3. Building Materials – 100 Hard MCQs (SSC JE) (RRB JE)

byᒪEᗩᖇᑎ ᑕIᐯIᒪ EᗩᔕY -
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Building Materials – 100 Hard MCQs (SSC JE)

CEMENT, LIME & GYPSUM

1. The main function of gypsum in cement is to

A. Increase strength
B. Reduce heat of hydration
C. Regulate setting time
D. Increase fineness

Ans: C
Explanation: Gypsum prevents flash setting by controlling C₃A hydration.

2. The compound responsible for early strength of cement is

A. C₂S
B. C₃S
C. C₃A
D. C₄AF

Ans: B
Explanation: Tricalcium silicate gives early strength within 7 days.

3. High alumina cement gains most of its strength in

A. 1 day
B. 3 days
C. 7 days
D. 28 days

Ans: A
Explanation: HAC develops very high early strength within 24 hours.

4. Lime which sets under water is known as

A. Fat lime
B. Lean lime
C. Hydraulic lime
D. Quick lime

Ans: C
Explanation: Hydraulic lime contains clay impurities and sets in damp conditions.

5. The setting of lime mortar is mainly due to

A. Hydration
B. Oxidation
C. Carbonation
D. Crystallization

Ans: C
Explanation: Lime absorbs CO₂ and converts into CaCO₃.

AGGREGATES

6. Bulking of sand is maximum at moisture content of about

A. 2%
B. 5%
C. 8%
D. 12%

Ans: B
Explanation: Bulking peaks at around 4–6% moisture.

7. Flakiness index indicates

A. Strength of aggregate
B. Shape of aggregate
C. Surface texture
D. Porosity

Ans: B
Explanation: It measures thickness-to-length ratio.

8. Which aggregate property affects workability most?

A. Shape
B. Size
C. Texture
D. Grading

Ans: D
Explanation: Well-graded aggregates reduce voids and improve workability.

9. The test to find hardness of aggregates is

A. Crushing value
B. Impact value
C. Abrasion test
D. Soundness test

Ans: C
Explanation: Los Angeles abrasion test measures hardness.

10. The specific gravity of most natural aggregates lies between

A. 1.0–1.5
B. 1.5–2.0
C. 2.5–2.8
D. 3.0–3.5

Ans: C
Explanation: Normal aggregates have SG around 2.6.

CONCRETE

11. Workability of concrete is best measured by

A. Slump test
B. Flow table test
C. Compaction factor test
D. Vee-bee test

Ans: C
Explanation: Compaction factor is most accurate for low-workability mixes.

12. Water–cement ratio law was proposed by

A. Abrams
B. Duff Abrams
C. Lea
D. Feret

Ans: A
Explanation: Abrams law: strength inversely proportional to w/c ratio.

13. The minimum curing period for OPC concrete is

A. 3 days
B. 5 days
C. 7 days
D. 14 days

Ans: C
Explanation: IS 456 recommends at least 7 days.

14. Bleeding in concrete results in

A. Increased strength
B. Increased permeability
C. Reduced workability
D. Faster setting

Ans: B
Explanation: Water rises, leaving voids → permeability increases.

15. The modulus of elasticity of concrete mainly depends on

A. Cement content
B. Aggregate type
C. Water content
D. Age of concrete

Ans: B
Explanation: Stiffer aggregates give higher modulus.

BRICKS & STONES

16. Efflorescence in bricks is due to

A. Sulphates
B. Chlorides
C. Soluble salts
D. Carbonates

Ans: C
Explanation: White patches are due to salt crystallization.

17. The strongest brick bond is

A. Stretcher bond
B. English bond
C. Flemish bond
D. Header bond

Ans: B
Explanation: English bond alternates courses of headers and stretchers.

18. Good building stone should have water absorption less than

A. 5%
B. 10%
C. 15%
D. 20%

Ans: A
Explanation: IS recommends ≤5% for good quality stone.

19. Seasoning of timber is done to

A. Increase weight
B. Reduce moisture
C. Improve color
D. Increase elasticity

Ans: B
Explanation: Removes excess moisture to prevent decay and warping.

20. The most durable timber is

A. Teak
B. Sal
C. Deodar
D. Pine

Ans: A
Explanation: Teak has natural oils that resist decay.

STEEL & METALS

21. The carbon content in mild steel is about

A. 0.05%
B. 0.25%
C. 0.8%
D. 1.5%

Ans: B
Explanation: Mild steel contains 0.15–0.30% carbon.

22. Corrosion of steel in concrete is mainly due to

A. Sulphates
B. Carbonation
C. Alkali reaction
D. Chlorides

Ans: D
Explanation: Chlorides break passive film.

23. Galvanizing is coating of steel with

A. Lead
B. Tin
C. Zinc
D. Chromium

Ans: C
Explanation: Zinc protects steel by sacrificial action.

24. Stainless steel contains minimum chromium

A. 5%
B. 8%
C. 10.5%
D. 15%

Ans: C
Explanation: ≥10.5% Cr gives corrosion resistance.

25. Ductility of steel is measured by

A. Elongation test
B. Hardness test
C. Impact test
D. Fatigue test

Ans: A
Explanation: % elongation indicates ductility.

BITUMEN & ASPHALT

26. Penetration test measures

A. Ductility
B. Hardness
C. Softening point
D. Viscosity

Ans: B
Explanation: Depth of penetration shows hardness.

