Size distribution of aggregate particles is determined by:

The correct method for determining the size distribution of aggregate particles used in refractory castables isscreen analysis. This is a standardized technique for analyzing particle size distribution by passing material through a series of sieves with progressively smaller openings.

As specified in API 936 and related technical literature such as API TR 978 and API TR 980, aggregate grading and size distribution directly affect the packing density and therefore the performance of monolithic refractories. The screen analysis is fundamental in determining if aggregates fall within the prescribed grading ranges, which is critical for workability, density, and mechanical strength.