For aggregates used in PCC, another common gradation description for fine aggregate is the fineness modulus. It is described in ASTM C 125 and is a single number used to describe a gradation curve. It is defined as:
The larger the fineness modulus, the more coarse the aggregate. A typical fineness modulus for fine aggregate used in PCC is between 2.70 and 3.00.
Standard Test Methods
- ASTM C 125: Standard Terminology Relating to Concrete and Concrete Aggregates