What is this blog post about?
This post is published for civil engineers who works at materials testing laboratory. It also helps civil engineering students and pass out candidates. In this post, the reference IS 4031 (Part-2): 1999 is used. This blog post covers definitions, apparatus list, IS code, test procedure, calculation sheet, formula and expression of result of fineness of cement by Blaine air permeability test as per IS 4031 Part-2 (1999). Here fineness of cement is represented by specific surface and expressed as total surface area in cm²/g.
You can also use this method for determination of fineness of various other materials. However, it should be understood that the values obtained are relative rather than absolute.
(For definitions and related questions, check FAQs.)
Fineness of Cement by Blaine Air Permeability Test | IS: 4031 Part-2
Fineness of cement can be calculated by using air permeability method or by using sedimentation method or from particle size analysis (sieve analysis). Sieve analysis (by dry sieving) measures the cement particle size whereas air permeability method and sedimentation method measures specific surface area of cement. Here we have explained the one method fineness of cement by Blaine Air Permeability Test as per IS 4031 Part-2 (1999).
Now read IS code reference, apparatus list, test procedure, formula, result and lab report about fineness test of cement by Blaine air permeability method one by one.
Blaine Air Permeability Test IS Code
IS: 4031 Part-2 (1999) is used to determine the fineness of cement by Blaine air permeability method.
Other References Used in Blaine Air Permeability Test
The following IS code references are followed in Blaine air permeability test to determine the fineness of cement.
- IS: 3535 (1980) – For methods of sampling hydraulic cements.
- IS: 5516 (1996) – For specification of variable flow type (Blaine) air permeability apparatus.
Blaine air permeability test is used for
Blaine air permeability test is used for determining the fineness of cement by measuring the specific surface area of fine materials in cm²/g of test sample.
Apparatus Used in Blaine Air Permeability Test of Cement
- Blaine Air Permeability Apparatus: Conforming to IS 5516 (1996).
- Timer/Stopwatch: Capable of reading to the nearest 0.2 s or better and accurate to 1 percent.
- Weighing balance: Capable of weighing up to 3 g to the nearest 1 mg (for cement) and capable of weighing about 50 g to 110 g to the nearest 10 mg (for mercury).
- Pycnometer or other convenient: For determining the density of cement.
- Manometer liquid: A non-volatile, non-hygroscopic liquid of low viscosity and density such as dibutyl phthalate or light mineral oil.
- Light oil: To prevent formation of mercury amalgam on the inner surface of the cell.
- Mercury: of reagent grade or better.
- Circular discs of filter paper: Having a smooth circumference and of medium porosity (Mean pore Diameter = 7μm).
- Light grease: For ensuring an airtight joint between cell and manometer and in the stopcock.
- Cement sample: of known specific surface.
Sampling and Selection of Test Specimens:-
The samples of the cement will be taken according to the requirements of IS 3535: 1980 (Methods of sampling hydraulic cements) and the relevant standard specification for the type of cement being tested.
Mix thoroughly the representative sample of the cement, selected as above, before testing.
Temperature and Humidity Requirements
The temperature of moulding room, all materials for test and calibration should be maintained at a temperature of 27±2 °C and the relative humidity level not exceeding 65%. All materials for test and calibration should be protected from absorption of atmospheric moisture during storage. The temperature may be determined at 20±2 °C, if desired by the purchaser.
Procedure for Blaine Air Permeability Test of Cement
The procedure for Blaine air permeability test of cement (to determine the fineness in sense of specific surface area) will be conducted as below.
A. Compaction of Cement Bed
Preparation of the Sample
- Take the sample of cement of known specific surface for the test.
- Agitate the sample for 2 minutes in a stoppered jar to disperse agglomerates.
- Wait for 2 minutes and stir the resulting powder gently by using a clean dry rod in order to distribute the fines throughout the cement.
Determination of the Density of Cement (ρ)
- Determine the density of the cement (ρ) using a device such as a Pycnometer or Le-chatelier flask. Use a non-reactive liquid in the determination.
- The quantity of cement used will depend on the nature of the apparatus but shall be such that the determined value of ρ is accurate to 0.01 g/cm³.
- Verify the accuracy of ρ by a repeat determination and record the mean of the two determinations to the nearest 0.01 g/cm³ as the density (ρ).
Formation of the Cement Bed
- Weigh the quantity of cement, using the following formula assuming porosity e = 0.500. M₁ = 0.500ρV. Where, ρ is the density of cement (3.15 g/cm³ for OPC) and V is the volume of cement bed (in cm³).
- Place the perforated disc on the ledge at the bottom of the cell.
- Place a new filter paper disc on top of the perforated disc ensuring its full coverage and flatness by pressing with a clean dry rod.
- Then, place the weighed quantity of cement sample, M₁, 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.
- Insert the plunger to make contact with the filter paper disc and press it gently but firmly, until the lower face of the cap of the plunger is in contact with the cell.
- Slowly withdraw the plunger about 5 mm, rotate it by 90° and gently but firmly press the bed once again until the plunger cap is in contact with the cell.
- The cement bed is now compacted and ready for air permeability test. Slowly withdraw the plunger.
Note: If the plunger does not touch the surface of the cell after step, reduce the trial quantity of cement. If the plunger falls in easily without being pressed by the plunger, increase the trial quantity of cement.
B. Calibration of Apparatus
Determination of the Cement Bed Volume (V)
- Apply a very thin layers of light mineral oil to the cell interior.
- Place the perforated disc on the ledge in the cell.
- Place two new filter paper discs on top of the perforated disc ensuring its full coverage and flatness by pressing with a clean dry rod.
- Fill the cell with mercury.
