Civil Engineering — MCQ Practice Questions & Answers

Question 1

What is the water-cement ratio for M20 grade concrete as per IS 456:2000?

Accepted Answer

Correct answer: D. 0.55 — For M20 concrete, the maximum water-cement ratio is 0.55 to achieve the specified 28-day compressive strength.

Answer

A. 0.40

Answer

B. 0.45

Answer

C. 0.50

Question 2

What is the recommended slump for RCC columns according to IS 456:2000?

Accepted Answer

Correct answer: A. 25-50 mm — For RCC columns, the recommended slump is 25-50 mm to ensure adequate compaction and workability.

Answer

B. 50-100 mm

Answer

C. 100-150 mm

Answer

D. 150-200 mm

Question 3

Hydration of cement produces which of the following as main products?

Accepted Answer

Correct answer: A. Calcium Silicate Hydrate and Calcium Hydroxide — CSH (Calcium Silicate Hydrate) and CH (Calcium Hydroxide) are the main hydration products that give strength to concrete.

Answer

B. Silicon Dioxide and Aluminum Oxide

Answer

C. Iron Oxide and Magnesium Oxide

Answer

D. Calcium Carbonate only

Question 4

What is the minimum concrete cover for reinforcement in foundations as per IS 456:2000?

Accepted Answer

Correct answer: C. 50 mm — IS 456:2000 specifies 50 mm minimum concrete cover for reinforcement in submerged/buried foundations.

Answer

A. 25 mm

Answer

B. 40 mm

Answer

D. 75 mm

Question 5

Which of the following factors increases the compressive strength of concrete?

Accepted Answer

Correct answer: C. Use of pozzolanic materials — Pozzolanic materials like fly ash and silica fume react with calcium hydroxide to improve strength and durability.

Answer

A. Increase in water-cement ratio

Answer

B. Decrease in curing time

Answer

D. Increase in slump value

Question 6

What is the typical strength gain pattern of concrete in the first 28 days?

Accepted Answer

Correct answer: B. Rapid growth in first 7 days, then slower — Concrete gains approximately 40-50% strength in 7 days due to rapid hydration, then strength gain slows down gradually.

Answer

A. Linear growth throughout

Answer

C. Slow initial growth, then rapid after 14 days

Answer

D. Constant growth at all stages

Question 7

What is the effect of adding admixtures like retarders in concrete?

Accepted Answer

Correct answer: B. Delays setting time — Retarders delay the setting time of concrete, allowing more time for placement and compaction in large structures.

Answer

A. Increases early strength

Answer

C. Reduces water requirement

Answer

D. Increases workability permanently

Question 8

What is the recommended curing period for concrete in normal conditions?

Accepted Answer

Correct answer: B. 7 days — IS 456:2000 recommends minimum 14 days of moist curing for normal Portland cement in normal temperature conditions.

Answer

A. 3 days

Answer

C. 14 days

Answer

D. 28 days

Civil Engineering - MCQ Practice Questions