27. The softening point of bitumen is determined by

A. Ring & Ball test
B. Ductility test
C. Flash point test
D. Float test

Ans: A

28. Cutback bitumen is produced by

A. Adding cement
B. Adding kerosene
C. Adding lime
D. Adding water

Ans: B
Explanation: Solvent reduces viscosity.

29. Emulsified bitumen is preferred because

A. Higher strength
B. Can be used in wet conditions
C. Cheaper
D. Faster setting

Ans: B

30. Tar differs from bitumen because it is obtained from

A. Petroleum
B. Coal
C. Wood
D. Limestone

Ans: B

GLASS, PAINTS & PLASTICS

31. Toughened glass is produced by

A. Chemical treatment
B. Annealing
C. Rapid cooling
D. Slow heating

Ans: C

32. Paint that prevents rusting is

A. Enamel paint
B. Cement paint
C. Anti-corrosive paint
D. Distemper

Ans: C

33. The base of oil paint is

A. Pigment
B. Vehicle
C. Solvent
D. Drier

Ans: B

34. Plastic used for electrical fittings is

A. PVC
B. Bakelite
C. Polythene
D. Nylon

Ans: B

35. Thermosetting plastic is

A. PVC
B. Nylon
C. Bakelite
D. Polythene

Ans: C

MODERN MATERIALS

36. Fly ash concrete improves

A. Workability
B. Durability
C. Sulphate resistance
D. All of these

Ans: D

37. Geopolymer concrete uses

A. OPC
B. Lime
C. Alkali activators
D. Gypsum

Ans: C

38. Fiber reinforced concrete improves

A. Compressive strength
B. Tensile strength
C. Durability
D. Density

Ans: B

39. Self-compacting concrete flows due to

A. High water content
B. Superplasticizers
C. Air entrainment
D. Fly ash

Ans: B

40. Aerated concrete is made light by

A. Adding lime
B. Adding aluminum powder
C. Adding gypsum
D. Adding clay

Ans: B

MISCELLANEOUS

41. Pozzolanic materials react with

A. Water
B. Lime
C. Cement
D. Gypsum

Ans: B

42. The fire resistance of concrete mainly depends on

A. Cement type
B. Aggregate type
C. Water content
D. Age

Ans: B

43. The best adhesive for timber joints is

A. Fevicol
B. Epoxy
C. Casein glue
D. Phenol resin

Ans: D

44. Efflorescence is most common in

A. Cement
B. Bricks
C. Timber
D. Steel

Ans: B

45. The heaviest building stone is

A. Granite
B. Basalt
C. Marble
D. Limestone

Ans: B

46. Fire bricks are made of

A. Silica
B. Alumina
C. Magnesia
D. Clay

Ans: B

47. The durability of concrete increases with

A. High w/c ratio
B. Low w/c ratio
C. More sand
D. More air

Ans: B

48. The main defect in timber due to fungi is

A. Shakes
B. Knots
C. Rot
D. Warping

Ans: C

49. Bituminous paint is used for

A. Decoration
B. Waterproofing
C. Insulation
D. Fireproofing

Ans: B

50. White cement differs from OPC due to

A. Low iron content
B. High lime content
C. High silica
D. Gypsum

Ans: A

51–100 (Rapid Hard-Level MCQs)

(Short explanations to keep it concise)

  1. Soundness of cement is tested by Le-Chatelier – prevents expansion.

  2. Rapid hardening cement contains more C₃S.

  3. Lime used in plaster → Fat lime.

  4. Aggregate impact value shows toughness.

  5. Rounded aggregates give better workability.

  6. Maximum size of aggregate affects economy & strength.

  7. Fineness of cement tested by sieve/Blaine.

  8. Air-entrained concrete resists freeze-thaw.

  9. Pozzolana reduces heat of hydration.

  10. Hollow bricks reduce dead load.

  11. Best stone for flooring → Marble.

  12. Timber preservative → Creosote oil.

  13. Seasoning reduces shrinkage.

  14. High carbon steel is hard but brittle.

  15. Rust is hydrated ferric oxide.

  16. Stainless steel resists due to passive film.

  17. Bitumen flash point indicates fire safety.

  18. Ductility of bitumen → elongation test.

  19. Glass wool is thermal insulator.

  20. Distemper is water-based paint.

  21. Emulsion paint dries by evaporation.

  22. PVC softens on heating → thermoplastic.

  23. Bakelite is used in switches.

  24. FRP has high strength-to-weight.

  25. GGBS improves durability.

  26. SCC reduces labour & vibration.

  27. AAC blocks are lightweight.

  28. Polymer concrete uses resins.

  29. Sulphate attack affects C₃A.

  30. Alkali-aggregate reaction causes cracking.

  31. Efflorescence is aesthetic defect.

  32. White ants damage timber.

  33. Waterproofing admixture reduces capillary pores.

  34. Fire resistance of steel is poor.

  35. Best roofing tile material → Terracotta.

  36. Terrazzo contains marble chips.

  37. Glass fiber resists corrosion.

  38. Shotcrete is sprayed concrete.

  39. Ready-mix concrete improves quality control.

  40. Bituminous felt used for DPC.

  41. Epoxy paint gives chemical resistance.

  42. Sound insulation improved by porous materials.

  43. Thermal insulation best by cork.

  44. Concrete creep increases with stress level.

  45. Shrinkage mainly due to loss of moisture.

  46. Setting time affected by temperature.

  47. Retarders delay initial setting.

  48. Accelerators speed up hydration.

  49. Superplasticizers reduce water demand.

  50. Durability of concrete depends on exposure condition.

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