- Remove any air bubbles with a clear dry rod. Ensure that the cell is full by pressing a glass plate on the surface of the mercury until it flushes with the cell of top.
- Empty the cell and weight the mercury to the nearest 0.01 g (M₂) and record the temperature.
- Remove one filter paper disc from the compacted cement bed.
- Place a new filter paper disc on top of the perforated disc ensuring its full coverage and flatness.
- Refill the cell with mercury removing air bubbles and levelling the top as described above.
- Remove the mercury and weight it to the nearest 0.01 g (M₃) and record the temperature.
- Calculate the bed volume by the formula.
Where,
V = Bed volume in (cm³),
M₂ and M₃ as calculated above and
D = Density of mercury.
V = Bed volume in (cm³),
M₂ and M₃ as calculated above and
D = Density of mercury.
Determination of the Apparatus Constant
- From a supply of standard reference cement of known specific surface, prepare a compacted cement bed (as Part-A: Compaction of cement bed).
- Measure its permeability by the procedures given in Part-C.
- Record the time as tₒ and the temperature of test using the same bed.
- Repeat twice the procedure on the same cement bed and record the additional values of time and temperature.
- Repeat the whole procedure on two further samples of the same cement sample. For each of the three samples calculated the means of the three times and temperatures.
- For each sample calculate the apparatus constant, K as following formula and take the mean of the three values of K as the constant K for the apparatus. (with the specified porosity of e = 0.500)
Where,
Sₒ = Specific surface of the standard reference cement, in cm²/g.
tₒ = Time recorded for the manometer drop for the standard reference cement (mean of 3 reading).
Ƞₒ = Viscosity of air at the (test) room temperature. Obtain it's value from Table-1.
ρₒ = Density of reference cement sample in g/cm³.
Sₒ = Specific surface of the standard reference cement, in cm²/g.
tₒ = Time recorded for the manometer drop for the standard reference cement (mean of 3 reading).
Ƞₒ = Viscosity of air at the (test) room temperature. Obtain it's value from Table-1.
ρₒ = Density of reference cement sample in g/cm³.
Table-1: Density of Mercury D, Viscosity of Air (n) and √0.1ηₒ as Function of Temperature
Temparature (°C) |
Mass Density of Mercury (g/cm³) |
Viscosity of Air (in *Pa.S) |
√0.1ηₒ |
---|---|---|---|
16 | 13.56 | 0.00001788 | 0.001337 |
18 | 13.55 | 0.00001798 | 0.001341 |
20 | 13.55 | 0.00001808 | 0.001345 |
22 | 13.54 | 0.00001818 | 0.001348 |
24 | 13.54 | 0.00001828 | 0.001352 |
26 | 13.53 | 0.00001837 | 0.001355 |
28 | 13.53 | 0.00001847 | 0.001359 |
30 | 13.52 | 0.00001857 | 0.001363 |
32 | 13.52 | 0.00001867 | 0.001366 |
34 | 13.51 | 0.00001876 | 0.001370 |
C. Air Permeability Test of Cement Sample
- Insert the conical surface of the cell into the socket at top of the manometer. (Use if necessary a little light grease to ensure an airtight joint and take care not disturb the cement bed.)
- Close the top of the cylinder with a suitable plug.
- Open the stopcock and raise the manometer liquid to the level of the highest etched line on the cylinder.
- Close the stopcock and ensure that the level of the manometer liquid remains constant.
- If it falls, remake the cell-manometer joint and check the stopcock, repeat the leakage test until the improved sealing produces a steady level of the liquid.
- Open the stopcock and by gentle aspiration adjust the level of the liquid, to that of the highest etched line.
- After this close the stopcock.
- Remove the plug form the top of the cylinder.
- The manometer liquid will begin to flow.
- Start the timer as the manometer liquid reaches the second etched line and stop it as the manometer liquid reaches the third etched line.
- Record the time as t to the nearest 0.2 second and the temperature to the nearest 1 °C.
- Repeat the procedure with further samples on the same cement bed and record the additional values of time and temperature.
- Now, repeat the whole procedure (from preparing a fresh cement bed to permeability test with further cement samples) and record the additional values of time and temperature.
- Calculate the specific surface or fineness of cement sample as under at 27±2 °C, at e = 0.500.
Where,
K = apparatus constant as calculated earlier.
S = Specific Surface area of the standard reference cement cm²/g
t = measured time t (mean of two value)
ρ = Density of cement
Expression of Result
Where the porosity is e = 0.500, the four times and temperatures resulting from the procedure of air permeability test (Part-C) shall be examined to check that the temperatures all fall within the specified range of 27±2 °C or 20±2 °C.
The resulting value of S, to the nearest 10 cm²/g, shall be reported as the specific surface of the cement.
A difference of 1 percent between the means of the fineness measurements carried out on two different powder beds from one and the same sample is acceptable.
The standard deviation of the repeatability is about 50 cm²/g and of the reproducibility is about 100 cm²/g.
FAQs
How to determine the fineness of cement?
Fineness of cement can be determine by using air permeability method or by using sedimentation method or from particle size analysis (sieve analysis). Sieve analysis (dry sieving) measures the cement particle size whereas air permeability method and sedimentation method measures specific surface area of cement. Here we have explained about particle Blaine air permeability test of cement.
What is Blaine air permeability test?
Blaine air permeability test is a laboratory test which is used to determine the fineness of cement by measuring the specific surface area of fine materials in cm²/g of test sample.
What is the use of Blaine air permeability test?
Blaine air permeability test is used to determine the fineness of cement by measuring the specific surface area of fine materials in cm²/g of test sample.
Next to read: