What is the fineness of cement?
The fineness of cement is the property of cement that indicates particle size of cement and specific surface area. and indirectly affect the heat of hydration.
Importance/effect of fineness of cement
- The fineness of cement affects hydration rate hence the rate of strength gain.
- The smaller the particle size, the greater the surface area-to-volume ratio, and thus, the more area available for water-cement interaction per unit volume.
- Therefore finer cement reacts faster with water and the rate of development of strength and corresponding heat of hydration is high.
- Fineness is a measure of how even each granule is, leading to a greater surface area and greater surface area more the adhesion.
- 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.
- A fineness test is used to check the proper grinding of cement and measures the surface area of the cement particles per unit mass.
It should not exceed the following percentage by weight for different types of cement.
- Ordinary Portland cement =10%
- Rapid hardening cement =5%
- Low heat cement =5%