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INTERVIEW QUESTIONS

# Top 50 Technical Interview Question for civil Engineers

What are the main features of Fresh Self Compacting Concrete?

As per IS 10262: 2019 Clause-7.2, A concrete mix can only be classified as self-compacting concrete, if the requirements for all below-mentioned characteristics are fulfilled:

a) Filling ability (Flowability),

b) Passing ability,

c) Segregation resistance, and

d) Viscosity

The above tests shall be carried out as per IS 1199 (Part 6).

What is the limitation of height difference for the pouring of Concrete for the RCC column?

The limitation of the height difference for the pouring of Concrete for the RCC column is 500 mm.

What is the Coarse aggregate size preferable for Self Compacting Concrete?

The Coarse aggregate size preferable for Self Compacting Concrete is 10 mm to 12mm.

Explain the concept of built up area and super built-up area.

Carpet Area : As its name suggests, Carpet Area is the area where we can spread a carpet, means area calculated from inner wall to wall distance inside the house. This would also include steps if any, inside the house. So essentially, Carpet area is nothing but the net usable area inside the house.

Built up Area : Built up area is Carpet Area + Area of walls and ducts+ 1/2 the Area of terrace. This is usually 10% more than the carpet area. A terrace is considered as half the actual area for calculating built up area.

Super Built up Area : This is built up area + area occupied by common amenities like lifts, corridors, awnings, club house, stairs. Super built up is usually around 25% more than Built up area. This is also called as Salable Area.

What are the IS Codes of practice for plain and reinforced concrete

(IS 456:2000)

How much is the time required Formwork Removal for Columns and beams?

( 24 Hours and 14 days )

What is the clear cover of Column and Beam?

(40mm and 25 mm Respectively)

What is cost of construction of building in your home town?

1200 to 1500 per sqft

What is the function of stirrups in the column?

Stirrups are provided to handle the shear force and to hold the rebars (main bars) in position.

#### Explain pre-tensioning and post-tensioning.

Sometimes, the interviewer wants to know if your knowledge of prestressing is extensive enough. You can answer this question by mentioning how these methods relate to prestressing and then state the differences between them.

Example:Â “Pre-tensioning and post-tensioning are two different methods used in prestressing. The core concept involves using tensioned wires or bars of steel as reinforcement structures in cured concrete. In the pre-tensioning method, the wires or bars are anchored to a metal support. Then we use hydraulic jacks to induce tension and fix side moulds. Concrete is then poured around the tensed structure to harden and accommodate the compressive force from the jacks.

The post-tensioning method is similar in concept as far as the placement of cables and concrete is concerned. However, tension is applied to the wires or cables after the concrete is hardened. This method works best for cases where modular concrete units need to be connected to create a larger member on-site.”

What is the reason that steel is given a circular shape?

The circular shape steel bar can perform the stress distribution in very efficient manner and the stress is distributed uniformly throughout the area. If the steel bar is triangular or quadrilateral than the stress lies on the sharp edge that would cause the failure of the structure.

What is the compressive strength of ordinary Portland cement after three days?

The compressive strength of ordinary Portland cement after three days shall not be less than 16 MPa.

Â What is the effect on the Bulking of Sand with an increase in moisture content?

With an increase in moisture content, the bulking of sand first increases to a certain maximum value and then decreases.

Name the main constituent of cement which is responsible for initial / Early strength of cement?

The main constituent of cement which is responsible for initial / Early strength of cement is Tricalcium Silicate.

What is the standard mortar mixing ratio of Cement and sand for testing the Compressive and Tensile strength of cement?

The standard mortar mixing ratio of Cement and sand for testing Compressive and Tensile strength of cement is 1:3.

What is the normal consistency of ordinary Portland cement?

The normal consistency of ordinary Portland cement is about 30%. As per IS 4031 Part-4, Generally it ranges between 26 to 33 percent.

What is the proportion of cement and sand for the plaster of the septic tank?

The proportion of cement and sand for the plaster of septic tank is 1:3 (1 part cement and 3 part sand).

What is the basic purpose of retarders in concrete?

The basic purpose of retarders in concrete is to increase the initial setting time of cement paste in concrete.

