The size of the particles of the cement is its fineness. The required fineness of good cement is achieved through grinding the clinker in the last step of the cement production process. As the hydration rate of cement is directly related to the cement particle size, the fineness of cement is very important.
Importance of Cement Fineness
- The fineness of cement affects the hydration rate, and in turn, the strength. Increasing fineness causes an increased rate of hydration, high strength, and high heat generation.
- Bleeding can be reduced by increasing fineness. However, increased fineness can also lead to the requirement of more water for workability, resulting in a higher possibility of dry shrinkage.
- The increased surface area-to-volume ratio will ensure a more available area for water-cement interaction per unit volume.
Fineness Test of Cement
- AASHTO T 98 and ASTM C 115: Fineness of Portland Cement by the Turbidimeter.
- AASHTO T 128 and ASTM C 184: Fineness of Hydraulic Cement by the 150-mm (No.100) and 75-mm (No. 200) Sieves
- AASHTO T 153 and ASTM C 204: Fineness of Hydraulic Cement by Air-Permeability Apparatus o AASHTO T 192 and
- ASTM C 430: Fineness of Hydraulic Cement by the 45-mm (No. 325) Sieve.