The most superior material is used in
The most superior material is used in the surface layer of pavement as it is the layer which is exposed to more number of stresses.
The soil sub grade suitable for pavement is
The soil sub grade most suitable for pavement layer is gravel as it is very strong rock, black cotton is not suitable for pavement but suitable for crops, sand has a danger of liquefaction and red soil is not so advisable.
The drainage layer is
The drainage layer of the pavement is granular sub base course which collects water from pavement surfaces.
The minimum thickness of compacted sub grade is
The minimum thickness of sub grade required is 300mm and in highways it is 500 mm as they are provided with the maximum best facilities.
The most common test used in evaluating soil strength is
All the tests are performed but the most commonly used one is CBR, which is called as California bearing test, performed in India.
The CBR standard penetration is
The standard penetration value of the CBR value is 2.5mm, if 5 mm value is greater then the penetration test is repeated again.
Minimum thickness of seal coat is
The minimum thickness of the seal coat required is 20mm for bitumen pavement, seal coat is a layer above the flexible pavement surface.
The impact value of aggregate used in pavement is
The aggregate impact value should not be more than 30% for aggregate used in bitumen, if it is less than 30 the aggregate may be replaced.
The abrasion value of the aggregate in pavement should be less than
The abrasion value of aggregate should not be more than 40% for the aggregate tested by Los Angeles abrasion test, if it is more than 40, then it may be rejected.
The specifications for highway are prepared by
The specifications for the highway are prepared by MORTH, which is Ministry of Road Transport and Highway.