105° to 110°C for a period of 24 ± 1/2 hours.
- After the specified period of time remove the aggregates from the oven cool in an airtight container and weigh (C).
- Make at least two determinations for each test.
CALCULATIONS
Specific Gravity on oven dry basis = C/(B-A)
Apparent Specific Gravity = C/( (C-A)
Specific Gravity on SSD basis = B /(B-A)
Water absorption = ((B-C)/ C ) ×100
- A = Weight of Surface Saturated aggregate in water (Al — A2)
- B = Weight of Surface Saturated aggregate in air
- C = Weight of oven dried aggregate
REPORT
- Report the individual and the mean results to the nearest second decimal.
DETERMINATION OF SPECIFIC GRAVITY OF AGGREGATES (ABOVE 10MM)
IS 2386 (Part 3)1963
| Description |
Units |
Test I | Test 2 |
Average |
| Weight of surface saturated aggregate in water (A) |
gms |
|||
| Weight of surface saturated aggregate in air (B) |
gms |
|||
| Weight of oven dried sample in air ( C ) |
gms |
|||
|
Specific gravity on oven dried basis C/(B-A) |
– |
|||
| Specific gravity on SSD basis B/(B-A) |
– |
|||
| Apparent Specific gravity C/(C-A) |
– |
|||
| Water absorption (B-C)/C x 100 |
% |
|||
| Remarks: | ||||