Bitumen is widely used in road construction. It is usually available in dark colours ranging from brown to black. The main purpose of bitumen in road construction is to strongly bind and hold the other pavement components together and provide a smooth and levelled surface for the moving vehicles.
The main reason why bituminous is tested is:
- To provide data for specification requirements
- To control the quality and uniformity of the product during manufacturing and use.
- To predict and control the handling, storage, and field performance properties of the material
Some of the categories of tests include:
Ageing tests for determining bitumen ageing when it is exposed to heat, traffic and weather
- Loss on Heating Test
- Thin Film Oven Test (TFOT)
Consistency tests for determining the hardness and flow properties of bitumen
- Penetration Test
- Softening Point test
- Viscosity test
- Ductility
Purity test to determine if the bitumen has any foreign substances
- Solubility test using carbon disulphide or trichloroethylene
Safety test to determine safe temperatures to use bitumen
- Flash Point
Some of the tests on bituminous mixes include
- Mix designs to determine bitumen and aggregate proportions in a mix
- Stability and indirect tensile tests to determine strength of bituminous mixes
- Bitumen content to determine the amount of bitumen used in a mix
- Aggregate grading to determine stone sizes used in a mix
- Performance testing to predict how the mix shall perform when the road is opened to traffic
Bitumen Laboratory also carries out research on the use of new types of bitumen and bituminous mixes in order to cope with new challenges in road construction. Examples are polymer modified bitumens and performance graded bitumens.
Equipment:
A wide range of equipment is available to carry out the above tests including: Marshall test apparatus, core drilling machines, bitumen recovery apparatus, viscometers, universal asphalt tester, dynamic shear rheometer, wheel track tester, rotational viscometer, bituminous mix compactors and mixers etc.