Civil Engineer Interview Questions in L&t ,Afcon etc

What is the unit weight of Steel?
Ans   The unit weight of Steel is 78.5KN/m3

What’s the height of each floor?
Ans  3m

What is grouting?
Ans    Grout is a fluid form of concrete which is used to fill the voids.

What’s the slope of Staircase?
Ans Slope of stair should be between 25 degrees to 40 degrees.

What is Initial & final setting time of concrete?
Ans    Initial Setting time :30 minute

Final setting time : 10 hour

 What Are The Different Type Of Slump Test Indications?

Ans Slump tests are performed to empirically measure the work ability of fresh concrete. It is used to measure the consistency of the concrete. In general there are three different types of slumps that occur in slump tests.

They are as follows:

• True Slump: This type of slump is characterized by the general drop of the concrete mass evenly without visible signs of deterioration or disintegration. 
• Shear Slump: It indicates that the concrete mix is deficient in cohesion. This type of slump leads to segregation and bleeding. Henceforth in the long run effecting the durability of the concrete. 
• Collapse Slump: This type of slump is indicates that the mix of concrete is simply too wet. The mix is considered to be harsh and lean.

Who Provide Ultimate strength to cement

Di-calcium silicate

Why should curing not be done by ponding and polythene sheets?

The primary purpose of curing is to reduce the heat loss of concrete that is freshly placed to the atmosphere and in order to reduce the temperature gradient across the cross-section of the concrete. Ponding is not preferred for curing as this method of thermal curing is greatly affected by cold winds. In addition to that in ponding large amounts of water is used and has to be disposed off from the construction sites. Polythene sheets are used on the basis that it creates an airtight environment around the concrete surface henceforth reducing the chances of evaporation over fresh concrete surfaces. But the usage of polythene can be a drawback as it can be easily blown away by winds and also the water lost by self-desiccation cannot be replenished.

As per I.S. 456 – 1978, the pH value of water shall be

not less than 6

What is guniting ?

It is a process in which mixture of cement & sand in proportion of 1:3 is shooted on concrete surface with the help of cement gun under pressure of 2 to 3 kg/cm2 .It is a highly effective process for repairing concrete walls or damaged surfaces.

What is least cover provided for different RCC Members?

Footing = 50 mm

Column = 40mm

Beam = 25mm

Slab = 20mm

What is a floating foundation?

A floating foundation is the foundation of a building that does not use footings,The foundation actually does float on the earth and moves as the temperatures compact and expand the soil. It is also known as a slab foundation.

What is the meaning of suspended slab?

Suspended slabs are above-ground level slabs which are not directly in contact with the earth. They are commonly used to create floors for the upper story of houses, but can also be sat on top of pre-constructed walls to form a ground floor.

What is plinth level in building?

Plinth level is basically the level of the ground floor top which is usually kept higher than the ground level. By ground level we mean the natural surface level while the ground floor level is the surface finish level of the inner part of the building.

The reason to make plinth level a bit higher than the ground level is to prevent the rain or other runoff water from coming inside the building and on the other hand provide sufficient drainage to the surface water of the building.

What Should be the length of Crank in the slab ?

Length of the crank in slab

Here D is the Depth of slab -Top cover -Bottom cover

The length of a crank in the slab should be 0.42D .

What are commonly used method in the design of structures

Working stress method and limit state method

Why should pumping be not used in case of concreting works?

During the pumping operation the pump exerted pressure must overcome any friction between the pumping pipes and the concrete, also the weight of the concrete and the pressure head when the concrete is placed above the pumps. Since only water is pump able, all the pressure generated is by the water that is present in the concrete. The major problem due to pumping are segregation effects and bleeding. In order to rectify and reduce these effects, generally the proportion of the cement is increased in order to increase the cohesion , which leads to the reduction of segregation and bleeding. Also if a proper selection of the aggregate grading can vastly improve the concrete pump ability.

What are the specifications for tamping rod used in impact test?

16 mm steel rod with rounded end According to the IS code 2386, a 16 mm steel rod with rounded edge is used for tamping the sample filled inside the cylinder in three layers, 25 times each.

Questions for Experienced Engineer :-

What If the soil is dry, DPC for ground floor consists of the layer of:

Coarse sand layer of about 75-100mm thickness is provided over the entire area under the floor. Over this, a layer of plain concrete with a ratio of 1:4:8 of 100mm thickness is laid.

What is the loading rate used in compressive strength test?

14 N/mm² per minute As per IS codes, the loading on brick specimen in a CTM should be uniform at rate of 14 N/mm² per minute.

What is the maximum permissible tolerance for length and width respectively?

± 6mm and ± 3mm
The standard size of brick is length – 190mm and width – 90mm. When manufactured, size variations may occur by expansion or contraction while drying and burning process. Permissible tolerance is ± 6mm for length and ± 3mm for width and height

Shear cracks between the main wall and cross wall can be corrected using:

Toothing The place where the main and cross wall joins, there can be cracks developed. It is due to poor bonding between walls. Bonding can be increased by toothing, where a projection of brick is done into the other wall, interlocking it.