Civil Engineer Interview Questions asked in MNC Companies ?

Who invented Portland cement ?

Joseph Aspdin patented Portland cement in 1824. 

Which equipment is used to test the setting time of cement ?

Vicat apparatus The split type vicat mould is used as an alternative to single mould. This mould consist of a split ring having an internal diameter 80+/- 0.1mm and a height 40+/_0.5mm. A non-porous base plate is provided. The split mould is provided with a suitable clamping ring.

Procedure

  • Keep the vicat apparatus on a level base (when using vicat apparatus with dashpot, keep the bearing movable rod to its highest position and pin it.) Unscrew the top of the dashpot. Half fill the dashpot with any suitable oil of viscosity and screw the top. Work the plunger a number of times.
  • Attach the plunger for determining standard consistency to the movable rod. Work the plunger a number of times.
  • Take 400 gm of cement in a pan and a weighed quantity of water in a beaker.
  • Prepare a paste with the water added to cement. Start a stopwatch at the time of adding water to cement.
  • Keep the vicat mould on a non porous plate and fill the cement paste in it.
  • After completely filling the mould, shake it slightly to expel the air. Smooth off the surface of the paste making it level with the top of the moulder. The cement paste thus prepared is the test block.
  • Place the test block resting on the non porous plate under the movable rod, bearing the needle.
  • Lower the plunger gently to touch the surface of the cement paste and quickly release; (when vicat apparatus with dashpot is used, place the mould filled with cement paste and the non absorbent plate on the base plate of the vicat apparatus. Raise the plunger of the dash pot, bring it in contact with the top cap of the movable bearing rod.
  • Remove the pin holding the movable bearing rod to the surface of the cement paste and quickly release by pushing down the plunger to sink in to the paste). This operation shall be done immediately after filling the mould.
  • Prepare trial test specimens with varying percentages of water until plunger penetrates to a point 5 to 7mm from the bottom of the vicat mould, which is read on the scale. Express the water required as percentage by weight of the dry cement.

What is Green cement ?

Green cement is a form of cement produced with the help of a carbon-negative manufacturing process. Green cement is an eco-friendly product which resolves serious environmental issues and minimizes the carbon footprint of cement production.

In Other word , Green concrete is defined as a concrete which uses waste material as at least one of its components, or its production process does not lead to environmental destruction, or it has high performance and life cycle sustainability.

What kind of cement would you use for completing the project with less budget and without compromising on the quality ?

OPC cement is usually recommend for RCC structural work (like foundations, columns, roof and beams)

PPC cement is recommended for non-structural works (Like Plastering, Tiling etc.,). This will not only save you costs but also enhance the quality of construction by reducing cracks (Due to less heat of hydration ).

What happens when sugar is added to concrete ?

In simple terms, sugar acts as a retarder and delays the setting time of concrete.

What is meant by 80/100 grade bitumen ?

If grade of bitumen is 80/100 then penetration value lies between 8 to 10 mm. This grade is mostly used in India. Bitumen is also graded based on viscosity grading. 80/100 belongs to VG 10 group. Other grades of bitumen can be 30/40 (3-4 mm penetration value on penetration test), 60/70 (6–7 mm penetration).

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