Porosity of a Rock Sample

Introduction:
In civil engineering, understanding the porosity of rock samples is crucial for various applications, such as determining the permeability, water absorption capacity, and stability of the rock. Porosity refers to the percentage of void spaces or pores within a rock sample. This can be determined by comparing the weight of the dry sample with its weight after saturation and immersion in a liquid.

Given Data:
- Oven dry weight of rock sample = 0.655 kg
- Weight of rock sample after saturation with kerosene = 0.732 kg
- Weight of kerosene displaced by the rock sample = 0.301 kg

Calculating the Porosity:
The porosity of the rock sample can be calculated using the following formula:

Porosity = (Volume of void spaces / Total volume) x 100

In this case, the volume of void spaces can be determined by subtracting the volume of the rock sample before saturation with kerosene from the volume of the saturated rock sample. The total volume is the volume of the saturated rock sample.

Step 1: Calculate the Volume of the Rock Sample:
The volume of the rock sample can be calculated by dividing its dry weight by its density. The density of the rock sample can be determined using the formula:

Density = Dry weight / Dry volume

Assuming the density of the rock sample is constant, the dry volume can be calculated by dividing the dry weight by the density.

Dry Volume = Dry Weight / Density

Step 2: Calculate the Volume of the Saturated Rock Sample:
The volume of the saturated rock sample can be calculated by dividing its weight after saturation by the density of the kerosene.

Saturated Volume = Saturated Weight / Kerosene Density

Step 3: Calculate the Volume of Void Spaces:
The volume of void spaces can be determined by subtracting the volume of the rock sample before saturation from the volume of the saturated rock sample.

Void Volume = Saturated Volume - Dry Volume

Step 4: Calculate the Porosity:
Finally, the porosity can be calculated by dividing the volume of void spaces by the total volume of the saturated rock sample and multiplying by 100.

Porosity = (Void Volume / Saturated Volume) x 100

Conclusion:
By following the above steps and using the given data, you can calculate the porosity of the rock sample. The porosity is a crucial parameter in civil engineering, as it helps in determining the water absorption capacity, permeability, and stability of the rock sample.