Fineness Modulus
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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:
where:
- = fineness modulus
- = 0.150 mm (No. 100), 0.30 mm (No. 50), 0.60 mm (No. 30), 1.18 mm (No. 16), 2.36 mm (No. 8), 4.75 mm (No. 4), 9.5 mm (0.375-in.), 19.0 mm (0.75-in.), 37.5 mm (1.5-in.), and larger increasing in the size ratio of 2:1.
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
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APA
Pavement Interactive. (2018, September 5). Fineness modulus. HeadLight. Retrieved [the date you read it], from https://pavementinteractive.org/reference-desk/testing/aggregate-tests/fineness-modulus/
ASCE
Pavement Interactive. (2018). “Fineness Modulus.” HeadLight, <https://pavementinteractive.org/reference-desk/testing/aggregate-tests/fineness-modulus/> ([the date you read it]).
BibTeX
@misc{pavint-fineness-modulus,
author = {{Pavement Interactive}},
title = {Fineness Modulus},
year = {2018},
publisher = {HeadLight},
howpublished = {\url{https://pavementinteractive.org/reference-desk/testing/aggregate-tests/fineness-modulus/}},
note = {Accessed [date]}
}