Cut back Bitumen
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cut back bitumen
penetration grade bitumen
polymer modified bitumen
Bitumen is the oldest known Engineering Material and has been used from the earliest times as an Adhesive, Sealant and Waterproofing Agent. A non-crystalline Solid or Viscous material having adhesive properties derived from Petroleum either by Batural or Refinery processes, and substantially soluble in carbon disulphide. Bitumen are Black or Brown in colour. This may occur naturally but are usually made as end products from distillation of or extracts from selected crude.
Penetration Grade Bitumen -Used in road surfacing, and some industrial applications
Additional processing yields other grades of bitumen products and their applications are
Oxidized Bitumen - Produced by more vigorous air blowing; they are more 'rubber like' and less temperature susceptible than the paving grades. Used in roofing, waterproofing, electrical products, and many others.
Hard Grade Bitumen - Harder paving grades and are used in making paints and enamels etc
Cutback Bitumen - Blends of penetration bitumen with Solvent such as kerosene used in spraying and some mixing applications
Emulsion - Stabilized Suspensions of bitumen in Water. used largely in road surfacing applications
Polymer Modified Bitumen - Mixtures of selected bitumen with polymers such as Thermoplastics or Elastomer used in many applications On the Roads Hot Mixtures
Typically hot bitumen is delivered to a fixed asphalt plant where the hot mixture is produced and then transported to the road site for laying and compaction to produce the finished road surface. Different specification binders allow the road construction industry to create surfaces that facilitate different performance .
Surface Dressing is a process commonly used for road maintenance. It normally consists of spraying a thin film of binder onto the road surface using a mobile spray vehicle. This is immediately followed by the application of a layer of stone chipping that are rolled to embed them into the surface. Emulsions and cutbacks are usually used in the spray application. Variations on these two main themes have also been developed for bituminous road surfacing.
The 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.
This test is carried out by the Ring and Ball method, which consists of suspending a brass ring containing the test sample of Bitumen in water at a given temperature. A steel ball is placed upon the bituminous material, the water is then heated at the rate of 5 deg C increase per minute. The temperature at which the softened bituminous material first touches a metal plate at a specified distance below the ring is recorded as the Softening point of the sample.
In the interest of safety, legislation has been introduced in most countries fixing minimum flash point limits to prevent the inclusion of highly inflammable volatile fractions in kerosene distillates. According to Controller of Explosives classification it falls in the category of Class B Petroleum Products. Its flash point (Abel) is stipulated as Min. 35 deg C in the IS specification.