Bitumen is a non-crystalline viscous material, black or dark brown, which is substantially soluble in carbon disulphide (CS2), possessing adhesive and waterproofing qualities.
It consists essentially of hydrocarbons and would typically comprise at least 80% carbon and 15% hydrogen, the remainder being oxygen, sulphur, nitrogen and traces of various metals.
Asphalt is a word with different meanings. In American usage asphalt, or, in full, asphalt cement, is used to mean bitumen (or bitumen binder). In the term ‘rock asphalt’ it defines a mineral substance that may be impregnated with bitumen or pitch.
Outside America, the word asphalt means a mixture of bitumen and mineral aggregates laid as a road surface.
Penetration Grade Bitumen is commonly used in road surfacing and some industrial applications. Additional processing yields other grades of bitumen products and their application.
Penetration Test determines the hardness of Bitumen by measuring the depth ( in tenths of a mm) to which a standard and loaded needle will vertically penetrate in 5 seconds, a sample of Bitumen maintained at a temperature of 25 deg C ( 77deg F).
Hence the softer the bitumen, the greater will be its number of penetration units. (80/100, 60/70, 40/50)
SPECIFICATION OF PENETRATION GRADE BITUMEN
|BITUMEN 80/100||BITUMEN 60/70||BITUMEN 40/50||ASTM / AASHTO|
|Specification Gravity @25/25 °C||1.01/1.06||1.00/1.05||1.00/1.05||D-70|
|Penetration @ 25 ° C||80/100||60/70||40/50||D-5|
|Softening Point ° C||45/52||49/56||52/60||D-36|
|Ductility @ 25 ° C CMS||100 MIN||100 MIN||100 MIN||D-113|
|Loss on Heating (wt)%||0.5 MAX||0.2 MAX||0.2 MAX||D-6|
|Drop in Penetration After Heating %||20 MAX||20 MAX||20 MAX||D-6 & D-5|
|Flash Point °C||225 MIN||250 MIN||250 MIN||D-92|
|Solubility in CS@ (wt)%||99.5 MAX||99.5 MAX||99.5 MAX||D-4|
|Density @25° C||1.01/1.06||1.00/1.05||1.00/1.05||D70|