Penetration Test of Bitumen(डामर) (Experimental Procedure, Observations and Result)

Aim: - To determine the Consistency of the bitumen.

Apparatus required: - Penetrometer apparatus, thermometer, stopwatch, transfer dish, containers, and water cooling bath.

 Procedure: -

1.      Soften the material to a pouring consistency at a temperature not more than 90⁰C for bitumen above the approximate softening point and stir it thoroughly until it is homogenous and is free from air bubbles and water. Pour the melt into the container to a depth atleast 10-15mm in excess of the expected penetration. Protect the sample from dust and allow it to cool in an atmosphere at a temperature between 15⁰ to 30⁰C for one hour. Then place it along with the transfer dish in the water bath at 25.0⁰ ±0.1⁰C and allow it to remain for 1hr to1hr 30min or 2hr. The test is carried out at 25.0⁰ ±0.1⁰C, unless otherwise stated.

2.      Clean the needle with benzene, dry it and load with weight. The total moving load required is 100gms, including the weight of the needle, carrier and super-imposed weights. After that the sample container is taken out of water bath for testing.

3.      Adjust the needle to make contact with the surface of the sample. This may be done by placing the needle point with its image reflected by the surface of the bituminous material.

4.      Make the pointer of the dial to read zero or note the initial dial reading.

5.      Release the needle for exactly five seconds.

6.      Adjust the penetration machine to measure the distance penetrated.

7.      Make at least 3 reading at points on the surface of the sample not less than 10mm apart. Other samples are then tested with same procedure stated above. The needle should be cleaned with benzene and dried after each test.

Observation Table: -  

TABLE 4.1: - Observations of Penetrometer Value

Readings	Trial 1	Trial 2	Trial 3	Mean value
Penetrometer dial initial readings	0	0	0	-
Penetrometer dial final readings	51	53	53	53
Penetration value @ 100g, 250C, 5 sec,1/10mm	Average value = 53(Grade VG 30 )

Result: - The penetration value of sample taken is 53. Hence the bitumen is of grade VG – 30.