ASTM C127 submerged weight and SSD weight?

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SUMMARY

The ASTM C127 standard for aggregate testing clarifies that the submerged weight of aggregates is lower than their saturated surface dry (SSD) weight due to buoyancy effects. Specifically, the specific gravity (SG) of the rock must account for the SG of water, which is 1. For example, a rock with an SG of 3 weighing 3 tonnes will have a submerged weight of 2 tonnes. The water held in the pores of SSD aggregates does not contribute to the submerged weight, as it effectively becomes part of the surrounding water.

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  • Understanding of ASTM C127 aggregate testing standards
  • Knowledge of specific gravity (SG) calculations
  • Familiarity with buoyancy principles
  • Basic concepts of water absorption in aggregates
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  • Research ASTM C127 testing procedures for aggregates
  • Study specific gravity calculations for various materials
  • Explore buoyancy effects in fluid mechanics
  • Investigate water absorption methods in construction materials
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Geotechnical engineers, civil engineers, material scientists, and professionals involved in aggregate testing and construction material evaluation will benefit from this discussion.

goldfish9776
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in ASTM C127 Aggregate test , why the weight of SSD is higher than water submerged weight?
 
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Specific gravity, SG, of rock must have the SG of water (= 1) subtracted when rock is submerged to account for buoyancy.
If rock SG=3 and weighs 3 tonne, then when submerged in water it will weigh 2 tonne.
The weight of any water in the aggregate dissapears when it is submerged as it becomes part of the water.
 
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Baluncore said:
Specific gravity, SG, of rock must have the SG of water (= 1) subtracted when rock is submerged to account for buoyancy.
If rock SG=3 and weighs 3 tonne, then when submerged in water it will weigh 2 tonne.
The weight of any water in the aggregate dissapears when it is submerged as it becomes part of the water.
tas why we will always feel that we will be lighter when we are in the water ?
 
goldfish9776 said:
will always feel that we will be lighter when we are in the water ?
Yes.
Our body is made mostly of water. But our lungs are lighter and our bones are heavier, so our bodies have a density very close to that of water.
When we breath in, with lungs full of air we float. When we breath out, the weight of our bones sinks us. More fat makes us float better because it has a density less than water.
 

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