The Blaine air-permeability apparatus consists essentially of a means of drawing a definite quantity of air through a prepared bed of cement of definite porosity. The Blaine works by drawing a definite quantity of air through of bed of cement exhibiting a definitive porosity value. The number and size of the pores in a prepared bed of definite porosity is a function of the size of the particles and determines the rate of airflow through the bed. The standard Humboldt Blaine Air Permeability Apparatus consists of: calibrated U-tube manometer, ground glass joint, stainless steel test cell and plunger, rubber aspirator bulb and perforated disc. Includes an 8 oz
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Procedure consists of 4 steps a Determination of the density of cement To determine the density or specific gravity of cement click here. Place the perforated disc on the ledge in cell.
Place two new filter paper discs on the perforated disc. Fill the cell with mercury. Level the mercury to the top of the cell with a glass plate. Remove the mercury from cell and it, M1. Remove the top filter paper from the permeability cell and compress a trial quantity of 2.
Place the other filter paper above the cement bed. 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. Calculate the volume occupied by the cement bed in the cell from the following equation.
Place the weighed quantity of standard cement, W, in the cell taking care to avoid loss. Tap the cell to level the cement. Place a second new filter paper disc on the leveled cement. 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 , repress the cement bed, and then slowly withdraw. 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.
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. 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. Calculate fineness of cement using following formula.
Blaine Air Permeability Apparatus
The pressure drop across the flowmeter measured by a manometer is proportional to the flowrate, and the proportionality constant can be measured by direct calibration. The pressure drop across the bed is measured by a similar manometer. The apparatus is maintained at a constant temperature, and dry air is used so that the air viscosity can be obtained from tables. Rigden method[ edit ] This was developed  in the desire for a simpler method. The bed is connected to a wide-diameter u-tube containing a liquid such as kerosene. On pressurizing the space between the u-tube and the bed, the liquid is forced down.
FINENESS OF CEMENT BY BLAINES AIR PERMEABILITY METHOD (IS-4031-PART-2)
We have several options to choose from included an automatic air permeability test apparatus, a manual air permeability test apparatus, a PC-controlled air permeability test apparatus. The Blaine air permeability tester is mainly used to measure the fineness of the cement, which in turn can be an indication of speed of setting and rate of strength development. The testing principle is based on the permeability of air through a sample under certain conditions. This is the ideal testing instrument for cement and concrete testing. We offer variety of Blaine systems fitting the needs of the industry. The entire test can be run semi-automatically with a greater degree of freedom for the operator than the manual Blaine test apparatus.
Air permeability specific surface