Bitumen is the oldest known engineering material and has been used from the earliest times as an adhesive, sealant and waterproofing agent. Bitumen has been found to be used as long ago as 6000 B C , the ship-building industry in Sumeria used naturally occurring bitumen, found in surface seepage in the area.
A non-crystalline solid or viscous material having adhesive properties derived from petroleum either by natural 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 petroleum oils.
There appears to have been little development in materials used until the 19th century when the refining of bitumen from crude petroleum oils began. The vast majority of bitumen used by today's construction industry is refined bitumen, derived from crude oil. It is a sophisticated product available in many forms and grades developed by the bitumen industry for specific uses. The process of refining bitumen was pioneered in the early 1900s in the United States, giving rise to a myriad of contemporary industrial application .
Bitumen is obtained essentially by distillation of a blend of crudes containing at least one bitumen crude. The others, which are lighter, go to satisfy requirements for different types of fuel and combustibles. Contrary to a common but mistaken idea, bitumen is not an oil residue that the petroleum industry wants to get rid of at little cost. In reality, to produce bitumen of good quality with constant properties, refiner meticulously select one or more bitumen crude, following very strict internal approval procedures.
Of the 1300 types of crude oil classified worldwide, only 10 % are suitable for producing bitumen capable of meeting the specifications for use. These types are known as bitumen crude. In short , bitumen is a blend of hydrocarbons, solid and semi-solid and brown or black in colour. Having been used as an adhesive, sealant and waterproofing agent for over 8,000 years, its being used in the construction and maintenance of roads, airfields and all areas where asphalt is used; roofing; damp proofing; dam, reservoir and pool linings; soundproofing, pipe coatings, paints, and many others. Asphaltic bitumen is valued for a variety of properties. It is water proof, ductile, adhesive, chemically inert and resistant to atmospheric exposure and the effects of dilute acids and alkalis.
Bitumen is produced from selected crude oils through a process of Fractional Distillation. The crude oil is heated to temperatures of between 300 and 350 degrees Celsius and fed into a distillation column allowing the lightest fractions of the crude to separate, through vaporization, from the heavier fractions, which remain liquid.
The higher boiling point fractions are then drawn-off via a heat exchanger and enter a vacuum distillation column. This process produces a "short residue" that is used to manufacture several grades of bitumen. The pressure and temperature conditions within the vacuum process will determine the hardness of the short residue, and. The short residue may be further modified by 'air blowing' in which air is passed through the residue at temperatures of 250 - 300 degrees Celsius. site. As an up-to-date business, we want to give you the opportunity to stay in touch with our company and our offers. A new content management system will enable us to always keep you up to date.
SPECIFICATION
Specification 40/50 60/70 80/100 Test Specific Gravity @ 25/25°C. 1.01/1.06 1.01/1.06 1.00/1.05 D 70 Penetration @ 25 °C. 40.5 60/70 80/10 D 5 Softening Point °C 52/60 49/56 45/52 D 36 Ductility @ 25 °C. 100 min. 100 min. 100 min. D 113 Loss on Heating (wt)% 0.2 max. 0.2 max. 0.5 max. D 6 Drop in Penetration % 20 max. 20 max. 20 max. D 6 & D-5 Flash Point °C. 250 min. 250 min. 225 min. D 92 Solubility in CS2 (wt) % 99.5 min. 9.5 min. 99.5 min. D 4 Spot Test Negative Negative 0.2 max. AASHOT
Additional processing
Processing of bitumen yileds 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
Bitumen is always applied hot, cutbacks are applied either hot or cold and emulsion is always applied cold. When the emulsion breaks the water evaporates leaving bitumen.
Bitumen is used as a binder for aggregates to produce hot mix asphalts .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
This 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 chippings 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 surfacings.
Bitumen is the oldest known engineering material and has been used from the earliest times as an adhesive, sealant and waterproofing agent. Bitumen has been found to be used as long ago as 6000 B C , the ship-building industry in Sumeria used naturally occurring bitumen, found in surface seepage in the area. 