Generally the result of this test shows the softing (Flowing) of bitumen .also it determines the grade of bitumen according to standard specification explained above.
Penetration: Consistency (suitability) of a bituminous material expressed as the distance in tenths of a millimeter ,that a standard needle vertically penetrates a sample of the material under known conditions of loading ,time, and temperature called penetration.
1.Penetration Instrument 2. Penetration Needles 3.Sample Container
4.Water Bath 5.Timing Device 6.Transfering Device
The amount needed for this test is obtained from the big tab sample which taken from tank or Batch Plant. the procedure for taking the sample is followed to Bitumen sampling Page .
Heat the sample slowly ,be care to don't increase the Heating fast, and also avoid to increase the heating temperature more than 90 c ,and for more than 30 minute duration. avoid shaking the heated sample in order to avoid inserting the air bulb into sample.
Pour the Heated sample into the Container up to a certain depth which after cooling its depth be about 1 cm more than the normal penetration of needle. prepare two separate sample if needed. slowly cover the above surface of the sample to avoid dust and external effect to the surface. and let it to get cool at a normal atmosphere temperature (about 15 -30 C), for 1-1.5 hours .
Now it is time to prepare the needle and the penetration instrument for test, the shape and weight of the needle and the effecting instruments are as follow:
Needle:
Must be made of a very hard material and be resist to elongation and deflection, height of the needle must be approximately 5 cm .
Its height must be 1 to 1.02 mm thickness, the needle's tip must be rounded and be symmetry in each faces. the angle of the tip must not be more than 9.7° degree.
The roughness of the needle's tip must not exceed 0.2
The weight of the needle with it tail must be 2.5±0.05 Gr.
Penetration Instrument:
Any Instrument which can Handle the needle and can move it vertically down with measuring device and without fraction and oscillation (movement).
the weigh of the needle and the Holder of the needle must be 100±0.05 Gr. (this weight also contain an Iron ring Which it weight is approximately 50 Gr.)
It must have a flat surface for putting the sample vertically in needle direction.
Examine that needle holder and also water temperature and also existence of all instruments needed. Dry the needle which has been for 5 minute in a pure water ,assemble the needle into the needle Holder of the penetration instrument.
After these steps Put the sample into a movable Dish and put it at bottom of the needle and close the tip of the needle up to touching the needle on the surface of the bitumen in Can .(it is important that the sample must be submerged in water in testing duration). immediately start the timer and release the holder of the needle to drop down to the sample, wait for 5 seconds and immediately stop the holder and timer simultaneously ,then push down the data reader up to touch the upper surface of needle Holder ,now it is simple to read and record the amount of penetration of the needle into the sample.
After this step repeat this procedure three times for one sample ,but it must be noted that the penetration of the second and the third must be at least 1 cm far from the previous penetration place. and also must use a new ,clean needle for each penetration, and also must be remembered that the previous needle must not removed from the sample .
Report the Recording Data as Follow
Report the Average of the tested penetration values with nearest value of 0.1,and the deference between two value must not be more than:
For Penetration 0-49 maximum deference between values must not be more than 2
For Penetration 50-149 maximum deference between values must not be more than 4
For Penetration 150-249 maximum deference between values must not be more than 6
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For seeing the penetration test Procedures just click here
For seeing a completed sample of test Click Here
