Volume of Cement Bed in blaine device

Dear Expert,

Though i am not knowledgeable to NIST 114, but as per IS 4032 it is determined using mercury of known specific gravity.

In this method, first the total volume of cell is determined by filling it with mercury and using two blaine whatman circles. Thereafter by hit and trial method, a fixed amount of cement is filled in the cell so that a compact bed of cement, after pressing with plunger in orthogonal direction,may be formed.

On this bed, again mercury is filled to fully fill the cell again. Now diffrence in volume of mercury is the volume of the cement bed, which is used in calculation to determine actual weight of the cement for blaine determination.

Regards,

Gulam Dastgir

yes , but my concern is the weight of the cement sample used for calibration  , in ASTM - it said that the weight is 2.8g

this mean that I will make the calibration with 2.8g only or the weight will depend on the sense of plunger pressing and I should try several weights starting with 2.8 g ??

Dear Electron,

This is the initial emprically derived weight to start on. But if we are not getting a compact bed with weight, then we to tweak this weight accordingly. The minor changes occurs due to change in specific gravity of cement samples. 2.8 gm is assumed on the sp. gr. of cement to be 3.15 (OPC).

Regards,

Gulam Dastgir