Contents:

**Fineness Modulus of Cement by Dry Sieving**

**Apparatus **

- 90µm Sieve.
- Balance capable of weighing 10g to the nearest 10mg.
- Glass rod
- Stoppered jar
- Pan and Lid

**Procedure to Determine Fineness of Cement**

- Stir the sample of cement to be tested by shaking for 2 minutes in a stoppered jar to disperse lumps. Stir the resulting powder gently using a clean dry rod in order to distribute the fines throughout the cement.
- Attach a pan under the sieve to collect the cement passing the sieve.
- Weigh approximately 10 g of cement to the nearest 0.01 g and place it on the sieve. Fit the lid over the sieve.
- Shake the sieve by swirling, planetary and linear movement until no more fine material passes through it.
- Remove and weigh the residue. Express its mass as a percentage (
**R**) of the quantity first placed in the sieve._{1} - Repeat the steps 3 to 5 with a fresh sample to obtain
**R**._{2} - If the results differ by more than 1 percent absolute, carry out a third sieving and calculate the mean of the three values.

**Calculation**

**R**= (R

_{avg }_{1}+R

_{2}+R3) / 3 Fineness modulus of cement =

**R**/ 100

_{avg}**Importance of Cement Fineness**

- The fineness of cement affects 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.

**Read More: Fineness Modulus of Sand (Fine Aggregates) – Calculations, Values**