ASTM C127 outlines standard procedures for the determination of specific gravity and absorption capacity of coarse aggregate.
Equipment:
1. Balance
2. Wire basket
with 3.35mm or finer wire mesh
3. Water tank
4. Oven
Sample:
Particles larger than
4.75mm. Weight of sample should be prepared based on the nominal maximum size.
Procedure:
1. Dry the sample
in oven to constant mass at temperature of 110±5°C, then cool in air at room
temperature for 1 to 3 hours.
2. Immerse the
sample in water at room temperature for 24±4 hours.
3. Remove the
sample from water. Roll it in large absorbent cloth until all visible films of
water are removed. The sample is now in saturated surface dry (SSD) condition.
4. Weigh the
sample and record it as B (g).
5. Place the
sample in wire basket and fully immerse it in water at 23±2°C. Remove the
entrapped air by shaking the basket in the process.
6. Weigh the
sample and record it as C (g).
7. Dry the sample
in oven to constant mass at temperature of 110±5°C, then cool in air at room
temperature for 1 to 3 hours, or until the aggregate is cooled to a temperature
less than 50°C.
8. Weigh the
sample and record it as A (g).
Calculation:
1. Specific
gravity (oven dry) = A/(B-C)
2. Specific
gravity (SSD) = B/(B-C)
3. Apparent
specific gravity = A/(A-C)
4. Absorption = [(B-A)/A]x100%
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