SRIMUKHA

Fineness by Blaine’s Air Permeability

Code: This test is done as per (IS-4031-PART-2).

Procedure:

Procedure consists of 4 steps

(a)Determination of the density of cement

To determine the density or specific gravity of cement click here.

(b)Determination of the bed volume

i) Apply a very thin film of light mineral oil to the cell interior. Place the perforated disc on the ledge in cell. Place two new filter paper discs on the perforated disc.
ii) Fill the cell with mercury. Level the mercury to the top of the cell with a glass plate.
iii) Remove the mercury from cell and it, M1.

iv) Remove the top filter paper from the permeability cell and compress a trial quantity of 2.80 g of cement into the space above filter paper to the gauge line in the cell. Place the other filter paper above the cement bed.
v) Fill the remaining space in the cell above the filter paper with mercury. Level the mercury to the top of the cell with a glass plate and remove mercury from the cell and weigh it, M2.
vi) Calculate the volume occupied by the cement bed in the cell from the following equation.
vii) Average at least two volume determinations that agree to within ±0.005cm3 and record this value.

(c)Determination of apparatus constant

i) Take an amount (W) of standard cement so as to give the cement bed of porosity e=0.500.
ii) Place the perforated disc on the ledge at the bottom of the cell and place on it a new filter paper disc. Place the weighed quantity of standard cement, W, in the cell taking care to avoid loss.
iii) Tap the cell to level the cement. Place a second new filter paper disc on the leveled cement.
iv) Compress the cement with the plunger until the plunger collar is in contact with the top of the cell. Slowly withdraw the plunger a short distance, rotate 900, repress the cement bed, and then slowly withdraw.
v) Attach the permeability cell to the manometer tube with an air tight connection and slowly evacuate the air in the manometer U-tube until the liquid reaches the top mark, then tightly close the valve.
vi) Start the timer when the bottom of the meniscus reaches next to the top mark and stop the timer when the bottom of the meniscus reaches the bottom mark. Record the time t and temp. of test.
vii) Repeat the whole procedure on two further samples of the same reference cement. Calculate the average time of the three determinations. Then calculate the apparatus constant using the formula given below.

(d)Determination of fineness

i) Repeat the steps (1 to 6) as done in determination of apparatus constant, but this time using the cement whose fineness is to be calculated.
ii) Calculate fineness of cement using following formula.

Uses:

To determine the fines of cement.