Description :

O scribd e o maior site social de leitura e publicacao do mundo. Generic class of petroleum substances known as bitumens and their derivatives bitumens are used mostly for road paving or roofing but find uses in a variety of other applications where waterproofing and adhesion are important required properties. Highway eng ii 7 4 bitumen bound pavement materials penetration grade bitumens penetration grade bitumens or asphalt cements are in consistency from semi solid to semi liquid at room temperature such bitumens are graded according to their viscosity mainly used in the us the most common grading are ac 25 ac 5 ac 10 ac 20 and ac 40. Having in a general way considered the preparation and characteristic properties of the bitumens used in road and paving work their application for this purpose may be taken up in the present paper it is hardly practicable to describe in detail the various methods of applying bitumens and of constructing bitu minous roads and pavements. Types of bitumen and their properties and uses in areas of road construction it is necessary for the material to be fluid in nature at the time of laying ie during surface dressing it is also essential for the material to regain back to its original hardness and property after setting this is ensured by cutback bitumen