Concrete MCQ Quiz in मराठी - Objective Question with Answer for Concrete - मोफत PDF डाउनलोड करा

Last updated on Mar 12, 2025

पाईये Concrete उत्तरे आणि तपशीलवार उपायांसह एकाधिक निवड प्रश्न (MCQ क्विझ). हे मोफत डाउनलोड करा Concrete एमसीक्यू क्विझ पीडीएफ आणि बँकिंग, एसएससी, रेल्वे, यूपीएससी, स्टेट पीएससी यासारख्या तुमच्या आगामी परीक्षांची तयारी करा.

Latest Concrete MCQ Objective Questions

Top Concrete MCQ Objective Questions

Concrete Question 1:

A concrete design mix with a low water/cement ratio and also using larger aggregates results in ________.

  1. high flowability
  2. gains in concrete compressive strength
  3. no change in strength
  4. reduction in concrete compressive strength

Answer (Detailed Solution Below)

Option 2 : gains in concrete compressive strength

Concrete Question 1 Detailed Solution

Explanation:

Abram's law:

According to Abram's law for complete (or full) compaction, and at a certain age and normal temperature, the strength of concrete can be taken to be inversely proportional to the water-cement ratio.

RRB JE CE R 25 15Q Concrete Technology Subject Test Part 1 Nitesh D1

In concrete design mixing with a low water/cement ratio, increases the compressive strength of concrete.

Size of Aggregates: 

Larger size aggregates have less surface area, so it decreases the water demand and increases the workability at a given water-cement ratio.

Concrete Question 2:

Which of the following is not a Non-destructive test method conducted on harden concrete ?

  1. Splitting tension test​
  2. Nuclear method
  3. Rebound Hammer method
  4. Radioactive method

Answer (Detailed Solution Below)

Option 1 : Splitting tension test​

Concrete Question 2 Detailed Solution

CONCEPT:

Non-destructive Tests:

Non-destructive tests are used to ascertain the quality of hardened concrete (strength, durability, elastic properties), generally following test are characterized as non-destructive test are:

1. Schmidt Rebound hammer test

2. Ultrasonic Pulse velocity test

3. Penetration method

4. Pull out Test method

5. Radioactive and nuclear test method

Destructive Test:

In the case of destructive tests, the concrete specimens (cube, cylinder, etc) are loaded till destruction in the laboratory, and strength properties are determined from the tests. The following test are characterized as destructive test are:

1. Compressive strength

2. Tensile strength

  • Splitting tensile test
  • Modulus of rupture test

3. Bond strength 

Concrete Question 3:

Steam curing of concrete is adopted for:

  1. Precast structures
  2. Columns
  3. Beams
  4. Walls

Answer (Detailed Solution Below)

Option 1 : Precast structures

Concrete Question 3 Detailed Solution

Steam curing is advantageous where early strength gain in concrete is important or where additional heat is required to accomplish hydration, as in cold weather.

Curing of concrete by steam under pressure:

  1. Increases the rate of gain of compressive strength of concrete
  2. Reduces the shear strength of concrete
  3. Increases the speed of chemical reaction

Steam curing substantially reduces the time for attaining strength for any concrete.

For pre-casting, the time for concrete to attain strength is considered as idling time. If this time is minimized, we can have more precast elements produced in less time using the same set of moulds.

Hence steam curing is mostly adopted for pre-cast structures.

Concrete Question 4:

Match List – I (Admixture) with List – II (Action in concrete) and select the correct answer using the codes given below the lists:

List – I

List – II

A.

Calcium Lignosulphonate

1.

Accelerators

B.

Aluminum powders

2.

Retarder

C.

Tartaric acid

3.

Air entrainer

D.

Sodium silicate

4.

Water reducer

  1. A - 1    B - 3    C - 2    D - 4
  2. A - 4    B - 3    C - 2    D - 1
  3. A - 4    B - 2    C - 3    D - 1
  4. A - 1    B - 2    C - 3    D - 4

Answer (Detailed Solution Below)

Option 2 : A - 4    B - 3    C - 2    D - 1

Concrete Question 4 Detailed Solution

Admixtures

Functions

Typical compounds

Application

Disadvantages

Accelerating admixtures

or accelerators

 More rapid gain of strength or higher early strength.

More rapid setting.

