In " the mean diameter of aggregate fraction ", how does this “mean diameter”come to be? Should the diameter of individual aggregate be measured and then averaged? But my main problem is how to measure the diameter of a single aggregate?Is it the longest or the shortest length? Because aggregates are not regular graphics after all.
It would be technically sound if you consider the roundness or sphericity of such aggregates, i.e., what are the diameters of the largest possible mathematically perfect sphere or circle that can be obtained from such aggregates.
When you measure mean weight diameter of aggregates, it does not mean that you physically measure the length, width, etc of the aggregates in centimeter or millimeter. Rather, us you a set of sieve with different but known mesh sizes (diameter).
Then you assume those aggregates remaining on a specific sieve have diameters equal to the diameter of the sieve.
Then, you multiply the mass proportions of soil aggregates left on the ith sized sieve with mesh size (diameter) of the sieve.
I agree with Abhishek. In soil physics related studies, we use the roundness or sphericity values.
You may read this article: https://ascelibrary.org/doi/10.1061/%28ASCE%29GT.1943-5606.0001575
Dear Dr. Sandun,
You are right. As you said "In soil physics related studies, we use the roundness or sphericity values".
If her question is about estimating mean weight diameter (MWD) of aggregates, she may use a set of sieves to do that.
But if she wants to physically measure the diameter of a single aggregate, whether we assume it as round or spherical, how to measure its diameter is a challenging question.
Any ways, one can estimate average diameter of irregular aggregate by taking a number of measurements along different edges of the aggregate.
Hi
Well there is no general best method of determining particle size analysis.The best method in particular case depends on the soil nature and purpose of analysis.This also depend on time constraints and apparatus availability.
Following link may be useful.
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