Tests on Bitumen to Check Quality and Properties for Pavement
To ensure the quality of bitumen several tests are performed which are as follows.
Ductility Tests on Bitumen
- Ductility test
- Flash and Fire point test
- Float test
- Loss on heating test
- Penetration test
- Softening point test
- Specific gravity test
- Viscosity test
- Water content test
The property of bitumen which allows it to undergo deformation or elongation is called ductility of bitumen. The ductility of bitumen is measured by the distance in Cm (centimeter), to which the bitumen sample will elongate before breaking when it is pulled by standard specimen at specified speed and temperature.
Firstly the bitumen sample is heated to 75-100oC and melted completely. This is poured into the assembled mold which is placed on brass plate. To prevent sticking the mold and plate are coated with glycerin and dextrin. After filling the mold, placed it in room temperature for 30-40 minutes and then placed it in water for 30 minutes.
Then take it out and cut the excess amount of bitumen with the help of hot knife and level the surface. Then place the whole assembly in water bath of ductility machine for 85 to 95 minutes. Then detach the brass plate and the hooks of mold are fixed to machine and operate the machine.
The machine pulls the two clips of the mold horizontally and then bitumen elongates. The distance up to the point of breaking from the starting point is noted as ductility value of bitumen. The minimum value should be 75cm.