Calcium chloride Calcium formate Triethanolamine (TEA)

Soluble inorganic salts

Sodium nitrite

Sodium sulphate

Sodium aluminate

Sodium silicate

1. Normal rate of strength development at low temperature.

2. To counter retarding effects

3. Shorter stripping times.

4. Plugging of pressure leaks.

5. Sprayed concreting.

1. Possible cracking due to heat evolution.

2. Possibility of corrosion of embedded effects reinforcement.

Retarding admixtures or retarders

Delayed setting

Soluble carbohydrate

derivatives:

starch

Hydroxylated carboxylic acids,

Inorganic retarders

Sugars

1. Maintain workability at high temperatures.

2. Reduce rate of heat evolution.

3. Extend placing times, e.g., ready-mixed concrete.

4. Prevent cold joint formation.

 

May promote bleeding.

Water-reducing accelerators

Increased workability with faster gain of strength.

Mixtures of calcium chloride and lignosulfonate.

Water reducer with faster strength development.

Risk of corrosion.

Water-reducing retarders

Increased workability and delayed setting

Mixtures of sugars or hydroxylated carboxylic acids and lignosulfonate.

Water reducer, with slower loss of workability.

 

Air-entraining agents

Entrainment of air into concrete.

 

Aluminum powders,
Natural wood resins, fats, lignosulfonates, alkyl sulfates, sodium salts of petroleum, sulfonic acids.

Enhanced durability to frost without increasing cement content, improvement in workability, lowered permeability and cellular concrete.

Careful control of air content, water-cement ratio, temperature, type and grading of aggregate and mixing time is necessary.

Damp-proofing or water-proofing agents

1. Water-repellent, i.e. prevention of water from entering cap

2. Reduced water permeability of concrete.

Potash soaps, calcium-stearate, aluminium-stearate, butylstearate, petroleum

1. Reduced permeability.

2. Enhanced durability.

3. Increased freeze-thaw resistance.

4. Reduced drying shrinkage.

5. Reduced surface staining.

6. Water tightness of structures without using every low water-cement ratio.

1. Not efficient under high hydrostatic pressure.

2. Requires low water-cement ratio and full compaction.

Plasticizers (water reducers)-8 to 15 percent water reduction

Higher flowability

Hydroxylated carboxylic acid derivatives Calcium and sodium lignosulfonates.

1. Higher workability with strength unchanged.

2. Higher strength with workability unchanged.

3. Less cement for same strength and workability.

Certain special types of cements like sulphate resistant cement (low C3A content) and expansive cement do not perform well.

Superplasticizers (Super-water reducers) – 15 to 30 per cent water reduction

Greatly enhanced workability.

Sulfonated Melamine formaldehyde resin, sulfonated naphthalene-formaldehyde resin, Mixtures of saccharates and acid amides.

1. Water reducer, but over a wider range.

2. Facilitate production of flowing or self-leveling concrete

1. Tendency to segregate.

2. Flowability is not long lasting.

3. During hot weather the workability retention period decreases fast.

Concrete Question 5:

What is the approximate ratio of 7 days compressive strength to 28 days compressive strength of cement concrete?

  1. 0.65
  2. 0.95
  3. 1.5
  4. 2

Answer (Detailed Solution Below)

Option 1 : 0.65

Concrete Question 5 Detailed Solution

Explanation:

The 7 days compressive strength is approximately 0.65 times the  28 days compressive strength of cement concrete.

Strength of concrete is generally tested after 28 days as concrete cube strength because concrete gains strength with time after casting. It takes much time for concrete to gain 100 % strength and the time for the same is still unknown. The rate of gain of concrete compressive strength is higher during the first 28 days of casting and then it slows down.

The below table shows the concrete compressive strength with age:

Age

Strength (Percent)

1 day

16 %

3 days

40 %

7 days

65 %

14 days

90 %

28 days

99 %

Concrete Question 6:

While compacting the concrete by a mechanical vibrator, the slump should not exceed

  1. 2.5 cm
  2. 5 cm
  3. 7.5 cm
  4. 10 cm

Answer (Detailed Solution Below)

Option 2 : 5 cm

Concrete Question 6 Detailed Solution

Explanation:

The slump test is the most commonly used method of measuring the consistency of concrete which can be employed either in the laboratory or at the field.

Slump value is the amount (depth) by which the concrete settles down after removing the slump cone.

  

The table below reveals the type if vibrator required for compact for different values of slumps.

