Air Permeability Test and Specific Surface

The air permeability test is a method used to measure the fineness of cement. It is also known as the Blaine air permeability test, named after its inventor, Paul-Emile Blaine. The test measures the specific surface area of cement, which is a measure of the total surface area of cement particles in a given mass.

Specific Surface Area in mm2/g

The specific surface area is usually expressed in terms of mm2/g, which means the surface area in square millimeters per gram of cement. The specific surface area of cement is an important parameter for determining its quality and performance. A higher specific surface area indicates that the cement particles are finer, which means they have a larger surface area per unit mass.

Options Given and Correct Answer

In the air permeability test, the specific surface is measured in terms of Blaine fineness, which is expressed in terms of mm2/g. The options given in the question are:

a) 1000
b) 2000-2500
c) 2500-5000
d) 225000-350000

The correct answer is option 'D', which means the specific surface area in the air permeability test is between 225000-350000 mm2/g. This range is typical for ordinary Portland cement, which is the most commonly used type of cement in construction.

Conclusion

The air permeability test is an important method used to measure the fineness of cement. It measures the specific surface area of cement, which is expressed in terms of mm2/g. The correct answer to the question is option 'D', which means the specific surface area in the air permeability test is between 225000-350000 mm2/g for ordinary Portland cement.

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