Materials for Construction

Question 1

Q1. The compressive strength of concrete is primarily affected by:
A) Type of aggregate
B) Water–cement ratio
C) Mixing speed
D) Curing temperature

Answer 1

B – Compressive strength mainly depends on w/c ratio.

Question 2

Q2. The standard curing period for normal Portland cement concrete is:
A) 3 days B) 7 days C) 14 days D) 28 days

Answer 2

D (28 days) – Standard full-strength period.

Question 3

Q3. Specific gravity of Portland cement is approximately:
A) 2.5 B) 2.8 C) 3.15 D) 3.5

Answer 3

C (3.15) – Typical SG of cement.

Question 4

Q4. Workability of concrete is tested using:
A) Rebound hammer B) Slump test C) Compressive test D) Sieve analysis

Answer 4

B – Slump test = workability measure.

Question 5

Q5. Fineness modulus (FM) of sand indicates:
A) Grading of aggregates
B) Moisture content
C) Bulk density
D) Specific gravity

Answer 5

A – FM represents aggregate coarseness.

Question 6

Q6. Bulking of sand occurs due to:
A) Large particles B) Moisture film C) Cement reaction D) Air voids

Answer 6

B – Caused by moisture film around grains.

Question 7

Q7. Water–cement ratio for general reinforced concrete is usually:
A) 0.30 – 0.40 B) 0.40 – 0.60 C) 0.60 – 0.80 D) > 0.80

Answer 7

B (0.40–0.60) – Normal RC mix range.

Question 8

Q8.Ordinary Portland Cement (OPC) initial setting time =
A) 15 min B) 30 min C) 45 min D) 60 min

Answer 8

B (30 min) – Min initial setting time (OPC).

Question 9

Q9. Aggregate impact value (AIV) should be:
A) < 30 % B) 40 % C) 50 % D) > 60 %

Answer 9

A (< 30 %) – Spec limit for strong aggregate.

Question 10

Q10. Compaction factor test measures:
A) Air content B) Workability C) Strength D) Flowability

Answer 10

B – Compaction factor = workability index.

Question 11

Q11. Soundness test of cement determines:
A) Presence of lime B) Excess free lime causing expansion C) Water demand D) Fineness

Answer 11

B – Checks expansive lime or magnesia

Question 12

Q12. Air-entrained concrete improves:
A) Strength B) Workability and freeze–thaw resistance C) Density D) Shrinkage

Answer 12

B – Improves workability + freeze–thaw resistance.

Question 13

Q13.Reinforcing steel grade 40 has yield strength of approximately:
A) 250 MPa B) 275 MPa C) 280 MPa D) 300 MPa

Answer 13

B (275 MPa) – Grade 40 ≈ 40 ksi ≈ 275 MPa.

Question 14

Q14. Deformed bars are used to:
A) Reduce cracks B) Improve bond with concrete C) Ease cutting D) Reduce weight

Answer 14

B – Ribs improve bond strength.

Question 15

Q15. Admixtures in concrete are used to:
A) Change color B) Modify workability and setting time C) Reduce cement content D) Lower aggregate cost

Answer 15

B – Admixtures alter setting/flow behavior.

Question 16

Q16. Pozzolanic materials include:
A) Clay B) Silica fume, fly ash, rice husk ash C) Cement clinker D) Iron filings

Answer 16

B – Pozzolans = siliceous materials.

Question 17

Q17. Creep in concrete is:
A) Instant strain B) Gradual deformation under sustained load C) Shrinkage D) Elastic recovery

Answer 17

B – Creep = time-dependent strain.

Question 18

Q18.Tensile strength of concrete is roughly ___ of its compressive strength.
A) 5–8 % B) 8–12 % C) 10–15 % D) 20–25 %

Answer 18

B (8–12 %) – Concrete’s tensile ≈ 10 % of compressive.

Question 19

Q19. Bulk density of normal-weight concrete is:
A) 18 – 20 kN/m³ B) 21 – 24 kN/m³ C) 24 – 27 kN/m³ D) > 28 kN/m³

Answer 19

B (21–24 kN/m³) – Normal density range.

Question 20

Q20. Shrinkage of concrete occurs mainly due to:
A) Temperature rise B) Loss of moisture C) Cement hydration D) Aggregate size

Answer 20

B – Shrinkage from moisture loss.

Question 21

Q21. Bitumen penetration grade 60/70 means:
A) Soft grade B) Medium hard C) Hardest D) Light oil

Answer 21

B – Pen 60/70 = medium hard bitumen.

Question 22

Q22. Timber seasoning aims to:
A) Add moisture B) Remove moisture to prevent decay C) Increase weight D) Darken color

Answer 22

B – Seasoning reduces moisture to avoid decay.

Question 23

Q23. Brick compressive strength (1st class brick) minimum:
A) 7 MPa B) 10 MPa C) 12 MPa D) 15 MPa

Answer 23

C (12 MPa) – Min compressive strength for 1st class brick.

Question 24

Q24. Paint failure due to chalking happens when:
A) Paint blisters B) Pigment powder comes off surface C) Peeling occurs D) Metal rusts

Answer 24

B – Chalking = powdering of paint surface.

Question 25

Q25. Modulus of rupture (MR) in concrete represents: A) Direct compression B) Flexural tensile strength C) Shear stress D) Impact strength

Answer 25

B – MR = flexural tensile strength of concrete.