Type of Vibrator

 Value of Slump (mm) 

Power Driven

Less than 25 mm

Hand Driven

25 – 50 mm

 Mechanical Vibrator 

50 mm

Normal Vibrator

100 mm

Concrete Question 7:

For cylindrical concrete specimens, the number of strokes when compacting by hand is not less than ___________ to perform the compression test of concrete in the laboratory.

  1. 20 per layer
  2. 25 per layer
  3. 30 per layer
  4. 35 per layer

Answer (Detailed Solution Below)

Option 3 : 30 per layer

Concrete Question 7 Detailed Solution

Concept: -

Compressive Strength Test of concrete:

According to IS: 516 (1959),

For cylindrical specimens:

  • The number of strokes per layer should not be less 30

For cubical specimen

Case 1)

  • The concrete of 150×150 mm size is compacted with 35 strokes per layer

Case2) 

  • Concrete of 100×100 mm size is compacted with 25 strokes per layer.

 Additional Information

  • Test specimens should be stored at a temperature of 27 ± 3 ℃ at 90% humidity for 24 ± 1/2 hours from the time of addition of water. After this time, specimens are removed from mould and placed in water and taken out just before the test.
  • After 28 days or 7 days of curing, the specimen is placed in a compression testing machine which applies a gradual load of 14 MPa per minute.
  • The average of three values is taken as the compressive strength of concrete, provided that individual variation is not more than ± 15% of the average.
  • 7 days compressive strength = 2/3 of 28 days compressive strength.
  • Cube strength = 1.25 cylindrical strength.

Concrete Question 8:

Which of the following methods is NOT used for measuring air content in fresh concrete?

  1. Blaine air permeability method
  2. Pressure method
  3. Gravimetric method
  4. Volumetric method

Answer (Detailed Solution Below)

Option 1 : Blaine air permeability method

Concrete Question 8 Detailed Solution

Concept:

Measurement of air content in fresh concrete:

Mainly there are three methods of measuring the air contents of fresh concrete is as follows:

  1. Gravimetric Method
  2. Volumetric Method
  3. Pressure Method

Gravimetric Method:

  • This method is simple and does not require any special equipment, as such it is the first method used for calculating the air contents in concrete.
  • The method principally comprises the determination of den­sity of fresh concrete compacted by a standard method.
  • This density is then compared with the theoretical density of air-free concrete calculated from mix proportions and specific gravities of the constituent materials of the concrete.

Volumetric Method:

  • This method aims at measuring the volume of air in the sample of fresh concrete directly.
  • The sample of a known volume of concrete is taken and all air is removed from it by any method and then the amount of water required to restore the original volume is determined.
  • This method is tedious and time-consuming.

Pressure Method:

  • This is the most popular and best-suited method for site use.
  • It is based on the relation between the volume of air and the applied pressure (at a constant temperature) given by Boyle’s law.
  • This meter is directly graduated for the percentage of air and propor­tions or properties of materials need not be known.
  • This meter is not suitable for use with porous aggre­gates and needs calibration if used at high altitudes.

Explanation:

Blaine air permeability method:

  • It is used for determining the fineness of Portland Cement measures the specific surface area of fine materials in square centimeters per gram of test sample.

Concrete Question 9:

Revibration is a process used to manufacture which of the following type of concrete?

  1. Aerated concrete
  2. Lightweight concrete
  3. High performance concrete
  4. Sulphur Impregnated concrete

Answer (Detailed Solution Below)

Option 3 : High performance concrete

Concrete Question 9 Detailed Solution

Explanation:

The process of adding a finely ground, fully hydrated Portland cement to the fresh concrete in order to make high-strength concrete is called seeding.

There are some more special methods of making high strength(performance) concrete and are given below

  1. Revibration
  2. High speed slurry mixing;
  3. Use of admixtures
  4. Inhibition of cracks
  5. Sulphur impregnation;
  6. Use of cementitious aggregates

Concrete Question 10:

In a compaction factor test of concrete, if the compaction value is less than 0.95 and greater than 0.85, then the standard of the workability is:

  1. Very good
  2. Fair
  3. Medium
  4. Good

Answer (Detailed Solution Below)

Option 3 : Medium

Concrete Question 10 Detailed Solution

Workability

Compacting Factor (CF)

Slump Value (mm)

Very Low

CF < 0.78

0-25

Low

0.78 < CF < 0.85

25-50

Medium

0.85 < CF < 0.95

50-100

High

CF > 0.95

100-175


More is the compacting factor more will be the workability and more will be slump value.

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