What is the relation between Length and Width of Septic Tank?

If L is the length and W is the width of the septic tank, then

Minimum Length = 2 x Width

Maximum Length = 4 x width

What is the minimum crushing strength of a good building stone aggregate?

The minimum Crushing strength of a good building stone aggregate IS 100 MPa.

What causes the disease of dry rot in timber?

Lack of Ventilation causes dry rot in timber.

What is the percentage of moisture content in a well-seasoned timber?

The percentage of moisture content in a well-seasoned timber is 10 to 12 percent.

Â What is the average life of first-class timber?

The average life of first-class timber is more than 10 years.

Â What is the maximum percentage of water absorption of first-class brick?

The maximum percentage of water absorption of first-class brick is 20 percent.

What is the use of Le-Chatelierâ€™s device?

Answer:Â The Le-Chatelierâ€™s device is used for determining the soundness of cement.

Density of material

Name the Plasticizers used for Self Compacting Concrete?

As per IS 10262: 2019 Clause-8.3 (c), Poly Carboxylate Ethers (PCE) is an admixture that is used as Plasticizers (Water reducing admixture) to reduce water in Self Compacting Concrete (SCC).

How much water reduction is possible with Polu Carboxylate Ethers (PCE)?

As per IS 10262: 2019 Clause-8.3 (c), Use of high range water reducing admixture like polycarboxylate ether-based high range water reducing admixture (water reduction > 30 percent) and sometimes also using a viscosity modifying admixture (VMA) in appropriate dosages.

What is the desirable size of Fines for Self Compacting Concrete?

As per IS 10262: 2019 Clause-8.3 (a), the desirable size of Fines for Self Compacting Concrete is 0.125 mm or 125 Micron.

What is the amount of Fines preferable for Self Compacting Concrete?

As per IS 10262: 2019 Clause-8.3 (a), Sufficient amount of fines (< 0.125 mm) preferably in the range of 400 kg/m3 to 600 kg/m3, inclusive of suitable quantities of fine aggregate and mineral admixtures like fly ash in suitable proportions, may be used for flowability while ensuring compliance with engineering properties particularly shrinkage.

What is the Maximum and Minimum limitation of water for Self Compacting Concrete?

As per IS 10262: 2019 Clause-8.3 (b), the Maximum and Minimum limitation of water for Self Compacting Concrete is from 150 to 210 kg/m3

Name the main constituent of cement which is responsible for the initial setting of cement?

The main constituent of cement which is responsible for the initial setting of cement is Tricalcium Aluminate.

Name the most commonly used retarder in concrete?

The most commonly used retarder in concrete is Gypsum.

What is the percentage of moisture content in a well-seasoned timber?

The percentage of moisture content in a well-seasoned timber is 10 to 12 percent.

What is the standard proportion of lime and sand in the mortar normally used in brick construction?

The standard proportion of lime and sand in the mortar normally used in brick construction is 1:2.

What is the proportion of cement and sand for the plaster of the septic tank?

The proportion of cement and sand for the plaster of septic tank is 1:3 (1 part cement and 3 part sand).

What is the allowable freeboard in a septic tank?

The allowable freeboard in a septic tank is 300 m to 450 mm.

Among Deodar, Chir, Shishum, and Pine, Which of the flowing trees yields hardwood?

Shishum yields hardwood.

What are the minimum concrete cylinders should be cast for each set to be tested for compression strength ?

Â (Â 4Â )
What is the maximum allowable fresh concrete temperature ?

Â (Â 32Â OCÂ )

In what temperature range should concrete specimen be cured as per ASTM specification?

Â (23 +- 2_Â OC)Â Â Â Â Â Â Â Â Â Â

Â  At what age concrete cylinders should be tested ? Â

(3,7,28 Days)

The diameter of standard tamping rod casting six inches diameter cylinder is

Â 5/8″ (16mm)Â and its length approximately isÂ 24″(600mm)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â

Â How many seconds does ASTM specifies to remove the slump cone?Â

( 5 +- 2 sec)

How many hours should CBR samples be soaked?Â

(Â  96 HrsÂ  )