Processed sample cement weighing about 64 g to the nearest 0.05 g must be
tested.
Fill the bottle with kerosene free from water and oil whose density is at least 62
API. Up to point gradations between zero and 1 mL, dry the inner surface of the
bottle at the highest level of kerosene if necessary, and use rubber on the surface of
the table used for the test when filling the bottle.
The bottle, which is filled with kerosene, is placed in a water bath and the first
reading to kerosene level is recorded. To record the first reading correctly install the
bottle in the water bath vertically. Put a cement sample weighing 64 g with accuracy
to 0.05 g inside the bottle with small batches at the same temperature of kerosene,
taking into account when putting the cement inside the bottle to avoid cement dropping
out or its adhesion on the internal surfaces of the bottle at the highest level. The
bottle can be placed on the vibrating machine when putting the cement inside the
bottle to expedite the process and prevent adhesion of granulated cement with the
internal surfaces of the bottle.
After laying the cement inside the bottle, put a cap on the bottle mouth and then
spin diagonally on the surface so as to expel the air between the granules of cement,
and continue moving the bottle until the emergence of air bubbles stops from the
kerosene surface inside the bottle.
Put the bottle in the water bath and then take the final reading, and record the
reading at the lower surface of kerosene so as to avoid the impact of surface tension.
For the first and final readings, make sure that the bottle is placed in a water bath
with constant temperature for a period not to exceed the difference in temperature
between the first and final readings of about 0.2°C.
The difference between the first and final reading is the volume of the moving
liquid by the cement sample.
The volume of the moving liquid = final reading – first reading
4.2.1.4 D efine Cement Fineness by Using Blaine Apparatus
This test is used to determine the surface area by comparing the test sample with the
specific reference. The greater surface area increases the speed of concrete hardening
and obtains early strength. This test determines the acceptance of the cement.
There are many tests to define cement fineness
论文范文http://www.chuibin.com/ and one is a Blaine apparatus as
stated in many codes such as the Egyptian code.
This test depends on calculating the surface area by comparing the sample test and
the reference sample using a Blaine apparatus to determine the time required to pass
a definite quantity of air inside a cement layer with defined dimensions and porosity.
A Blaine apparatus is shown in Figure 4.4. The first step in testing is to determine
the volume of the cement layer using mercury in the ring device of the Blaine apparatus.
Cement is then added and by knowing the weight of the cement before and
after adding it as well as the mercury density, the volume of the cement layer can be
calculated.
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