Viscosity test of bitumen
- 1. VISCOSITY TEST FOR BITUMEN PRESENTED BY:AMRIT PANDIT ACEM/069/A/005 KATHMANDU, NEPAL
- 2. Objective • To become familiar with the term viscosity, its influence and effects, its techniques and application in the field of engineering especially for design of the road pavements.
- 3. Introduction • In general, viscosity defines the consistency. • Viscosity=Shear stress/shear rate • It is the measure of the resistance against the flow and here, particularly we are dealing with the road binders like bitumen.
- 4. • Like that of penetration, bitumen has the upper hand in determining the stability of the road pavements. • It greatly influences the strength of pavement at the application temperature.
- 5. • At low degree, the binders simply lubricates the aggregates( road metals along with aggregates if any) rather than providing a film for the binding actions. • Similarly, at high temperature resists the compaction effort and results in heterogenous mix.
- 6. A type of orifice viscometer.
- 7. Types of Viscometer • Orifice viscometer: Test Setup: 50 ml of material is made to flow through a cup through a orifice at the standard test conditions and specified temperature(60).
- 8. • Furol Viscometer: Specified test which is used only to measure the viscosity of liquid bituminous material. Time required for 50 ml of sample to flow through orifice at standarized temperature.
- 9. • Besides sliding plates and Brookfield viscometer are used for all grades of bitumen but are irrespective of the temperature.
- 10. Table 1:Specification for test temperature and range of viscosity for road tar(as per IS 215-1981) Road tar type RT1 RT2 RT3 RT4 RT5 Orifice size(mm) 10 10 10 10 10 Test temperature 35 45 45 55 65 Viscosity in sec 30-55 30-55 35-60 35-70 35-70
- 11. Interpretation • If the time required for the bitumen is a bit longer then it has higher degree of viscosity otherwise less time signifies the low degree of viscosity. • So it is best to choose the appropriate degree and should neither be of higher nor be of lower degree.
- 13. Application in Engineering • Viscosity test and many other Bitumen Tests are done to ensure the quality of Bitumen. • Application of Bitumen in real life: 1. Hydraulics and erosion control in catchment area. 2. Embankment protection. 3. Road pavement. 4. Binders in asphalt for roads. 5. Water proofing, surfacing of road etc.