Sunday, January 5, 2014

One liners - Transportation Engineering for GATE, PSUs - Part 9

Hello there,
How have you been? Here is another round of one liners for your preparation for the GATE and PSUs examinations.

  • For Sandy soils, most common method of stabilization is Soil bitumen stabilization.
  • For bituminous or asphalt concrete, proportioning of materials is determined from laboratories.
  • Limiting gradient on highways is associated with the requirement of maximum tractive effort for a short distance.
  • In group index method of flexible pavement design, daily volume of commercial vehicles decides the thickness of base and surface course.
  • In bituminous pavement, alligator cracking is mainly due to fatigue arising from repeated stress application.
  • The main function of prime coat is to improve bond between the existing base and surfacing of new construction.
  • The design of horizontal transition curve length for highways should take into account three factors namely, allowable values of rate of change of centrifugal acceleration and superelevation and the minimum length formula given by the IRC.
  • Penetration test is performed for the gradation of the asphalt cement.
  • Marshall test is performed for design of bituminous concrete mix.
  • Ring and ball test is performed to determine the softening point.
  • Benkelman beam test is performed for overlay design.
  • Reflection cracking is observed in bituminous overlay over cement concrete surface.
  • General landslide prevention works on the hill roads are retaining walls, catch water drains and breast walls.
  • In the Los Angeles Abrasion Test on aggregate, if the speed of the drum is increased to 50 rpm, then the abrasion value will increase.
  • Low bitumen content in bituminous pavement causes ravelling in bituminous pavement.
  • In desire-line diagram width of desire-line is proportional to the number of trips in both directions.

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